The folds observed in the imbricates of Silurian
and Devonian rocks could have different origins.
Open-hole log data (including an MDT - Modular Formation Dynamic Tester) and well-site geological measurements and observations indicate hydrocarbon potential in the Silurian
Tannezuft and Acacus sandstones, Devonian Ouan Kasa sandstones and the Triassic TAGI sandstones.EeEe
Ancestral horseshoe crabs (Class Merostomata, Order Xiphosurida, Suborder Synziphosurina), often found associated with eurypterids in Silurian
and Devonian strata, are sporadically represented in the geologic column (Stormer, 1955).
The jawed polychaete fauna is dominated by polychaetaspids, mochtyellids, and paulitinids as would be expected from a Silurian
assemblage (Eriksson et al.
This analysis of biofacies is compared to other Early Silurian
associations, especially in Scandinavia and Great Britain.
and Devonian rocks in Indiana southwest of the Cincinnati Arch.
The Devonian System is represented by the Mackinac Breccia, which is composed of fragmented shale, limestone, and dolomite from formations of the Upper Silurian
and Lower Devonian.
The Fusselman Formation consists of two major lithostratigraphic units, a thin basal, Late Ordovician (Hirnantian) oolite that is overlain unconformably by a thicker Llandoverian (Silurian
) complex of carbonates.
Dimitri Kaljo's scientific focus has been on Ordovician and Silurian
fossils, stratigraphy, palaeogeography, and more recently, geochemistry.
This paper focuses on a relatively quiet interval from Late Ordovician (Ashgill) to Late Silurian
times when an enormous volume of sediment eroded from post-Middle Ordovician highlands was deposited in extensive basins on the Ganderian composite plate.
[USA], Sept 1 (ANI): Around 420 million years back in the pre-historic Silurian
Period, Earth suffered a major mass extinction, which wiped out almost 23 per cent of the marine life.