Editing OR/17/042 Context of study area

Jump to navigation Jump to search

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.

This page supports semantic in-text annotations (e.g. "[[Is specified as::World Heritage Site]]") to build structured and queryable content provided by Semantic MediaWiki. For a comprehensive description on how to use annotations or the #ask parser function, please have a look at the getting started, in-text annotation, or inline queries help pages.

Latest revision Your text
Line 23: Line 23:
 
Throughout the Plio‐Pleistocene, the global climate signal underwent a progressive intensification resulting in the strengthening of the glacial‐interglacial climate signal. This drove changes in the distribution of solar insolation (heat) across the planet’s surface, enhanced seasonality and the sequential establishment of regular cold‐warm climate cycles over 21 ka (Pliocene), 41 ka (from c.2.6 Ma) and finally 100 ka (from c.1 Ma) time‐scales. These climatic cycles, have amplified the dynamics of earth surface processes (e.g. weathering rates, vegetation cover and sediment availability) and the behaviour of geological systems (e.g. rivers, slopes, glaciers etc). Put simply, the landscape of the UK has become more dynamic over the past two and a half million years with progressively increased rates of weathering, erosion and sediment mobility (in response to denudational isostasy).
 
Throughout the Plio‐Pleistocene, the global climate signal underwent a progressive intensification resulting in the strengthening of the glacial‐interglacial climate signal. This drove changes in the distribution of solar insolation (heat) across the planet’s surface, enhanced seasonality and the sequential establishment of regular cold‐warm climate cycles over 21 ka (Pliocene), 41 ka (from c.2.6 Ma) and finally 100 ka (from c.1 Ma) time‐scales. These climatic cycles, have amplified the dynamics of earth surface processes (e.g. weathering rates, vegetation cover and sediment availability) and the behaviour of geological systems (e.g. rivers, slopes, glaciers etc). Put simply, the landscape of the UK has become more dynamic over the past two and a half million years with progressively increased rates of weathering, erosion and sediment mobility (in response to denudational isostasy).
  
Throughout the Miocene‐Pleistocene time‐interval (23&nbsp;Ma to 0.012&nbsp;Ma), much of the EISB and most likely the Cheshire Basin were probably emergent. Major regional depositional centres include the Celtic Deep and St George’s Channel troughs within the Irish Sea Basin, which accumulated between 100–200 metres of sediment (Tappin ''et al''., 1994<ref name="Tappin 1994"></ref>; Jackson ''et al''., 1995<ref name="Jackson 1995"></ref>; British Geological Survey, 2009<ref name="British Geological Survey 2009">British Geological Survey. 2009. St George’s Channel Special Sheet. Bedrock Geology (with Tertiary subcrop). 1:250&nbsp;000 (Keyworth, Nottingham: British Geological Survey).    </ref>). Subaerial exposure of the SSG and MMG means that the bedrock of the Cheshire Basin is likely to have been susceptible to modification by warm and cold‐climate weathering and other landscape‐forming processes. Cold climate periglacial and glacial processes are likely to have played a particularly significant role in modifying substrate properties during the past 2.6 million years. Weathering may have resulted in significant episodes of cement removal, fracture formation and natural hydraulic fracturing of the near‐ surface bedrock interval. Glaciers have been active agents in the British landscape periodically over the past 2.6 million years (Lee ''et al''., 2011<ref name="Lee  2011">Lee, J R, Rose, J, Hamblin, R J, Moorlock, B S, Riding, J B, Phillips, E, Barendregt, R W, and Candy, I. 2011. The Glacial History of the British Isles during the Early and Middle Pleistocene: Implications for the long‐term development of the British Ice Sheet. 59–74 in Quaternary Glaciations–Extent and Chronology, A Closer look. Developments in Quaternary Science. Ehlers, J, Gibbard, P L, and
+
Throughout the Miocene‐Pleistocene time‐interval (23&nbsp;Ma to 0.012&nbsp;Ma), much of the EISB and most likely the Cheshire Basin were probably emergent. Major regional depositional centres include the Celtic Deep and St George’s Channel troughs within the Irish Sea Basin, which accumulated between 100–200 metres of sediment (Tappin ''et al''., 1994<ref name="Tappin 1994"></ref>; Jackson ''et al''., 1995<ref name="Jackson 1995">Jackson, D I, Jackson, A A, Evans, D, Wingfield, R T R, Barnes, R P, and Arthur, M J. 1995. ''United Kingdom offshore regional report: the geology of the Irish Sea''. (London, HMSO for the British Geological Survey).    </ref>; British Geological Survey, 2009<ref name="British Geological Survey 2009">British Geological Survey. 2009. St George’s Channel Special Sheet. Bedrock Geology (with Tertiary subcrop). 1:250&nbsp;000 (Keyworth, Nottingham: British Geological Survey).    </ref>). Subaerial exposure of the SSG and MMG means that the bedrock of the Cheshire Basin is likely to have been susceptible to modification by warm and cold‐climate weathering and other landscape‐forming processes. Cold climate periglacial and glacial processes are likely to have played a particularly significant role in modifying substrate properties during the past 2.6 million years. Weathering may have resulted in significant episodes of cement removal, fracture formation and natural hydraulic fracturing of the near‐ surface bedrock interval. Glaciers have been active agents in the British landscape periodically over the past 2.6 million years (Lee ''et al''., 2011<ref name="Lee  2011">Lee, J R, Rose, J, Hamblin, R J, Moorlock, B S, Riding, J B, Phillips, E, Barendregt, R W, and Candy, I. 2011. The Glacial History of the British Isles during the Early and Middle Pleistocene: Implications for the long‐term development of the British Ice Sheet. 59–74 in Quaternary Glaciations–Extent and Chronology, A Closer look. Developments in Quaternary Science. Ehlers, J, Gibbard, P L, and
 
