Editing Geological history of Yorkshire

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 14: Line 14:
 
== Ordovician to Silurian ==
 
== Ordovician to Silurian ==
  
The Ordovician to Silurian sedimentary sequence, now exposed in the '''inliers''' along the Craven '''Fault''' Belt near Settle ([[Lower Palaeozoic rocks of the Craven Inliers - an excursion|Excursion 1]]), has similarities with that of the Lake District. '''Turbiditic''' sandstones, with interbedded siltstone, conglomerate and mudstone (see '''clastic rocks''') of probable Early Ordovician age are possibly several kilometres in total thickness. They were tightly '''folded''', uplifted and eroded in the Middle Ordovician interval when a subaerial volcanic island arc was active on the northern margin of Eastern Avalonia, parts of which are preserved in the Lake District. Subsequent crustal extension produced a foreland basin, resulting in the return of marine conditions with a '''transgression''' in the Late Ordovician, when shallow water, mixed clastic–'''carbonate rocks''' 450 m thick, which are locally richly fossiliferous, were deposited. In the Silurian, 35 m of '''graptolitic''' mudstones and siltstones were laid down in the Llandovery as the seas deepened. The infilling of the foreland basin, the remnant seaway between Laurentia and Avalonia, occurred in the Wenlock and Ludlow, with a 1600 m thick succession of mainly turbiditic sandstones and siltstones.
+
The Ordovician to Silurian sedimentary sequence, now exposed in the inliers along the Craven Fault Belt near Settle ([[Lower Palaeozoic rocks of the Craven Inliers - an excursion|Excursion 1]]), has similarities with that of the Lake District. Turbiditic sandstones, with interbedded siltstone, conglomerate and mudstone (see clastic rocks) of probable Early Ordovician age are possibly several kilometres in total thickness. They were tightly folded, uplifted and eroded in the Middle Ordovician interval when a subaerial volcanic island arc was active on the northern margin of Eastern Avalonia, parts of which are preserved in the Lake District. Subsequent crustal extension produced a foreland basin, resulting in the return of marine conditions with a transgression in the Late Ordovician, when shallow water, mixed clastic–carbonate rocks 450 m thick, which are locally richly fossiliferous, were deposited. In the Silurian, 35 m of graptolitic mudstones and siltstones were laid down in the Llandovery as the seas deepened. The infilling of the foreland basin, the remnant seaway between Laurentia and Avalonia, occurred in the Wenlock and Ludlow, with a 1600 m thick succession of mainly turbiditic sandstones and siltstones.
  
The collision between Eastern Avalonia, Laurentia and Baltica culminated in the compression and deformation of the Lower Palaeozoic rocks of Northern England in early Devonian times. The Acadian Orogeny, the terminal phase of the '''Caledonian Orogenic''' cycle, formed a continental area of fold mountains and rugged uplands striking northeast-southwest across most of the area that is now the British Isles. Granite '''magmas''' were generated at depth during the orogeny and injected as '''plutons''' into the deformed sedimentary pile. No granites crop out at the surface in Yorkshire, but the Wensleydale Granite and a probable granite under Market Weighton have been detected at depth by geophysical survey. The Wensleydale Granite has been proved by a borehole and dated at 400 ± 10 '''Ma'''.
+
The collision between Eastern Avalonia, Laurentia and Baltica culminated in the compression and deformation of the Lower Palaeozoic rocks of Northern England in early Devonian times. The Acadian Orogeny, the terminal phase of the Caledonian Orogenic cycle, formed a continental area of fold mountains and rugged uplands striking northeast-southwest across most of the area that is now the British Isles. Granite magmas were generated at depth during the orogeny and injected as plutons into the deformed sedimentary pile. No granites crop out at the surface in Yorkshire, but the Wensleydale Granite and a probable granite under Market Weighton have been detected at depth by geophysical survey. The Wensleydale Granite has been proved by a borehole and dated at 400 ± 10 Ma.
  
 
== Devonian ==
 
== Devonian ==

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)

  [] · [[]] · [[|]] · {{}} · · “” ‘’ «» ‹› „“ ‚‘ · ~ | °   · ± × ÷ 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>

Templates used on this page: