Results 171 to 180 of about 1,497,171 (212)

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
openaire   +1 more source

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
openaire   +1 more source

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.
openaire   +1 more source

Mottled upper Ordovician carbonates in Northwest Georgia

Journal of Sedimentary Research, 1975
Abstract Mottled red and gray-green, silty limestones and calcareous siltstones occur in the Sequatchie Formation (Upper Ordovician) near Ringgold, Georgia. X-ray diffraction and optical methods show that the red mottles are due to the presence of diagenetic hematite, which was formed by oxidation of iron expelled from detrital ...
F. H. Manley, D. E. Ogren, L. C. Webb
openaire   +1 more source

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
openaire   +1 more source

Facies of Middle and Upper Ordovician Rocks of Iowa

AAPG Bulletin, 1955
ABSTRACT 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.
openaire   +1 more source

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.
openaire   +1 more source

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
openaire   +1 more source

Upper Ordovician Glaciation in Northwest Africa? Discussion

Geological Society of America Bulletin, 1971
Faunal, paleomagnetic, and sedimentological arguments that claim to show the existence of a continental ice sheet in northwest Africa during the Ordovician and Silurian are questionable. Neither the fauna nor the relevant pole positions necessitate the presence of land ice.
openaire   +1 more source

Palynostratigraphy of upper Cambrian-upper Ordovician intracratonic clastic sequences, North Africa

1999
Detailed palynological study of subsurface sections in the Algerian Sahara (boreholes Nl-2 and Uc-101) and southern Tunisia (boreholes Sn-1 and St-1) enables precise dating and intrabasinal and extrabasinal stratigraphic correlation. Most of the study samples proved palyniferous, yielding abundant, well preserved acritarchs (148 species) together with ...
VECOLI M., TONGIORGI, MARCO, ABDESSELAM ROUGHI F. F., BENZARTI R., MASSA D.   +4 more
openaire   +3 more sources