نتایج جستجو برای: mafic migmatites
تعداد نتایج: 2136 فیلتر نتایج به سال:
In the Santander Massif of Eastern Cordillera Colombia, intense Pliocene to Holocene sulfide-rich gold mineralization occurs in a six kilometers long section La Baja fault zone, where it crosses partially migmatized gneisses and intrusions Triassic-Cretaceous quartz monzonites granites. These intrusives are mineralogically texturally similar neosome migmatites that they intrude. The as medium l...
Empirical studies of zircon in migmatites document features compatible with growth during heating at suprasolidus conditions. However, numerical modelling behaviour suggests that is expected to grow only cooling and melt crystallization. Here, phase equilibrium coupled mineral–melt Zr partitioning used an attempt reconcile the observations from predictions previous models anatectic systems. In ...
A common and puzzling feature of migmatite terranes is the presence of synkinematic leucosomes oriented perpendicular to the maximum principal compressive stress axis, s1, particularly leucosomes oriented parallel to the axial plane of folds. These are parallel to planes of compaction, but experiments predict that leucosomes should form in dilational bands oriented instead at small angles to s1...
Over summer 2017, I continued my research on dikes emplaced during the waning stages of the Neoproterozoic-Ordovician Ross Orogen, a continental arc along the present day location of the Transantarctic Mountains in Antarctica. The dikes intrude calc-alkaline plutons constituting the main intrusive phase as well as metasedimentary rocks formed during early stages of orogenesis. These dikes compr...
Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and it...
Mafic Mound” is a distinctive and enigmatic feature 75 km across and 1km high near the center of the vast South Pole-Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression and a homogeneous high-Ca pyroxene-bearing composit...
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