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P-form (geology)
A P-form (for ''plastically moulded form'') is a smoothed depression eroded by ice into bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater .... Three classes of P-form are recognised: transverse forms, longitudinal forms and non-directional forms and each of these are further subdivided on the basis of their shape. They are present on scales from tens of centimetres to several kilometres. The term was introduced in 1965 by glaciologist R Dahl though questioned by later authors with Kor introducing the term S-form (for ''sculpted form'') in 1991. Their origin is still debated but include i) the presence of debris within the base of moving ice, ii) of saturated till trapped between the base of a glacier and the bedrock, iii) of subglacial meltwater under pressure and iv) a mix of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedrock
In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), 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 geophysics, geophysical methods is an important task in most civil engineering projects. Superficial deposition (geology), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciologist
Glaciology (; ) is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice. Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on people includes the fields of human geography and anthropology. The discoveries of water ice on the Moon, Mars, Europa and Pluto add an extraterrestrial component to the field, which is referred to as "astroglaciology". Overview A glacier is an extended mass of ice formed from snow falling and accumulating over a long period of time; glaciers move very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers. Areas of study within glaciology include glacial history and the reconstruction of past glaciation. A glaciologist is a person who studies glaciers. A glacial geologist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of '' glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is depos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
