Late Ordovician strata within the Cincinnati Basin record a mass faunal migration event during the C4 and C5 depositional sequences. The geographic source region for the invaders and the paleoceanographic conditions that facilitated dispersal into the Cincinnati Basin has previously been poorly understood. Using Parsimony Analysis of Endemicity, biogeographic relationships among Laurentian and ...

Abstract Volcanic ash interbeds in the Late Ordovician strata South China record highfrequency volcanic activity. To assess impact of these events on climate and marine biological evolutionary crisis during Mass Extinction (LOME), we present high-resolution measurements mercury (Hg) concentrations organic carbon isotope ratios (δ13Corg) an Ordovician–Silurian sedimentary succession (Muchanggou ...

Morphological similarities indicate that Palaeozoic problematic tubeworms, e.g. tentaculitids, cornulitids, microconchids, trypanoporids, Anticalyptraea, and Tymbochoos, form a monophyletic group. This group may also include hederelloids. Members of this group share affinities with lophophorates and their evolution could have partly been driven by predation. The extinction of Palaeozoic tubewor...

The distinctive, branched thrombolite, Favosamaceria cooperi new group and form, is found widely in the Great Basin, USA, where it is restricted to the Late Cambrian Saukia trilobite Zone. This thrombolite is distinguished by a hedgerow, mazelike organization of ridges similar to garden walls (maceriae) in plan view, branching of ridges into daughter ridges and columns, the polymorphic nature o...

An anomalocaridid from the Ordovician exposes a second set of body flaps and reopens the question of how the two branches of arthropod legs evolved.

Siliciclastic rocks of the upper Byrd Group in the Transantarctic Mountains record rapid denudation and molasse deposition during Ross orogenesis along the early Paleozoic convergent margin of Gondwana. These rocks, which stratigraphically overlie Lower Cambrian Byrd carbonate deposits, are dominated by fresh detritus from proximal igneous and metamorphic sources within the Ross Orogen. Biostra...

Abstract We present a ? 13 C carb chemostratigraphy for the Late Ordovician Hirnantian Stage based on 208 whole-rock samples from six outcrops in Oslo–Asker district, southern Norway. Our data include Norwegian type section and Ordovician–Silurian boundary at Hovedøya Island. The most complete record of Isotope Carbon Excursion (HICE) is identified coastal exposure Konglungø locality where pres...