http://earthwise.bgs.ac.uk/index.php?action=history&feed=atom&title=OR%2F21%2F006_Manual_pickingOR/21/006 Manual picking - Revision history2026-05-07T15:48:45ZRevision history for this page on the wikiMediaWiki 1.42.3http://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51805&oldid=prevAjhil: /* Manual facies interpretation in offshore Chalk successions (North Sea) */2021-05-19T09:04:07Z<p><span dir="auto"><span class="autocomment">Manual facies interpretation in offshore Chalk successions (North Sea)</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:04, 19 May 2021</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual facies interpretation in offshore Chalk successions (North Sea)===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual facies interpretation in offshore Chalk successions (North Sea)===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Manually picked geophysical log responses underpin the stratigraphical nomenclature for the Chalk in the North Sea (here including strata of earliest Palaeocene age) (Johnson & Lott, 1993; Lott & Knox, 1994; Gradstein & Waters, 2018; Figure 13). Formations are recognised by broad increases or decreases in gamma-ray and sonic log values, and by recognition of particular patterns of inflections in a series of reference boreholes, with microfossils (foraminifera, dinoflagellate cysts & nannofossils) where available providing a correlatable framework of age- related marker-horizons. Patterns of intraformational log variability (that are not stratigraphically formalised) have been described in the context of facies variation, for example, significantly high gamma-ray log responses in the basal part of the Ekofisk Formation, corresponding with a mud- rich chalk interval (Johnson & Lott, 1993). The logs illustrated by Johnson and Lott (1993) and Lott and Knox (1994) suggest significant potential for identifying facies subdivisions, and Mortimore (2014, figs 5.5–5.9) highlighted some of these on logs that he illustrated. In the context of the history of North Sea Chalk sedimentation (Mortimore, 2014), these facies are likely to be significantly more variable and diachronous than for onshore Chalk successions.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Manually picked geophysical log responses underpin the stratigraphical nomenclature for the Chalk in the North Sea (here including strata of earliest Palaeocene age) (Johnson & Lott, 1993<ins style="font-weight: bold; text-decoration: none;"><ref name="Johnson & Lott 1993">JOHNSON, H, and LOTT, G K. 1993. 2. Cretaceous of the Central and Northern North Sea. In: Knox, R W O'B, and Cordey, W G. (eds.) ''Lithostratigraphic nomenclature of the UK North Sea''. British Geological Survey, Nottingham.</ref></ins>; Lott & Knox, 1994<ins style="font-weight: bold; text-decoration: none;"><ref name="Lott & Knox 1994">LOTT, G K, and KNOX, R W O’B. 1994. Post Triassic of the Southern North Sea. Volume 7. In: Knox, R W O’B. & Cordey, W G. (eds), ''Lithostratigraphic nomenclature of the UK North Sea''. British Geological Survey, Nottingham.</ref></ins>; Gradstein & Waters, 2018; Figure 13). Formations are recognised by broad increases or decreases in gamma-ray and sonic log values, and by recognition of particular patterns of inflections in a series of reference boreholes, with microfossils (foraminifera, dinoflagellate cysts & nannofossils) where available providing a correlatable framework of age-related marker-horizons. Patterns of intraformational log variability (that are not stratigraphically formalised) have been described in the context of facies variation, for example, significantly high gamma-ray log responses in the basal part of the Ekofisk Formation, corresponding with a mud-rich chalk interval (Johnson & Lott, 1993). The logs illustrated by Johnson and Lott (1993) and Lott and Knox (1994) suggest significant potential for identifying facies subdivisions, and Mortimore (2014, figs 5.5–5.9) highlighted some of these on logs that he illustrated. In the context of the history of North Sea Chalk sedimentation (Mortimore, 2014), these facies are likely to be significantly more variable and diachronous than for onshore Chalk successions.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig13.jpg|thumb|center|500px| '''Figure 13'''&nbsp;&nbsp;&nbsp;&nbsp;Chalk Group units recognised by geophysical log inflection patterns in the North Sea. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig13.jpg|thumb|center|500px| '''Figure 13'''&nbsp;&nbsp;&nbsp;&nbsp;Chalk Group units recognised by geophysical log inflection patterns in the North Sea. ]]</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"> </del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Pros and cons of manual facies interpretation on geophysical logs in carbonate-dominated systems==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Pros and cons of manual facies interpretation on geophysical logs in carbonate-dominated systems==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For carbonate systems like the Chalk, the main advantage of manually interpreting carbonate facies on geophysical logs is that it overcomes the problem of subtle log-responses to facies contrasts, and the difficulty this creates for establishing appropriate cut-off values for automated systems of facies interpretation. For the Chalk Group, recognising changes in the frequency and overall pattern of low amplitude geophysical log responses is the most important aspect of facies and stratigraphy interpretation. This conclusion likely reflects the fact that the Chalk was deposited on a deeply flooded shelf, with more subtle facies responses to sea level oscillation than might be predicted for a shallow carbonate platform or ramp setting. The main disadvantages of the manual picking methodology are that it is usually time-consuming; requires detailed knowledge of stratigraphical trends and regional facies variation, and may be guided by a conceptual model that is flawed and over-looks the significance of log responses that are inconsistent with this model. Where large-scale log responses are developed in carbonate facies systems, there is a potential role for using threshold cut-off values to highlight first-order anchor points for log interpretation and correlation.