Hughes, P D (editors). 15. (Amsterdam: Elsevier.)    </ref>, 2012<ref name="Lee 2012">Lee, J R, Busschers, F S, and Sejrup, H P. 2012. Pre‐Weichselian Quaternary glaciations of the British Isles, The Netherlands, Norway and adjacent marine areas south of 68°N: implications for long-term ice sheet development in northern Europe. ''Quaternary Science Reviews'', Vol.&nbsp;44, 213–228.</ref>; Thierens ''et al''., 2012<ref name="Thierens 2012">Thierens, M, Pirlet, H, Colin, C, Latruwe, K, Vanhaecke, F, Lee, J R, Stuut, J B, Titschack, J, Huvenne, V A I, Dorschel, B, Wheeler, A J, and Henriet, J P. 2012. Ice‐rafting from the British–Irish ice sheet since the earliest Pleistocene (2.6 million years ago): implications for long‐term mid‐latitudinal ice‐sheet growth in the North Atlantic region. ''Quaternary Science Reviews'', Vol.&nbsp;44, 229–240.</ref>). The largest glaciation occurred approximately 0.45&nbsp;Ma (the Anglian) with ice sheets extending southwards towards London (Perrin ''et al''., 1979<ref name="Perrin 1979">Perrin, R M S, Rose, J, and Davies, H. 1979. The distribution, variation and origins of pre‐Devensian tills in eastern England. ''Philosophical Transactions of the Royal Society of London'', Vol.B287, 535–570.</ref>; Bowen ''et al''., 1986<ref name="Bowen 1986">Bowen, D Q, Rose, J, Mccabe, A M, and Sutherland, D G. 1986. Correlation of Quaternary glaciations in England, Ireland, Scotland and Wales. ''Quaternary Science Reviews'', Vol.&nbsp;5, 299–340.    </ref>) and through St George’s Channel and the Celtic Deep troughs (Tappin ''et al''., 1994<ref name="Tappin 1994"></ref>). Although no direct evidence occurs for this glaciation within the Cheshire Basin, the occurrence of erratic clasts from Cheshire (SSG) in tills in the West Midlands, demonstrates that ice crossed the study area from the Irish Sea Basin (Rice, 1968<ref name="Rice 1968">Rice, R J. 1968. The Quaternary deposits of central Leicestershire. ''Philosophical Transactions of the Royal Society of London'', Vol.&nbsp;A262, 459–509.    </ref>; Bridge and Hough, 2002<ref name="Bridge  2002">Bridge, D Mcc, and Hough, E. 2002. ''Geology of the Wolverhampton and Telford district: sheet description of the British Geological Survey 1:50&nbsp;000 series sheet 153'' (England and Wales): Nottingham, British Geological Survey, 75pp.</ref>). Much of the modern topography of the Cheshire Basin corresponds to the Late Devensian glaciation (c.27–17&nbsp;ka) when the area was inundated by Irish Sea, Welsh and Lake District ice forming part of the Last British‐Irish Ice Sheet (Price ''et al''., 1963<ref name="Price 1963">Price, D, Wright, W B, Jones, R C B, Tonks, L H, and Whitehead, T H. 1963. Geology of the  Country around Preston (one‐inch Geological Sheet 75 New Series). Memoirs of the Geological Survey of Great Britain, England and Wales: HMSO, London.      </ref>; Thomas and Chiverrell, 2007; Clark ''et al'', 2012<ref name="Clark 2012">Clark, C D, Hughes, A L, Greenwood, S L, Jordan, C, and Sejrup, H P.  2012.  Pattern  and  timing of retreat of the last British‐Irish Ice Sheet. ''Quaternary Science Reviews'', Vol.&nbsp;44, 112–146.</ref>) (Figure&nbsp;3.4). Glaciation (and deglaciation) of the Cheshire Basin resulted in the deposition of a variable thickness (locally exceeding 25 metres) of glacial deposits including tills, glaciofluvial and glaciolacustrine sediments which can be observed as the surface geology in much of the modern landscape (Figure&nbsp;3.5; Price ''et al''., 1963<ref name="Price 1963"></ref>; Worsley, 1967<ref name="Worsley 1967">Worsley, P. 1967. Problems in naming the Pleistocene deposits of north‐east Cheshire Plain. ''Mercian Geologist'', Vol.&nbsp;2, 51–55.</ref>; Johnson, 1968; Longworth, 1985<ref name="Longworth 1985">Longworth, D. 1985. The Quaternary history of the Lancashire Plain. 178–200 in ''The Geomorphology of north‐west England''. Johnson, R H. (editor). Manchester Univeristy Press.</ref>; Wilson and Evans, 1990<ref name="Wilson 1990">Wilson, A A, and Evans, W B. 1990. ''Geology of the Country around Blackpool''. Memoir of the Britsih Geological Survey, Sheet 66 (England and Wales).</ref>). Over much of the Cheshire Basin, these superficial deposits have largely (but not completely) buried the Triassic bedrock, with the latter likely to have been modified either by direct ice‐bed traction and/or by glacial meltwater incision.
 
