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ⓘ Red Crag Formation. The Red Crag Formation is a geological formation in England. It outcrops in south-eastern Suffolk and north-eastern Essex. The name derives ..




Red Crag Formation
                                     

ⓘ Red Crag Formation

The Red Crag Formation is a geological formation in England. It outcrops in south-eastern Suffolk and north-eastern Essex. The name derives from its iron-stained reddish colour and crag which is an East Anglian word for shells. It is part of the Crag Group, a series of notably marine strata which belong to a period when Britain was connected to continental Europe by the Weald–Artois Anticline, and the area in which the Crag Group was deposited was a tidally dominated marine bay. This bay would have been subjected to enlargement and contraction brought about by transgressions and regressions driven by the 40.000-year Milankovitch cycles.

The sediment in the outcrops mainly consists of coarse-grained and shelly sands that were deposited in sand waves megaripples that migrated parallel to the shore in a south-westward direction. The most common fossils are bivalves and gastropods that were often worn by the abrasive environment. The most extensive exposure is found at Bawdsey Cliff, which is designated a Site of Special Scientific Interest SSSI; here a width of around 2 kilometres 1.2 mi of Crag is exposed. At the coastline by Walton-on-the-Naze, remains of Megalodon were found.

The Red Crag Formation at depth in eastern Suffolk clearly has one member, the Sizewell Member, a coarse shelly sand with thin beds of clay and silt. It was interpreted as having been deposited in large scale sand waves where the sea bed was deeper. The overlying Thorpeness Member, was provisionally assigned to the Red Crag based on its lithology but there is more evidence to suggest that it is part of the Norwich Crag Formation.

It has been proposed that the Red Crag started in the late Pliocene and to have possibly extended up into the early Pleistocene, but there is disagreement on more precise dating. According to the British Geological Survey, the Red Crag sits within a segment of time from about 3.3 to 2.5 mya. It is considered that the Red Crag at Walton-on-the–Naze is the oldest and that it was deposited in only a few decades at some time between 2.9 and 2.6 mya. This has led to the UK stratigraphic stage name Waltonian, which is usually correlated with the final Pliocene Reuverian Stage in the Netherlands. There are difficulties in reconciling how the Red Crag equates with international chronological stages. In particular, the start and end dates are poorly defined due to the general paucity of age-diagnostic stratigraphic indicators and the fragmentary nature of the geology. It can also be difficult to separate the Red Crag from the overlying Norwich Crag Formation.

                                     
  • Red Crag Formation and in others unconformably on Coralline Crag Palaeogene formations and Chalk Group bedrock. It is overlain by the Wroxham Crag Formation
  • Anglia: Red Crag Wroxham Crag Corralline Crag Norwich Crag Club de Radioaficionados de Guatemala, an amateur radio organization in Guatemala The Crag the
  • constituent formations of the Crag Group are the Coralline Crag mid to late Pliocene the Red Crag late Pliocene early Pleistocene the Norwich Crag early
  • Pleistocene Red Crag Formation and it is the type site for the Waltonian, the first British stage of the Pleistocene. However, some authorities date the Red Crag
  • northern branch is formed by the trio of Buttermere fells, High Crag High Stile and Red Pike. The Buttermere Fells, also known as Buttermere Edge, form
  • rocks of the marine Red Crag Formation with a megaripple sequence showing the gradual reduction in depth of the sea. The Red Crag spans the end of the
  • Pliocene and early Pleistocene Red Crag Formation It has beach cobbles and fossils from a littoral fauna, whereas other Red Crag sites have deposits from deeper
  • Pleistocene and are related to the Red Crag Formation There is a considerable difference in elevation compared with the Red Crag of East Anglia, suggesting differential
  • The pale crag martin Ptyonoprogne obsoleta is a small passerine bird in the swallow family that is resident in northern Africa and in southwestern Asia
  • dinoflagellates to be constructed for horizons of the Red Crag and Norwich Crag Formations and for these formations to be thus correlated with strata of equivalent
                                     
  • and Pudding Force. At the head of the valley a large rock formation is found named Force Crag which forms a waterfall Low Force as Pudding Beck passes
  • consisting of a tooth and a right inner ear periotic bone from the Red Crag Formation of the Crag Group dating to the Early Pleistocene in England was referred
  • long section provides the largest exposure of the Early Pleistocene Red Crag Formation and it is rich in fossils of marine molluscs. It is described by
  • subsidiary top of Black Crag is Pillar. Southward is a long descending ridge heading toward the shore of Wastwater. The high point is Red Pike, before the terminal
  • geologist Frederick W. Harmer to define his Butley division of the Red Crag Formation and it has many fossils of marine molluscs. There is access to the
  • crossing Hart Crag Dove Crag Little Hart Crag and Red Screes. Dove Crag shows its unassuming back to Rydal in the west, while great crags command the
  • During the Gelasian, the Red Crag Formation of Butley, the Newbourn Crag the Norwich Crag Formation and the Weybourne Crag Formation all from East Anglia
  • Castle Crags is a dramatic and well - known rock formation in Northern California. Elevations range from 2, 000 feet 610 m along the Sacramento River near
  • regional stages of Europe. Some authorities describe the British Red Crag Formation and Waltonian stage as late Piacenzian, while others regard them as
  • Coralline Crag Formation It has many bryozoan fossils. There is access to the site by a track from Lambert s Lane. Designated Sites View: Red House Farm
  • flanks of Red Pike. Red Pike presents an almost continuous wall of crags above Mosedale, particularly above Black Comb. Bull and Black Crags meanwhile

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