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Topics related to "mafic rock"

igneous rock
igneous rock One of three major classes of rock produced by the cooling and solidifying of molten magma. All igneous rocks are crystalline and most resist erosion. Extrusive, or volcanic, igneous rocks, such as basalt, form by the rapid cooling of molten material at the surface. Intrusive, or hyper... Read more
petrology
petrology branch of geology specifically concerned with the origin, composition, structure, and properties of rocks , primarily igneous and metamorphic, and secondarily sedimentary. It includes petrography, the systematic description and classification of rocks using microscopic examination of roc... Read more
Sela
Sela or Selah [Heb.,=rock], in the Bible, unidentified town, S of the Dead Sea. Amaziah captured it and renamed it Joktheel. Some identify Sela with Petra . Sela in the first chapter of Judges seems to be another rock. ... Read more
rock
rock aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their origin, into three major classes—igneous, sedimentary, and metamorphic. Igneous Rocks ... Read more
Cephas
Cephas , in the Gospels, Jesus' name for St. Peter. It is a transliteration of the Aramaic word for rock, and identical in meaning with "Peter" in Greek. ... Read more
metamorphic rock
metamorphic rock An aggregate of minerals formed by the recrystallization of pre-existing rocks in response to a change of pressure, temperature, or volatile content. Metamorphic rocks can generally be divided into four types: (a) regional metamorphic rocks, formed in response to changes leading to ... Read more
schist
schist , metamorphic rock having a foliated, or plated, structure called schistosity in which the component flaky minerals are visible to the naked eye. Schists are distinguished from the other foliated rocks, slates and gneisses, by the size of their mineral crystals; these are larger than those ... Read more
sedimentary rock
sedimentary rock Type of rock formed by deposition of sediment derived from pre-existing rocks, which may have been sedimentary, igneous or metamorphic. Most sediment accumulates on the bed of the sea, having been dumped there by rivers, or having accumulated as dead sea creatures fall to the seafl... Read more
joint
joint in geology, fracture in rocks along which no appreciable movement has occurred (see fault ). Nearly vertical, or sheet, joints that result from shrinkage during cooling are commonly found in igneous rocks. Similar joints occur in thick beds of sandstone and gneiss, with the sheets resembling... Read more
rock crawler
rock crawler name applied to the slender, wingless insects of the family Grylloblattidae in the order Orthoptera. They have long antennae and range in length from 1/2 to 1 in. (15-30 mm). Rock crawlers occur at altitudes of 1,500 to 6,500 ft (450-2,000 m), where they live in caves, under rock... Read more

Encyclopedia entries related to "mafic rock"

seismic properties of rocks
Book article from: The Oxford Companion to the Earth ...composition is complex because rocks are combinations of minerals...velocities of the crystalline rocks which constitute most of the...seismic velocity of a particular rock. Figure 1, which is a compilation...velocities. Clastic sedimentary rocks (sandstone and shale) are...felsic) is slower than ...
cleavage and other tectonic foliations in rocks
Book article from: The Oxford Companion to the Earth ...banding such as alternating mafic and felsic layers in...foliation. A cleaved rock has fabric domains of...Continuously cleaved rocks have cleavage zones so...continuously cleaved rocks lack microlithons, whereas a rock with spaced cleavage...appearance of these beautiful rocks. They ...
igneous rock classification
Book article from: The Oxford Companion to the Earth ...SiO 2 ) content of the rock. Rocks with less than 45 per cent by...to express the idea that the rocks are acidic or alkaline in the...describe the silica content of the rock. Rocks that are rich in silica...may be replaced by felsic and mafic , respectively. The simple...
Continent
Encyclopedia entry from: The Gale Encyclopedia of Science ...or felsic. Oceanic crust is mafic, relatively rich in magnesium...hence the word “mafic”—and...the continental margin and the mafic crust of the ocean floor are...several structural segments. A rock foundation called the craton...ancient igneous and metamorphic rocks ...
supergene and residual deposits
Book article from: The Oxford Companion to the Earth ...intense weathering of iron-rich rocks such as mafic and ultramafic volcanic rocks. During weathering, acid solutions remove much of the rock-forming elements and, because mafic and ultramafic rocks are poor in aluminum, the remaining...
granulite and the granulite facies
Book article from: The Oxford Companion to the Earth ...range of siliceous metamorphic rocks with a medium- to coarse...used exclusively for silicate rocks that have experienced granulite...for lower-grade psammitic rocks is now obsolete. True granulites...emplacement of mantle-derived mafic magmas, providing a source...
Bowen, Norman Levi
Book article from: The Oxford Companion to the Earth ...foremost investigators of igneous rocks in the twentieth century, N...Daly. His classical studies of rock-forming minerals began with...x2013;magnesium silicates (mafic minerals) found in igneous rocks. He soon discovered the so...basaltic magma, a succession of rocks of progressively more ...
iron–nickel deposits
Book article from: The Oxford Companion to the Earth ...laterites and those associated with mafic and ultramafic rock types in a wide range of tectonic...calcium are leached from the rock into the underlying water...form above ultramafic igneous rocks the nickel and iron contained...the minerals that comprise the rocks may be concentrated to ...
chromites
Book article from: The Oxford Companion to the Earth ...and is found, usually in small amounts, in mafic and ultramafic rocks (igneous rocks containing a large proportion of olivine and pyroxene...Many show features analogous to sedimentary rocks. Occurrences are isolated, but are of economic...
lithosphere
Book article from: The Oxford Companion to the Earth ...crust is essentially a compositional boundary between mafic and ultramafic rocks, characterized by a rapid increase in seismic P...Since this depends on the elastic deformation of rocks at frequencies of about 0.01–1 Hz...

