نتایج جستجو برای: multiple magma source
تعداد نتایج: 1150256 فیلتر نتایج به سال:
Petrologic studies of igneous rocks often rely on whole-rock analyses alone to deduce source and melting histories. Whole-rock compositions represent a mixture of the processes responsible for the final texture and composition of the rock, but do not emphasize the evolutionary processes that the rock may have experienced. We examine the major, minor, and trace element compositions of plagioclas...
When volcanoes are active, there are characteristic signs such as ground movement, sounds, heat and ejected material. Each of these signs is a result of, and hence an information source for, fluid motion in volcanic conduits. Here we briefly review some of the links between these signs and fluid flow processes and suggest future directions that should allow advancement of eruption forecasting a...
Martian meteorite ALH84001 (ALH) is the oldest known igneous rock from Mars and has been used to constrain its early history. Lutetium-hafnium (Lu-Hf) isotope data for ALH indicate an igneous age of 4.091 +/- 0.030 billion years, nearly coeval with an interval of heavy bombardment and cessation of the martian core dynamo and magnetic field. The calculated Lu/Hf and Sm/Nd (samarium/neodymium) ra...
Numerous post-ophiolite intrusions exposed into the late Cretaceous–Paleocene Sabzevar ophiolite belt, northeast Iran. The intrusions consist of calc-alkaline intermediate to felsic rocks with metaluminous to peraluminous in nature and adakitic affinities. Based on U-Th-Pb dating on separated zircons by SHRIMP Ⅱ, the emplacement age of these rocks into the ophiolite zone is constrained to ~45 M...
Upper Eocene shoshonitic rocks have very good exposures in the Qaleh-Khargooshi area. These rocks have a wide range of SiO2 content (absarokite to toscanite) and belong to fifth phase of Eocene volcanism in this area. Clinopyroxene is present in all members of shoshonitic group as phenocryst, but they have altered in toscanites. The study of clinopyroxenes composition shows that this mineral h...
[1] A hydrovolcanic eruption near Cone D on the floor of Okmok caldera, Alaska, began on 12 July 2008 and continued until late August 2008. The eruption was preceded by inflation of a magma reservoir located beneath the center of the caldera and ∼3 km below sea level (bsl), which began immediately after Okmok’s previous eruption in 1997. In this paper we use data from several radar satellites a...
in the future, competitive advantages will be given to organisations that can extract valuable information from massive data and make better decisions. in most cases, this data comes from multiple sources. therefore, the challenge is to aggregate them into a common framework in order to make them meaningful and useful.this paper will first review the most important multi-criteria decision analy...
The shallow part of Kilauea’s magma system is conceptually well-understood. Long-period and short-period (brittle-failure) earthquake swarms outline a near-vertical magma transport path beneath Kilauea’s summit to 20 km depth. A gravity high centered above the magma transport path demonstrates that Kilauea’s shallow magma system, established early in the volcano’s history, has remained fixed in...
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