Earth Science, Geologic Time & Fossils, HOW-KIR
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
Cloud formation, a key part of the water cycle, begins as moist air ascends into the atmosphere. This occurs because,......
Scientists are still debating how tectonic plates move, but most of experts believe that the movement of plates......
Fog is a cloud of small water droplets near ground level. It is formed by the condensation of water vapor on tiny......
People and all other known forms of life inhabit one very old planet. In numerical terms, the best estimate of......
Earth’s creation is a fascinating tale of interstellar material coming together to form the planet we now call......
The short answer is the hard work of the Colorado River, but the real answer is more complex. About six million......
Aleš Hrdlička was a physical anthropologist known for his studies of Neanderthal man and his theory of the migration......
Marion King Hubbert was an American geophysicist and geologist known for his theory of the migration of fluids......
Alexander von Humboldt was a German naturalist and explorer who was a major figure in the classical period of physical......
humic acid, one of two classes of natural acidic organic polymer that can be extracted from humus found in soil,......
humid continental climate, major climate type of the Köppen classification that exhibits large seasonal temperature......
humid subtropical climate, major climate type of the Köppen classification characterized by relatively high temperatures......
humidity, the amount of water vapour in the air. It is the most variable characteristic of the atmosphere and constitutes......
William Jackson Humphreys was an American atmospheric physicist who applied basic physical laws to explain the......
humus, nonliving, finely divided organic matter in soil, derived from microbial decomposition of plant and animal......
Ellsworth Huntington was a U.S. geographer who explored the influence of climate on civilization. An instructor......
Huronian System, major division of Precambrian rocks in North America (the Precambrian began about 3.8 billion......
Several scales of tropical cyclone intensity have been developed, one of the first being the Saffir-Simpson hurricane......
James Hutton was a Scottish geologist, chemist, naturalist, and originator of one of the fundamental principles......
Thomas Henry Huxley was an English biologist, educator, and advocate of agnosticism (he coined the word). Huxley’s......
Hyaenodon, extinct genus of carnivorous mammals that first appeared in the fossil record about 42 million years......
Alpheus Hyatt was an American zoologist and paleontologist who achieved eminence in the study of invertebrate fossil......
hydraulic equivalence, size–density relationship that governs the deposition of mineral particles from flowing......
hydrologic sciences, the fields of study concerned with the waters of Earth. Included are the sciences of hydrology,......
- Introduction
- Interception, Precipitation, Runoff
- Groundwater, Aquifers, Recharge
- Catchment Hydrology, Modeling, Simulation
- Lakes, Ecology, Limnology
- Lakes, Water Quality, Ecology
- Ocean Circulation, Water Cycle, Marine Ecosystems
- Glaciology, Hydrology, Geomorphology
- Water Management, Conservation, Floods
- Droughts, Climatic Patterns, Water Cycle
hydrology, scientific discipline concerned with the waters of the Earth, including their occurrence, distribution,......
hydrometeor, any water or ice particles that have formed in the atmosphere or at the Earth’s surface as a result......
hydrometeorology, branch of meteorology that deals with problems involving the hydrologic cycle, the water budget,......
hydrosphere, discontinuous layer of water at or near Earth’s surface. It includes all liquid and frozen surface......
- Introduction
- Biogeochemical, Water Cycle, Oceans
- Rivers, Oceans, Waters
- Congruent, Incongruent, Weathering
- Lakes, Water Cycle, Ecosystems
- Groundwater, Aquifers, Recharge
- Water Cycle, Oceans, Atmosphere
- Cycle, Evaporation, Precipitation
- Precipitation, Distribution, Water Cycle
- Water Cycle, Oceans, Atmosphere
- Water Cycle, Oceans, Atmosphere
- Sodium Imbalance, Water Cycle, Oceans
- Pollution, Climate Change, Conservation
- Greenhouse Gases, Climate Change, Oceans
hydroxylapatite, phosphate mineral, calcium hydroxide phosphate [Ca5(PO4)3OH], that forms glassy, often green crystals......
hygrometer, instrument used in meteorological science to measure the humidity, or amount of water vapour in the......
hypsometric curve, cumulative height frequency curve for the Earth’s surface or some part thereof. A hypsometric......
hälleflinta, (Swedish: “rock flint”), white, gray, yellow, greenish, or pink fine-grained rock that consists of......
hübnerite, manganese-rich variety of the mineral wolframite...
