|Eastern Mojave Vegetation||Glossary|
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Area Of Critical Environmental Concern (ACEC). An area within public lands where special management attention is required to protect and prevent irreparable damage to important historic, cultural or scenic values, fish and wildlife resources, or other natural systems or processes, or to protect life and safety from natural hazards. (FLPMA, Section 103(a)).
adamellite Synomymous with and perhaps a preferable name for quartz monzonite.
alluvial. Referring to water carried material.
alluvial fan. A gently sloping (ten degrees or less) fan shaped deposit of sediments formed where an intermittent stream undergoes an abrupt reduction in slope. Coarsest materials are found near the apex of the fan (nearest the mountain or hill front) whereas the finest materials occur farthest from the mountain front.
alluvium. Material, including sand, clay, gravel, and mud, deposited in river beds, lakes, alluvial fans, valleys, and elsewhere by modern streams.
amphibolite. A crystalloblastic rock consisting mainly of amphibole and plagioclase with little or no quartz. As the content of quartz increases, the rock grades into hornblende-plagioclase gneiss.
amphibolite facies. The set of metamorphic mineral assemblages in which basic rocks are represented by hornblende + plagioclase, the latter being oligoclase-andesine or a more calcic variety, The facies is typical of regional metamorphism under moderate to high pressures and temperatures.
anemophilous Pollinated by wind. See also: entomophilous.
Animal Unit Month (AUM). A unit of measure of the impact of a grazing animals on range land. An AUM is equivalent to the amount of forage required by a 1,000 pound cow for 1 month (BLM, 1980, p. 68). A calf might give an AUM value, sheep another, etc..
Locations: San Andreas Fault Zone.
anisotropy the condition of having different properties in different directions, as in geologic strata that transmit sound waves with different velocities in the vertical or horizontal directions.|
Boness and Zoback (2006) present shear velocity anisotropy data from local earthquake sources as an independent tool to analyze the state of stress close to active faults on a regional scale.
anthropology. the science that deals with the origins, physical and cultural development, racial characteristics and social customs and beliefs of mankind.
Other articles: Glossary syncline
anticline. A configuration of folded, stratified rocks in which the rocks dip or incline in two directions away from the crest, like the two halves of a pitched roof. The reverse of a "syncline".
Locations: Badwater Basin.
archaea. Any of a group of microorganisms that resemble bacteria but are different from them in certain aspects of their chemical structure, such as the composition of their cell walls. Archaea usually live in extreme, often very hot or salty environments, such as hot mineral springs or deep-sea hydrothermal vents, but some are also found in animal digestive systems. The archaea are considered a separate kingdom in some classifications, but a division of the prokaryotes (Monera) in others. Some scientists believe that archaea were the earliest forms of cellular life. Also called archaebacterium.
arid. Zero to ten inches precipitation per year. Potential for evaporation exceeds annual precipitation.
ash. 1. Inorganic residue remaining after ignition of combustible substances, quantitatively determined by definite prescribed methods. 2. Volcanic dust and particles less than 4 mm. in diameter.
ash, volcanic. Uncemented pyroclastic material consisting of fragments mostly under 4 mm. in diameter. Without a qualifying adjective, the term should be applied only to essential ejecta.
ash fall. 1. A rain of airborne volcanic ash falling from an eruption cloud. Characteristic of vulcanian eruptions. 2. A deposit of volcanic ash resulting from such a fall and lying on the ground surface. (AGI)
ash flow. 1. An avalanche of volcanic ash, generally a highly heated mixture of volcanic gases and ash, traveling down the flanks of a volcano or along the surface of the ground and produced by the explosive disintegration of viscous lava in a volcanic crater or by the explosive emission of gas charged ash from a fissure or group of fissures. Ash flows of the type described at Mount Pelee are considered to represent the feeblest type of the nuee ardente. The solid materials contained in a typical ash flow are generally unsorted and ordinarily include volcanic dust, pumice, scoria, and blocks in addition to ash. 2. A deposit of volcanic ash and other debris resulting from such a flow and lying on the ground surface. Syn: ignimbrite. (AGI)
ash flow tuff. A tuff resulting from an ash flow.
Other articles: Glossary welded_tuff
Aso lava. A type of indurated pyroclastic deposit produced during the explosive eruptions that formed the Aso Caldera of Kyushu, Japan. Chiefly a lavalike tuff consisting of lenses or spindles of black and gray obsidian lying in a tuffaceous matrix that displays a streaky, varicolored banding or eutaxitic structure. Possibly erupted as extremely hot, gas rich dust and ash carrying large clots of molten, vesiculated volcanic glass. Similar to deposits variously described as welded tuff, welded pumice, ignimbrite, and tuff-lava. (AGI)
Other articles: Eastern Mojave Geology 149000
aulacogen. A long lived deeply subsiding trough, at times fault bounded, that extends at high angles from a geosyncline far into an adjacent foreland platform.
The Neoproterozoic Pahrump Group is thought to have been deposited in an east-west aulacogen.
