Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Geology J-O
| Question | Answer |
|---|---|
| Joint | A large and relatively planar fracture in a rock across which there is no relative displacement of the two sides. |
| Juvenile gas | Gases that come to the surface for the first time from the deep interior. |
| Kerogen | A mixture of organic substances found in many fine-grained sedimentary rocks and a major constituent of oil shale. |
| Kettle | A small hollow or depression formed in glacial deposits when outwash was deposited around a residual block of ice that later melted. |
| Kilobar | A unit of pressure equal to 1000 bars. |
| Kimberlite | A peridotite containing garnet and olivine and found in volcanic pipes, through which it may come from the upper Mantle. |
| Laccolith | A sill-like igneous intrusion that forces apart two strata and forms a round, lens-shaped body many times wider than it is thick. |
| Lahar | A mudflow of unconsolidated volcanic ash, dust, breccia, and boulders mixed with rain or the water of a lake displaced by a lava flow. |
| Laminar flow | A flow regime in which particle paths are straight or gently curved and parallel. |
| Landslide | The rapid downslope movement of soil and rock material, often lubricated by groundwater, over a basal shear zone; also the tongue of stationary material deposited by such an event. |
| Lapilli | A fragment of volcanic rock formed when magma is ejected into the air by expanding gases. The size of the fragments ranges from sand- to cobble-size. |
| Lateral moraine | A moraine formed along the side of a valley glacier and composed of rock scraped off or fallen from the valley sides. |
| Lava | Magma or molten rock that has reached the surface. |
| Lava tube | A sinuous, hollow tunnel formed when the outside of a lava flow cools and solidifies and the molten material passing through it is drained away. |
| Leaching | The removal of elements from a soil by dissolution in water moving downward in the ground. |
| Left-lateral fault | A strike-slip fault on which the displacement of the far block is to the left when viewed from either side. |
| Levee | A low ridge along a stream bank, formed by deposits left when floodwater decelerates on leaving the channel; also an artificial barrier to floods built in the same form. |
| Limb (fold) | The relatively planar part of a fold or of two adjacent folds (for example, the steeply dipping part of a stratum between an anticline and syncline). |
| Limestone | A sedimentary rock composed principally of calcium carbonate (CaCO2), usually as the mineral calcite. |
| Lineation | Any linear arrangement of features found in a rock. |
| Lithification | The processes that convert a sediment into a sedimentary rock. |
| Lithology | The systematic description of rocks, in terms of mineral composition and texture. |
| Lithosphere | The outer, rigid shell of the Earth, situated above the asthenosphere and containing the crust, continents, and plates. |
| Lode | An unusually large vein or set of veins containing ore minerals. |
| Longitudinal dune | A long dune parallel to the direction of the prevailing wind. |
| Longitudinal profile | A cross section of a stream from its mouth to its head, showing elevation versus distance to the mouth. |
| Longshore current | A current that moves parallel to a shore and is formed from the momentum of breaking waves that approach the shore obliquely. |
| Longshore drift | The movement of sediment along a beach by swash and backwash of waves that approach the shore obliquely. |
| Lopolith | A large laccolith that is bowl-shaped and depressed in the center, possibly by subsidence of an emptied magma chamber beneath the intrusion. |
| Lowland | Land of general low relief at the lower levels of regional elevation. |
| Low-velocity zone | A region in the Earth, especially a planar layer that has lower seismic-wave velocities than the region immediately above it. |
| Luster | The general textural impression of a mineral surface, given by the light reflected from it. Terms such as metallic, submetallic are standardized but subjective. |
| Maar volcano | A volcanic crater without a cone, believed to have been formed by an explosive eruption of trapped gases. |
| Mafic mineral | A dark-colored mineral rich in iron and magnesium, especially a pyroxene, amphibole, or olivine. |
| Magma | Molten rock material that forms igneous rocks upon cooling. Magma that reaches the surface is referred to as lava. |