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For carbonate systems like the Chalk, the main advantage of manually interpreting carbonate facies on geophysical logs is that it overcomes the problem of subtle log-responses to facies contrasts, and the difficulty this creates for establishing appropriate cut-off values for automated systems of facies interpretation. For the Chalk Group, recognising changes in the frequency and overall pattern of low amplitude geophysical log responses is the most important aspect of facies and stratigraphy interpretation. This conclusion likely reflects the fact that the Chalk was deposited on a deeply flooded shelf, with more subtle facies responses to sea level oscillation than might be predicted for a shallow carbonate platform or ramp setting. The main disadvantages of the manual picking methodology are that it is usually time-consuming; requires detailed knowledge of stratigraphical trends and regional facies variation, and may be guided by a conceptual model that is flawed and over-looks the significance of log responses that are inconsistent with this model. Where large-scale log responses are developed in carbonate facies systems, there is a potential role for using threshold cut-off values to highlight first-order anchor points for log interpretation and correlation.</div></td></tr>
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</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51804&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T09:00:59Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:00, 19 May 2021</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11a). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11a). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: '''1)''' increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl-rich New Pit Chalk); '''2)''' significant low-resistivity punctuations coincident with high gamma-ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; ''3)'' discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: '''1)''' increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl-rich New Pit Chalk); '''2)''' significant low-resistivity punctuations coincident with high gamma-ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; <ins style="font-weight: bold; text-decoration: none;">'</ins>''3)<ins style="font-weight: bold; text-decoration: none;">'</ins>'' discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: '''1)''' patterns that closely match enhance confidence of interpretation; '''2)''' trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; '''3)''' where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: '''1)''' patterns that closely match enhance confidence of interpretation; '''2)''' trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; '''3)''' where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51803&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T09:00:12Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:00, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l89">Line 89:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig11.jpg|thumb|center|500px| '''Figure 11'''&nbsp;&nbsp;&nbsp;&nbsp;'''(a):''' Sonic and gamma-ray log 'event bundle' characterising Late Turonian Chalk. The bundle consists of a marl-rich, low resistivity/slow sonic interval, overlain by a succession that progressively builds in resistivity/sonic velocity, interrupted by inflections representing marl seams. The bundle is capped by a high resistivity/high sonic velocity hardground-rich interval; '''(b):''' Transitional log responses across the boundary of the Holywell Nodular Chalk and New Pit Chalk formations, marked by declining resistivity and increasing gamma-ray log values. Care is needed to consistently identify boundary levels within these transitional responses. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig11.jpg|thumb|center|500px| '''Figure 11'''&nbsp;&nbsp;&nbsp;&nbsp;'''(a):''' Sonic and gamma-ray log 'event bundle' characterising Late Turonian Chalk. The bundle consists of a marl-rich, low resistivity/slow sonic interval, overlain by a succession that progressively builds in resistivity/sonic velocity, interrupted by inflections representing marl seams. The bundle is capped by a high resistivity/high sonic velocity hardground-rich interval; '''(b):''' Transitional log responses across the boundary of the Holywell Nodular Chalk and New Pit Chalk formations, marked by declining resistivity and increasing gamma-ray log values. Care is needed to consistently identify boundary levels within these transitional responses. ]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure <del style="font-weight: bold; text-decoration: none;">11A</del>). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure <ins style="font-weight: bold; text-decoration: none;">11a</ins>). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: 1) increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl-rich New Pit Chalk); 2) significant low-resistivity punctuations coincident with high gamma-ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; 3) discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: <ins style="font-weight: bold; text-decoration: none;">'''</ins>1)<ins style="font-weight: bold; text-decoration: none;">''' </ins>increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl-rich New Pit Chalk); <ins style="font-weight: bold; text-decoration: none;">'''</ins>2)<ins style="font-weight: bold; text-decoration: none;">''' </ins>significant low-resistivity punctuations coincident with high gamma-ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; <ins style="font-weight: bold; text-decoration: none;">''</ins>3)<ins style="font-weight: bold; text-decoration: none;">'' </ins>discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: 1) patterns that closely match enhance confidence of interpretation; 2) trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; 3) where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: <ins style="font-weight: bold; text-decoration: none;">'''</ins>1)<ins style="font-weight: bold; text-decoration: none;">''' </ins>patterns that closely match enhance confidence of interpretation; <ins style="font-weight: bold; text-decoration: none;">'''</ins>2)<ins style="font-weight: bold; text-decoration: none;">''' </ins>trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; <ins style="font-weight: bold; text-decoration: none;">'''</ins>3)<ins style="font-weight: bold; text-decoration: none;">''' </ins>where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Confirm that stratigraphical picks are consistent with regional structural trends and up-to- date geological map data from the borehole vicinity. Consider the availability of outcrop biostratigraphical data to constrain near-surface log interpretations. If inconsistencies are apparent, determine if there are other data to support a stratigraphical/structural explanation for this. If not, re-evaluate correlation and decide if the error is likely to be with first or second-order features. If first-order features are suspected to be incorrectly assigned, consider the wider implications of this for other borehole correlations and if necessary re-evaluate the correlation of all first-order features in all boreholes.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Confirm that stratigraphical picks are consistent with regional structural trends and up-to-date geological map data from the borehole vicinity. Consider the availability of outcrop biostratigraphical data to constrain near-surface log interpretations. If inconsistencies are apparent, determine if there are other data to support a stratigraphical/structural explanation for this. If not, re-evaluate correlation and decide if the error is likely to be with first or second-order features. If first-order features are suspected to be incorrectly assigned, consider the wider implications of this for other borehole correlations and if necessary re-evaluate the correlation of all first-order features in all boreholes.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Refine interpretation of stratigraphical boundaries to ensure consistency. In the Chalk Group, consistency of interpretation is affected by two issues: 1) the transitional nature of facies changes at stratigraphical boundaries, and 2) log resolution. In stratotype sections the boundaries of Chalk units are named marker-beds, but these are not always easily recognisable as discrete entities on borehole logs, and the associated shifts in facies patterns that they signal are rarely precisely coincident. In such cases, trends in log patterns, for example increasing/declining resistivity/gamma-ray profiles become important for boundary interpretation, and a consistent decision needs to be made about where along the trend line a boundary is likely to be located.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Refine interpretation of stratigraphical boundaries to ensure consistency. In the Chalk Group, consistency of interpretation is affected by two issues: <ins style="font-weight: bold; text-decoration: none;">'''</ins>1)<ins style="font-weight: bold; text-decoration: none;">''' </ins>the transitional nature of facies changes at stratigraphical boundaries, and <ins style="font-weight: bold; text-decoration: none;">'''</ins>2)<ins style="font-weight: bold; text-decoration: none;">''' </ins>log resolution. In stratotype sections the boundaries of Chalk units are named marker-beds, but these are not always easily recognisable as discrete entities on borehole logs, and the associated shifts in facies patterns that they signal are rarely precisely coincident. In such cases, trends in log patterns, for example increasing/declining resistivity/gamma-ray profiles become important for boundary interpretation, and a consistent decision needs to be made about where along the trend line a boundary is likely to be located.</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Inability to identify stratigraphy-defining marker-beds can be associated with geophysical data of particular vintage. A significant number of single point resistivity logs in BGS archives record data at widely spaced depth increments. Although the trends are still meaningful for stratigraphical interpretation, multiple marker-beds that are usually separately resolved on continuous logs may be covered by a single inflection on vintage logs. This problem can be mitigated if gamma-ray logs are also available. A good example of facies transition at a stratigraphical boundary is the junction of the Holywell Nodular Chalk and New Pit Chalk (Figure <del style="font-weight: bold; text-decoration: none;">11B</del>), and Figure 12 compares the difference in marker-bed resolution revealed by vintage single point and modern continuous resistivity logging. Therefore log age and quality is a proxy of data uncertainty; borehole with less uncertain data should be prioritised and the most uncertain data considered for exclusion.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"># </ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Inability to identify stratigraphy-defining marker-beds can be associated with geophysical data of particular vintage. A significant number of single point resistivity logs in BGS archives record data at widely spaced depth increments. Although the trends are still meaningful for stratigraphical interpretation, multiple marker-beds that are usually separately resolved on continuous logs may be covered by a single inflection on vintage logs. This problem can be mitigated if gamma-ray logs are also available. A good example of facies transition at a stratigraphical boundary is the junction of the Holywell Nodular Chalk and New Pit Chalk (Figure <ins style="font-weight: bold; text-decoration: none;">11b</ins>), and Figure 12 compares the difference in marker-bed resolution revealed by vintage single point and modern continuous resistivity logging. Therefore log age and quality is a proxy of data uncertainty; borehole with less uncertain data should be prioritised and the most uncertain data considered for exclusion.