Earth Science, Geologic Time & Fossils, TRO-WüS
Planet Earth has billions of years of history, from the time when it was an inhospitable ball of hot magma to when its surface stabilized into a variety of diverse zones capable of supporting many life-forms. Many are the species that lived through the various geologic eras and left a trace of their existence in the fossils that we study today. But Earth is never done settling, as we can see from the earthquakes, tsunamis, volcanic eruptions, and other phenomena manifested in Earth’s crust, oceans, and atmosphere.
Earth Science, Geologic Time & Fossils Encyclopedia Articles By Title
trona, an evaporite mineral, hydrated sodium bicarbonate [Na3H(CO3)2·2H2O], occasionally encountered as a saline......
tropical and subtropical desert climate, major climate type of the Köppen classification dominated in all months......
tropical and subtropical steppe climate, major climate type of the Köppen classification that occurs primarily......
tropical cyclone, an intense circular storm that originates over warm tropical oceans and is characterized by low......
tropical monsoon and trade-wind littoral climate, major climate type of the Köppen classification characterized......
tropical storm, organized centre of low pressure that originates over warm tropical oceans. The maximum sustained......
tropical wet-dry climate, major climate type of the Köppen classification characterized by distinct wet and dry......
Tropidoleptus, genus of extinct brachiopods (lamp shells) found as fossils only in marine rocks of the Devonian......
Tropites, genus of extinct cephalopods (animals similar to the modern squid and octopus but with an external shell)......
troposphere, lowest region of the atmosphere, bounded by the Earth beneath and the stratosphere above, with its......
tsunami, catastrophic ocean wave, usually caused by a submarine earthquake, an underwater or coastal landslide,......
tuff, a relatively soft, porous rock that is usually formed by the compaction and cementation of volcanic ash or......
tundra climate, major climate type of the Köppen classification characterized by sub-freezing mean annual temperatures,......
turquoise, hydrated copper and aluminum phosphate [CuAl6(PO4)4(OH)8·4H2O] that is extensively used as a gemstone.......
William Henry Twenhofel was a geologist noted for his investigations of sedimentation processes. He taught at the......
twilight glow, weak, widespread, and relatively steady glow from the sky that is observed around twilight; it is......
John Tyndall was an Irish experimental physicist who, during his long residence in England, was an avid promoter......
tyuyamunite, radioactive, yellow, soft, and waxy uranium and vanadium oxide mineral, Ca(UO2)2(VO4)2·5–8H2O. It......
Alfred Elis Törnebohm was a Swedish geologist and pioneer in the study and analysis of mountain structure. In 1888,......
Uintatherium, extinct genus of large, hoofed mammals found as fossils in North America and Asia in terrestrial......
ulexite, borate mineral, NaCaB5O6(ΟH)6·5H2O, that consists of hydrated sodium and calcium borate. Individual crystals......
Ultisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Ultisols are reddish, clay-rich, acidic soils that......
umangite, a copper selenide (Cu3Se2) occurring only in small grains or fine granular aggregates with other copper......
Umbrisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO).......
undertow, a strong seaward bottom current returning the water of broken waves back out to sea. There is in fact......
Ungava-Quebec Crater, geologically young crater, produced by an impact event involving a meteorite, located in......
uniformitarianism, in geology, the doctrine suggesting that Earth’s geologic processes acted in the same manner......
updraft and downdraft, in meteorology, upward-moving and downward-moving air currents, respectively, that are due......
uplift, in geology, an increase in the vertical elevation of Earth’s surface in response to natural causes. Broad,......
urban climate, any set of climatic conditions that prevails in a large metropolitan area and that differs from......
vadose zone, region of aeration above the water table. This zone also includes the capillary fringe above the water......
Van Allen radiation belt, doughnut-shaped zones of highly energetic charged particles trapped at high altitudes......
Van earthquake of 2011, severe earthquake that struck near the cities of Erciş and Van in eastern Turkey on October......
vanadate mineral, any of the many naturally occurring compounds of vanadium (V), oxygen (O), and various metals;......
vanadinite, vanadium mineral in the pyromorphite series of the apatite group of phosphates, lead chloride vanadate,......
Bernhardus Varenius was a major figure in the revival of geographic learning in Europe, whose scholarly general......
variscite, phosphate mineral, hydrated aluminum phosphate (AlPO4·2H2O), which is valued as a semiprecious gemstone......
varved deposit, any form of repetitive sedimentary rock stratification, either bed or lamination, that was deposited......
Venyukovia, genus of extinct mammallike reptiles (therapsids) that are found as fossils in Permian deposits in......
Vertisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO).......
Vertisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Vertisols are clay-rich soils that undergo significant......
vesuvianite, common silicate mineral that occurs in crystalline limestones near their contacts with igneous rocks,......
Paul Vidal de La Blache was a French geographer who had a profound influence on the development of modern geography.......
Vindija, site of paleoanthropological excavations in the Hrvatsko Zagorje region of Croatia, known for Neanderthal......
vivianite, phosphate mineral, hydrated iron phosphate [Fe3(PO4)2·8H2O], that occurs as colourless when freshly......
Johan Herman Lie Vogt was a Norwegian geologist and petrologist who pioneered in the use of physical-chemical methods......
volcanic eruption, an eruption of molten rock, hot rock fragments, and hot gases through a volcano, which is a......
volcanic glass, any glassy rock formed from lava or magma that has a chemical composition close to that of granite......
volcanic winter, cooling at Earth’s surface resulting from the deposition of massive amounts of volcanic ash and......
volcanism, any of various processes and phenomena associated with the surficial discharge of molten rock, pyroclastic......
volcano, vent in the crust of Earth or another planet or satellite, from which issue eruptions of molten rock,......
