Earth science
Earth science, or geoscience, is primarily the study of planet Earth. More specifically, 'Earth sciences' refers to those sciences that deal with the study of the Earth, its components and processes. Earth science includes those fields that study the firmament (the lithosphere or ground that makes up the land and the ocean floor), the waters (the hydrosphere which includes the oceans, the seas, rivers, lakes and so forth), and the atmosphere itself, the air around us. The study of other planet's atmospheres and lithospheres is often considered part of the Earth sciences, especially in the case of terrestrial planets. As a consequence, the Earth sciences have a strong multidisciplinary character.
Earth science also can encompass and is related to those disciplines that study the same topics on extra-terrestrial bodies such as the moon, the planets and asteroids.
Each aspect of these domains may be divided even further into separate but interrelated disciplines of study. Geology, which encompasses the lithosphere, includes vulcanology (the study of volcanoes), hydrology (the study of water through the atmosphere, surface, subsurface and oceans), mineralogy (the study of the composition of the geosphere, specifically the mineral composition of the geosphere), and geomorphology (the study of the forces that shape the geosphere and their different forms).
"Spheres" of study
There are three main ‘spheres’ of study in the earth sciences:
- atmosphere (from the Greek root atmos meaning 'vapor' and sphaira, meaning 'sphere'),
- lithosphere (Greek - lithos rock or 'stone'),
- hydrosphere (Greek – hydros, meaning 'water') correspond, respectively, to the gas, the solid ground, and the water of the earth.
There are other ‘spheres’ but these are subdivisions of the main ones. The pedosphere (Greek pedon or ‘soil’) refers to the outer layer of the lithosphere. It interacts directly with the atmosphere and the hydrosphere. The cryosphere (Greek root kryos, frost or ice) is the glacial layer, its study is called glaciology.[1]
Disciplines and sub-disciplines
There are a large number of subdisciplines and related disciplines that involve overlapping fields of study[2]. A perusal of university majors and journal topics demonstrates a fundamental characteristic of earth science: Although the geosciences are basically about the non-living aspects of the earth,[3] the interaction non-living and living organisms, past and present, is also a very large area of study within earth sciences.
Geology
Astrogeology
As the study of the geology of other planets and extraterrestrial materials, it is concerned with the geology (the surface as well as interior processes) of all solid bodies in the solar system, including the major planets and their satellites, asteroids, comets, and meteorites.[4][5] Astrogeology is synonymous with ‘exogeology’ and ‘planetary geology.’ Astrogeology utilises geological studies on Earth and incorporates remote sensing of planetary bodies (e.g. telescopy) to study such geological process as volcanism, floods, cratering, tectonics, and sand movement.[6]
Crystallography and mineralogy
The study of crystals and minerals.
Economic geology
The study of economically valuable mineral and ore deposits.
Engineering geology
The study of the geological characteristics of sites where engineering operations are going to be carried out.
Environmental geology
The study of how geological processes affect environmental conditions.
Exploration geology
the search for new mineral deposits.
Field geology
Geochemistry
The study of the impact of chemical reactions on geologic features.
Geochronology
The study of dating geological events. Events encompass such things as volcanic activity, seismic activity (earthquakes), flooding, drought, heavy rainfall, erosion, changes in the courses of rivers and the boundaries of bodies of water, meteor impacts, glaciation, extinctions, other catastrophic events such as major fires, proliferation of specific life forms (e.g. the Cambrian explosion), changes in the magnetic orientation of the earth, and changes in the atmosphere and climate. Researchers in the field employ methods that provide dates such as measuring the evidence left from radioactive decay, primarily the ratios of uranium, lead and thorium.
Gemology
the study of gemstones.
Geological heritage
The study of conservation of geologically important sites.
Geomagnetism
The study of changes in the magnetic orientation of the earth.
Geomorphology
The study of landforms. Fluvial geomorphology, for example, studies how human use impacts natural settings in a watershed and determines the shape of river channels. Fluvial geomorphology attempts to predict what physical changes will occur to a water channel in response to alterations in watershed conditions; and how changes will impact human infrastructure and fish habitat.[7]
Geophysics
The study of the physical properties of the Earth.
Glaciology
The study of glaciers, their formation, movement and environmental impact
Hydrogeology
the study of the movement of water through the Earth.
Mining geology
the study of the geology of a mine site.
Petroleum geology and coal geology
The study of ancient organic deposits (fossil fuels).
Physical geography
A field within geography which studies patterns and processes of the hydrosphere, biosphere, atmosphere, and lithosphere to understand the physical topography and weather and the global patterns of life on Earth. An inter-related discipline, it draws upon geology, ecology, and climatology particularly with regard to the study of the impact of weathering and erosion. Physical geography is usually contrasted with and complemented by its sister science human geography.
