7629961
Description
Flashcards by Nilesh Mayank, updated more than 1 year ago
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Created by Nilesh Mayank
almost 8 years ago
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| Question | Answer |
| proportions of the dominant components of the condensate? | early condensates or refractories-- 5% metals-- 20% silicates-- 40% |
| relationship between basalts and the mantle indicate | Mantle samples with the most primitive compositions will be those that have NOT experienced the extraction of basaltic magma |
| U, 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. |
| What 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. |
| Highland | Anorthosite (rich in PLAGIOCLASE FELDSPAR 90%; 10% MAFIC MINERALS) ~ 4.4 Ga |
| Maria | BASALTIC in composition ~ 3.8-4.2 Ga |
| Achondrites- | reminiscent of terrestrial Igneous rocks. |
| Mantle -- composition | ilicates composition- achondrite-rich in Mg |
| xenoliths -- | green colour contrast with the grey black colour of the host volcanic rocks. |
| Peridotites - | rich in minerals olivine and pyroxene silicates rich in magnesium and iron. density 3200 kg m−3 |
| Ophiolites -- | obducted oceanic crust. edimentary rocks overlie rocks of basaltic composition, overlie peridotite. |
| Siderophiles -- | found in the metallic phase. 2.0 < E < 2.4 D >1 compatible |
| lithophiles -- | bond with oxygen, especially in silicate or oxide E <1.6 D <1 incompatible |
| Chalcophiles -- | form covalent bonds with elements such as S. 1.6 < E < 2.0 |
| Upper Crust -- Granodiorite | granite containing plagioclase and alkali feldspar 1:1 & 20% quartz |
| Lower Crust -- Granulites | metamorphic rocks that have been subjected to high pressures and temperatures lost volatile components and their mineralogy is plagioclase feldspar, pyroxenes and garnets |
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