| Magma chamber | A magma-filled cavity within the lithosphere. |
| Magmatic water | Water that is dissolved in a magma or that is derived from such water. |
| Magnetic anomaly | The value of the local magnetic field remaining after the subtraction of the dipole portion of the Earth's field. |
| Magnetic coupling | The transfer of momentum between celestial bodies, especially dust and gas clouds, through magnetic forces. |
| Magnetic north pole | (1) The point where the Earth's surface intersects the axis of the dipole that best approximates the Earth's field. (2) The point where the Earth's magnetic field dips vertically downward. |
| Magnetic stratigraphy | The study and correlation of polarity epochs and events in the history of the Earth's magnetic field as contained in magnetic rocks. |
| Magnetometer | An instrument for measuring either one orthogonal component or the entire intensity of the Earth's magnetic field at various points. |
| Magnitude | A measure of earthquake size, determined by taking the common logarithm base 10) of the largest ground motion observed during the arrival of a P-wave or seismic surface wave and applying a standard correction for distance to the epicenter. |
| Manganese nodule | A small, rounded concretion found on the deep ocean floor that may contain as much as 20 percent manganese and smaller amounts of iron, copper, and nickel oxides and hydroxides. |
| Mantle | The main bulk of the Earth, between the crust and core, ranging from depths of about 40 to 3480 kilometers. It is composed of dense mafic silicates and divided into concentric layers by phase changes that are caused by the increase in pressure with depth |
| Massive rock | A rock that is little or not at all broken by joints, cracks, foliation, or bedding, tending to present a homogeneous appearance. |
| Mass movement | A downhill movement of soil or fractured rock under the force of gravity. |
| Mass spectrometer | An instrument for separating ions of different mass but equal charge (mainly isotopes in geology) and measuring their relative quantities. |
| Maturity | A stage in the geomorphic cycle in which maximum relief and well-developed drainage are both present. |
| Meander | Broad, semicircular curves in a stream that develop as the stream erodes the outer bank of a curve and deposits sediment against the inner bank. |
| Mechanical weathering | The set of all physical processes by which an outcrop is broken up into small particles. |
| Medial moraine | A long stripe of rock debris carried on or within a glacier resulting from the convergence of lateral moraines where two glaciers join. |
| Medical geology | The application of geologic science to problems of health, especially those relating to mineral sources of toxic or nutritious elements and natural dispersal of toxic pollutants. |
| Mesophere | The lower mantle. |
| Metamorphism | The changes of mineralogy and texture imposed on a rock by pressure and temperature in the Earth's interior. Meteoric water |
| Meteorite | A stony or metallic object from inter-planetary space that penetrates the atmosphere to impact on the surface. |
| Micrometeorite | A meteorite less than 1 millimeter in diameter. |
| Microseism | A weak vibration of the ground that can be detected by seismographs and which is caused by waves, wind, or human activity, but not by an earthquake. |
| Migmatite | A rock with both igneous and metamorphic characteristics that shows large crystals and laminar flow structures. Probably formed metamorphically in the presence of water and without melting. |
| Mineral | A naturally occurring element or compound with a precise chemical formula and a regular internal lattice structure. Organic products are usually not included. |
| Mineralogy | The study of mineral composition, structure, appearance, stability, occurrence, and associations. |
| Miogeosyncline | A Geosyncline that is situated near a craton and receives chemical and well-sorted elastic sediments from the continent. |
| Mohorovic discontinuity | The boundary between crust and mantle, marked by a rapid increase in seismic wave velocity to more than 8 kilometers per second. Depth |
| Mohs scale of hardness | An empirical, ascending scale of mineral hardness with talc as 1, gypsum 2, calcite 3, fluorite 4, apatite 5, orthoclase 6, quartz 7, topaz 8, corundum 9, and diamond 10. |
| Monadnock | An isolated hill or mountain rising above a peneplain. |
