Geology of the Llanidloes area: Introduction - Revision history

http://earthwise.bgs.ac.uk/index.php?action=history&feed=atom&title=Geology_of_the_Llanidloes_area%3A_Introduction Geology of the Llanidloes area: Introduction - Revision history 2026-04-30T20:36:36Z Revision history for this page on the wiki MediaWiki 1.42.3 http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29962&oldid=prev Jeth1 at 08:44, 26 October 2016 2016-10-26T08:44:54Z

<p></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, 26 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l5">Line 5:</td> <td colspan="2" class="diff-lineno">Line 5:</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>This Sheet Explanation provides a summary of the geology of the district covered by Geological 1:50&nbsp;000 Series Map Sheet 164 (Llanidloes), published in 2010 as a Bedrock and Superficial Deposits edition. The district mostly lies within the county of Powys, but includes small parts of Ceredigion in the extreme west and south-west. Much of the western part of the district is occupied by the deeply dissected uplands of the Cambrian Mountains, a designated Area of Outstanding Natural Beauty. In this area the land rises to 740&nbsp;m on the flanks of Plynlimon (Pumlumon Fawr), the highest summit in the range. It falls away towards the eastern part of the district into rolling countryside that includes the important catchment of the River Severn (Afon Hafren) and its tributaries, the largest of which are the rivers Carno, Trannon, Cerist, Clywedog and Dulas. A major reservoir (Llyn Clywedog) occupies the upper reaches of the Clywedog valley, its purpose being to regulate river discharge and groundwater levels within the catchment. The south-western part of the district is drained by the River Wye (Afon Gwy) and its tributaries, that flow south-eastwards via Llangurig. The sources of both the Severn and Wye are situated on the eastern flanks of Plynlimon within the western part of the district.</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>This Sheet Explanation provides a summary of the geology of the district covered by Geological 1:50&nbsp;000 Series Map Sheet 164 (Llanidloes), published in 2010 as a Bedrock and Superficial Deposits edition. The district mostly lies within the county of Powys, but includes small parts of Ceredigion in the extreme west and south-west. Much of the western part of the district is occupied by the deeply dissected uplands of the Cambrian Mountains, a designated Area of Outstanding Natural Beauty. In this area the land rises to 740&nbsp;m on the flanks of Plynlimon (Pumlumon Fawr), the highest summit in the range. It falls away towards the eastern part of the district into rolling countryside that includes the important catchment of the River Severn (Afon Hafren) and its tributaries, the largest of which are the rivers Carno, Trannon, Cerist, Clywedog and Dulas. A major reservoir (Llyn Clywedog) occupies the upper reaches of the Clywedog valley, its purpose being to regulate river discharge and groundwater levels within the catchment. The south-western part of the district is drained by the River Wye (Afon Gwy) and its tributaries, that flow south-eastwards via Llangurig. The sources of both the Severn and Wye are situated on the eastern flanks of Plynlimon within the western part of the district.</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>The town of Llanidloes is the main centre of population, with smaller settlements at Llangurig, Carno, Trefeglwys, Caersws and Staylittle; the Newtown conurbation impinges on the eastern part of the district. Much of the district is given over to beef and dairy farming, although sheep are reared in the remote upland areas in the west and extensive forestry plantations have been developed in places. The Ordovician and Silurian rocks of the district have been exploited locally, in the past, as a source of building material and, recently, commercial quantities of sandstone aggregate have been excavated at Penstrowed Quarry [SO 0680 9100]. The district includes part of the Central Wales Mining Field from which substantial volumes of lead and zinc ore were extracted during the 19th and early 20th centuries. A number of former mine sites are still visible, notably along the Van, Nant-y-ricket, Dylife, Dyfngwm and Llanerchyraur lodes (Jones, 1922<ref name="Jones 1922">Jones, O T. 1922. Lead and zinc: the mining district of north Cardiganshire and west Montgomeryshire. Memoir of the Geological Survey of Great Britain, Special Report on Mineral Resources. No.&nbsp;20.</ref>; <del style="font-weight: bold; text-decoration: none;"><span style="background:#ffff00"></del>IGS, 1974<del style="font-weight: bold; text-decoration: none;"></span></del>), and the historic Bryntail Mine, below the Clywedog Dam has been restored as a site of industrial archaeological interest.</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>The town of Llanidloes is the main centre of population, with smaller settlements at Llangurig, Carno, Trefeglwys, Caersws and Staylittle; the Newtown conurbation impinges on the eastern part of the district. Much of the district is given over to beef and dairy farming, although sheep are reared in the remote upland areas in the west and extensive forestry plantations have been developed in places. The Ordovician and Silurian rocks of the district have been exploited locally, in the past, as a source of building material and, recently, commercial quantities of sandstone aggregate have been excavated at Penstrowed Quarry [SO 0680 9100]. The district includes part of the Central Wales Mining Field from which substantial volumes of lead and zinc ore were extracted during the 19th and early 20th centuries. A number of former mine sites are still visible, notably along the Van, Nant-y-ricket, Dylife, Dyfngwm and Llanerchyraur lodes (Jones, 1922<ref name="Jones 1922">Jones, O T. 1922. Lead and zinc: the mining district of north Cardiganshire and west Montgomeryshire. Memoir of the Geological Survey of Great Britain, Special Report on Mineral Resources. No.&nbsp;20.</ref>; IGS, 1974), and the historic Bryntail Mine, below the Clywedog Dam has been restored as a site of industrial archaeological interest.