Paleogeography and paleogeology
Paleogeography is the study of the earth’s surface in the distant past. “The study of paleogeography has two principle goals. The first goal is to map the past positions of the continents. The second goal is to illustrate the changing distribution of mountains, lowlands, shallow seas, and deep ocean basins through time.” [8]
Paleogeology is the study of geologic conditions in the past which are manifest in the features of subterranean layers. Both employ analyses of long cylinders of bored rock or cores drilled from the earth which are charted and subjected to analytic comparisons.[9]
Paleomagnetism
Paleomagnetism studies magnetic fields of the Earth in the past. Paleomagnetism measures the remnant magnetic field often preserved in iron-bearing rock formations. Paleomagnetic analysis can determine whether a rock was magnetized near the Pole or near the Equator and provides direct evidence of a continent's N-S (latitudinal) position, but not the E-W (longitudinal) position. [8]
By reconstructing the positional drift of masses of bedrock, geologists have been able to determine that the the Earth's magnetic field has reversed polarity several times in the last 3 billion years.
Petrology
the study of rocks (igneous, metamorphic and sedimentary)
Sedimentary geology
Sedimentary geology encompasses the subdisciplines of sedimentology & stratigraphy. The field addresses all aspects of research into sediments and sedimentation processes at all spatial and temporal scales, sedimentary systems and basin analysis, subsurface analysis of sedimentary sequences, diagenesis (processes involving biological, physical and chemical changes in sediment which may then culminate in lithification), chemical sedimentology and numerical modelling (analysis of stratification facies).
Sedimentology is the study of the production, composition, transport, and deposition of sediment.
Stratigraphy is the study of existing layers or rocks and minerals and the process of layering (stratification). The primary focuses are the process of sedimentation encompassing such dynamics as changes in sea level, tectonic activity, and climatic effects on the production of sediment (e.g. particulates carried in water runoff due to flooding) and material sequentially layered through volcanic activity. (see Geologic ages of earth history)
There are other subfields as well. Lithostratigraphy is the study of strata to determine the history of geological processes and events through lithology, using well logs, mineral composition and quantity, grain size, texture and color. Chronostratigraphy is the study of the ages of strata through comparison, and correlation of separated strata to elucidate their relative and absolute ages. The interdisciplinary biologic stratigraphy (or biostratigraphy), employs the analysis of plant and animal fossils using principles of paleontology and stratigraphy to date and correlate strata using evidence as may be presented by such organisms as pollen and spores, marine microfossils (e.g. diatoms, foraminifera, and nannofossils) to determine the absolute and relative age and the environment that existed during deposition of a particular formation.[10][11][12][13][14]
Seismology
The study of earthquakes and wave propagation through the earth.
Structural geology
The study of geological structures.
Tectonics
Structural geology on a continental scale, primarily concerned with the movement of crustal plates.
Soil science
The study of properties of soils from
Vulcanology
the study of volcanoes.
Oceanography
The study of the earth’s oceans.
Limnology
The branch of hydrology that pertains to the study of fresh water bodies: lakes, ponds, and streams, reservoirs, rivers, wetlands, and groundwater. Limnology also encompasses salt water in-land lakes. Limnology is derived from the Greek word limne - 'marsh' or 'pond' and the Latin limnaea – 'thing pertaining to a marsh'.
Integrating physical, chemical, and biological components, limnology studies the biogeochemical changes of standing (lentic) water ecosystems: their interactions within and water movement through drainage basins and their exchanges with the atmosphere. Inland water ecosystems are an integral component of a system that encompasses drainage area and atmosphere, running (lotic) waters and ground waters, chemical changes and interactions that occur en route, and includes components of the land being transported to the water.[15]
Hydrology
The interdisciplinary study of the movement, characteristics and distribution of water, surface-water (fresh water and salt water), groundwater, and water-quality [16][17] Subdisciplines include:
- Chemical hydrology: the study of the chemical characteristics of water. Also called hydrochemistry, chemical hydrology deals with the chemical characteristics of the surface water (freshwater and marine) and subterranean water. Water is a chemical solvent and, interacting chemically with materials with which it comes into contact, can dissolve many elements.
- Drainage basin management hydrology.
- Ecohydrology (the study of interactions between organisms and the hydrologic cycle.
- Engineering Hydrology
- Global hydrology
- Groundwater Hydrology
- Hydrobiology
- Hydrogeology is the study of the presence and movement of water in aquifers.
- Hydroinformatics is the adaptation of information technology to hydrology and water resources applications.
- Hydrometeorology is the study of the transfer of water and energy between land and water body surfaces and the lower atmosphere.
- Isotope hydrology is the study of the isotopic signatures of water.
- Operational Hydrology
- Qualitative Hydrology
- Sedimentology
- Surface hydrology is the study of hydrologic processes that operate at or near the Earth's surface.
- Water resources development and management
Atmospheric sciences
Meteorology
The study of the weather - the day to day movements of air masses and airborne water.
Climatology
The study of the climate - the long-term patterns in the weather and changes therein.
See also effect of sun angle on climate.
