نتایج جستجو برای: upper devonian
تعداد نتایج: 206790 فیلتر نتایج به سال:
Steams, C. and Van der Voo, R., 1987. Paleomagnetic results from the Lower Devonian Llandstadwell Formation, Dyfed, Wales. Tectonophysics, 143: 329-334. A paleomagnetic investigation of the Lower Devonian Llandstadwell Eormation in southwest Wales has yielded a characteristic direction (declination = 196’. inclination = 5’) that passes a fold test. Comparison of the corresponding virtual geomag...
During the mid-Palaeozoic, vascular land plants (i.e., tracheophytes) underwent a great radiation that triggered development of biosphere – so-called Silurian–Devonian terrestrial revolution. However, little is known about how different plant groups impacted this process. A newly constructed dataset macrofossil genera used to characterize tempo and mode vegetation it spread out over subaerial h...
Exceptional braincase preservation in some Devonian placoderm fishes permits interpretation of muscles and cranial nerves controlling eye movement. Placoderms are the only jawed vertebrates with anterior/posterior obliques as in the jawless lamprey, but with the same function as the superior/inferior obliques of other gnathostomes. Evidence of up to seven extraocular muscles suggests that this ...
A large data base consisting of 40,679 well locations and 196,687 lithologic records was created from Illinois, Indiana, and Wisconsin well construction records for wells drilled during the period 1980-1997. The purpose of the database is to provide information for mapping the surface, thickness, transmissivity and hydraulic conductivity of the Quaternary, Silurian/Devonian, and Cambrian/Ordovi...
The Pricaspian Depression in the southeast of the East European Platform is one of the deepest depressions formed over the Baikal folded basement. The sedimentary cover consists of four structural levels corresponding to the major stages of its formation. The Riphean and the Vendian beds constitute the first structural level. The second one comprises deposits from the Devonian to the Upper Tria...
Improperly abandoned gas wells threaten human health and safety as well as pollute the air and water. In the next 20 years, tens of thousands of new gas wells will be drilled into the Marcellus, Utica, and Upper Devonian shale formations of Pennsylvania. Pennsylvania currently requires production companies to post a bond to ensure environmental reclamation of abandoned well sites, but the size ...
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