منابع مشابه
Early Crustal Evolution of Mars1
■ Abstract The bulk of the ∼50-km-thick Martian crust formed at ∼4.5 Gyr B.P., perhaps from a magma ocean. This crust is probably a basaltic andesite or andesite and is enriched in incompatible and heat-producing elements. Later additions of denser basalt to the crust were volumetrically minor, but resurfaced significant portions of the Northern hemisphere. A significant fraction of the total t...
متن کاملThermal and crustal evolution of Mars
[1] We present a coupled thermal-magmatic model for the evolution of Mars’ mantle and crust that may be consistent with estimates of the average crustal thickness and crustal growth rate. By coupling a simple parameterized model of mantle convection to a batchmelting model for peridotite, we can investigate potential conditions and evolutionary paths of the crust and mantle in a coupled thermal...
متن کاملGeochemical evolution and petrogenesis of the eocene Kashmar granitoid rocks, NE Iran: implications for fractional crystallization and crustal contamination processes
Kashmar granitoids of Taknar zone, in north part of Lut block, intruded into volcanic rocks and consist of granites, granodiorites, monzodiorite and gabbrodiorites. They are composed of mainly plagioclase, alkali-feldspar, quartz, amphibole, biotite and pyroxene minerals. Harker diagram variation, including negative correlations CaO, MgO, FeO, TiO2 and V and positive correlations K2O, Rb, Ba, a...
متن کاملProterozoic crustal evolution in the NW Himalaya (India) as recorded by circa 1.80 Ga mafic and 1.84 Ga granitic magmatism
Single zircon dating of the Rampur metabasalts of the Larji–Kullu–Rampur window in the Lesser Himalayas yielded an evaporation age of 1800913 Ma. The zircon age is considerably younger than the previously published whole rock Sm–Nd age of 2510990 Ma, suggesting that the Sm–Nd age may be geologically meaningless and that the Sm–Nd whole rock array may have resulted from mixing. In the NW Himalay...
متن کاملCrustal structure of the Kaapvaal craton and its significance for early crustal evolution
High-quality seismic data obtained from a dense broadband array near Kimberley, South Africa, exhibit crustal reverberations of remarkable clarity that provide well-resolved constraints on the structure of the lowermost crust and Moho. Receiver function analysis of Moho conversions and crustal multiples beneath the Kimberley array shows that the crust is 35 km thick with an average Poisson’s ra...
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ژورنال
عنوان ژورنال: Journal of the Geological Society of India
سال: 2014
ISSN: 0016-7622,0974-6889
DOI: 10.1007/s12594-014-0046-x