Paleoclimatology
Paleoclimatology[22] is the study of ancient climates. Different types of rock and minerals form under specific climatic conditions: wet and dry, warm and cool. This is also true of ancient life forms whose presence may be determined from the fossil record. As the earth’s surface changes climatically and continents move tectonically, the amount of sunlight will vary and effect conditions on the surface, leading to changes which then become buried in the strata. Coal deposits develop under wet conditions, bauxite deposits are evident where it was warm and wet, evaporites and calcretes occur under warm and dry conditions, and tillites where it was wet and cool. The ancient distribution of different rock types provide evidence of how the global climate has changed through time and how the continents have travelled across climatic belts. [8]
Interdisciplinary divisions
Geoarcheology
Geomicrobiology
Studies microbes and their interactions in geologic systems
Paleobiogeography
Paleobiogeography studies microbial fossils and their interactions in geologic systems. The distribution of plants and animals in the ancient past helps reveal the latitudinal and relative position of the continents. Ancient plant organisms reflect temperature and rainfall in the distant past. The similarity or dissimilarity of life on different continents can be used to estimate their geographic proximity and may reveal when these continents were connected or isolated from each other. [8]
Paleobotany
the study of ancient plant life. Paleontology may be divided further into vertebrate, invertebrate and micropaleontology
Paleoecology
the study of ancient environments.
Paleontology
the study of ancient life forms.
Palynology
the study of ancient spores and pollens.
References
- ↑ Woodhouse's English-Greek Dictionary The University of Chicago Library. pp 944, 801, 719, 967, 791, 347
- ↑ See for example Branches of geoscience Australian Museum of Geosciences
- ↑ What is geoscience? Australian Museum of Geosciences
- ↑ Planetary geology Manual of Remote Sensing. Department of Astronomy, Cornell University
- ↑ “Astrogeology” Encyclopedia Britannica
- ↑ Center for Earth and Planetary Studies National Air and Space Museum, Smithsonian
- ↑ What is Fluvial Geomorphology? Field Geology Services
- ↑ 8.0 8.1 8.2 8.3 The Paleogeographic Method Christopher R. Scotese, University of Texas, Arlington
- ↑ Holocene palaeogeographic development of the Rhine-Meuse delta Faculty of Geosciences, Dept. of Physical Geography, University of Utrecht, Netherlands
- ↑ University of Georgia Stratigraphy Lab
- ↑ USC Sequence Stratigraphy Web University of South Carolina, Dept. of Geology
- ↑ A numerical model of sediment-laden turbulent flow in an open channel National Research Council Canada
- ↑ Schlumberger Oilfield Glossary
- ↑ Glossary of meteorology American Meteorlogical Society
- ↑ http://aslo.org/education/limnology.html What is Limnology?] Robert G. Wetzel, University of North Carolina. Advancing the Science of Limnology and Oceanography (ASLO)
- ↑ American Institute of Hydrology
- ↑ British Hydrological Society
- ↑ International Glossary of hydrology
- ↑ Water resources of the United States USGA
- ↑ Swiss Federal Institute of Aquatic Science and Technology
- ↑ Virtual campus in hydrology and water resources management A cooperative of Institute of Soil and Water resources Management (Hydrology and Land Improvement Laboratory) EPFL, Lausanne, Switzerland; Technical University of Civil Engineering Bucharest, Romania (TUCEB); University Timisoara, Faculty of Hydrotechnics, Romania; Technical University "Gheorghe Asachi" of Iasi (T.U.I.), Romania; Sophia University "St Kliment Ohridski", Geology and Geography Faculty ; National Institute of Meteorology and Hydrology ; Institute of Water Problems, Bulgaria; Kharkiv State Technical University of Civil Engineering and Architecture (KSTUCA), Ukrainia; Ukrainian Scientific Research Institute of Ecological Problems (USRIEP), Ukrainia; Technical University of Moldova, Faculty of Urban Engineering and Architecture, Chisinau, Moldova
- ↑ Spelling of ‘paleo-‘ is commonly ‘palaeo-‘ in Common Wealth countries, e.g. Australia, the UK, etc.
Interdisciplinary Links in Citizendium
- Stage (geology)
- Age (geology)
- Geologic ages of earth history
- Chronostratigraphy
- Geochronology
- Geochronometry
Resources
- Australian Museum of Geosciences [1]
- Geoscience Information Society [2]
- American Geological Institute [3]
- Geological Society of New Zealand [4]
- University of Missouri-Kansas City, Geoscience Department [5]
- Kansas University Geology Department [6]
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian [7]
- United States Geological Services (USGS) Gazetteer of Planetary Nomenclature [8]
- Minerology Database [9] contains 4,442 individual mineral species descriptions with links and a comprehensive image library.
- Minerology Database [10] localities, photos and data
- Links for Minerologists Introduction to Crystallography Institute of Mineralogy, University of Würzburg,
- University of Texas, Austin Paleomap Project
- Division of Earth Sciences National Science Academies Press. Retrieved 17 April, 2007