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Ichnofabric Index
The Droser-Bottjer ichnofabric index is a method used to quantify the degree of bioturbation in a sedimentary rock. It involves grading the amount of trace fossil activity on a scale of 1–6; a value of 1 indicates that bioturbation is entirely absent, whereas the highest grade would involve a Bed (geology), bedding plane containing over 60% trace fossil cover. Application Ichnofabric index can be applied in either a vertical or horizontal aspect. The vertical component provides an indication of the interplay between physical and chemical aspects of the environment and the degree of biological activity. The vertical ichnofossil index is harder to measure; it involves quantifying the amount of disturbance to the original sedimentary fabric. References Trace fossils {{trace-fossil-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helminthopsis01
''Helminthopsis'' is the ichnogenus of a type of trace fossil that is found preserved on the bedding planes of fine-grained sedimentary rocks. It is characterized by short, curvilinear, non-branching, parallel-sided, unlined traces on bedding surfaces. It is thought to represent the submarine feeding trails of an invertebrate organism that worked the surface of muddy substrates in search of food. Because ''Helminthopsis'' traces never cross over themselves, the ichnogenus is distinguished from similar traces assigned to the ''Gordia'' ichnogenus. The similar sounding, but now obsolete, ichnogenus ''Helminthoida'' refers to a somewhat similar trace characterized by regular, back-and-forth meanders, whereas ''Helminthopsis'' traces are irregular. See also * Trace fossil * Ichnology References Trace fossils {{trace-fossil-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioturbation
Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity. The formal study of bioturbation began in the 1800s by Charles Darwin experimenting in his garden. The disruption of aquatic sediments and terrestrial soils through bioturbating activities provides significant ecosystem services. These include the alteration of nutrients in aquatic sediment and overlying water, shelter to other species in the form of burrows in terrestrial and water ecosystems, and soil production on land.Shaler, N. S., 1891, The origin and nature of soils, in Powell, J. W., ed., USGS 12th Annual report 1890–1891: Washington, D.C., Government Printing Office, p. 213-45. Bioturbators are deemed ecosystem engineers because they alter resource availability to other species through the physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedimentation is any process that causes these particles to settle in place. Geological detritus originates from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or Mass wasting, mass movement, which are called agents of denudation. Biological detritus is formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur when dissolved minerals precipitate from aqueous solution, water solution. The sedimentary rock cover of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trace Fossil
A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or by mineralization. The study of such trace fossils is ichnology - the work of ichnologists. Trace fossils may consist of physical impressions made on or in the substrate by an organism. For example, burrows, borings ( bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints, feeding marks, and root cavities may all be trace fossils. The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). However, most sedimentary struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bed (geology)
In geology, a bed is a layer of sediment, sedimentary rock, or volcanic rock "bounded above and below by more or less well-defined bedding surfaces".Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds., 2005. ''Glossary of Geology'' (5th ed.). Alexandria, Virginia; American Geological Institute. p 61. A bedding surface or bedding plane is respectively a curved surface or Euclidean planes in three-dimensional space, plane that visibly separates each successive bed (of the same or different lithology) from the preceding or following bed. In Cross section (geology), cross sections, bedding surfaces or planes are often called bedding contacts. Within conformable successions, each bedding surface acted as the depositional surface for the accumulation of younger sediment. Definitions Specifically in sedimentology, a bed can be defined in one of two major ways.Davies, N.S., and Shillito, A.P. 2021, ''True substrates: the exceptional resolution and unexceptional preservation of de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
