Results 31 to 40 of about 1,952 (183)
Reconstructing a Super-Eruption From the Upper Ordovician Period in the Eastern Pyrenees, Spain [PDF]
LithosphereThe Pyrenean basement rocks, NE of the Iberian Peninsula, southwestern Europe, include evidence of several pre-Variscan magmatic episodes which indicate the complex geodynamic history of this segment of the northern Gondwana margin from late ...
Joan Marti +2 more
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New data on Upper Carboniferous–Lower Permian deposits of Bol'shevik Island, Severnaya Zemlya Archipelago [PDF]
Polar Research, 2015 We present here a detailed study of the Upper Carboniferous–Lower Permian stratigraphy of Bol'shevik Island in the Severnaya Zemlya Archipelago, consisting of the analysis of sedimentary structures and lithostratigraphy, U/Pb detrital zircon dating and ...
Victoria B. Ershova +5 more
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Energy Science &Engineering, EarlyView.On the basis of core and log data, a Bayesian‐Optimized Random Forest model achieved 92.76% accuracy in classifying tight sandstone reservoirs. A gray relational analysis‐derived evaluation index shows > 80% consistency with actual gas zones. ABSTRACT Tight sandstone gas (TSG), an unconventional oil–gas resource, has heterogeneous reservoirs ...
Yin Yuan +8 more
wiley +1 more source
Cornulitids from the Upper Ordovician of northwestern Russia [PDF]
Carnets de géologie (Notebooks on geology), 2017 Four cornulitid species occur in the Rakvere Regional Stage in NW Russia. The new species Conchicolites rossicus is here described; it is the earliest known Conchicolites from the Ordovician of Baltica. The new species has very small tubes with sharp, strong and regular annulations.
Olev Vinn, Anna Madison
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Geological Journal, EarlyView.The Pangkaimen Au–Ag deposits belong to the epithermal Au deposits, which are of great significance for guiding the research and development of this type of gold deposit. Metallogenic model diagram of Pangkaimen Au–Ag deposit. ABSTRACT The gold (Au) metallogenic belt in the northern Great Xing'an Range is characterised by the wide occurrence of the ...
Sheng Lu +8 more
wiley +1 more source
New Results From the Pre‐Pottery Neolithic Site of Al Uyaynah, Tabuk, in Northwestern Saudi Arabia
Arabian Archaeology and Epigraphy, EarlyView.ABSTRACT Al Uyaynah is a low sandstone mound on an alluvial plain, long known for its extensive surface remains of stone‐built circular and rectangular structures. Following test excavations in 2012, more detailed excavation was undertaken in 2016 within one of the largest rectangular stone structures.
Khalid Alasmari +6 more
wiley +1 more source
Recent developments in the Upper Ordovician and lower Silurian conodont biostratigraphy in Estonia [PDF]
Estonian Journal of Earth Sciences, 2007 The current state of and the latest developments in the conodont-based biostratigraphical studies of Upper Ordovician and lower Silurian strata in Estonia are discussed.
Männik, Peep
doaj
An extremely brief end Ordovician mass extinction linked to abrupt onset of glaciation
Solid Earth Sciences, 2019 The end Ordovician mass extinction (EOME) was the second most severe biotic crisis in Phanerozoic, and has been widely linked to a major glaciation. However, robust geochronology of this interval is still lacking.
Ming-Xing Ling +17 more
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Boreas, EarlyView.Map of Lower sediment (LS) thickness is a surrogate for the distribution of Thorncliffe Formation (TF) and ~75% of TF thickness from the slope of Niagara Escarpment east to Brighton. Inset images show the LS sequence at the Don Valleys brickyards (DVBY) and undeformed TF sand and gravel (~15 m) below Newmarket Till (NT) at sites L and Co.
David R. Sharpe +3 more
wiley +1 more source
Petroleum Exploration and Development, 2012 The control of structural evolution on the development of different types of Ordovician reservoirs in the Ordos Basin is discussed by studying the evolution of the Ordovician top boundary in geological times, and the mechanisms of formation and evolution
Xinquan RAN +5 more
doaj +1 more source