Early Geological Explorations of the Silurian System in Iowa
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Early Silurian (Llandovery) Trilobite fauna from
The aim of this study is to analyze the assemblage of trilobites in the Silurian sequences of Iran by exploring stratigraphic section of the Silurian Niur Formation (Asadli section). Based on comprehensive field studies and laboratory investigations three Trilobite genera were identified in the study area including Calymene blumenbachii, Gravicalymene convolva, Dalmanites brevigladiolus </...
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The upper part of Shirgesht (UPS) and lower part of Niur (LPN) formations (Ordovician-Silurian) consist of sandstone, shale and limestone, respectively. The petrography and geochemical analysis conducted to evaluate provenance of siliciclastic deposits in order to understand the paleogeography of Central Iran during the Early Paleozoic time. This study shows that quartz and K-feldspar are the m...
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Gold was obtained through washing or panning of the river sands during initial periods of civilisation. With the advent of knowledge of metallurgical processing of ores it was recovered through mining of in-situ quartz reefs, and then from auriferous sulphide ores. The metal mining activities are evidenced in the form of large number of ‘ancient metal mines’ or ‘old workings’ and ‘placer mining...
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Palaeomagnetic data are presented from early Silurian (Upper Llandovery) lavas from the Tortworth Silurian inlier of south-west England. Two magnetization components are recognized on the basis of contrasting demagnetization characteristics. A lower unblocking-temperature component (<350 "C) is oriented parallel to the Earth's present magnetic field at the sampling site (N = 46, declination = 3...
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Among the many parameters affecting the design of hydraulic structures on fissured rocks are orientation of principal permeability axes and degree of anisotropy of fissured rocks. Geological explorations rarely provide this type of information. If at all the information is available, methods employed are computationally cumbersome and inefficient. A new concept of simple equations and geometric...
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