Sedimentology encompasses the study of modern sediments such as sand,[1] mud (silt),[2] and clay,[3] and the processes that result in their deposition.[4] Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures.[5]
Sedimentary rocks cover most of the Earth's surface, record much of the Earth's history, and harbor the fossil record. Sedimentology is closely linked to stratigraphy, the study of the physical and temporal relationships between rock layers or strata.
The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed. By comparing similar features today to features in the rock record—for example, by comparing modern sand dunes to dunes preserved in ancient aeolian sandstones—geologists reconstruct past environments.
Friday, March 12, 2010
Fields and related disciplines
Fields
* Geodesy,[1] measurement of the Earth: GPS, vertical and horizontal motions of the Earth's surface, navigation, the study of the Earth's gravitational field, and the size and form of the Earth
* The study of large-scale motions of the Earth's surface and interior, including:
* Tectonophysics, the study of the physical processes that cause and result from plate tectonics
* Geodynamics, the study of modes of transport deformation within the Earth: rock deformation, mantle flow and convection, heat flow, lithosphere dynamics
* Seismology, the study of earthquakes and the propagation of elastic waves through the Earth
* Most of our knowledge of the Structure of the Earth is derived from seismology
* Shallow seismology is used in exploration geophysics (to find oil and gas) and for environmental characterization of the subsurface
* Geomagnetism, the study of the Earth's magnetic field, including its origin, telluric currents driven by the magnetic field, the Van Allen belts, and the interaction between the magnetosphere and the solar wind. This field is associated with paleomagnetism, or the measurement of the orientation of the Earth's magnetic field over the geologic past.
* Mathematical Geophysics, The development and applications of mathematical methods [2] and techniques for the solution of geophysical problems.[3]
* Geophysical surveying:
* Exploration and engineering geophysics, using surface methods to detect or infer the presence and position of concentrations of ore minerals and hydrocarbons
* Archaeological geophysics, for archaeological imaging or mapping
* Environmental and Engineering Geophysics, for locating underground storage tanks (UST's) or utilities, delineating landfills, locating voids or potential subsidence, finding depth to, P-wave or S-wave velocity of, or rippability of bedrock, or the pathway of groundwater movement
* Geodesy,[1] measurement of the Earth: GPS, vertical and horizontal motions of the Earth's surface, navigation, the study of the Earth's gravitational field, and the size and form of the Earth
* The study of large-scale motions of the Earth's surface and interior, including:
* Tectonophysics, the study of the physical processes that cause and result from plate tectonics
* Geodynamics, the study of modes of transport deformation within the Earth: rock deformation, mantle flow and convection, heat flow, lithosphere dynamics
* Seismology, the study of earthquakes and the propagation of elastic waves through the Earth
* Most of our knowledge of the Structure of the Earth is derived from seismology
* Shallow seismology is used in exploration geophysics (to find oil and gas) and for environmental characterization of the subsurface
* Geomagnetism, the study of the Earth's magnetic field, including its origin, telluric currents driven by the magnetic field, the Van Allen belts, and the interaction between the magnetosphere and the solar wind. This field is associated with paleomagnetism, or the measurement of the orientation of the Earth's magnetic field over the geologic past.
* Mathematical Geophysics, The development and applications of mathematical methods [2] and techniques for the solution of geophysical problems.[3]
* Geophysical surveying:
* Exploration and engineering geophysics, using surface methods to detect or infer the presence and position of concentrations of ore minerals and hydrocarbons
* Archaeological geophysics, for archaeological imaging or mapping
* Environmental and Engineering Geophysics, for locating underground storage tanks (UST's) or utilities, delineating landfills, locating voids or potential subsidence, finding depth to, P-wave or S-wave velocity of, or rippability of bedrock, or the pathway of groundwater movement
Geophysics
Geophysics,
a major discipline of the Earth sciences and a subdiscipline of physics, is the study of the whole Earth by the quantitative observation of its physical properties. Geophysical data are used in academics to observe tectonic plate motions, study the internal structure of the Earth, supplement data provided by geologic maps, and to nondestructively observe shallow deposits. Geophysical survey data are used to analyze potential petroleum reservoirs and mineral deposits, to locate groundwater, to locate archaeological finds, to find the thicknesses of glaciers and soils, and for environmental remediation. The theories and techniques of geophysics are employed extensively in the planetary sciences in general.
a major discipline of the Earth sciences and a subdiscipline of physics, is the study of the whole Earth by the quantitative observation of its physical properties. Geophysical data are used in academics to observe tectonic plate motions, study the internal structure of the Earth, supplement data provided by geologic maps, and to nondestructively observe shallow deposits. Geophysical survey data are used to analyze potential petroleum reservoirs and mineral deposits, to locate groundwater, to locate archaeological finds, to find the thicknesses of glaciers and soils, and for environmental remediation. The theories and techniques of geophysics are employed extensively in the planetary sciences in general.
Geochemistry
Geochemistry
The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earth's chemical components in time and space, and their interaction with the hydrosphere and the atmosphere.
The most important fields of geochemistry are:
1. Isotope geochemistry:Determination of the relative and absolute concentrations of the elements and their isotopes in the earth and on earth's surface.
2. Examination of the distribution and movements of elements in different parts of the earth (crust, mantle, hydrosphere etc.) and in minerals with the goal to determine the underlying system of distribution and movement.