Hughes, P D (editors). 15. (Amsterdam: Elsevier.)    </ref>, 2012<ref name="Lee 2012">Lee, J R, Busschers, F S, and Sejrup, H P. 2012. Pre‐Weichselian Quaternary glaciations of the British Isles, The Netherlands, Norway and adjacent marine areas south of 68°N: implications for long-term ice sheet development in northern Europe. ''Quaternary Science Reviews'', Vol.&nbsp;44, 213–228.</ref>; Thierens ''et al''., 2012<ref name="Thierens 2012">Thierens, M, Pirlet, H, Colin, C, Latruwe, K, Vanhaecke, F, Lee, J R, Stuut, J B, Titschack, J, Huvenne, V A I, Dorschel, B, Wheeler, A J, and Henriet, J P. 2012. Ice‐rafting from the British–Irish ice sheet since the earliest Pleistocene (2.6 million years ago): implications for long‐term mid‐latitudinal ice‐sheet growth in the North Atlantic region. ''Quaternary Science Reviews'', Vol.&nbsp;44, 229–240.</ref>). The largest glaciation occurred approximately 0.45&nbsp;Ma (the Anglian) with ice sheets extending southwards towards London (Perrin ''et al''., 1979<ref name="Perrin 1979">Perrin, R M S, Rose, J, and Davies, H. 1979. The distribution, variation and origins of pre‐Devensian tills in eastern England. ''Philosophical Transactions of the Royal Society of London'', Vol.B287, 535–570.</ref>; Bowen ''et al''., 1986<ref name="Bowen 1986">Bowen, D Q, Rose, J, Mccabe, A M, and Sutherland, D G. 1986. Correlation of Quaternary glaciations in England, Ireland, Scotland and Wales. ''Quaternary Science Reviews'', Vol.&nbsp;5, 299–340.    </ref>) and through St George’s Channel and the Celtic Deep troughs (Tappin ''et al''., 1994<ref name="Tappin 1994"></ref>). Although no direct evidence occurs for this glaciation within the Cheshire Basin, the occurrence of erratic clasts from Cheshire (SSG) in tills in the West Midlands, demonstrates that ice crossed the study area from the Irish Sea Basin (Rice, 1968<ref name="Rice 1968">Rice, R J. 1968. The Quaternary deposits of central Leicestershire. ''Philosophical Transactions of the Royal Society of London'', Vol.&nbsp;A262, 459–509.    </ref>; Bridge and Hough, 2002<ref name="Bridge  2002">Bridge, D Mcc, and Hough, E. 2002. ''Geology of the Wolverhampton and Telford district: sheet description of the British Geological Survey 1:50&nbsp;000 series sheet 153'' (England and Wales): Nottingham, British Geological Survey, 75pp.