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British Coastal Deposits Group
The British Coastal Deposits Group is a Quaternary lithostratigraphic group (a sequence of rock strata or other definable geological units) present in coastal and estuarine areas around the margins of Great Britain. They are a mix of sands, gravels, silts, clays and peat and, north of a line between the Ribble and Tyne, include glacio-eustatically raised deposits. They lie unconformably on deposits of variously the Britannia Catchments Group (with which they also interfinger), Albion Glacigenic Group, Caledonia Glacigenic Group, Dunwich Group, Crag Group or earlier bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be .... Their upper boundary is the present day ground surface. References {{Reflist Quaternary geologic formations Geology of England Geology of Scotland G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and '' lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Scotland
The geology of Scotland is unusually varied for a country of its size, with a large number of differing geological features.Keay & Keay (1994) page 415. There are three main geographical sub-divisions: the Highlands and Islands is a diverse area which lies to the north and west of the Highland Boundary Fault; the Central Lowlands is a rift valley mainly comprising Palaeozoic formations; and the Southern Uplands, which lie south of the Southern Uplands Fault, are largely composed of Silurian deposits. The existing bedrock includes very ancient Archean gneiss, metamorphic beds interspersed with granite intrusions created during the Caledonian mountain building period (the Caledonian orogeny), commercially important coal, oil and iron bearing carboniferous deposits and the remains of substantial Palaeogene volcanoes. During their formation, tectonic movements created climatic conditions ranging from polar to desert to tropical and a resultant diversity of fossil remains. Scotla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of England
The geology of England is mainly sedimentary. The youngest rocks are in the south east around London, progressing in age in a north westerly direction.Southampton University retrieved 21/1/07 The Tees–Exe line marks the division between younger, softer and low-lying rocks in the south east and the generally older and harder rocks of the north and west which give rise to higher relief in those regions. The geology of England is recognisable in the landscape of its counties, the building materials of its towns and its regional extr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary Geologic Formations
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedrock
In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedrock is often called an outcrop. The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith. Engineering geology The surface of the bedrock beneath the soil cover (regolith) is also known as ''rockhead'' in engineering geology, and its identification by digging, drilling or geophysical methods is an important task in most civil engineering projects. Superficial deposits can be very thick, such that the bedrock lies hundreds of meters below the surface. Weathering of bedrock Exposed bedrock experiences weathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion. Bedrock may also experience ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crag Group
The Crag Group is a geological group outcropping in East Anglia, UK and adjacent areas of the North Sea. Its age ranges from approximately 4.4 to 0.478 million years BP, spanning the late Pliocene and early to middle Pleistocene epochs. It comprises a range of marine and estuarine sands, gravels, silts and clays deposited in a relatively shallow-water, tidally-dominated marine embayment on the western margins of the North Sea basin. The sands are characteristically dark green from glauconite but weather bright orange, with haematite 'iron pans' forming. The lithology of the lower part of the Group is almost entirely flint. The highest formation in the Group, the Wroxham Crag, contains over 10% of far-travelled lithologies, notably quartzite and vein quartz from the Midlands, igneous rocks from Wales, and chert from the Upper Greensand of southeastern England. This exotic rock component was introduced by rivers such as the Bytham River and Proto-Thames. The constituent format ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dunwich Group
The Dunwich Group is a Pleistocene lithostratigraphic group (a sequence of rock strata or other definable geological units) present in England north of the upper Thames and, downstream, a line drawn east from near Marlow to Clacton-on-Sea and which encompasses river terrace deposits of the Proto-Thames and other rivers. It unconformably overlies Triassic to Pleistocene bedrock and superficial deposits. In turn, it is often overlain by deposits of the Albion Glacigenic Group and sometimes by those of the Britannia Catchments Group or British Coastal Deposits Group and interfingers in places with those of the Crag Group. No deposits potentially assignable to the group have been identified north of East Anglia or the English Midlands The Midlands (also referred to as Central England) are a part of England that broadly correspond to the Kingdom of Mercia of the Early Middle Ages, bordered by Wales, Northern England and Southern England. The Midlands were important in the In ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caledonia Glacigenic Group
The Caledonia Glacigenic Group is a Quaternary lithostratigraphic group (a sequence of rock strata or other definable geological units) present across the whole of Great Britain to the north and west of the furthest limit of Devensian glaciation i.e. throughout Scotland, Wales and northern England. It consists of a wide range of deposits deriving from the Devensian glaciation of glacial, glaciofluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvio ..., glaciolacustrine and glaciomarine origin. It was previously known as the South Britain Glacigenic Group. Its upper boundary is the present day ground surface or an unconformable contact with the Britannia Catchments Group or the British Coastal Deposits Group. The following subgroups are defined:McMillan, A A, Hamblin, R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albion Glacigenic Group
The Albion Glacigenic Group is a Quaternary lithostratigraphic group (a sequence of rock strata or other definable geological units) present in those parts of Great Britain which lie north of the southern limit of Anglian glaciation, but south of the Devensian glacial limit, and also includes deposits in the Isle of Man and offshore areas. It consists of a wide range of unconsolidated superficial deposits including till, sands, gravels, silts and clay of glacial, glaciofluvial, glaciolacustrine Sediments deposited into lakes that have come from glaciers are called glaciolacustrine deposits. These lakes include ice margin lakes or other types formed from glacial erosion or deposition. Sediments in the bedload and suspended load are carried ... and glaciomarine origin. Its upper boundary is the present day ground surface or unconformable contact with units of the Caledonia Glacigenic Group, the Britannia Catchments Group or the British Coastal Deposits Group. It was previ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Britannia Catchments Group
The Britannia Catchments Group is a Quaternary lithostratigraphic group (a sequence of rock strata or other definable geological units) present in all parts of Great Britain and including the Isle of Man. It includes a wide range of deposits including alluvium, river terrace deposits, peat, head, cover sand and blown sand of fluvial, lacustrine, mass movement, periglacial and aeolian origin. Its lower boundary is defined as an unconformable contact with the underlying Albion Glacigenic Group (in England and Wales), the Caledonia Glacigenic Group (in Scotland), the Dunwich Group, Crag Group or with older bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be .... Its upper boundary is generally the present day ground surface but it interfingers locally with the British Coastal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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