- Introduction
- Lava, Gas, Hazards
- Ash Falls, Eruptions, Magma
- Secondary Damage, Eruptions, Hazards
- Eruptions, Types, Magma
- Pinatubo, Philippines, 1991
- Hawaii, Mauna Loa, 1984
- Vesuvius, Tambora, Krakatoa, Pelee
- Forecasting, Warning, Monitoring
- Eruptions, Cone, Magma
- Calderas, Magma, Eruptions
- Lava Domes, Magma, Eruptions
- Eruptions, Magma, Structure
- Hot Springs, Geysers, Magma
- Plate Boundaries, Magma, Eruptions
- Rift, Magma, Eruptions
- Magma, Eruptions, Geothermal
volcanology, discipline of the geologic sciences that is concerned with all aspects of volcanic phenomena. Volcanology......
Voltzia, a genus of fossil cone-bearing plants dating to the Early Triassic epoch (beginning 251 million years......
Yrjö Väisälä was a Finnish meteorologist and astronomer noted for developing meteorological measuring methods and......
Wabar Craters, group of meteorite craters discovered in 1932 in the Rubʿ al-Khalī desert of Saudi Arabia. The largest......
Selman Abraham Waksman was a Ukrainian-born American biochemist who was one of the world’s foremost authorities......
water cycle, cycle that involves the continuous circulation of water in the Earth-atmosphere system. Of the many......
water mass, body of ocean water with a distinctive narrow range of temperature and salinity and a particular density......
water table, upper level of an underground surface in which the soil or rocks are permanently saturated with water.......
waterspout, a small-diameter column of rapidly swirling air in contact with a water surface. Waterspouts are almost......
wave, a ridge or swell on the surface of a body of water, normally having a forward motion distinct from the oscillatory......
wavellite, hydrated aluminum phosphate [Al3(PO4)2(OH)3·5H2O], a common phosphate mineral that typically occurs......
weather, state of the atmosphere at a particular place during a short period of time. It involves such atmospheric......
weather bureau, agency established by many countries to observe and report the weather and to issue weather forecasts......
weather forecasting, the prediction of the weather through application of the principles of physics, supplemented......
weather map, any map or chart that shows the meteorological elements at a given time over an extended area. The......
weather modification, the deliberate or the inadvertent alternation of atmospheric conditions by human activity,......
weather satellite, any of a class of Earth satellites designed to monitor meteorological conditions (see Earth...
weathering, disintegration or alteration of rock in its natural or original position at or near the Earth’s surface......
Wedekindellina, genus of fusulinid foraminiferans, an extinct group of protozoans that possessed a hard shell of......
Alfred Wegener was a German meteorologist and geophysicist who formulated the first complete statement of the continental......
Wei Yuan was a historian and geographer of the Qing dynasty (1644–1911/12). Wei was a leader in the Statecraft......
Abraham Gottlob Werner was a German geologist who founded the Neptunist school, which proclaimed the aqueous origin......
West Greenland Current, cool flow of water proceeding northward along the west coast of Greenland. See Greenland...
wet equatorial climate, major climate type of the Köppen classification characterized by consistently high temperatures......
What Causes a Rainbow?, The formation of a rainbow begins with the refraction of sunlight as it enters a raindrop.......
The main contributors to acid rain are sulfur dioxide (SO2) and nitrogen oxides (NOx; the combination of NO and......
Soil erosion, like rock erosion, is caused by the movement of water and wind, and glaciers. Since soil (whether......
whirlpool, rotary oceanic current, a large-scale eddy that is produced by the interaction of rising and falling......
whirlwind, a small-diameter columnar vortex of rapidly swirling air. A broad spectrum of vortices occurs in the......
Light emitted from stars does not actually twinkle but only appears to twinkle when viewed from Earth. As starlight......
The temperature people feel outside is largely based on the absorption of radiant energy from the Sun. Differing......
Wilkins Ice Shelf, a large body of floating ice covering the greater part of Wilkins Sound off the western coast......
willemite, white or greenish yellow silicate mineral, zinc silicate, Zn2SiO4, that is found as crystals, grains,......
J. Tuzo Wilson was a Canadian geologist and geophysicist who established global patterns of faulting and the structure......
wind, in climatology, the movement of air relative to the surface of the Earth. Winds play a significant role in......
wind chill, a measure of the rate of heat loss from skin that is exposed to the air. It is based on the fact that,......
wind shear, rapid change in wind velocity or direction. A very narrow zone of abrupt velocity change is known as......
windstorm, a wind that is strong enough to cause at least light damage to trees and buildings and may or may not......
winter, coldest season of the year, between autumn and spring; the name comes from an old Germanic word that means......
witherite, a carbonate mineral, barium carbonate (BaCO3), that is, with the exception of barite, the most common......
Witwatersrand System, major division of Precambrian rocks in South Africa (the Precambrian began about 3.8 billion......
Wolf Creek Crater, huge meteorite crater 65 miles (105 km) south of Halls Creek, Western Australia. The crater......
wolframite, chief ore of tungsten, commonly associated with tin ore in and around granite. Such occurrences include......
woolly rhinoceros, (genus Coelodonta), either of two extinct species of rhinoceros found in fossil deposits of......
World Meteorological Organization (WMO), specialized agency of the United Nations (UN) created to promote the establishment......
Worthenia, genus of extinct gastropods (snails) preserved as common fossils in rocks of Devonian to Triassic age......
wulfenite, lead molybdate, PbMoO4, a minor source of molybdenum and the second most common molybdenum mineral.......
wurtzite, a zinc sulfide mineral that occurs typically in Potosí, Bolivia; Butte, Mont.; and Goldfield, Nev. It......
Georg Wüst was a German oceanographer who, by collecting and analyzing many systematic observations, developed......