3. Cosmochemistry: Analysis of the distribution of elements and their isotopes in the cosmos.
4. Biogeochemistry: Field of study focusing on the effect of life on the chemistry of the earth.
5. Organic geochemistry: A study of the role of processes and compounds that are derived from living or once-living organisms.
6. Regional, environmental and exploration geochemistry: Applications to environmental, hydrological and mineral exploration studies.
Victor Goldschmidt is considered by most to be the father of modern geochemistry and the ideas of the subject were formed by him in a series of publications from 1922 under the title ‘Geochemische Verteilungsgesetze der Elemente’.
The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earth's chemical components in time and space, and their interaction with the hydrosphere and the atmosphere.
The most important fields of geochemistry are:
1. Isotope geochemistry:Determination of the relative and absolute concentrations of the elements and their isotopes in the earth and on earth's surface.
2. Examination of the distribution and movements of elements in different parts of the earth (crust, mantle, hydrosphere etc.) and in minerals with the goal to determine the underlying system of distribution and movement.
3. Cosmochemistry: Analysis of the distribution of elements and their isotopes in the cosmos.
4. Biogeochemistry: Field of study focusing on the effect of life on the chemistry of the earth.
5. Organic geochemistry: A study of the role of processes and compounds that are derived from living or once-living organisms.
6. Regional, environmental and exploration geochemistry: Applications to environmental, hydrological and mineral exploration studies.
Victor Goldschmidt is considered by most to be the father of modern geochemistry and the ideas of the subject were formed by him in a series of publications from 1922 under the title ‘Geochemische Verteilungsgesetze der Elemente’.
Further Branches Of Petrology
Branches
There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary, and another dealing with experimental techniques:
* Igneous petrology focuses on the composition and texture of igneous rocks (rocks such as granite or basalt which have crystallized from molten rock or magma). Igneous rocks include volcanic and plutonic rocks.
* Sedimentary petrology focuses on the composition and texture of sedimentary rocks (rocks such as sandstone, shale, or limestone which consist of pieces or particles derived from other rocks or biological or chemical deposits, and are usually bound together in a matrix of finer material).
* Metamorphic petrology focuses on the composition and texture of metamorphic rocks (rocks such as slate, marble, gneiss, or schist which started out as sedimentary or igneous rocks but which have undergone chemical, mineralogical or textural changes due to extremes of pressure, temperature or both)
* Experimental petrology employs high-pressure, high-temperature apparatus to investigate the geochemistry and phase relations of natural or synthetic materials at elevated pressures and temperatures. Experiments are particularly useful for investigating rocks of the lower crust and upper mantle that rarely survive the journey to the surface in pristine condition. The work of experimental petrologists has laid a foundation on which modern understanding of igneous and metamorphic processes has been built.
There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary, and another dealing with experimental techniques:
* Igneous petrology focuses on the composition and texture of igneous rocks (rocks such as granite or basalt which have crystallized from molten rock or magma). Igneous rocks include volcanic and plutonic rocks.
* Sedimentary petrology focuses on the composition and texture of sedimentary rocks (rocks such as sandstone, shale, or limestone which consist of pieces or particles derived from other rocks or biological or chemical deposits, and are usually bound together in a matrix of finer material).
* Metamorphic petrology focuses on the composition and texture of metamorphic rocks (rocks such as slate, marble, gneiss, or schist which started out as sedimentary or igneous rocks but which have undergone chemical, mineralogical or textural changes due to extremes of pressure, temperature or both)
* Experimental petrology employs high-pressure, high-temperature apparatus to investigate the geochemistry and phase relations of natural or synthetic materials at elevated pressures and temperatures. Experiments are particularly useful for investigating rocks of the lower crust and upper mantle that rarely survive the journey to the surface in pristine condition. The work of experimental petrologists has laid a foundation on which modern understanding of igneous and metamorphic processes has been built.
Branch Of Geology
Petrology (from Greek: πέτρα, petra, rock; and λόγος, logos, knowledge) is the branch of geology that studies rocks, and the conditions in which rocks form.
Lithology once was approximately synonymous with petrography, but in current usage, lithology is a subdivision of petrology focusing on macroscopic hand-sample or outcrop-scale description of rocks, while petrography is the speciality that deals with microscopic details.
In the oil industry, lithology, or more specifically mud logging, is the graphic representation of geological formations being drilled through, and drawn on a log called a mud log. As the cuttings are circulated out of the borehole they are sampled, examined (typically under a 10x microscope) and tested chemically when needed.
Lithology once was approximately synonymous with petrography, but in current usage, lithology is a subdivision of petrology focusing on macroscopic hand-sample or outcrop-scale description of rocks, while petrography is the speciality that deals with microscopic details.
In the oil industry, lithology, or more specifically mud logging, is the graphic representation of geological formations being drilled through, and drawn on a log called a mud log. As the cuttings are circulated out of the borehole they are sampled, examined (typically under a 10x microscope) and tested chemically when needed.
Geology Introduction
Geology (from the Greek γῆ, gê, "earth" and λόγος, logos, "speech") is the science and study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, structure, physical properties, dynamics, and history of Earth materials, and the processes by which they are formed, moved, and changed. The field is a major academic discipline, and is also important for mineral and hydrocarbon extraction, knowledge about and mitigation of natural hazards, some engineering fields, and understanding past climates and environment.
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