نتایج جستجو برای: picritic melt
تعداد نتایج: 16962 فیلتر نتایج به سال:
Melting of the mantle during continental breakup leads to magmatic intrusion and volcanism, yet our understanding of the location and dominant mechanisms of melt generation in rifting environments is impeded by a paucity of direct observations of mantle melting. It is unclear when during the rifting process the segmented nature of magma supply typical of seafloor spreading initiates. Here, we u...
[1] Seismic studies repeatedly image a low‐velocity layer overlying the mantle transition zone in tectonic settings ranging from subduction zones to continental cratons. This layer has been hypothesized to result from the presence of a dense partial melt formed by dehydration melting as relatively wet transition zone material is advected by convection currents into the low‐water‐solubility uppe...
the rapid melting of a semi- infinite body due to the absorption of a cw laser beam radiation has been studied. the enthalpy technique for the solution of phase change problems has been used in an explicit finite difference form to calculate the transient temperature distribution in the semi-infinite body and the growth rate of the melt pool. the technique has been modified so that it is not ne...
the nain and ashin ophiolites are located in northeastern isfahan province, in western central-east iranian microplate. pillow lavas are one of the most significant cretaceous rock units. the lower partial melting degree in mantle peridotites of ashin ophiolite, and the derived melt by melting their clinopyroxene caused a more basic (basalt) and enriched nature for the ashin pillow lavas, where...
Lavas from the Puʻu ʻŌʻō eruption of Kīlauea Volcano are thought to partially bypass the shallow magma reservoir beneath the volcano's summit, and thus, provide a relatively direct “window” to the mantle. Here we use high-precision U-series isotope measurements of Puʻu ʻŌʻō lavas (1985–2001) to investigate the timing and mechanism of melt transport within the Hawaiian mantle plume. The lavas di...
We report the first systematic study of H2O speciation in dacitic melt with total dissolved H2O ranging from 1.4 to 2.6 wt%. Samples were heated in a one-atmosphere tube furnace at 480–590 °C for certain durations and then quenched in water or air. Species concentrations were measured with Fourier transform infrared (FTIR) spectroscopy. At a given temperature, the equilibrium constant for the r...
Acrylamide was grafted in low density polyethylene during melt processing in the presence of a free radical initiator using a torque rheometer in a closed system. Effects of processing time, acrylamide and benzoyl peroxide concentrations were studied. FTIR studies revealed that the degree of grafting increased by an increase in acrylamide concentration. Maximum grafting was obtained at 7 mi...
the incorporation of several anti-rodent masterbatches into polyethylene (pe) granules used for gas pipes and the effects of the masterbatches on the physical properties of the pipes were studied. four commercial anti-rodent masterbatches from different international companies including, clariant, alchemix, polyone, and newgen were used in this research. each of the masterbatch was primarily dr...
the aim of this study is to prepare novel sorbitol based extended release tablets by melt dispersion method using carbamazepine as a model drug. carbamazepine was melted along with sugar alcohol to get melt dispersion granules (mgds) and was characterized by differential scanning calorimetry (dsc), powder x-ray diffractometry (xrd) and solubility study. the physical and chemical parameters of m...
Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental background. The southern limit of melt coinci...
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