Coll. No. 1110, 26 May 2015
Coll. No. 1113, 26 May 2015
auricle. A structure resembling an ear or an earlobe. In botany, and particularly grasses thereof, an auricle in a small lobe at the juncture of the leaf sheath and leaf blade.
autecology n. Study of the requirements, tolerances, and responses of a single organism (Oosting 1956:12). The ecology of a species or of individual organisms in relation to the environment (Webster).
avalanche, volcanic. Avalanche usually refers to a large mass of ice and snow, sometimes accompanied by other material, moving rapidly down a mountain slope. A volcanic avalanche is a general term relating to movement of large masses of volcanic material, ususally tephra, moving rapidly down a mountain slope without regard for temperature and gas content.
axiolite, axiolitic. No definition in AGI, 1962. Defined in Ross and Smith, 1961.
Other articles: Glossary alluvial_fan
bajada. 1. The slope or continuous apron comprised of merged alluvial fans. 2. A series of merged alluvial fans along the base of a mountain range.
Other articles: Glossary roof_pendant
batholith 1. Originally defined in 1895 as a stock-shaped or shieldshaped mass of igneous rock intruded as the fusion of older formations. On removal of its rock cover and on continued denudation, this mass holds its diameter or grows broader to unknown depths. 2. A body of intrusive rock, with the general characteristics of stocks, but of much larger size than is generally attributed to stocks or bosses.
bench. A strip of relatively level earth or rock, raised and narrow. A small terrace or comparatively level platform breaking the continuity of a declivity (AGI).
block. An angular fragment over 256 mm. in diameter showing little or no modification in form due to transportation; similar in size to a boulder. (AGI, 1962).
blueschist. At high pressure and low temperature, albite feldspar breaks down and forms the pyroxene jadeite and amphiboles like glaucophane and aegerine. The amphiboles are bluish, hence the term "blueschist."
High pressures (5 to over 8 kb) and low to moderate temperatures of 250° to 600° C (480° to 1,100° F) form blueschist facies. Blueschist facies is typical of subduction-zone metamorphism as tectonic plates fold over one another.
bolson. In arid regions, a basin filled with alluvium and intermittent lakes and having no surface water outlet.
breccia Rock composed in sharp-angled fragements cemented in a fine matrix.
Bryozoa. Phylum of tiny colonial animals equipped with a circle or loop or tentacles surrounding the mouth that build calcareous structures of many kinds, mostly marine. Ordovician to Recent. The phylum of invertebrate animals which are popularly called "moss animals". (Called Polyzoa by some zoologists.)
Other articles: Field Notes Coll. No. 470 26-Jun-07
callus. The hardened, sometimes sharp base of the floret of certain grasses.
capture. See stream capture.
carbonate bank. A submarine plateau composed of limestone, much like the present-day Bahamas.
carbonate mineral. Mineral formed by the combination of the complex ion (CO3)2- with a positive ion. Common example: CaCO3, calcium carbonate, the primary constituent of limestone.
Other articles: Frasera albomarginata 100200
caudex. The woody base of an othersize herbaceous perennial (Munz, 1965). 1. The thickened base of the stem of certain perennials (Webster).
California Desert Conservation Area (CDCA). The 25 million acre CDCA contains over 12 million acres of public lands administered by the BLM. The boundaries are formed by the Nevada border and Colorado River on the east. The United States / Mexico boundary forms the southern boundary. Western boundaries are mostly desert areas on the east sides of the Peninsular Ranges, the Transverse Ranges, the Tehachapi Mountains and the Sierra Nevada.
Other articles: Kelbaker Road 16000
cinder cone. A type of volcano which is built exclusively or in large part of pyroclastic ejecta dominated by cinders (particles 0.01 to 1 inch in diameter). Seldom exceeds 1,500 feet in height. Slopes up to 30 or 40 degrees.
cismontane. Situated on this side of the mountains.
Cismontane California is west of the Cascades--Sierra and Transverse--Peninsular crests.
Other articles: Eastern Mojave Climate Climate
climate 1. Meterological conditions, including temperature, precipitation, and wind, that prevail in a region. 2. A region manifesting particular meterological conditions. 3. A prevailing condition or atmosphere. See also: weather
connate. Anatomy. firmly united; fused. Botany congenitally joined, as leaves and "connate petals."
coprolite. Fossil animal excrement. Fossil animal scats.
Eastern Mojave Geology
coral. Any of the numerous chiefly colonial marine coelenterates of the class Anthozoa, marked by calcareous skeletons massed in a variety of shapes and often forming reefs or islands.
cordillera. A comprehensive term for an entensive series or broad assemblage of more or less parallel ranges, systems, and chains of maintains (together with their associated valleys, basins, plains plateaus, rivers, and lakes), the component parts having various trends, but the mass itself having one general direction; esp., the main mountain axis of a continent, as the great mountain region of western North America from the eastern face of the Rocky Mountains to the Pacific
Ocean, or the parallel chains of the Andes in South America; a mountain province.
craton. A relatively immobile part of the earth, generally of large size.
Other articles: Eastern Mojave Geology 172300
crinoid. an echinoderm of the class Crinoidea, having a cup-shaped body to which are attached branched, radiating arms, comprising the sea lilies, feather stars, and various fossil forms.
crisped refers to the margin or rdge of a leaf. Curled or wavy (Welsh, Stanley L., et al. 1987).
crystalline. The orderly arrangement of atoms in a crystal. Rock which is made up of crystals. Examples: igneous and metamorphic rocks.
crystallization. The process of forming crystals by cooling a molten substance.