Results 221 to 230 of about 2,124,047 (278)

The geochemistry of the sedimentary rocks from the Huadi No. 1 well in the Wufeng-Longmaxi formations (Upper Ordovician-Lower Silurian), South China, with implications for paleoweathering, provenance, tectonic setting and paleoclimate

Marine and Petroleum Geology, 2019
The Late Ordovician-Early Silurian transition was a critical interval in Earth's history, marked by mass extinction, the Gondwana glaciation and volcanic events.
Xiangying Ge, Chuan-long Mou, Qian Yu, Wei Liu, X. Men, Jianglin He   +5 more
semanticscholar   +1 more source

Upper Ordovician of Central Texas

AAPG Bulletin, 1953
Discovery of Upper Ordovician strata in the Llano uplift of central Texas is here reported. These rocks, named the Burnam limestone, are considered to be correlative with some part of the Richmond group, because of the presence in them of Halysites (Catenipora), Streptelasma rusticum, Austinella, Mcewanella raymondi, Strophomena aff. S.
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The lithostratigraphy of the upper Ordovician of central Portugal

Journal of the Geological Society, 1988
A lithostratigraphic scheme for the upper Ordovician of central Portugal is described incorporating previously-erected local lithostratigraphic terms and new units. Thirteen formations (10 new), including 11 members (eight new), with one named bed, are arranged into four groups (three new). A description of each unit is given, together with comments on
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Upper Ordovician Shales in Central Kansas

AAPG Bulletin, 1947
Shales approximately equivalent in age to Maquoketa beds in Iowa and to Sylvan strata in Oklahoma form the topmost Ordovician over much of central Kansas. They normally consist of two members: (1) an upper dolomitic gray shale, which is siliceous and cherty in some areas, and (2) a lower soft flaky shale.
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Sedimentology of Upper Ordovician regressive strata in Västergötland

Geologiska Föreningen i Stockholm Förhandlingar, 1980
Abstract The sedimentology of the upper Ashgillian Dalmanitina Beds in the Billingen-Falbygden area in Vastergotland is studied. They exhibit facies of shallow-water type. In contrast, the underlying Ulunda, Jonstorp and Nittsjo formations (‘Tretaspis Shales’) and the overlying Llandoverian Rastrites Shale were formed in notably deeper water.
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Middle and Upper Ordovician stratigraphy of the southernmost Appalachians

1986
Abstract Facies changes in Middle and Upper Ordovician stratigraphy can be seen in a series of exposures on I-59 and Alabama 77 in the vicinity of Gadsen, Alabama (Fig. 1).
Thornton L. Neathery, James A. Drahovzal
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New Upper Ordovician edrioasteroids from Morocco

Geological Society, London, Special Publications, 2018
Abstract Edrioasteroids from the Katian, Lower Ktaoua and Upper Tiouririne formations provide new data on several previously described species and two new species of edrioasteroids. Ontogenetic and palaeoecological data are provided for Moroccopyrgus matacarros .
Colin D. Sumrall, Samuel Zamora
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Facies of Middle and Upper Ordovician Rocks of Iowa

AAPG Bulletin, 1955
Recent subsurface and outcrop studies of the Middle and Upper Ordovician rocks in Iowa show that facies changes are of considerable importance in the interpretation of the geologic history and in the correlation of the strata, which are oil-bearing in adjoining states. From the area of outcrop in northeastern Iowa the beds dip generally southwest below
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New finding of Upper Ordovician flora in Kazakhstan

International Geology Review, 1965
Sixteen occurrences of fossils of Ordovician land plants are recorded from Kazakhstan. These plant remains occur together with a fauna which dates the beds as Upper Ordovician (Caradocian). The fragmentary specimens belong to at least three ancient types of land flora: Psilopsida, Lycopsida, and Sphenopsida.
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Upper Cambrian and Lower Ordovician Rocks in Kansas

Bulletin (Kansas Geological Survey), 1948
This report deals with Upper Cambrian and pre-Simpson Lower Ordovician beds that lie below the surface in Kansas and crop out in the surrounding states. The investigation was begun as a project of the Kansas Geological Survey and was completed under the auspices of the United States Department of the Interior.
Raymond P. Keroher, Jewell J. Kirby
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