Deposition environment

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Deposition milieu is a geological term that describes the environmental conditions under which a sediment was deposited or a fossil was embedded (" paleoenvironment "). In the Fossilisationslehre the depositional environment plays a major role, as the fate of the rock or fossil ( diagenesis , epigenesis , etc.) depends on it. An adjective in combination with the terms "sediment" or "deposition area" is used as a designation. The term is closely related but not congruent with that of the sedimentary facies , which describes the formation of a rock, more precisely material, structure , texture , fossil content, etc., whereby all these criteria depend on the environmental conditions in the deposition area.

Designations

The following attributes are common to characterize storage areas or their sediments in more detail:

  • aeric or subaeric: in the open air (not to be confused with aeolian , an attribute that describes wind as a transport medium before the time of deposition)
  • terrestrial : belonging to the solid land surface, originated on the land
    • palustrian (palustrin): deposit in the area of ​​a bog
  • fluviatil : related to flowing water, e.g. B. river or stream beds, river beaches ( sliding slopes ), floodplains of rivers ( alluvial plains )
    • fluvioglacial (also: glazifluvial or glazifluviatil): material transported or deposited from glacial streams. The designation is ordered according to the predominant process, i.e. H. glaciofluvial with a predominantly glacial influence or fluvio-glacial with predominantly fluvial influence. Sander z. B. correspond to a fluvio-glacial deposit area.
  • delta : Deposits in the area of ​​a river delta (transition area to the marine environment, see below)
  • estuarine: deposit in the area of ​​an estuary (transition area to the marine environment, see below)
  • glacial: term for processes, formations, etc. that occur in connection with glaciers or continental ice sheets (overlaps with the glacier as a transport medium).
    • supraglacial: deposition or transport on the surface of the glacier
    • subglacial: material in the glacier bedrock is transported or deposited at the glacier base
    • Englacial: material transported inside the glacier (e.g. medial moraines or material that falls into crevasses )
    • periglacial : formed during a cold period in the unglaciated area
  • lacustric (lacustrine, lacustrine, lacuster) or limnic: related to the surroundings of a freshwater lake
  • paralisch: in summary for the deposition in the area of ​​coastal waters and coastal plain
  • brackish: related to brackish water , d. e., on waters with salinity below the mean salinity of the oceans, e.g. B. on estuaries of large rivers ( deltas , estuaries ) or so-called dilution basins
  • hypersalinar: refers to waters with a salt content above the mean salt content of the oceans ( salt lakes , oversalted lagoons or so-called concentration basins ) (see also →  Evaporit )
  • marine : biological: living in the sea ( lat. mare ) or coming from there or belonging to the sea; geological: all processes and forms that take place with the help of the sea and the sea, with regard to the salinity of the sedimentation environment, denotes bodies of water that have the average salinity of the oceans (in this context also referred to as fully marine milieu ). In detail, it can be further subdivided into:
  • submarine: term for processes, formations, etc. Ä. That occur below the sea surface.
  • littoral : on the coast, here too
    • sublittoral: in shallow shelves, almost constantly covered by water, below the range of influence of normal tides
    • eulitoral: in the tidal zone between the high and low water lines, in the area of ​​influence of the normal tides
    • supralitoral: in the splash zone above the high water line of normal tides
    • epilitoral: in the area of ​​influence of the sea shore
  • tidal : in the area of ​​influence of the tides, here too
    • subtidal: below the range of influence of normal tides
    • intertidal: in the area of ​​influence of normal tides
    • supratidal: above the range of influence of normal tides
  • oceanic: in the free ocean
  • neritic orShallow: on the shelf , up to 200 m depth, relatively close to the coast
  • pelagic ordeep marine: marine areas with a depth of more than 200 m (outer shelf, continental slope and deep sea basin ), relatively remote from the coast
    • hemipelagic: the coastal pelagic sea areas
  • basinal: in the topographically or bathymetrically deepest parts of a sedimentary basin
  • distal: a deposition site that is relatively distant in relation to the place of origin ( delivery area ) of a sediment (characterizes ieL siliciclastic sedimentary facies)
  • proximal: a deposition site relatively close in relation to the place of origin (delivery area) of a sediment (characterizes ieL siliciclastic sedimentary facies)

literature

  • Maurice E. Tucker: Introduction to Sedimentary Petrology. Enke, Stuttgart, 1985, ISBN 3-432-94781-X , pp. 2-4.

Remarks

  1. ↑ a b the bank designations that are formed with -litoral also apply here (see littoral)
  2. ^ Lexicon of Geosciences. Spectrum - Akademischer Verlag, Heidelberg u. a. 2000-2002.
  3. ^ Erwin J. Hentschel, Günther H. Wagner: Zoological dictionary. Animal names, general biological, anatomical, physiological terms and short biographies (=  UTB . Volume 367 ). 6th, revised and expanded edition. Gustav Fischer Verlag, Jena 1996, ISBN 3-334-60960-X , p. 382 .
  4. ^ Hans Murawski , Wilhelm Meyer : Geological dictionary . 11th, revised and expanded edition. Elsevier - Spectrum - Academic Publishing House, Munich a. a. 2004, ISBN 3-8274-1445-8 , pp. 126 .