Icadyptes, genus of extinct giant penguin that lived about 37 million to 35 million years ago, during the second......
ice age, any geologic period during which thick ice sheets cover vast areas of land. Such periods of large-scale......
ice formation, any mass of ice that occurs on the Earth’s continents or surface waters. Such masses form wherever......
ice shelf, thick mass of floating ice that is attached to land, formed from and fed by tongues of glaciers extending......
Icelandic low, large persistent atmospheric low-pressure centre that forms between Iceland and southern Greenland.......
Ichthyornis, (order Ichthyornithiformes), extinct seabird of the Late Cretaceous Period (99.6 million to 66 million......
ichthyosaur, any member of an extinct group of aquatic reptiles, most of which were very similar to porpoises in......
Ichthyostega, genus of extinct animals, closely related to tetrapods (four-legged land vertebrates) and found as......
Ida, (Darwinius masillae), nickname for the remarkably complete but nearly two-dimensional skeleton of an adapiform......
Joseph Paxson Iddings was an American geologist who demonstrated the genetic relationships of neighbouring igneous......
Muḥammad al-Idrīsī was an Arab geographer and adviser to Roger II, the Norman king of Sicily. He wrote one of the......
Muḥammad al-Idrīsī was an Arab geographer and adviser to Roger II, the Norman king of Sicily. He wrote one of the......
igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth......
- Introduction
- Minerals, Magma, Crystals
- Granular, Magma, Crystals
- Intrusive, Extrusive, Textures
- Clastic Structures
- Plutonic, Classification, Rocks
- Volcanic, Hypabyssal, Classification
- Magma Types, Formation, Composition
- Albite, Anorthite, System
- Assimilation, Magma, Crystallization
- Intrusive, Magma, Plutonic
- Convergent Plate, Magma, Intrusive
ijolite, intrusive igneous rock that is composed essentially of nepheline and an alkali pyroxene, usually aegirine-augite.......
illuviation, Accumulation of dissolved or suspended soil materials in one area or layer as a result of leaching......
Ilmarinen, one of the chief deities in Finno-Ugric religion, functioning both as creator deity and as weather god.......
impact structure, remains of an ancient meteorite impact on Earth’s surface, generally in the form of a circular......
Inceptisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Inceptisols are soils of relatively new origin......
index fossil, any animal or plant preserved in the rock record of the Earth that is characteristic of a particular......
Indricotherium, genus of giant browsing perissodactyls found as fossils in Asian deposits of the Late Oligocene......
induration, hardening of rocks by heat or baking; also the hardening of sediments through cementation or compaction,......
inosilicate, any of a class of inorganic compounds that have structures characterized by silicate tetrahedrons......
Institut Géographique National (IGN), one of the foremost centres of mapmaking and geographic research in France,......
internal wave, a type of gravity wave that occurs on internal “surfaces” within ocean waters. These surfaces represent......
International Council for the Exploration of the Sea (ICES), international organization that promotes marine research......
International Geographical Union (IGU), international body of geographers, founded in 1922, with a membership representing......
International Geophysical Year (IGY), worldwide program of geophysical research that was conducted from July 1957......
intrusive rock, igneous rock formed from magma forced into older rocks at depths within the Earth’s crust, which......
inyoite, a colourless and transparent borate mineral (CaB3O3(OH)5·4H2O) that occurs as massive granular or sperulitic......
ionosphere and magnetosphere, regions of Earth’s atmosphere in which the number of electrically charged particles—ions......
iridescence, interference of light either at the surface or in the interior of a material that produces a series......
iridosmine, mineral consisting of an alloy of iridium and a smaller proportion of osmium. It occurs in gold-bearing......
