نتایج جستجو برای: Plio-Quaternary lavas
تعداد نتایج: 16137 فیلتر نتایج به سال:
Plio-Quaternary volcanic eruptions in southeast of Nehbandan are composed of basic rocks, overlying the Late Cretaceous flysch-type and younger alluvium deposits. Petrographically, these rocks are basalt, basaltic andesite and andesite. These lavas are characterized by porphyritic, microlitic-porphyry, trachytic and glomeropophyritic textures. They contain plagioclase, clinopyroxene (augite), o...
The Plio–Quaternary volcanic eruptions have made basaltic lavas in NW Iran and Azerbaijan. Basaltic lavas with prismatic structure cover the Plio-Pliostocene volcano-sedimentary or Quaternary alluviums. The studied regions are situated in Azerbaijan provinces in areas of Monnavar, Herris, Ahar, Kaleibar, Mahabad, Salmas, Maku, Marand, Sarab and Zunuz. The studied sample rocks are olivine basalt...
Both the Sistan Suture Zone of eastern Iran and the Nehbandan Fault contain Plio-Quaternary Nehbandan mafic lavas. Positive anomalies in the large ion lithophile elements (LILE) and negative anomalies in Nb (niobium) exist in these mafic lavas. This indicates the occurrence of subduction magmatism and post-collision volcanism. Petrologic and geochemical analyses distinguished two groups of lava...
Cenozoic volcanic activity in Morocco started the Miocene and proceeded, after a short break, during Pliocene Quaternary. Calc-alkaline magmatic occurred first was accompanied by eruption of transitional lavas, followed Plio-Quaternary alkali basaltic activity, which emplaced within Neogene sedimentary basins Rif belt its foreland. From calc-alkaline to alkaline magmatism, passing through term,...
Trachyandesites, trachytes and latites associated with ignimbrite and pyrocalstic rocks, characterized by shoshonitic affinity are the main Plio-Quaternary volcanic rocks in the Sabalan region (Ardabil). Plagioclase, K-feldspar, biotite associated with clinopyroxene and glass are the main constituents of these lavas. Plagioclases are andesine to labradorite while clinopyroxenes have augitic com...
The volcanic rocks with the Plio-Quaternary age, are exposed in the northern part of the Sanandaj-Sirjan zone, in northwest Urmia. The main mineral phases are olivin + clinopyroxene ± plagioclase, that are present as both phenocrysts to microcrystalline with other minor minerals. The dominant textures of these rocks are porphyry, microlithic porphyry, hyalo-porphyry, glomeroporphyritic and vesi...
Recycled subducted ocean crust has been traced by elevated 187Os/188Os in some studies and by high nickel and low manganese contents in others. Here, we show that these tracers are linked for Quaternary lavas of Iceland, strengthening the recycling model. An estimate of the osmium isotopic composition of both the recycled crust and the mantle peridotite implies that Icelandic Quaternary lavas a...
Understanding the evolution of river systems in southern Africa is fundamental to constrain landscape and sediment dispersal patterns. It widely considered that upper Zambezi River was connected with Limpopo during Cretaceous, forming what then largest Africa. Crustal flexure Paleogene severed drainage from Limpopo, setting framework modern systems. We present first evidence—based on heavy-mine...
The region of Chelghoum Laid - Tadjenanet is located in eastern Algeria, the high plains. This area characterized by a varied age (Mio-Plio-Quaternary) formations and human demand answered groundwater hosted into superficial aquifer Mio-Plio-Quaternary formations. However, overexploitation this leads to drop piezometric surface an increase salinity. salinity water. A hydrochemical study using c...
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