نتایج جستجو برای: type flood basalts
تعداد نتایج: 1365507 فیلتر نتایج به سال:
Introduction: In Table 1 we have compiled the chemical compositions, including Ni and Co, of representative basalts from Earth, Moon, Mars and Vesta. The SiO2 and MgO concentrations of all basalts cover only a small compositional range, suggesting a similar extent of fractionation. The Ni and Co contents increase with the radius of the planet, with very low concentrations in Vesta and increasin...
The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB) under one class i.e., as mid-oceanic ridge basalts (MORB). Hence, a method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB). We have applied Artificial Neur...
The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary age. Peak volcanic activity took place in the north-central part of the Lut block during the Eocene, and then dramatically decr...
Introduction: Major ambiguities remain in our current understanding of the geochemical evolution of the moon. That situation arises partly because (a) our geochemical and isotopic data sets for mare basalts are overly influenced by samples from the Procellarum KREEP Terrain (PKT [1]), and (b) samples of the highland crust useful for isotopic studies are limited in both quantity and quality. Fut...
Across the globe, flood control standards for reservoir engineering appear different due to various deciding factors such as flood features, society, economy, culture, morality, politics, and technology resources, etc. This study introduces an in-depth comparison of flood control standards for reservoir engineering for different countries. After the comparison and analysis, it is concluded that...
We report 230Th-238U disequilibrium data on mid-ocean ridge basalts recovered 5 to 40 kilometers off the ridge axis near 9 degrees 30'N of the East Pacific Rise. These data indicate near-symmetrical eruptions of normal mid-ocean ridge basalts (NMORBs) and incompatible element-enriched mid-ocean ridge basalts (EMORBs) as far as 20 kilometers off axis. Our results suggest large-scale subsurface l...
Some workers have held that mid-ocean ridge basalts are fractionated from high pressure (15-30 kbar) picritic primary magmas whereas others have favored primary magmas generated at about 10 kbar with compositions close to those of mid-ocean ridge basalts. Of critical significance are presumed differences in composition between experimentally determined primary magmas and the least fractionated ...
This chapter summarizes the oxygen isotope geochemistry of terrestrial basalts and their mantle sources, including the conceptual framework for interpreting such data and the phenomenology of known variations. In particular, the first section outlines the motivations for and first-order results of oxygen isotope studies of terrestrial and lunar basalts over the last 30 years; the second section...
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