نتایج جستجو برای: trachyte
تعداد نتایج: 108 فیلتر نتایج به سال:
The 39-day long eruption at the summit of Eyjafjallajökull volcano in April-May 2010 was of modest size but ash was widely dispersed. By combining data from ground surveys and remote sensing we show that the erupted material was 4.8±1.2·10¹¹ kg (benmoreite and trachyte, dense rock equivalent volume 0.18±0.05 km³). About 20% was lava and water-transported tephra, 80% was airborne tephra (bulk vo...
A ferromagnetic oxide mineral with spinel structure was separated from Hawaiian volcanic rocks ranging from basalt to trachyte . The chemical compositions of all the specimens have been arranged on an oxygen reaction line, and can safely be interpreted as the result of a process of either oxidation or reduction of material with composition on or near this line. In the trachyte the mineral was f...
The Matangkaka manganese deposit is an unusual Quaternary epithermal stratabound oxide from Ambitle Island in the Feni Group, New Ireland Province, Papua Guinea. a small volcanic island that has undergone explosive and effusive activity. Oldest rocks on consist of mafic–intermediate lavas epiclastic Pleistocene Volcano (Waramung Volcanics). These rest unconformably Oligocene calcilutites Basin....
Petrological data have been acquired on the natural trachytes from the Chaîne des Puys, French Massif Central, and on experimental products from phase equilibria in order to (i) constrain the storage conditions of the trachytic magmas that lead to explosive eruptions (dome destructions as block-and-ash flows or pumice-and-ash flows) and (ii) provide phase relationships and chemical compositions...
Tectonically active regions are characterized by complex landscapes comprising soils with heterogeneous physicochemical properties. Spatial variability of nutrient sources enhances landscape biodiversity and creates habitats potentially attractive for animals humans. In this study, we analyze the role geological processes in distributions soil nutrients southern Kenya Rift, a key region interpr...
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