Earth science

From Citizendium
Revision as of 09:19, 14 April 2007 by imported>Nereo Preto (Introduction)
Jump to navigation Jump to search

Earth science, or geoscience, is 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, expecially in the case of terrestrial planets. As a consequence, the Earth sciences have a strong multidisciplinary character.

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 commonly three ‘spheres’ in the earth sciences. Atmosphere (from the Greek root atmos meaning ‘vapor’ and sphaira, meaning ‘sphere’), lithosphere (Greek - lithos rock or ‘stone) and hydrosphere (Greek – hydros, meaning ‘water’) corresponding, respectively, to the gas, the solid ground and the water of the earth. There are other ‘spheres’ as well. The pedosphere (Greek pedon or ‘soil’) refers to the outerlayer of the lithosphere. It interacts directly with the atmosphere and the hydrosphere. The study of the glaciology, involves the glacial layer or cryosphere (Greek root kryos, frost or ice)[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

For more information, see: 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 ore deposits.

Engineering geology

the study of the geological characteristics of sites where engineering operations are going to be carried out.

Environmental geology/geosciences

the study of how geological processes affect the environment.

Exploration geology

the search for new mineral deposits.

Field Geology

Geochemistry

the study of the chemistry of the Earth.

Geochronology

the study of dating geological events.

Gemmology

the study of gemstones.

Geological Heritage

The study of conservation of geologically important sites.

Geomagnetism

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 impact of study 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]

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.

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 how waves move through the Earth, including earthquakes.

Structural geology

the study of geological structures.

Tectonics/Structural geology

the study of the major structural features of the Earth or the broad structure of a region.

Soil science

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

[18][19][20][21]

Atmospheric sciences

Meteorology

Climatology

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

  1. Woodhouse's English-Greek Dictionary The University of Chicago Library. pp 944, 801, 719, 967, 791, 347
  2. See for example Branches of geoscience Australian Museum of Geosciences
  3. What is geoscience? Australian Museum of Geosciences
  4. Planetary geology Manual of Remote Sensing. Department of Astronomy, Cornell University
  5. “Astrogeology” Encyclopedia Britannica
  6. Center for Earth and Planetary Studies National Air and Space Museum, Smithsonian
  7. What is Fluvial Geomorphology? Field Geology Services
  8. 8.0 8.1 8.2 8.3 The Paleogeographic Method Christopher R. Scotese, University of Texas, Arlington
  9. Holocene palaeogeographic development of the Rhine-Meuse delta Faculty of Geosciences, Dept. of Physical Geography, University of Utrecht, Netherlands
  10. University of Georgia Stratigraphy Lab
  11. USC Sequence Stratigraphy Web University of South Carolina, Dept. of Geology
  12. A numerical model of sediment-laden turbulent flow in an open channel National Research Council Canada
  13. Schlumberger Oilfield Glossary
  14. Glossary of meteorology American Meteorlogical Society
  15. http://aslo.org/education/limnology.html What is Limnology?] Robert G. Wetzel, University of North Carolina. Advancing the Science of Limnology and Oceanography (ASLO)
  16. American Institute of Hydrology
  17. British Hydrological Society
  18. International Glossary of hydrology
  19. Water resources of the United States USGA
  20. Swiss Federal Institute of Aquatic Science and Technology
  21. 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
  22. Spelling of ‘paleo-‘ is commonly ‘palaeo-‘ in Common Wealth countries, e.g. Australia, the UK, etc.

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