</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>The district is underlain by a succession of Late Ordovician (Ashgill) to Silurian sedimentary rocks, over 5&nbsp;km thick, deposited between 450 and 420 million years ago in the Early Palaeozoic Welsh Basin ([[Media:P930911.jpg |'''Figure P930911''']]). The basin developed on a fragment of the ancient supercontinent of Gondwana, known as Eastern Avalonia (e.g. Pickering et al., 1988<ref name="Pickering 1988">Pickering, K T, Bassett, M G, and Siveter, D J. 1988. Late Ordovician–early Silurian destruction of the Iapetus Ocean: Newfoundland, British Isles and Scandinavia&nbsp;—&nbsp;a discussion. Transactons of the Royal Society of Edinburgh: Earth Sciences, Vol.&nbsp;79, 361–382.</ref>), that drifted northwards to collide with the continents of Baltica and Laurentia during the Late Ordovician and Silurian (Soper and Hutton, 1984<ref name="Soper 1984">Soper, N J, and Hutton, D H W. 1984. Late Caledonian sinistral displacements in Britain: implications for a three-plate collision model. Tectonics, Vol.&nbsp;3, 781–794.</ref>; Soper and Woodcock, 1990<ref name="Soper 1990">Soper, N J, and Woodcock, N H. 1990. Silurian collision and sediment dispersal patterns in southern Britain. Geological Magazine, Vol.&nbsp;127, 527–542.</ref>; Woodcock and Strachan, 2000<ref name="Woodcock 2000">Woodcock, N H. 2000. Late Ordovician to Silurian evolution of Eastern Avalonia during convergence with Laurentia. 168–184 in Geological history of Britain and Ireland. Woodcock, N H, and Strachan, R A (editors). (Oxford: Blackwell Science.)</ref>). To the east and the south of the basin lay the Midland Platform, a relatively stable shallow marine shelf that was subject to periodic emergence. The basinal sediments are predominantly deep marine turbiditic facies that were introduced into the district by density currents from southerly, south-easterly and north-westerly quadrants. Coeval shallower-water ‘shelfal’ sediments were deposited north and east of the district, and locally impinge on its northern margins. Thickness variations within the major sedimentary units suggest that, at times, syndepositional fault movements were an important control on their distribution. During late Silurian (Ludlow) times, shallowing of the basin occurred, and sandstones, variably interpreted as a turbiditic (Cave and Hains, 2001<ref name="Cave 2001">Cave, R, and Hains, B A. 2001. Geology of the country around Montgomery and the Ordovician rocks of the Shelve Inlier. Memoir of the British Geological Survey, Sheet 165 (England and Wales).</ref>) or storm-generated facies (Tyler and Woodcock, 1987<ref name="Tyler 1987">Tyler, J E, and Woodcock, N H. 1987. The Bailey Hill Formation: Ludlow Series turbidites in the Welsh Borderland reinterpreted as distal storm deposits. Geological Journal (Thematic Issue), Vol.&nbsp;22, 73–86.</ref>), were laid down over the eastern part of the district and adjacent areas. The shallowing was a result of tectonic reconfiguration of the basin, a precursor to the late Caledonian (Acadian) Orogeny that affected the region during the late Early Devonian, around 400 million years ago.</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>The district is underlain by a succession of Late Ordovician (Ashgill) to Silurian sedimentary rocks, over 5&nbsp;km thick, deposited between 450 and 420 million years ago in the Early Palaeozoic Welsh Basin ([[Media:P930911.jpg |'''Figure P930911''']]). The basin developed on a fragment of the ancient supercontinent of Gondwana, known as Eastern Avalonia (e.g. Pickering et al., 1988<ref name="Pickering 1988">Pickering, K T, Bassett, M G, and Siveter, D J. 1988. Late Ordovician–early Silurian destruction of the Iapetus Ocean: Newfoundland, British Isles and Scandinavia&nbsp;—&nbsp;a discussion. Transactons of the Royal Society of Edinburgh: Earth Sciences, Vol.&nbsp;79, 361–382.</ref>), that drifted northwards to collide with the continents of Baltica and Laurentia during the Late Ordovician and Silurian (Soper and Hutton, 1984<ref name="Soper 1984">Soper, N J, and Hutton, D H W. 1984. Late Caledonian sinistral displacements in Britain: implications for a three-plate collision model. Tectonics, Vol.&nbsp;3, 781–794.</ref>; Soper and Woodcock, 1990<ref name="Soper 1990">Soper, N J, and Woodcock, N H. 1990. Silurian collision and sediment dispersal patterns in southern Britain. Geological Magazine, Vol.&nbsp;127, 527–542.</ref>; Woodcock and Strachan, 2000<ref name="Woodcock 2000">Woodcock, N H. 2000. Late Ordovician to Silurian evolution of Eastern Avalonia during convergence with Laurentia. 168–184 in Geological history of Britain and Ireland. Woodcock, N H, and Strachan, R A (editors). (Oxford: Blackwell Science.)</ref>). To the east and the south of the basin lay the Midland Platform, a relatively stable shallow marine shelf that was subject to periodic emergence. The basinal sediments are predominantly deep marine turbiditic facies that were introduced into the district by density currents from southerly, south-easterly and north-westerly quadrants. Coeval shallower-water ‘shelfal’ sediments were deposited north and east of the district, and locally impinge on its northern margins. Thickness variations within the major sedimentary units suggest that, at times, syndepositional fault movements were an important control on their distribution. During late Silurian (Ludlow) times, shallowing of the basin occurred, and sandstones, variably interpreted as a turbiditic (Cave and Hains, 2001<ref name="Cave 2001">Cave, R, and Hains, B A. 2001. Geology of the country around Montgomery and the Ordovician rocks of the Shelve Inlier. Memoir of the British Geological Survey, Sheet 165 (England and Wales).</ref>) or storm-generated facies (Tyler and Woodcock, 1987<ref name="Tyler 1987">Tyler, J E, and Woodcock, N H. 1987. The Bailey Hill Formation: Ludlow Series turbidites in the Welsh Borderland reinterpreted as distal storm deposits. Geological Journal (Thematic Issue), Vol.&nbsp;22, 73–86.</ref>), were laid down over the eastern part of the district and adjacent areas. The shallowing was a result of tectonic reconfiguration of the basin, a precursor to the late Caledonian (Acadian) Orogeny that affected the region during the late Early Devonian, around 400 million years ago.</div></td></tr> </table>

