Boulder clay, in geology, is a deposit of clay, often full of boulders, which is formed in and beneath glaciers and ice-sheets wherever they are found, but is in a special sense the typical deposit of the Glacial Period in northern Europe and North America. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. Boulder clay is variously known as till or ground moraine (Ger. Till is unsorted glacial sediment Glacial drift is a general term for the coarsely graded and extremely heterogeneous Sediments of glacial origin Moraine refers to any glacially formed accumulation of unconsolidated glacial debris (soil and rock which can occur in currently glaciated and formerly glaciated regions such as those Blocklehme, Geschiebemergel or Grundmoraene; Fr. argile a blocc1ux, moraine profonde; Swed. Krosstenslera). It is one of the group of poorly sorted materials described by the non-genetic term diamicton. In geology diamicton (also diamict) is a very poorly sorted Sediment. It is usually a stiff, tough clay devoid of stratification; though some varieties are distinctly laminated. Occasionally, within the boulder clay, there are irregular lenticular masses of more or less stratified sand, gravel or loam. Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Gravel is rock that is of a specific Particle size range In Geology, gravel is any loose rock that is larger than two millimeters (2mm Loam is Soil composed of Sand, Silt, and Clay in relatively even concentration (about 40-40-20% concentration respectively considered As the boulder clay is the result of the abrasion (direct or indirect) of the older rocks over which the ice has travelled, it takes its color from them; thus, in Britain, over Triassic and Old Red Sandstone areas the clay is red, over Carboniferous rocks it is often black, over Silurian rock it may be buff or grey, and where the ice has passed over chalk the clay may be quite white and chalky (chalky boulder clay). See also Kingdom of Great Britain Great Britain (Breatainn Mhòr Prydain Fawr Breten Veur Graet Breetain is the larger of the two main islands The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago The Old Red Sandstone is a Rock formation of considerable importance to early Paleontology. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Silurian is a geologic period and system that extends from the end of the Ordovician period about 443 Ice is a Solid phase, usually crystalline, of a Non-metalic substance that is liquid or gas at Room temperature, such as Ammonia Chalk (ʧɔːk is a soft white porous Sedimentary rock, a form of Limestone composed of the Mineral Calcite. Much boulder clay is of a bluish-grey color where unexposed, but it becomes brown upon being weathered. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere.
The boulders are held within the clay in an irregular manner, and they vary in size from mere pebbles up to masses many tons in weight. A pebble is a clast of rock with a Particle size of 4 to 64 Millimeters based on the Krumbein phi scale of Sedimentology Units of mass There are three similar units of Mass called the ton: Long ton (simply ton in countries such as the United Usually they are somewhat oblong, and often they possess a flat side or sole; they may be angular, sub-angular, or well rounded, and, if they are hard rocks, they frequently bear grooves and scratches caused by contact with other rocks while held firmly in the moving ice. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere Like the clay in which they are borne, the boulders belong to districts over which the ice has travelled; in some regions they are mainly limestones or sandstones; in others they are granite, basalts, gneisses, etc. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Sandstone is a Sedimentary rock composed mainly of Sand -size Mineral or rock grains. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Gneiss (ˈnaɪs is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally ; indeed, they may consist of any hard rock. By the nature of the contained boulders it is often possible to trace the path along which a vanished ice-sheet moved; thus in the glacial drift of the east coast of England many Scandinavian rocks can be recognized. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Terminology and usage As a cultural term "Scandinavia" has no official definition and is subject to usage by those who identify with the culture in question as well
With the exception of foraminifera, which have been found in the boulder clay of widely separated regions, fossils are practically unknown; but in some maritime districts marine shells have been incorporated with the clay. The Foraminifera, ("Hole Bearers" or forams for short are a large group of Amoeboid Protists with reticulating Pseudopods fine FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. A seashell, also known as a sea shell, is the Common name for a hard protective outer layer a shell or in some cases a " test " that was created
An classic example a boulder clay cliff can be seen at the rapidly eroding cliffs of Hornsea, situated along the Holderness coast in East Yorkshire. Hornsea is a small Seaside resort Town and Civil parish in the East Riding of Yorkshire, England at the eastern end of the Trans Holderness is an area of England on the coast of Yorkshire. An area of rich agricultural land Holderness was marshland until it was drained in the Middle Ages
References
- This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. The Encyclopædia Britannica Eleventh Edition (1910–1911 is a 29-volume reference work that marked the beginning of the Encyclopædia Britannica The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
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