</ref>). Much of the modern topography of the Cheshire Basin corresponds to the Late Devensian glaciation (c.27–17&nbsp;ka) when the area was inundated by Irish Sea, Welsh and Lake District ice forming part of the Last British‐Irish Ice Sheet (Price ''et al''., 1963<ref name="Price 1963">Price, D, Wright, W B, Jones, R C B, Tonks, L H, and Whitehead, T H. 1963. Geology of the  Country around Preston (one‐inch Geological Sheet 75 New Series). Memoirs of the Geological Survey of Great Britain, England and Wales: HMSO, London.      </ref>; Thomas and Chiverrell, 2007; Clark ''et al'', 2012<ref name="Clark 2012">Clark, C D, Hughes, A L, Greenwood, S L, Jordan, C, and Sejrup, H P.  2012.  Pattern  and  timing of retreat of the last British‐Irish Ice Sheet. ''Quaternary Science Reviews'', Vol.&nbsp;44, 112–146.</ref>) (Figure&nbsp;3.4). Glaciation (and deglaciation) of the Cheshire Basin resulted in the deposition of a variable thickness (locally exceeding 25 metres) of glacial deposits including tills, glaciofluvial and glaciolacustrine sediments which can be observed as the surface geology in much of the modern landscape (Figure&nbsp;3.5; Price ''et al''., 1963<ref name="Price 1963"></ref>; Worsley, 1967<ref name="Worsley 1967">Worsley, P. 1967. Problems in naming the Pleistocene deposits of north‐east Cheshire Plain. ''Mercian Geologist'', Vol.&nbsp;2, 51–55.</ref>; Johnson, 1968; Longworth, 1985<ref name="Longworth 1985">Longworth, D. 1985. The Quaternary history of the Lancashire Plain. 178–200 in ''The Geomorphology of north‐west England''. Johnson, R H. (editor). Manchester Univeristy Press.</ref>; Wilson and Evans, 1990<ref name="Wilson 1990">Wilson, A A, and Evans, W B. 1990. ''Geology of the Country around Blackpool''. Memoir of the Britsih Geological Survey, Sheet 66 (England and Wales).</ref>). Over much of the Cheshire Basin, these superficial deposits have largely (but not completely) buried the Triassic bedrock, with the latter likely to have been modified either by direct ice‐bed traction and/or by glacial meltwater incision.
  

Please note that all contributions to Earthwise may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Earthwise:Copyrights for details). Do not submit copyrighted work without permission!

Cancel Editing help (opens in new window)

  [] · [[]] · [[|]] · {{}} · · “” ‘’ «» ‹› „“ ‚‘ · ~ | ° &nbsp; · ± × ÷ ² ³ ½ · §
[[Category:]] · [[:File:]] · <code></code> · <syntaxhighlight></syntaxhighlight> · <includeonly></includeonly> · <noinclude></noinclude> · #REDIRECT[[]] · <translate></translate> · <languages/> · ==References== · {{reflist}} · ==Footnote== · {{reflist|group=note}} · <ref group=note> · __notoc__ · {{DEFAULTSORT:}} <div class="someclass noprint"></div> {{clear}} <br>

Template used on this page: