A modern analogue for the Lower Ordovician Obolus conglomerate of Estonia

Article Abstract:

The coast of Namibia is dominantly made up of shell fragments of the inarticulate brachiopod Discinisca. The situation is analogous to the occurrence of similar organisms in the phosphate-rich Obolus Conglomerate unit of the Ordovician Kallavere Formation in northern Estonia. Occurrence of phosphorite deposits in the Namibian coast is attributed to the upwelling of phosphite-rich water, the Benguela system, which encourages the abundance of organisms secreting phosphate rich shells. A similar paleo-upwelling system is being postulated to explain the Estonian deposits.

Sedimentation and deposition, Deposition (Geology), Phosphate minerals, Brachiopoda, Shell deposits, Phosphate rock, Brachiopods

---

Palaeomagnetism of Late Ordovician igneous intrusions from the northern Welsh Borderlands: implications to motion Eastern Avalonia and regional rotations

Article Abstract:

Palaeomagnetic studies of the rotations in Late Ordovician dolerites of the northern Welsh Basin and of Lower Palaezoic inliers of Eastern Avalonia indicate that the Breidden Hills Inlier has the maximum rotation. Local rotations about a bend in the Severn Valley Fault System cause fractures between the Breidden Hills Inlier and the neighboring Shelve Inlier and rotation of Late Ordovician fold axes. There is a rapid movement of the Avalonian Plate toward southern palaeolatitudes, as revealed by studies on Upper Ordovician.

Paleontology, Rock deformation, Ordovician period, Diabase

---

Similar abstracts:

• Abstracts: Sedimentology of the Permian Radok Conglomerate in the Beaver Lake of MacRobertson land, East Antarctica. Inter-related plutonism and deformation in South Victoria Land, Antarctica
• Abstracts: Conodonts from the lower Ordovician at Hunneberg, south-central Sweden
• Abstracts: A deep-marine ichnofaunal assemblage from Llandovery strata of the Welsh Basin, west Wales, UK. Evidence for temperate soil development during the Early Devensian in Gower, South Wales
• Abstracts: Geochemistry and tectonic significance of augen gneisses from the southern Menderes Massif (West Turkey). Discussions of cathodoluminescence of recent biogenic carbonates: an environmental and ontogenetic fingerprint

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.