scholarly journals Pauxillites thaddei a new lower Ordovician hyolith from Morocco

2015 ◽  
pp. 51-54 ◽  
Author(s):  
Martin Valent
Keyword(s):  
Lower Ordovician

The Ibexian Series (Lower Ordovician), a replacement for "Canadian Series" in North American chronostratigraphy

1993 ◽  
Author(s):  
R.J. Ross ◽  
L.F. Hintze ◽  
Raymond L. Ethington ◽  
J.F. Miller ◽  
M.E. Taylor ◽  
...  
Keyword(s):  
North American ◽  
Lower Ordovician

Lower Ordovician through Lower Devonian cratonic margin rocks of the southern Great Basin

1981 ◽  
Vol 92 (5) ◽  
pp. 255 ◽  
Author(s):  
RICHARD H. MILLER ◽  
GEORGE A. ZILINSKY
Keyword(s):  
Great Basin ◽  
Lower Devonian ◽  
Lower Ordovician

INVESTIGATING THE ROLE OF AMORPHOUS FABRICS ASSOCIATED WITH CALATHIUM IN THE LOWER ORDOVICIAN FILLMORE FORMATION, UTAH, USA, USING PETROGRAPHY AND GEOCHEMISTRY

2017 ◽  
Author(s):  
Yezi Yang ◽  
◽  
Katherine N. Marenco ◽  
Pedro J. Marenco
Keyword(s):  
Lower Ordovician

TESTING THE HEIGHT AND EXTENT OF THE LOWER ORDOVICIAN (SAUK) TRANSGRESSION USING THE ROCK RECORD ACROSS THREE CONTINENTS

2019 ◽  
Author(s):  
Timothy L. Clarey ◽  
◽  
Aedan C. Parkes
Keyword(s):  
Lower Ordovician ◽  
Rock Record

A Lower Ordovician geomagnetic pole from Pennsylvania

1979 ◽  
Vol 44 (1) ◽  
pp. 65-72 ◽  
Author(s):  
James C. Hower
Keyword(s):  
Lower Ordovician ◽  
Geomagnetic Pole

The first Early Ordovician graptolites and marine incursions in eastern Alborz, Iran

2021 ◽  
pp. 1-14
Author(s):  
Adrian W. A. Rushton ◽  
Mansoureh Ghobadi Pour ◽  
Leonid E. Popov ◽  
Hadi Jahangir ◽  
Arash Amini
Keyword(s):  
Northern Iran ◽  
Early Ordovician ◽  
Lower Ordovician ◽  
Shale Formation ◽  
Kopet Dagh ◽  
Semnan Province

Abstract Graptolites have been collected from sections through Lower Ordovician strata in northern Iran. At the Saluk Mountains, in the Kopet–Dagh region, mudrocks yielded fragmentary tubaria of Rhabdinopora sp. cf. R. flabelliformis, indicating the presence of lower Tremadocian strata there; stratigraphically, they lie between two limestone beds with the euconodont Cordylodus lindstromi. At Simeh–Kuh in the eastern Alborz Mountains (Semnan Province), upper Tremadocian – lower Floian strata include laminated dark mudstones that contain restricted graptolite faunas, mainly of small declined didymograptids; these are thought to represent incursions of plankton during periods of marine highstands. The lower major flooding surface in Simeh–Kuh coincides with an invasion of the graptolite biofacies and an incursion of Hunnegraptus? sp.; the second major flooding surface is associated with an incursion of Baltograptus geometricus. They were most probably synchronous with those in the lower part of the Hunnegraptus copiosus Biozone and at the base of the Cymatograptus protobalticus Biozone in the of the Tøyen Shale Formation succession of Västergötland, Scandinavia, suggesting that observed characters of sedimentation were eustatically controlled.

Rosselia ichnofabrics from the Lower Ordovician of the Alborz Mountains (northern Iran): palaeoecology, palaeobiology and sedimentology

2021 ◽  
Author(s):  
Aram Bayet-Goll ◽  
Dirk Knaust ◽  
Mehdi Daraei ◽  
Nasrin Bahrami ◽  
Farzaneh Bagheri
Keyword(s):  
Northern Iran ◽  
Lower Ordovician

scholarly journals High-resolution isotope stratigraphy of the Lower Ordovician St. George Group of western Newfoundland, Canada: implications for global correlation

2009 ◽  
Vol 46 (6) ◽  
pp. 403-423 ◽  
Author(s):  
Karem Azmy ◽  
Denis Lavoie
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Sea Level Changes ◽  
Global Correlation ◽  
Lower Ordovician ◽  
Isotope Stratigraphy ◽  
Platform Carbonates ◽  
The Baltic ◽  
Marine Platform ◽  
Bottom To Top

The Lower Ordovician St. George Group of western Newfoundland consists mainly of shallow-marine-platform carbonates (∼500 m thick). It is formed, from bottom to top, of the Watts Bight, Boat Harbour, Catoche, and Aguathuna formations. The top boundary of the group is marked by the regional St. George Unconformity. Outcrops and a few cores from western Newfoundland were sampled at high resolution and the extracted micritic materials were investigated for their petrographic and geochemical criteria to evaluate their degree of preservation. The δ13C and δ18O values of well-preserved micrite microsamples range from –4.2‰ to 0‰ (VPDB) and from –11.3‰ to –2.9‰ (VPDB), respectively. The δ13Ccarb profile of the St. George Group carbonates reveals several negative shifts, which vary between ∼2‰ and 3‰ and are generally associated with unconformities–disconformities or thin shale interbeds, thus reflecting the effect of or link with significant sea-level changes. The St. George Unconformity is associated with a negative δ13Ccarb shift (∼2‰) on the profile and correlated with major lowstand (around the end of Arenig) on the local sea-level reconstruction and also on those from the Baltic region and central Australia, thus suggesting that the St. George Group Unconformity might have likely had an eustatic component that contributed to the development–enhancement of the paleomargin. Other similar δ13Ccarb shifts have been recorded on the St. George profile, but it is hard to evaluate their global extension due to the low resolution of the documented global Lower Ordovician (Tremadoc – middle Arenig) δ13Ccarb profile.

A Uranium-Bearing Layer from the Lower Ordovician, Sweden

1970 ◽  
Vol 92 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Gösta Armands
Keyword(s):  
Lower Ordovician ◽  
Bearing Layer
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