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Parasequence
A parasequence is a fundamental concept of sequence stratigraphy. Parasequences are not directly related to sequences. Definition A parasequence is defined as a genetically related succession of bedsets that is bounded by marine flooding surface Marine flooding surfaces are a fundamental concept in sequence stratigraphy, where they form the limiting surfaces of parasequences. A marine flooding surfaces is defined as a sharp contact that separates overlying younger strata with deep-water ...s (or their correlative surfaces) on top and at the bottom. The succession is supposed to be relatively conformable in the sense that breaks in deposition within the parasequence are much shorter than the time of deposition of the parasequence itself. Most parasequences show a shallowing upward, which is sometimes also included into the definition. Properties Since parasequences are relatively conformable, so Walther's law applies within a parasequence. This is not necessarily the case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Stratigraphy
Sequence stratigraphy is a branch of geology, specifically a branch of stratigraphy, that attempts to discern and understand historic geology through time by subdividing and linking sedimentary deposits into unconformity bounded units on a variety of scales. The essence of the method is mapping of strata based on identification of surfaces which are assumed to represent time lines (e.g. subaerial unconformities, maximum flooding surfaces), thereby placing stratigraphy in chronostratigraphic framework allowing understanding of the evolution of the earth's surface in a particular region through time. Sequence stratigraphy is a useful alternative to a purely lithostratigraphic approach, which emphasizes solely based on the compositional similarity of the lithology of rock units rather than time significance. Unconformities are particularly important in understanding geologic history because they represent erosional surfaces where there is a clear gap in the record. Conversely wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence (geology)
In geology, a sequence is a stratigraphic unit which is bounded by an unconformity at the top and at the bottom. Definition In a more rigorous and general way a sequence is defined as a "relatively conformable .. genetically related succession of strata bounded by unconformities or their correlative surfaces" Special cases and related concepts Special cases of sequences include type 1 sequences and type 2 sequence In sequence stratigraphy, a sub discipline of geology, type 1 sequences and type 2 sequences are special sequences In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set ...s. A related concept are parasequences. Contrary to their name they are not smaller sequences. See also * Catena (soil) References Sequence stratigraphy {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Flooding Surface
Marine flooding surfaces are a fundamental concept in sequence stratigraphy, where they form the limiting surfaces of parasequences. A marine flooding surfaces is defined as a sharp contact that separates overlying younger strata with deep-water facies from underlying older strata with shallow-water facies. Therefore, marine flooding surfaces indicate a deepening and can display signs of erosion and/or nondeposition resulting in a hiatus Hiatus may refer to: * Hiatus (anatomy), a natural fissure in a structure * Hiatus (stratigraphy), a discontinuity in the age of strata in stratigraphy *''Hiatus'', a genus of picture-winged flies with sole member species '' Hiatus fulvipes'' * G ... or break in the sedimentary record. References {{reflist Sequence stratigraphy Sedimentology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedset
In geology, a bed is a layer of sediment, sedimentary rock, or pyroclastic material "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. 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 deep time snapshots on bedding surfaces.'' ''Sedimentology.'' published online 22 May 2021, doi: 10.1111/sed.12900. First, Campbell and Reineck and SinghReineck, H.E., and Singh, I.B., 1980. ''Depositional Sedimentary Environments'', (2nd ed.) Berlin, Germany: Springer-Verlag, 504 pp. use the term ''bed'' to refer to a thickness-independent layer comprising a coherent layer of sedimentary rock, sediment, or pyroclastic material bounded above and below by surfaces known as beddi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walther's Law
In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formation), and the changes that may occur in those attributes over a geographic area. A facies encompasses all of the characteristics of a rock including its chemical, physical, and biological features that distinguish it from adjacent rock. The term facies was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy, which replaced the earlier notions of Neptunism. Types of facies Sedimentary facies Ideally, a sedimentary facies is a distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment. Sedimentary facies are either descriptive or interpretative. Sedimentary facies are bodies of sediment t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
