نتایج جستجو برای: mafic dykes
تعداد نتایج: 2656 فیلتر نتایج به سال:
Approximately 90% of the upper crust exposed in southern Jordan is composed of intrusive rocks of latest Neoproterozoic age, grouped into two major subdivisions: the Aqaba (600–640 Ma) and the Araba (560–600 Ma) complexes. The Aqaba complex comprises several suites that range in composition from gabbro to high silica granite (45–80% SiO2) and follow a high-K calc-alkaline trend. This phase, whi...
Introduction: Mafic igneous rocks serve as probes of the interiors of their parent bodies – the compositions of the magmas contain an imprint of the source region composition and mineralogy, the melting and crystallization processes, and mixing and assimilation. Although complicated by their multifarious history, it is possible to constrain the petrologic evolution of an igneous province throug...
Introduction: A long-standing, fundamental question in planetary geoscience is: "How similar are the geological histories of Earth and Venus, and when and how did their evolution diverge?" Did Venus once have oceans and a more Earth-like climate, as suggested by Pioneer-Venus data [1]? If so, when, how, and why did it transition to current conditions, and are traces of this early period, and th...
The Alvand plutonic complex is composed of various plutonic rocks, mafic and felsic dikes (pegmatites and aplites). Pegmatites and aplites consist of quartz, feldspar, mica, tourmaline, garnet and allanite. Based on the mineralogycal compound, pegmatites can be divided into tourmaline-garnet-muscovite-bearing, aluminosilicate-bearing and tourmaline-bearing pegmatites and aplites are composed of...
Mafic and ultramafic layered rocks located in south of Orzuieh (Baft, Kerman province), consist of plagioclase bearing ultramafic rocks (including olivine, orthopyroxene , clinopyroxene and plagioclase), olivine gabbros (including plagioclase, olivine, orthopyroxene and clinopyroxene) and gabbronorites (including plagioclase, orthopyroxene and clinopyroxene and amphibole) and constitute the maf...
[1] High‐resolution compositional data from Moon Mineralogy Mapper (M) for the Moscoviense region on the lunar farside reveal three unusual, but distinctive, rock types along the inner basin ring. These are designated “OOS” since they are dominated by high concentrations of orthopyroxene, olivine, and Mg‐rich spinel, respectively. The OOS occur as small areas, each a few kilometers in size, tha...
2755. [19] Wieczorek, M. A. et al. (2013) Science 339, 671-675. Figure 1: Locations of floor-fractured craters [2] plotted on a basemap of crustal thickness [19]. Floor-fractured craters are preferentially located in regions of intermediate (20-30 km) crustal thickness. Mare deposits are located primarily on the lunar nearside and in regions of thinner crust. Figure 2: Crater Buch B (17.0°E, 39...
The Piedade Granite (approximately 600 Ma) was emplaced shortly after the main phase of granite magmatism in the Agudos Grandes batholith, Apiaí-Guaxupé Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyritic granites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite MBmg unit) and core (metaluminous titanite-bearing biotite monzogranite BmgT unit) and ...
Introduction: Several types of magnesian highlands rocks occur in the lunar samples including the mafic Mg-suite rocks, magnesian feldpathic granulites, and magnesian anorthosites. Some mafic magnesian rocks are easily accommodated into the magma ocean model, as large variations in Mg/Fe are expected as the magma ocean crystallizes, forming source regions for magnesian melts. The origin of othe...
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