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig12.jpg|thumb|center|500px| '''Figure 12'''&nbsp;&nbsp;&nbsp;&nbsp;Differences in inflection detail between single point resistivity logs (red line) and continuous resistivity logs. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig12.jpg|thumb|center|500px| '''Figure 12'''&nbsp;&nbsp;&nbsp;&nbsp;Differences in inflection detail between single point resistivity logs (red line) and continuous resistivity logs. ]]</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51802&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:44:26Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:44, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l91">Line 91:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11A). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11A). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: 1) increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl- rich New Pit Chalk); 2) significant low-resistivity punctuations coincident with high gamma- ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; 3) discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: 1) increase in gamma-ray log serrations 15–30 m above the base of the Plenus Marls (indicative of the marl-rich New Pit Chalk); 2) significant low-resistivity punctuations coincident with high gamma-ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; 3) discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: 1) patterns that closely match enhance confidence of interpretation; 2) trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; 3) where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: 1) patterns that closely match enhance confidence of interpretation; 2) trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; 3) where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51801&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:43:35Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:43, 19 May 2021</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ref name="Mortimore 1986"></ref>; Wood & Smith, 1978<ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref>; Whitham, 1991<ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM, F. 1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001)<ins style="font-weight: bold; text-decoration: none;"><ref name="Rawson 2001">RAWSON, P F, ALLEN, P , and GALE, A.S. 2001. The Chalk Group—a revised lithostratigraphy. ''Geoscientist'', Vol.11, 21.</ref></ins>, and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ref name="Mortimore 1986"></ref>; Wood & Smith, 1978<ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref>; Whitham, 1991<ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM, F. 1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51800&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:41:39Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:41, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l91">Line 91:</td>
<td colspan="2" class="diff-lineno">Line 91:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11A). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Look for any broad shifts in log profile that act to anchor the interpretation at one or more levels. A good example is the Cenomanian/Turonian boundary, at the base of the Holywell Nodular Chalk, where the mud-rich Plenus Marls are overlain by the highly cemented Melbourn Rock. This stark contrast in physical properties is marked by a major inflection in both resistivity/sonic and gamma-ray logs, and gamma-ray values below the Plenus Marls are consistently higher than above because of higher overall mud content (Figure 10). Another distinctive ‘event bundle’ occurs in Late Turonian Chalk successions, where a closely spaced successions of marls and hardgrounds in the lower part of the Lewes Nodular Chalk produce a series of sharp oscillations in resistivity/sonic and gamma-ray log signatures (Figure 11A). Confirm that this is consistent with any local or regionally available control data (e.g. published log interpretations, SOBI borehole data, and regionally relevant thickness data).</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: 1) increase in gamma- ray log serrations <del style="font-weight: bold; text-decoration: none;">15 – 30 </del>m above the base of the Plenus Marls (indicative of the marl- rich New Pit Chalk); 2) significant low-resistivity punctuations coincident with high gamma- ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; 3) discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Look for finer-scale marker-bed event bundles. These second-order features are usually slightly less obvious because they are either changes to a single log type, or trends in the pattern or amplitude of log values through a broader depth range. Typically these events only become more meaningful for interpretation in the context of the parameters set by the first order log features. Examples of second-order events are: 1) increase in gamma-ray log serrations <ins style="font-weight: bold; text-decoration: none;">15–30 </ins>m above the base of the Plenus Marls (indicative of the marl- rich New Pit Chalk); 2) significant low-resistivity punctuations coincident with high gamma- ray peaks in the middle and higher part of the New Pit Chalk, coinciding with increased frequency and thickness of marl seams; 3) discrete series of typically 6 gamma-ray log peaks just above the base of the Seaford Chalk.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: 1) patterns that closely match enhance confidence of interpretation; 2) trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; 3) where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Where interpreting a series of spatially associated boreholes, explore the detailed pattern of inflections between the anchor points formed by marker-beds in adjacent boreholes. This has three important functions: 1) patterns that closely match enhance confidence of interpretation; 2) trends in the spatial organisation of these inflections provides refined understanding of where sedimentary packages are expanded or condensed locally within successions; 3) where there is variability in the quality or availability of log data for different boreholes, but high confidence in likely correlation, then flattening adjacent boreholes on a common stratigraphical datum can provide increased information about the likely position of stratigraphical boundaries.</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51799&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:40:11Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:40, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l83">Line 83:</td>
