نتایج جستجو برای: tuffs
تعداد نتایج: 354 فیلتر نتایج به سال:
Zeolitic Alteration of Vitric Tuffs in the Akita Oil Field (Part 3) On the Noshiro sedimentary basin
Correlation of volcaniclastic deposits of the Bedded Tuff Member (K4) of the Kapthurin Formation (Kenya) provides the means to assess the nature of archaeological change during the later middle Pleistocene, a time period critical to human evolution but poorly represented at other African localities. Field stratigraphic evidence, and petrographic and electron microprobe geochemical analyses of v...
Zeolitic tuffs are found in different parts of the world. Iranian zeolite is a low-cost material that can be frequently found in nature. Surfactant-modified zeolite (SMZ) can be used for the adsorption of natural organic matter (NOM) from aqueous solutions. The adsorption study was conducted to evaluate the adsorption capacity of SMZ; furthermore, the effects of contact time, initial pH, and th...
Post-Eocene volcanic rocks of Alborz tectonic zone located in the NE of Qazvin, composed of rhyolite, trchydacite, trachyandesite, andesite, trachybasalt and basalt with porphyritic textures, pyroclastic rocks and volcanic red breccia which are settled alternatively on Eocene pyroclastics and tuffs. The volcanic rocks are enriched in LIL and depleted in HFS elements which may indicate a calc-al...
BACKGROUND The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the ...
Conceptual evaluation of the potential role of fractures in unsaturated processes at Yucca Mountain.
A wide array of field observations, in situ testing, and rock and water sampling (and subsequent analyses) within the unsaturated zone (UZ) of Yucca Mountain demonstrate the importance of fractures to flow and transport in the welded tuffs. The abundance of fractures and the spatial variability in their hydraulic properties, along with the heterogeneity within lithologic formations, make evalua...
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