Search results
Results from the WOW.Com Content Network
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.
A pile up to several hundred metres thick of Triassic sandstones, mudstones and siltstones underlies Wirral, Liverpool and the coastal plains to the north. The following sequence is encountered within Merseyside: Mercia Mudstone Group. Sidmouth Mudstone Formation (formerly 'Keuper Marl') Tarporley Siltstone Formation (formerly 'Keuper Waterstones')
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.
The oldest rocks exposed at or near the surface of Lincolnshire are the sandstones and mudstones of the early Triassic Sherwood Sandstone Group.Rocks from this and the overlying Mercia Mudstone and Penarth groups occur in the northwest of the county and along its western border but are generally concealed beneath a thick cover of recent deposits.
Mudstones, shales, lutites, and argillites are common qualifiers, or umbrella terms; however, the term mudrock has increasingly become the terminology of choice by sedimentary geologists and authors. The term "mudrock" allows for further subdivisions of siltstone, claystone, mudstone, argilite and shale. For example, a siltstone would be made ...
Rocks originating in the Carboniferous Period underlie the uplands of eastern and north Lancashire. Listed in order of succession i.e. lowermost/oldest first, they comprise the various limestones, mudstones, siltstones and sandstones of the Bowland High Group and Trawden Limestone Group, Craven Group, Millstone Grit Group, Pennine Coal Measures Group and Warwickshire Group.
The sequence in County Durham is divided into Lower, Middle and Upper formations. Each of the three are dominated by mudstones but contain abundant sandstones and coal seams. Ironstone bands occur in the lower part of the sequence. At least eleven marine bands (shelly mudstones in general) occur within the Coal Measures. Of these, the ...
During the Cambrian and Ordovician, sandstones and mudstones were laid down within the Welsh Basin, a relatively shallow marginal area of a broader and deeper ocean known as Iapetus, which lay to the north. Variations in water depth over this time, related both to crustal extension and to the growth and decline of a south polar ice-sheet, gave ...