<td colspan="2" class="diff-lineno">Line 83:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ref name="Mortimore 1986"></ref>; Wood & Smith, 1978<ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref>; Whitham, 1991</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ref name="Mortimore 1986"></ref>; Wood & Smith, 1978<ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref>; Whitham, 1991<ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM, F. 1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM, F. 1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td><td colspan="2" class="diff-side-added"></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51798&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:39:40Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:39, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l83">Line 83:</td>
<td colspan="2" class="diff-lineno">Line 83:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986; Wood & Smith, 1978; Whitham, 1991, 1993) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ins style="font-weight: bold; text-decoration: none;"><ref name="Mortimore 1986"></ref></ins>; Wood & Smith, 1978<ins style="font-weight: bold; text-decoration: none;"><ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref></ins>; Whitham, 1991</div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"><ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref></ins>, 1993<ins style="font-weight: bold; text-decoration: none;"><ref name="Whitham 1993">WHITHAM, F. 1993. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref></ins>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51797&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:36:42Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:36, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l83">Line 83:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001)<del style="font-weight: bold; text-decoration: none;"><ref name="Rawson 2001">RAWSON, P F, ALLEN, P , and GALE, A.S. 2001. The Chalk Group—a revised lithostratigraphy. ''Geoscientist'', Vol.11, 21.</ref></del>, and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<del style="font-weight: bold; text-decoration: none;"><ref name="Mortimore 1986"></ref></del>; Wood & Smith, 1978<del style="font-weight: bold; text-decoration: none;"><ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref></del>; Whitham, 1991<del style="font-weight: bold; text-decoration: none;"><ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM</del>, <del style="font-weight: bold; text-decoration: none;">F. </del>1993<del style="font-weight: bold; text-decoration: none;">. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref></del>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986; Wood & Smith, 1978; Whitham, 1991, 1993) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td></tr>
</table>Ajhilhttp://earthwise.bgs.ac.uk/index.php?title=OR/21/006_Manual_picking&diff=51796&oldid=prevAjhil: /* Manual log interpretation of facies packages that define formational units */2021-05-19T08:36:22Z<p><span dir="auto"><span class="autocomment">Manual log interpretation of facies packages that define formational units</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
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<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:36, 19 May 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l83">Line 83:</td>
<td colspan="2" class="diff-lineno">Line 83:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=== Manual log interpretation of facies packages that define formational units ===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001), and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986; Wood & Smith, 1978; Whitham, 1991, 1993) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Onshore UK Chalk Group stratigraphy was rationalised by Rawson et al. (2001)<ins style="font-weight: bold; text-decoration: none;"><ref name="Rawson 2001">RAWSON, P F, ALLEN, P , and GALE, A.S. 2001. The Chalk Group—a revised lithostratigraphy. ''Geoscientist'', Vol.11, 21.</ref></ins>, and comprises a highly distinctive arrangement of marker-beds and facies units (Mortimore, 1986<ins style="font-weight: bold; text-decoration: none;"><ref name="Mortimore 1986"></ref></ins>; Wood & Smith, 1978<ins style="font-weight: bold; text-decoration: none;"><ref name="Wood & Smith 1978">WOOD, C J, and SMITH, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. ''Proceedings of the Yorkshire Geological Society'', Vol.42, 263–287.</ref></ins>; Whitham, 1991<ins style="font-weight: bold; text-decoration: none;"><ref name="Whitham 1991">WHITHAM, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.48, 227–254.</ref>, 1993<ref name="Whitham 1993">WHITHAM</ins>, <ins style="font-weight: bold; text-decoration: none;">F. </ins>1993<ins style="font-weight: bold; text-decoration: none;">. The stratigraphy of the Upper Cretaceous Flamborough Chalk Formation north of the Humber, north-east England. ''Proceedings of the Yorkshire Geological Society'', Vol.49, 235–258</ref></ins>) into broader packages with particular geophysical log patterns. These facies packages correspond with Chalk formational units, and the methodology for their recognition is described below.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:OR21006fig10.jpg|thumb|center|500px| '''Figure 10'''&nbsp;&nbsp;&nbsp;&nbsp;Strong inflection patterns across the boundary of the Grey Chalk and White Chalk subgroups form a characteristic 'event-bundle' for anchoring interpretations and correlations. ]]</div></td></tr>
</table>Ajhil