The catastrophic disruption of the L chondrite parent body in the asteroid belt c. 470 Ma initiated a prolonged meteorite bombardment of Earth that started in the Ordovician and continues today. Abundant L chondrite meteorites in Middle Ordovician strata have been interpreted to be the consequence of the asteroid breakup event. Here we report a zircon U-Pb date of 467.50±0.28 Ma from a distinct...

BACKGROUND During the Ordovician the global diversity increased dramatically at family, genus and species levels. Partially the diversification is explained by an increased nutrient, and phytoplankton availability in the open water. Cephalopods are among the top predators of today's open oceans. Their Ordovician occurrences, diversity evolution and abundance pattern potentially provides informa...

Contrasts between the Cambrian Explosion (CE) and the Great Ordovician Biodiversification Event (GOBE) have long been recognized. Whereas the vast majority of body plans were established as a result of the CE, taxonomic increases during the GOBE were manifested at lower taxonomic levels. Assessing changes of ichnodiversity and ichnodisparity as a result of these two evolutionary events may shed...

The Ordovician radiation of marine life was among the most substantial pulses of diversification in Earth history and coincided in time with a major increase in the global level of orogenic activity. To investigate a possible causal link between these two patterns, the geographic distributions of 6576 individual appearances of Ordovician vician genera around the world were evaluated with respec...

Ireland is well known to geologists as containing some of the thickest successions of Early Ordovician (485!470 Ma; Walker et al. 2012) sedimentary rocks in the world. The carbon stable isotope compositions (dC value) of similarly aged rocks have been reported for only very few places in the world (i.e., Argentina, southern China, and southern France), and no such analyses have been performed o...

Ordovician conodont collections from several Argentinian basins including the Eastern Cordillera, Famatina and Precordillera allow recognition of a group conodonts that comprise new genus here named Condorodus n. gen. Species this have an apparatus composed six elements recovered so far: Pa, Pb, Sb1, Sb2, Sc Sd. The differences mainly between P support recognizing three species, older to younge...

. Early to middle Paleozoic arbonates ofeastern North America have been pervasively remagnetized. In order to determine the process of remagnetization, scanning and scanning transmission electron microscopy have been used to characterize magnetite in thin sections and in concentrated separates. Samples included Ordovician Knox carbonates from east Tennessee, Ordovician Trenton limestone and Dev...

All the stops for this trip are within the Crown Point Reservation State Historic Site. From the west, take NY Route 22 north from Ticonderoga, continuing north through the Village of Crown Point. Turn east approximately five miles north of the Village of Crown Point, following signs to the 'Bridge to Vermont'. From the east, take VT Route 22A north from Fairhaven, or south from Burlington area...