The Cambrian Burgess Shale-type biotas form a globally consistent ecosystem, usually dominated by arthropods. Elements of these communities continued into the Early Ordovician at high latitude, but our understanding of ecological changes during the Great Ordovician Biodiversification Event (GOBE) is currently limited by the paucity of Ordovician exceptionally preserved open-marine faunas. Here ...

The 495 to 450 Ma Famatinian orogen, exposed throughout central and northwestern Argentina, formed from east-directed subduction under the Gondwanan margin. Sierra de Narváez Las Planchadas preserve a rare upper-crustal section of arc. New mapping, structural analysis, detrital U–Pb zircon geochronology, as well major trace element geochemistry in – are presented give comprehensive geodynamic p...

This report provides oxygen isotopes from apatite of late Middle and Late Ordovician conodonts the southern Holy Cross Mountains in south-eastern Poland. It was a unique time interval characterised by significant change climate, tectonic, ocean chemistry. In early Ordovician, were located mid-latitude climatic zone at southwestern periphery Baltica; therefore, δ18Oapatite values this region pro...

Introduction. Hawkins Impact Cave is the only cave in the world known to have formed inside the central uplift of a complex impact crater. Discovered in 1989 by landowner Michael Hawkins (namesake) and mapped in 2003 [1], HIC lies in the core of the central uplift of the 3.8 km diameter Flynn Creek impact structure (36˚17'N, 85˚40'W) in the Highland Rim physiographic province of north-central T...

Abstract It remains unclear whether waning of the volcanic degassing CO2 source or enhancement mafic (Ca, Mg-silicate) weathering sink, both, caused global cooling leading to Ordovician greenhouse–icehouse transition. We present a uniquely age-constrained and integrated Middle–Late (470–450 Ma) continental isotopic proxy data set (87Sr/86Sr ?Nd(t)) from carbonate rocks Antelope Range central Ne...

Complete, articulated crinoids from the Ordovician peri-Gondwanan margin are rare. Here, we describe a new species, Iocrinus africanus sp. nov., from the Darriwilian-age Taddrist Formation of Morocco. The anatomy of this species was studied using a combination of traditional palaeontological methods and non-destructive X-ray micro-tomography (micro-CT). This revealed critical features of the co...

Abstract The Ordovician of North and West Africa comprises three main transgressive–regressive sequences understood as ‘second-order’ cycles 10–15 myr duration. Tide- to wave-dominated shallow-marine clastic successions, preserving incidental bryozoan carbonates the north, include fluvial deposits over most proximal southern stretches platform. boundary with Cambrian strata remains unclear but ...

Strike-slip deformation belts are interesting structures in the crust and of significance petroleum exploration. The Shunbei 5 fault belt (SB5), a long strike-slip Tarim Basin, played an important role formation recently discovered major oilfield known as oilfield. In this study, models plan view vertical profile were established to interpret SB5 with multi-cycled tectonic activities. To end, i...

Three magnetic components have been isolated in Ordovician formations of the Yangtze Paraplatform (South China Block). Two of these (Daqing A and Hongshiya B components) yield paleopoles that conform to the Carboniferous to Triassic segment of the apparent polar w•der path for South China, and are therefore interpreted as remagnetizations. The third component (declination/inclination = 30!ø/+66...