Jeth1 http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29845&oldid=prev Dbk at 12:17, 7 October 2016 2016-10-07T12:17:26Z

<p></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 13:17, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l149">Line 149:</td> <td colspan="2" class="diff-lineno">Line 149:</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>At the same time as the turbidites, debrites and disturbed beds were accumulating on the floor of the basin a constant fall-out of terrigenous sediment from suspension was taking place through the water column. These fine-grained '''hemipelagic''' mudstones commonly cap individual turbidite beds, and are interbedded with the various mass-flow units. Unlike the resedimented deposits, the hemipelagic material records more closely the environmental conditions that prevailed in the bottom waters of the basin at the time of deposition. Two distinct types of hemipelagite are present within the Welsh Basin. The first is a generally homogenous, pale greenish grey mudstone with darker burrow mottles that record deposition beneath oxygenated ('''oxic''') bottom waters, when benthonic (bottom-dwelling) organisms were able to colonise the sediment successfully ([[Media:P775110.jpg |'''Plate P775110''']]). The second type is a dark grey, very thinly laminated, pyritic and graptolitic mudstone that lacks any evidence of burrowing, having been deposited under oxygen-depleted ('''anoxic''') bottom conditions. The distribution of oxic and anoxic hemipelagite within the succession is one of the criteria by which the formational subdivision of strata in the Welsh Basin is achieved. Considerable thicknesses of strata contain one or the other type of mudstone, suggesting that either oxic or anoxic conditions were sustained across the basin floor for prolonged periods of time; at other times such periods were relatively brief, as indicated by rapid alternations of oxic and anoxic hemipelagic mudstone within the succession. The preservation of the fossilised remains of '''graptolites''' within the anoxic hemipelagite ([[Media:P775109.jpg |'''Plate P775109''']]) is critical in correlating the geological succession, and establishing the history of deposition within the Welsh Basin. The rapid evolutionary change of these planktonic colonial organisms during the Ordovician and Silurian allows the rocks in which they occur to be accurately dated, according to the established succession of UK graptolite biozones (see table; Zalasiewicz et al., 2009<ref name="Zalasiewicz 2009">Zalasiewicz, J A, Taylor, L, Rushton, A W A, Loydell, D K, Rickards, R B, and Williams, M. 2009. Graptolites in British stratigraphy. Geological Magazine, Vol.&nbsp;146, 785–850.</ref>).</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>At the same time as the turbidites, debrites and disturbed beds were accumulating on the floor of the basin a constant fall-out of terrigenous sediment from suspension was taking place through the water column. These fine-grained '''hemipelagic''' mudstones commonly cap individual turbidite beds, and are interbedded with the various mass-flow units. Unlike the resedimented deposits, the hemipelagic material records more closely the environmental conditions that prevailed in the bottom waters of the basin at the time of deposition. Two distinct types of hemipelagite are present within the Welsh Basin. The first is a generally homogenous, pale greenish grey mudstone with darker burrow mottles that record deposition beneath oxygenated ('''oxic''') bottom waters, when benthonic (bottom-dwelling) organisms were able to colonise the sediment successfully ([[Media:P775110.jpg |'''Plate P775110''']]). The second type is a dark grey, very thinly laminated, pyritic and graptolitic mudstone that lacks any evidence of burrowing, having been deposited under oxygen-depleted ('''anoxic''') bottom conditions. The distribution of oxic and anoxic hemipelagite within the succession is one of the criteria by which the formational subdivision of strata in the Welsh Basin is achieved. Considerable thicknesses of strata contain one or the other type of mudstone, suggesting that either oxic or anoxic conditions were sustained across the basin floor for prolonged periods of time; at other times such periods were relatively brief, as indicated by rapid alternations of oxic and anoxic hemipelagic mudstone within the succession. The preservation of the fossilised remains of '''graptolites''' within the anoxic hemipelagite ([[Media:P775109.jpg |'''Plate P775109''']]) is critical in correlating the geological succession, and establishing the history of deposition within the Welsh Basin. The rapid evolutionary change of these planktonic colonial organisms during the Ordovician and Silurian allows the rocks in which they occur to be accurately dated, according to the established succession of UK graptolite biozones (see table; Zalasiewicz et al., 2009<ref name="Zalasiewicz 2009">Zalasiewicz, J A, Taylor, L, Rushton, A W A, Loydell, D K, Rickards, R B, and Williams, M. 2009. Graptolites in British stratigraphy. Geological Magazine, Vol.