Irish elk, (Megaloceros giganteus), extinct species of deer, characterized by immense body size and wide antlers,......
iron (Fe), chemical element, metal of Group 8 (VIIIb) of the periodic table, the most-used and cheapest metal.......
Columbus O’D. Iselin was an American oceanographer who, as director of the Woods Hole Oceanographic Institution......
island arc, long, curved chain of oceanic islands associated with intense volcanic and seismic activity and orogenic......
isostasy, ideal theoretical balance of all large portions of Earth’s lithosphere as though they were floating on......
Isotelus, genus of trilobites (extinct arthropods) restricted to Europe and North America during the Ordovician......
Charles Thomas Jackson was an American physician, chemist, and pioneer geologist and mineralogist. Jackson received......
Japan earthquake and tsunami of 2011, severe natural disaster that occurred in northeastern Japan on March 11,......
jet stream, a region of long, narrow, high-speed winds that typically flow northeastward, eastward, and southeastward......
John Day Fossil Beds National Monument, series of rock formations in north-central Oregon, U.S., consisting of......
joint, in geology, a brittle-fracture surface in rocks along which little or no displacement has occurred. Present......
John Joly was an Irish geologist and physicist who, soon after 1898, estimated the age of the Earth at 100,000,000......
Brian Jones is a British aviator who on March 20, 1999, with captain Bertrand Piccard, completed the first nonstop......
Jurassic Period, second of three periods of the Mesozoic Era. Extending from 201.3 million to 145 million years......
Kabwe cranium, fossilized skull of an extinct human species (genus Homo) found near the town of Kabwe, Zambia (formerly......
Kahramanmaraş earthquake of 2023, an earthquake and a severe aftershock that struck near the border separating......
kainite, a naturally occurring double salt, hydrated potassium and magnesium sulfate-chloride, KMgSO4Cl·3H2O. It......
kamacite, mineral consisting of iron alloyed with 5–7 percent nickel by weight and found in almost all meteorites......
kaolin, soft white clay that is an essential ingredient in the manufacture of china and porcelain and is widely......
kaolisol, soil that is formed under the heat and heavy rainfall of the tropics, which leaches out the silica and......
Kashmir earthquake of 2005, disastrous earthquake that occurred on October 8, 2005, in the Pakistan-administered......
Kastanozem, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO).......
Heinrich Kayser was a German physicist who discovered the presence of helium in the Earth’s atmosphere. Kayser’s......
Kebara, paleoanthropological site on Mount Carmel in northern Israel that has yielded a trove of Neanderthal bones......
Keeling Curve, graph showing seasonal and annual changes in atmospheric carbon dioxide (CO2) concentrations since......
William Thomson, Baron Kelvin was a Scottish engineer, mathematician, and physicist who profoundly influenced the......
kernite, borate mineral, hydrated sodium borate (Na2B4O7·4H2O), that was formerly the chief source of borax (q.v.).......
Keweenawan System, division of late Precambrian rocks and time in North America (the Precambrian began about 4.6......
Robert Kidston was an English paleobotanist, noted for his discoveries and descriptions of plant fossils from the......
kieserite, a sulfate mineral, hydrated magnesium sulfate (MgSO4·H2O), that is abundant in evaporite deposits. It......
kimberlite, a dark-coloured, heavy, often altered and brecciated (fragmented), intrusive igneous rock that contains......
kimberlite eruption, small but powerful volcanic eruption caused by the rapid ascent of kimberlites—a type of intrusive......
Clarence King was an American geologist and mining engineer who organized and directed the U.S. Geological Survey......
Athanasius Kircher was a Jesuit priest and scholar, sometimes called the last Renaissance man, important for his......
Richard Kirwan was an Irish chemist known for his contributions in several areas of science. Kirwan, who was born......