- The term "Facies" can also refer to distinctive facial expressions associated with conditions such as Williams syndrome. A facial expression results from one or more motions or positions of the Muscles of the Face. Williams syndrome ( WS; also Williams-Beuren syndrome or WBS) is a rare Neurodevelopmental disorder caused by a deletion of about 26 genes from
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 (see Cross and Homewood 1997), which replaced the earlier notions of Neptunism. A geologist is a contributor to the Science of Geology, studying the physical structure and processes of the Earth and planets of the solar system ( July 17, 1814 - April 13, 1865) was a was a Swiss geologist and paleontologist. Year 1838 ( MDCCCXXXVIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian Calendar (or a Common Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification) Neptunism is a discredited and Obsolete scientific theory of Geology proposed by Abraham Werner in the late 18th century that proposed rocks
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Definition
The simplest definition of facies is provided by Reading (1996) - 'A facies is a body of rock with specified characteristics. . . A facies should ideally be a distinctive rock that forms under certain conditions of sedimentation, reflecting a particular process or environment. '
Facies types
Sedimentary facies
Generally, facies are distinguished by what aspect of the rock or sediment is being studied. Thus, facies based on petrological characters such as grain size and mineralogy are called lithofacies, whereas facies based on fossil content are called biofacies. In Geology, petrology (from Greek πέτρα petra, rock and λόγος logos, knowledge is the study of rocks and the conditions on which Palaeontology redirects here For the Scientific journal, see Palaeontology (journal.
These facies types are usually further subdivided, for examples, you might refer to a "tan, cross-bedded oolitic limestone facies" or a "shale facies". Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Shale (also called mudstone) is a fine-grained Sedimentary rock whose original constituents were Clay minerals or Muds It is characterized by The characteristics of the rock unit come from the depositional environment and original composition. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere In geology sedimentary depositional environment describes the combination of physical chemical and biological processes associated with the deposition of a particular type of sediment Sedimentary facies reflect depositional environment, each facies being a distinct kind of sediment for that area or environment. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock)
Since its inception, the facies concept has been extended to related geological concepts. For example, characteristic associations of organic microfossils, and particulate organic material, in rocks or sediments, are called palynofacies. Palynofacies studies examine the preservation of particulate Organic matter and Palynomorphs to provide information on the depositional environment of sediments Discrete seismic units are similarly referred to as seismic facies. Seismology (from Greek grc σεισμός seismos, "earthquake" and grc -λογία -logia) is the scientific study of Earthquakes
Metamorphic facies
The sequence of minerals that develop during progressive metamorphism (that is, metamorphism at progressivley higher temperatures) define a facies series and depend on the pressure, or range of pressures, at which the progressive metamorphism occurred. Historic definition The name facies was first used for specific Sedimentary environments in Sedimentary rocks by Swiss geologist Amanz Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i
Walther's Law of Facies
Walther's Law of Facies, named after the geologist Johannes Walther, states that the vertical succession of facies reflects lateral changes in environment. Conversely, it states that when a depositional environment "migrates" laterally, sediments of one depositional environment come to lie on top of another. (Stanley, 134) A classic example of this law is the vertical stratigraphic succession that typifies marine trangressions and regressions. A transgression is a geologic event during which Sea level rises relative to the land and the shoreline moves toward higher ground resulting in flooding However, the law is not applicable where the contact between different lithologies is non-conformable (i. e. sedimentation was not continuous), or in instances of rapid environmental change where non-adjacent environments may replace one another.
See also
References
- Cross, T. Metamorphic rock is the result of the transformation of an existing rock type the protolith, in a process called Metamorphism, which means "change Palynofacies studies examine the preservation of particulate Organic matter and Palynomorphs to provide information on the depositional environment of sediments Sequence stratigraphy is a relatively new branch of Geology that attempts to link relative Sea-level changes to Sedimentary deposits In Geology and related fields a stratum (plural strata) is a layer of rock or Soil with internally consistent characteristics that distinguishes A. and Homewood, P. W. , (1997), Amanz Gressly's role in founding modern stratigraphy. Geological Society of America Bulletin 109 (12) 1617-1630.
- Reading, H. G. (Ed. ), (1996), Sedimentary Environments and Facies. Blackwell Scientific Publications. ISBN 0-632-03627-3
- Stanley, Steven M. Earth System History. New York: W. H. Freeman and Company, 1999. ISBN 0-7167-2882-6
Dictionary
facies
-noun
- (plurale tantum) (medicine) facial features, like an expression or complexion, typical for patients having certain diseases or conditions (e.g. costive facies).
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