&nbsp;146, 785–850.</ref>).</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><div><ul></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;"><center></ins><div><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|424px|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|424px|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></div></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></ul></div<ins style="font-weight: bold; text-decoration: none;">></center</ins>></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>The effects of global (eustatic) sea-level fluctuation competed with tectonism in controlling the type and distribution of sedimentary facies within the Welsh Basin during the Ordovician and Silurian. Two distinct types of turbidite system occur within the basin (Davies et al., 1997<ref name="Davies 1997"></ref>). Slope-apron systems, mostly of mudstone, characterise the Ashgill (Ordovician) to early Telychian (Silurian) basinal successions, when eustacy was the dominant control. In contrast, mid to late Telychian and early Wenlock sedimentation was strongly influenced by tectonism that resulted from plate collision, when voluminous amounts of sand were deposited in the basin as a series of major turbidite lobe systems. Palaeocurrent data, together with geochemical and heavy mineral studies, indicate that the sediment supplied to these different systems was also of different provenance (Ball et al., 1992<ref name="Ball 1992">Ball, T K, Davies, J R, Waters, R A, and Zalasiewicz, J A. 1992. Geochemical discrimination of Silurian mudstones according to depositional process and provenance within the southern Welsh Basin. Geological Magazine, Vol.&nbsp;129, 567–572.</ref>; Morton et al., 1992<ref name="Morton 1992">Morton, A C, Davies, J R, and Waters, R A. 1992. Heavy minerals as a guide to turbidite provenance in the Lower Palaeozoic Southern Welsh Basin: a pilot study. Geological Magazine, Vol.&nbsp;129, 573–580.</ref>). Slope-apron systems are generally composed of material derived from the east, whereas the sandstone-lobe turbidite systems contain material derived from southerly sources.</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>The effects of global (eustatic) sea-level fluctuation competed with tectonism in controlling the type and distribution of sedimentary facies within the Welsh Basin during the Ordovician and Silurian. Two distinct types of turbidite system occur within the basin (Davies et al., 1997<ref name="Davies 1997"></ref>). Slope-apron systems, mostly of mudstone, characterise the Ashgill (Ordovician) to early Telychian (Silurian) basinal successions, when eustacy was the dominant control. In contrast, mid to late Telychian and early Wenlock sedimentation was strongly influenced by tectonism that resulted from plate collision, when voluminous amounts of sand were deposited in the basin as a series of major turbidite lobe systems. Palaeocurrent data, together with geochemical and heavy mineral studies, indicate that the sediment supplied to these different systems was also of different provenance (Ball et al., 1992<ref name="Ball 1992">Ball, T K, Davies, J R, Waters, R A, and Zalasiewicz, J A. 1992. Geochemical discrimination of Silurian mudstones according to depositional process and provenance within the southern Welsh Basin. Geological Magazine, Vol.&nbsp;129, 567–572.</ref>; Morton et al., 1992<ref name="Morton 1992">Morton, A C, Davies, J R, and Waters, R A. 1992. Heavy minerals as a guide to turbidite provenance in the Lower Palaeozoic Southern Welsh Basin: a pilot study. Geological Magazine, Vol.&nbsp;129, 573–580.</ref>). Slope-apron systems are generally composed of material derived from the east, whereas the sandstone-lobe turbidite systems contain material derived from southerly sources.</div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29844&oldid=prev Dbk at 12:16, 7 October 2016 2016-10-07T12:16:32Z

