Results 51 to 60 of about 65,602 (237)

Graptolites from Silurian (Llandovery Series) sedimentary deposits attributed to a forearc setting, Co To Formation, Co To archipelago, northeast Vietnam [PDF]

open access: yes, 2020
Newly collected graptolites from the Co To Formation, Co To archipelago, NE Vietnam, comprise assemblages indicative of two biostratigraphical levels within the lower Silurian, Llandovery Series, Telychian Stage: the co-occurrence of Spirograptus ...
Doan, Hung Dinh   +9 more
core   +1 more source

The first report of South American edrioasteroids and the paleoecology and ontogeny of rhenopyrgid echinoderms [PDF]

open access: yes, 2013
A new species of rhenopyrgid edrioasteroid Rhenopyrgus piojoensis sp. nov. is described form the Silurian (Lower Lud− low) Los Espejos Formation in the Precordillera of Argentina.
Heredia, Susana Emma   +3 more
core   +1 more source

Shale lithofacies types and reservoir characteristics from Ordovician Wufeng Formation to the first sub-member of the first member of Silurian Longmaxi Formation, northeast Zhaotong area

open access: yesShiyou shiyan dizhi, 2023
Shale lithofacies has an important influence on shale reservoirs. It controls the hydrocarbon generation capacity, storage performance and fracturing performance of shale to a certain extent.
Guanbao REN   +3 more
doaj   +1 more source

Geologic quadrangle map no. 47 [PDF]

open access: yes, 1978
Process Steps: 1. Either: a) a Portable Document Format (PDF) version of the map provided the Bureau of Economic Geology, University of Texas at Austin was converted from pdf to Tagged Image File Format (TIFF) or b) a paper map was scanned and saved in ...
Barnes, Virgil E. (Virgil Everett), 1903-1998
core   +1 more source

Tectonic overview of the West Gondwana margin [PDF]

open access: yes, 2008
The oceanic southern margin of Gondwana, from southern South America through South Africa, West Antarctica, New Zealand (in its pre break-up position), and Victoria Land to Eastern Australia is one of the longest and longest-lived active continental ...
Pankhurst, Robert J., Vaughan, Alan P.M.
core   +1 more source

Evidence from Rb–Sr mineral ages for multiple orogenic events in the Caledonides of Shetland, Scotland [PDF]

open access: yes, 2015
Shetland occupies a unique central location within the North Atlantic Caledonides. Thirty-three new high-precision Rb–Sr mineral ages indicate a polyorogenic history.
Bird, A. F.   +3 more
core   +3 more sources

Sediment‐stressed reefs over the past 420 Myr

open access: yesThe Depositional Record, EarlyView.
In order to fully elucidate the relationship between siliciclastic sedimentation and reef development, there needs to be a significant step change in how we record ancient and recent reefs. Only through the collection of constrained quantitative data, we can progress beyond the largely conjectural associations postulated for many ancient reefal systems.
Tanja Unger   +4 more
wiley   +1 more source

EVENT STRATIGRAPHY AND CORRELATION PROBLEMS OF THE ORDOVICIAN STRATA OF GORNY ALTAI AND SALAIR

open access: yesГеодинамика и тектонофизика, 2021
Study of the Ordovician sedimentary sequences of Gorny Altai and Salair has revealed lithological and paleontological features correlating with global sedimentary events:(1) The Acerocare Regressive Event (an initial event in the Early Tremadocian);(2 ...
N. V. Sennikov   +5 more
doaj   +1 more source

Detrital zircon SHRIMP U-Pb age study of the Cordillera Darwin Metamorphic Complex of Tierra del Fuego : sedimentary sources and implications for the evolution of the Pacific margin of Gondwana [PDF]

open access: yes, 2010
The Cordillera Darwin Metamorphic Complex in the southernmost Andes includes a basement of probable Palaeozoic age, a mid-Jurassic and younger volcano-sedimentary cover, and a suite of Jurassic granites, all of which were jointly metamorphosed during the
Calderon, M.   +6 more
core   +1 more source

Carbonate sedimentology: An evolved discipline

open access: yesThe Depositional Record, EarlyView.
Abstract Although admired and examined since antiquity, carbonate sediment and rock research really began with Charles Darwin who, during a discovery phase, studied, documented and interpreted their nature in the mid‐19th century. The modern discipline, however, really began after World War II and evolved in two distinct phases.
Noel P. James, Peir K. Pufahl
wiley   +1 more source

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