نتایج جستجو برای: hard rocks

تعداد نتایج: 168880  

2007
S. N. Das N. C. Mondal V. S. Singh

Identifying a good site for groundwater exploration in hard rock terrain is a challenging task. In hard rocks, groundwater occurs in secondary porosity developed due to weathering, fracturing, faulting, etc., which is highly variable and varies sharply within very short distances, contributing to near-surface inhomogeneity. In such situations topographic, hydrogeological and geomorphological fe...

2011
DAVID F. BARNES Thomas B. Nolan GORDON E. ANDREASEN ARTHUR GRANTZ

________________________________________ Introduction __ ___________________________________ Area covered.__________________________________ Aeromagnetic survey.___________________________ Gravity survey.________________________________ Acknowledgments--.. __1________________________ Geology __ __ ____________ _ Rock units_____________________________________ Carboniferous and older rocks._____...

Journal: :زمین شناسی اقتصادی 0
عادل ساکی هوشنگ پورکاسب

the cheshin meta-calcareous rocks (permo triassic) in southeast hamedan outcrop in association with a variety of pelitic schists and hornfels rocks. the intrusion of the alvand batholith (jurassic age) into pelitic and calcareous host rocks has produced metamorphic rocks in the hamedan area (cheshin village). on the basis of the dominance of calcite/dolomite, silicate and ore minerals, the calc...

شریفیان عطار, رضا , ملائی, حبیب ,

The Jajarm Bauxite deposit 16 kilometers E-W trending and overlis, the Karstic dolomite rocks of the Elika Formation. The study of texture and different phases has been carry out in order to understand the degree of crashing, particles size, condition of formation, degree of crystallization, porosity, distribution of constituent elements and beneficiation for the propose of digestion and p...

2009
M. L. Becker

There is a great need for more precise absolute ages for sedimentary rocks. We have been actively involved in developing techniques to directly date sedimentary rocks, rather than using associated igneous rocks, or using relative dating techniques. Sedimentary phosphate nodules (i.e. coprolites) are ideal candidates for absolute dating of sedimentary rocks. Phosphates occur commonly within the ...

2015
Alan D. Chapman Mihai N. Ducea Nadine McQuarrie Matthew Coble Lucian Petrescu Derek Hoffman

Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60–70 km) and high average elevations (3–4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rock...

2006
Ramananda Chakrabarti Asish R. Basu

The Lonar impact crater in the Deccan Traps of the Indian peninsula provides unique opportunities to study physical and chemical processes of impact cratering on basaltic targets, because terrestrial impact craters on basalts are extremely rare. Such studies are needed for determining provenance and other parameters of the excavated rocks and the cratering phenomenon that may have implications ...

Journal: :Environmental entomology 2011
Joseph McCaffrey Candace Galen

Formica neorufibarbis Emery is a dominant alpine ant in North America. Above timberline, colonies nest under rocks, placing brood against the rock surface to warm during the day. We tested the hypothesis that nest rock preference represents a mechanism of behavioral thermoregulation and used a demographic model to explore its impact on the species' altitudinal range. Under sunny conditions roc...

2002
Jim L. Oliver C. Jay Hodgson

rocks of the Stuhuni and King Salmon Groups; a pre-.Middlm: Triassic unconformity is found througbmt the North American Cordillera (Read and Okulitch, 1977, Siberling, 1973:. In the Stikine Terrane, late Triassic volcanic rocks ar: dominantly fragmental andcommonly alkalic. Based on bul:: rock chemistry, both extensional, ba:k-arc, and Fore-ar: tectonic settings have been suggested tor these r...

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