{"id":9114,"date":"2014-07-26T13:51:13","date_gmt":"2014-07-26T18:51:13","guid":{"rendered":"http:\/\/all-geo.org\/highlyallochthonous\/?p=9114"},"modified":"2014-07-26T13:51:13","modified_gmt":"2014-07-26T18:51:13","slug":"scenic-saturday-crossbeds-on-the-edge","status":"publish","type":"post","link":"https:\/\/all-geo.org\/highlyallochthonous\/2014\/07\/scenic-saturday-crossbeds-on-the-edge\/","title":{"rendered":"Scenic Saturday: Crossbeds on the Edge"},"content":{"rendered":"

\"A<\/span>Some of the famous features of the Peak District<\/a> are not really peaks at all – but there is nothing more scenic than a wander along one of the ‘Edges’.<\/p>\n

\"Birchen<\/a>

Birchen Edge near Baslow, Peak District, UK. Photo: Chris Rowan, 2014.<\/p><\/div>\n

These sheer cliffs, scattered along the eastern and western edges of the National Park, are made of beds of angular, coarse-grained sandstones, locally known as the Millstone Grit<\/a>. They form part of a Middle to Late Carboniferous (325–315 million year-old) sequence of sandstones and siltstones that were deposited on top of the limestones that now outcrop in the middle of the Peaks (where the porous bed of the River Manifold<\/a> is located), as rivers flowing south from what is now Scotland build a large delta out into a shallow, tropical sea[1]<\/a><\/sup>. The harder gritstone layers have eroded more slowly than the surrounding siltstone units and the underlying limestone, creating the rock-climbers’ paradise we see today.<\/p>\n

\"Another<\/a>

Another view along. Birchen Edge. Spot the sedimentary structures! Photo: Chris Rowan, 2014.<\/p><\/div>\n

Exploring these cliffs, and the more eroded tors scattered around on top of them, you can also see a lot of very impressive cross-bedding – the preserved signature of the currents that shaped and built that Carboniferous delta. <\/p>\n

\"Multiple<\/a>

Multiple layers of cross bedding in the Millstone Grit, Birchen Edge. Photo: Chris Rowan, 2014.<\/p><\/div>\n

\"A<\/a>

A closeup of one layer of crossbeds in the Millstone Grit – you can just about see some of the coarse sand grains that this unit is composed of. Photo: Chris Rowan, 2014.<\/p><\/div>\n

\"Cross<\/a>

Cross beds in one of the more eroded tors on top of Birchen Edge. These tors actually form part of a monument to Lord Nelson<\/a> erected in 1810. Photo: Chris Rowan, 2014.<\/p><\/div>\n

\"Looking<\/a>

Looking past some cross-beds in the Millstone Grit, over Bichen Edge. Photo: Chris Rowan, 2014.<\/p><\/div>\n

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    \n
  1. \n

    If you want a bit more geological info, this fact sheet (pdf)<\/a> is a good starting point  ↩<\/a><\/p>\n<\/li>\n<\/ol>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    Some of the famous features of the Peak District are not really peaks at all – but there is nothing more scenic than a wander along one of the ‘Edges’. These sheer cliffs, scattered along the eastern and western edges … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,144,27,26],"tags":[487,742,740,743],"class_list":["post-9114","post","type-post","status-publish","format-standard","hentry","category-geology","category-geomorphology","category-palaeozoic","category-photos","tag-carboniferous","tag-cross-bedding","tag-peak-district","tag-sedimentary-structures"],"_links":{"self":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/9114","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/comments?post=9114"}],"version-history":[{"count":6,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/9114\/revisions"}],"predecessor-version":[{"id":9120,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/9114\/revisions\/9120"}],"wp:attachment":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/media?parent=9114"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/categories?post=9114"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/tags?post=9114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}