نتایج جستجو برای: trachyte
تعداد نتایج: 108 فیلتر نتایج به سال:
Abstract La Réunion Island includes two major volcanic systems. About 0·5 Myr ago, Piton des Neiges volcano declined, while de la Fournaise grew on its flank. Since then the shield has produced homogeneous lavas with chemical compositions transitional between alkali and tholeiitic basalts. In April 2007, emitted a very small volume of trachytic pumice during largest historical eruption. We cond...
Abstract. Shallow-level igneous intrusions are a common feature of many sedimentary basins, and there is increased recognition the syn-emplacement deformation structures in host rock that help to accommodate this magma addition. However, sub-seismic structure reservoir-scale implications remain poorly understood. The Trachyte Mesa intrusion small (?1.5 km2), NE–SW trending satellite Oligocene-a...
We present new viscosity measurements for melts spanning a wide range of anhydrous compositions including: rhyolite, trachyte, moldavite, andesite, latite, pantellerite, basalt and basanite. Micropenetration and concentric cylinder viscometry measurements cover a viscosity range of 10 to 10 Pas and a temperature range from 700 to 1650 °C. These new measurements, combined with other published da...
The Campanian Ignimbrite is a 4200 km trachyte^phonolite pyroclastic deposit that erupted at 39 3 0 1ka within the Campi Flegrei west of Naples, Italy. Here we test the hypothesis that Campanian Ignimbrite magma was derived by isobaric crystal fractionation of a parental basaltic trachyandesitic melt that reacted and came into local equilibrium with small amounts (5^10 wt%) of crustal rock (ska...
The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X-ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or95); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and...
Interpretations of faunal assemblages from the late Miocene Mpesida Beds in the Tugen Hills of the Central Kenyan Rift Valley have figured prominently in discussions of faunal turnover and establishment of the modern East African communities. These faunal changes have important implications for the divergence of the human lineage from the African apes ca. 8-5 Ma. While fossil material recovered...
Since May 2018 till the end of 2021, Mayotte island has been locus a major submarine volcanic eruption characterized by offshore emission more than 6.5 km 3 basanitic magma. The occurred along WNW–ESE trending ridge on east flank where, in addition, several seemingly recent phonolitic bodies were also identified close to island. To define realistic scenarios magma ascent and potentially predict...
The Dongpuzi deposit is an epithermal gold located in the southern margin of Shaozihe volcanic fault basin Liaodong Peninsula. On basis fluid inclusion and C–H–O–S–Pb isotope data, a metallogenic model established for deposit. mineralization at has experienced quartz–pyrite (I), quartz–sulfide (II), quartz–calcite (III) stages. quartz from ore stage II liquid-dominated aqueous inclusions, which...
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