Dictionary entries related to "mafic rock"

mafic
Book article from: A Dictionary of Earth Sciences mafic Applied to any igneous rock which has a high proportion of pyroxene and olivine , such that its colour index is between 50 and 90 (i.e. it is dark coloured).
colour index
Book article from: A Dictionary of Earth Sciences ...methods used for classifying igneous rocks. If a rock has 60% modal mafic minerals it has a colour index of 60. Rocks with colour indices between 50 and 90 are termed ‘ mafic ’ rocks (e.g. basalts...
lamprophyre
Book article from: A Dictionary of Earth Sciences ...porphyritic , intrusive igneous rock, containing abundant euhedral...or opaque oxides, set in a mafic , felsic , or glassy groundmass...phenocrysts present in this rock type. The lamprophyres are...basis of their most abundant mafic component and the presence and...
melanosome
Book article from: A Dictionary of Earth Sciences ...Dark-coloured bands rich in mafic and aluminous minerals, e...feldspar components of the original rock along non-penetrative cleavage...regional metamorphic event. The mafic and aluminous components of...left over from the original rock.
schlieren
Book article from: A Dictionary of Earth Sciences ...linear, planar, or discoidal aggregates of mafic minerals more densely concentrated than in the host rock, with which they have diffused boundaries...schlieren may represent partly remobilized, mafic-rich xenoliths , streaked out by the flow...
granofels
Book article from: A Dictionary of Earth Sciences ...A little-used name for a massive granoblastic metamorphic rock , consisting of equant grains of quartz and feldspar , hence lacking a foliation . Minor mafic minerals consist of pyroxene and garnet . The anhydrous mineral assemblages of such rocks are produced under the high-grade, anhydrous granulite ...
melteigite
Book article from: A Dictionary of Earth Sciences ...melteigite An undersaturated, intrusive igneous rock containing essential nepheline and alkali...of 70–90. With decreasing mafic mineral content and increasing nepheline...ijolites and then into urtites . All three rock types are essentially feldspar-free...
basanite
Book article from: A Dictionary of Earth Sciences basanite An extrusive , mafic igneous rock consisting of a feldspathoid mineral ( nepheline , analcite...basanite, analcite-basanite, and leucite-basanite. These rocks are found in close association with alkali basalts . See also...
leucitite
Book article from: A Dictionary of Earth Sciences ...extrusive , undersaturated (see SILICA SATURATION ), mafic igneous rock consisting of essential leucite and augite , with accessory...apatite . When olivine or nepheline are also present, the rock is termed an olivineleucitite or a nepheline-leucitite...
leucosome
Book article from: A Dictionary of Earth Sciences ...as a high-grade metamorphic product (see METAMORPHISM ) in rocks of pelitic (see PELITE ) to psammitic (see PSAMMITE ) composition. The finer material between the leucosomes is enriched in mafic and aluminous minerals. Leucosomes may represent a low-melting...

