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Map of Mercia Mudstone Group's outcrop (Triassic) in Wales and southwest England The Mercia Mudstone Group is an early Triassic lithostratigraphic group (a sequence of rock strata ) which is widespread in Britain, especially in the English Midlands —the name is derived from the ancient kingdom of Mercia which corresponds to that area.
Overlying the Millstone Grit sequence is the thick Westphalian sequence of sandstones, mudstones and coal seams collectively referred to as the Pennine Coal Measures Group and which forms the Lancashire Coalfield, the western part of which extends into Merseyside. The youngest Carboniferous strata in the area are the non-productive (of coal ...
Mudstone on east beach of Lyme Regis, England. Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds.Mudstone is distinguished from shale by its lack of fissility.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
The Penarth Group is a Rhaetian age lithostratigraphic group (a sequence of rock strata) which is widespread in Britain.It is named from the seaside town of Penarth near Cardiff in south Wales where strata of this age are exposed in coastal cliffs southwards to Lavernock Point.
The Silurian (/ s ɪ ˈ lj ʊər i. ən, s aɪ-/ sih-LURE-ee-ən, sy-) [8] [9] [10] is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.1 million years ago (), to the beginning of the Devonian Period, 419.62 Mya. [11]
Assuming that all the English south of the Humber are listed within the Tribal Hidage, he produced a map that divides southern England into Mercia's provinces and outlying dependencies, using evidence from river boundaries and other topographical features, place-names and historical borders.
Carbonaceous mudstones and silicified limestones also occur locally at the top of the succession. [1] [2] The Trossingen Formation is restricted to the edge area of the Vindelizian Threshold and thus to the South German stratigraphic zone. The average thickness is about 40 to 50 m, in northern Franconia values between 55 and 60 m are reached.