<p></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 13:16, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">426px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">424px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29843&oldid=prev Dbk at 12:16, 7 October 2016 2016-10-07T12:16:13Z

<p></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 13:16, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">428px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">426px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29842&oldid=prev Dbk at 12:15, 7 October 2016 2016-10-07T12:15:53Z

<p></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 13:15, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">433px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">428px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29841&oldid=prev Dbk at 12:15, 7 October 2016 2016-10-07T12:15:29Z

<p></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 13:15, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">437px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">433px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29840&oldid=prev Dbk at 12:15, 7 October 2016 2016-10-07T12:15:10Z

<p></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 13:15, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">440px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">437px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29839&oldid=prev Dbk at 12:14, 7 October 2016 2016-10-07T12:14:45Z

<p></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 13:14, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">445px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">440px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29838&oldid=prev Dbk at 12:14, 7 October 2016 2016-10-07T12:14:21Z

<p></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 13:14, 7 October 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l150">Line 150:</td> <td colspan="2" class="diff-lineno">Line 150:</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><div><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<del style="font-weight: bold; text-decoration: none;">400px</del>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|<ins style="font-weight: bold; text-decoration: none;">445px</ins>|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling in Mottled Mudstone Member above the ‘''persculptus'' Band’; locality as Plate P775109. ]]</li></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></ul></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></ul></div></div></td></tr> </table>

Dbk http://earthwise.bgs.ac.uk/index.php?title=Geology_of_the_Llanidloes_area:_Introduction&diff=29732&oldid=prev Jrdav at 11:20, 21 September 2016 2016-09-21T11:20:24Z

<p></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 12:20, 21 September 2016</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l151">Line 151:</td> <td colspan="2" class="diff-lineno">Line 151:</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><ul></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><ul></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|400px|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775109.jpg|thumb|center|400px|'''Plate P775109'''&nbsp;&nbsp;&nbsp;&nbsp; Mottled Mudstone Member (late Hirnantian) of the Cwmere Formation, Hafren Forest [SN 8416 8992]. Persculptus Biozone graptolites from the ‘''persculptus'' Band’. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling<del style="font-weight: bold; text-decoration: none;">. </del>Mottled Mudstone Member; locality as Plate P775109. ]]</li></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><li style="display: inline-block;"> [[File:P775110.jpg|thumb|center|445px|'''Plate P775110'''&nbsp;&nbsp;&nbsp;&nbsp;Chondrites burrow-mottling <ins style="font-weight: bold; text-decoration: none;">in </ins>Mottled Mudstone Member <ins style="font-weight: bold; text-decoration: none;">above the ‘''persculptus'' Band’</ins>; locality as Plate P775109. ]]</li></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></ul></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></ul></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;"><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> </table>

Jrdav