Related newspaper, magazine, and trade journal articles from HighBeam Research

Petrogenetic Diversity and Petrographic Convergence of Some Spheroidal Structures in Mafic Intrusive Rocks
Magazine article from: Geolines; 1/1/2004; ; 700+ words ; ...occur frequently in mafic rocks along their primary contacts...granitoids of the same rock association and also...coming into contact with mafic magma batches. Less...microgranular enclaves in other rock types of the CBPC, namely...durbachite (Certovo bremeno) rock suite. Both the ...
Geochemistry and tectonic setting of mafic rocks in western Dronning Maud Land, East Antarctica: implications for the geodynamic evolution of the Proterozoic Maud Belt
Magazine article from: Journal of the Geological Society; 3/1/2007; ; 700+ words ; ...2005; Fig. 1). Extensive mafic sills of the 1107Ma Borgmassivet...the volcano-sedimentary rocks of the Ritscherflya Supergroup, whereas numerous mafic bodies occur as pre-, syn...Geochemical data for these mafic rocks are scarce in the literature...
Trace element constraints on mantle sources during mid-Proterozoic magmatism: evidence for a link between the Gardar (South Greenland) and Abitibi (Canadian Shield) mafic rocks.
Magazine article from: Canadian Journal of Earth Sciences; 4/1/2007; ; 700+ words ; ...sub.N] ratios (1.6-1.8) of the rocks derived from this source indicate the presence...of mantle source components of basaltic rocks in the geological record is essential for...distinct mantle sources were identified for mafic dike swarms (Condie et al. 1987; Tarney...
Geochemical comparison of mafic, felsic, and ultramafic rocks in the Hurricane Mountain melange to the Boil Mountain ophiolite complex, west-central Maine.
Magazine article from: Atlantic Geology; 3/1/2001; ; 700+ words ; ...supports a correlation between the mafic melange blocks and the upper mafic unit of the Boil Mountain ophiolite...and disruption of volcanic rocks, post or syn-Penobscottian...we test the hypothesis that mafic, felsic, and ultramafic blocks...
Freewest Acquires Dalhousie Mountain Nickel-Copper-Vanadium Property in West-Central Quebec HIGHLIGHTS: - New nickel occurrence assaying 0.87 percent nickel discovered within ultramafic-mafic plutonic rocks of the Bell River Complex - New occurrence closely associated with a strong conductor yielded by a recent airborne electromagnetic survey - Vanadium mineralization with assays of up to 1.27% V2O5 also discovered over a large area
Newspaper article from: CCNMatthews Newswire; 5/23/2007; 700+ words ; ...percent nickel at one locale and 0.44 percent copper, 0.31 percent nickel at a second location within layered gabbroic host rocks. Such mineralization is intimately associated with a strong 200- metre long conductor delineated by the TDEM survey. Also...
Freewest Acquires Dalhousie Mountain Nickel-Copper-Vanadium Property in West-Central Quebec; HIGHLIGHTS: - New nickel occurrence assaying 0.87 percent nickel discovered within ultramafic-mafic plutonic rocks of the Bell River Complex - New occurrence closely associated with a strong conductor yielded by a recent airborne electromagnetic survey - Vanadium mineralization with assays of up to 1.27% V2O5 also discovered over a large area.
News Wire article from: Canadian Corporate News; 5/23/2007; 700+ words ; ...percent nickel at one locale and 0.44 percent copper, 0.31 percent nickel at a second location within layered gabbroic host rocks. Such mineralization is intimately associated with a strong 200-metre long conductor delineated by the TDEM survey. Also...
SHRIMP U-Pb zircon geochronology of Neoproterozoic Korla mafic dykes in the northern Tarim Block, NW China: implications for the long-lasting breakup process of Rodinia
Magazine article from: Journal of the Geological Society; 9/1/2008; ; 700+ words ; ...Neoproterozoic widespread mafic dyke swarms, ultramafic-mafic intrusions, alkaline...and bimodal volcanic rocks occurring in many old...sample description. Mafic dykes in the Korla region...metamorphic and granitic rocks whose ages are uncertain...
Mafic intrusions on Campobello Island: implications for New Brunswick--Maine correlations.
Magazine article from: Atlantic Geology; 3/1/2001; ; 700+ words ; ...northeast, a sequence of intercalated turbidite and mafic volcanic rocks to the southwest, and mafic dyke swarms throughout. Petrographic, geochemical...amphibolite facies, and a protracted history of mafic magma injection from a similar source beginning...
Rupert Encounters 20 Metres of Target Mafic Volcanics at Red Lake.
News Wire article from: Canadian Corporate News; 12/21/2005; 700+ words ; ...intruded by several intermediate to mafic dikes, quartz-feldspar porphyries...hole cut a 20 metre section of mafic volcanic rocks interpreted to be either Bruce...20 metre intersection of the rock package our drill program has...Geo briefly describes the mafic volcanic intersection as ...
Rupert Encounters 20 Metres of Target Mafic Volcanics at Red Lake
Newspaper article from: CCNMatthews Newswire; 12/21/2005; 690 words ; ...intruded by several intermediate to mafic dikes, quartz- feldspar porphyries...hole cut a 20 metre section of mafic volcanic rocks interpreted to be either Bruce...20 metre intersection of the rock package our drill program has...Geo briefly describes the mafic volcanic intersection as ...