نتایج جستجو برای: Calcrete

تعداد نتایج: 70  

2014
Pablo G. Silva Cari Zazo

Pleistocene alluvial fan surfaces of the Campo de Cartagena-Mar Menor Basin (Murcia, SE Spain) are capped by thick mature calcretes. Calcrete profiles consist mainly of six different horizons: prismatic, chalky, nodular, massive, laminar and coated-gravels. Petrographic study of the calcretes has shown the occurrence of features such as alveolar septal structures, calcified filaments, coated gr...

Journal: :Geological Magazine 1902

Journal: :journal of mining and environment 2012
reza ghavami-riabi h.f.j theart

the trace element contents on the surface originated from mineralization would depend to the thickness of the calcrete layer above the ore deposit on the surface. a very thick layer of calcrete may not allow for much dispersion of the elements of interest in the surface. these elements may be concentrated in non-magnetic and magnetic part of calcrete. based on the current research, mineralogica...

H.F.J Theart Reza Ghavami-Riabi,

The trace element contents on the surface originated from mineralization would depend to the thickness of the calcrete layer above the ore deposit on the surface. A very thick layer of calcrete may not allow for much dispersion of the elements of interest in the surface. These elements may be concentrated in non-magnetic and magnetic part of calcrete. Based on the current research, mineralogica...

Journal: :American journal of physical anthropology 2013
Philip J Hopley Andy I R Herries Stephanie Edwards Baker Brian F Kuhn Colin G Menter

Following the discovery of the "Taung Child" (Australopithecus africanus) in 1924 in the Buxton-Norlim Limeworks near Taung, the fossil-bearing deposits associated with the Dart and Hrdlička pinnacles have been interpreted as the mined remnants of cave sediments that formed within the Plio-Pleistocene Thabaseek Tufa: either as a younger cave-fill or as contemporaneous carapace caves. When combi...

بیات, امید, خادمی, حسین , کریم زاده, حمیدرضا ,

Clay mineralogy of paleosols provides more information about Quaternary climatic changes and paleoenvironmental conditions. Clay minerals of an alluvial fan in eastern Isfahan were studied, using x-ray diffraction analysis. Studied paleosols are located on old Qf1 and Qf2 geomorphic surfaces. Qf1 geomorphic surface is older and topographically higher than Qf2. The results of clay mineralogy sho...

2007
Yifeng Wang Daniel Nahon

Calcretes are the calcite crusts widely developed at the Earth's surface in semi-arid regions (e.g., Goudie, 1983; Nahon, 1991; Wright and Tucker, 1991 ). Thickness of calcretes is tens of centimeters to a few meters, and increases downslope. Calcretes pseudomorphically replace all underlying silicate rocks. Parent rock structure and bulk volume are preserved. In the lower part of calcrete prof...

شمعانیان, غلامحسین, شفیعی, بهنام , کیا ‌اشکوریان, مریم ,

Paleosols of the study area is a part of the Eastern-Alborz Zone which is located about 50 km southeast of Azadshahr. These paleosols developed on floodplain and lacustrine facies of the Devonian Padeha Formation. Based on the field and textural evidences, two major paleosol horizons identified as A and B horizons. The A horizon consists of calcrete and noncalcrete paleosols which is located in...

Journal: :Molecular ecology 2007
Faith M Walker Andrea C Taylor Paul Sunnucks

Spatiotemporal distributions of key resources are hypothesized to underpin sociobiological patterns. Burrow availability and quality is of paramount importance to fossorial animals. The southern hairy-nosed wombat (Lasiorhinus latifrons) burrows in both hard and friable soils. Theoretical and empirical studies suggest that the harder substrate should promote closer geographical clustering of bu...

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