| Monocline | The S-shaped fold connecting two horizontal parts of the same stratum at different elevations. Its central limb is usually not overturned. |
| Moraine | A glacial deposit of till left at the margin of an ice sheet. See specifically by name, ground moraine, longitudinal moraine, medial moraine, and terminal moraine. |
| Mountain | A steep-sided topographic elevation larger than a hill; also a single prominence forming part of a ridge or mountain range. |
| Mudflow | A mass movement of material finer than sand, lubricated with large amounts of water. Mudstone |
| My. | Abbreviation for "million years." |
| Mylonite | A very fine lithified fault breccia commonly found in major thrust faults and produced by shearing and rolling during fault movement. |
| Native metal | A natural deposit of a metallic element in pure metallic form, neither oxidized nor combined with sulfur or other elements. |
| Neap tide | A tide cycle of unusually small amplitude, which occurs twice monthly when the lunar and solar tides are opposed-that is, when the gravitational pull of the Sun is at right angles to that of the Moon. |
| Nebula | An immense, diffuse body of interstellar gas and dust that has not condensed into a star. |
| Nebular hypothesis | A theory of the formation of the planets that states that a rotating nebula contracted and was then torn into fragments by centrifugal forces, with planets condensing from the fragments. |
| Neutron | An electrically neutral elementary particle in the atomic nucleus having the mass of one proton. |
| Neutron-activation analysis | A method of identifying isotopes of an element by bombarding them with neutrons and observing the characteristic radioactive decay products emitted. |
| Normal fault | A dip-slip fault in which the block above the fault has moved downward relative to the block below. |
| Oblique-slip fault | A fault that combines some strike slip motion with some dip-slip motion. |
| Obsidian | Dark volcanic glass of felsic composition. |
| Octahedral coordination | The packing of six ions around an ion of opposite charge to form an octahedron. |
| Oil field | An underground accumulation of oil and gas concentrated beneath an impermeable trap, preventing its escape upward. |
| Oil shale | A dark-colored shale containing organic material that can be crushed and heated to liberate gaseous hydrocarbons. |
| Old age | A stage in the geomorphic cycle, characterized by formation of a peneplain near sea level. |
| Oolite | A sedimentary carbonate particle composed of spherical grains precipitated from warm ocean water on carbonate platforms. Also a rock composed of such particles. |
| Opaque mineral | A mineral which transmits no light through a thin section under a microscope. Usually a native metal, sulfide, or metallic oxide mineral. |
| Ophiolite suite | An assemblage of mafic and ultra-mafic igneous rocks with deep-sea sediments supposedly associated with divergence zones and the sea-floor environment. |
| Orbit | The elliptical or hyperbolic path traced by a planet or meteorite or satellite in the presence of a more massive body. |
| Ore | A natural deposit in which a valuable metallic element occurs in high enough concentration to make mining economically feasible. |
| Ore mineral | The mineral of an ore that contains the useful element. |
| Original Horizontality, Principle of | The proposition of Steno, that all sedimentary bedding is horizontal at the time of deposition. |
| Orogenic belt | A linear region, often a former geo-syncline, that has been subjected to folding, and other deformation in a mountain-building episode. |
| Orogeny | The tectonic process in which large areas are folded, thrust-faulted, metamorphosed, and subjected to plutonism. The cycle ends with uplift and the formation of mountains. |
| Oscillation ripple | A ripple with a symmetrical cross section and a sharp peak formed by waves. |
| Outcrop | A segment of bedrock exposed to the atmosphere. |
| Outgassing | The release of juvenile gases to the atmosphere and oceans by volcanism. |
| Outwash | A glaciofluvial sediment that is deposited by meltwater streams emanating from a glacier. Overturned fold |
| Oxidation | A chemical reaction in which electrons are lost from an atom and its charge becomes more positive. |
| Oxidized element | An element occurring in the more positively charged of two common ionic forms. |
Created by:
CVTMSCA
Popular Earth Science sets