Flashcards
ES201
Flashcards do conjunto (16)
- 1proportions of the dominant components of the condensate?early condensates or refractories-- 5%
metals-- 20%
silicates-- 40% - 2relationship between basalts and the mantle indicateMantle samples with the most primitive compositions will be those that have
NOT experienced the extraction of basaltic magma - 3U, Th and K are incompatible elements (i.e. they are preferentially partitioned into silicate liquids) where will they be concentrated?The elements U, Th and K (and their radiogenic isotopes) are particularly
concentrated in the silicate-dominated outer layers of the Earth, and in
particular within the continental crust. - 4What process raised siderophile element abundances in the silicate mantle following core formation?Continued accretion of meteoritic materials from new impacts of meteorites with chondritic proportions of the siderophile elements.
- 5HighlandAnorthosite (rich in PLAGIOCLASE FELDSPAR 90%; 10% MAFIC MINERALS)
~ 4.4 Ga - 6MariaBASALTIC in composition
~ 3.8-4.2 Ga - 7Achondrites-reminiscent of terrestrial Igneous rocks.
- 8Mantle -- compositionilicates composition-
achondrite-rich in Mg - 9xenoliths --green colour contrast with the grey black colour of the host volcanic rocks.
- 10Peridotites -rich in minerals olivine and pyroxene silicates rich in magnesium and iron.
density 3200 kg m−3 - 11Ophiolites --obducted oceanic crust.
edimentary rocks overlie rocks of basaltic composition, overlie peridotite. - 12Siderophiles --found in the metallic phase.
2.0 < E < 2.4
D >1
compatible - 13lithophiles --bond with oxygen, especially in silicate or oxide
E <1.6
D <1
incompatible - 14Chalcophiles --form covalent bonds with elements such as S.
1.6 < E < 2.0 - 15Upper Crust -- Granodioritegranite containing plagioclase and alkali feldspar 1:1 & 20% quartz
- 16Lower Crust -- Granulitesmetamorphic rocks that have been subjected to high pressures and temperatures lost volatile components and their mineralogy is plagioclase feldspar, pyroxenes and garnets