The Qinling orogen (Fig. 1) extends for over 2000 km across central China, separating the Archean and Proterozoic Sino-Korean block in the north from the Proterozoic Yangtze block in the south. Although the orogen has been recognized as a continental collision zone for some time, the nature, age, and duration of the collision have been the subject of considerable debate (see review in Hacker et...

On the basis of a Mo-based geochemical proxy calibrated to the fossil record of fish, Dahl et al. argued that oxygen levels in the early Paleozoic were 15–50% of present atmospheric levels (PAL) and probably no more than a few percent PAL for the previous 2 billion years (1). It is an interesting result, but the study raised a number of issues. First, it is difficult to reconcile 15–50% PAL oxy...

The goal of this project is to trace into central northern B.C. stratigraphy known to host Mississippian volcanogenic massive sulphide deposits such as Kudz Ze Kayah, Wolverine, and Fyre Lake, which lie within the Yukon Tanana Terrane in the Finlayson Lake belt of central Yukon. It is part of the Jennings River/Wolf Lake component of the Ancient Pacific Margin NATMAP project, a cooperative effo...

The goal of this project is to trace into central northern B.C. stratigraphy known to host Mississippian volcanogenic massive sulphide deposits such as Kudz Ze Kayah, Wolverine, and Fyre Lake, which lie within the Yukon Tanana Terrane in the Finlayson Lake belt of central Yukon. It is part of the Jennings River/Wolf Lake component of the Ancient Pacific Margin NATMAP project, a cooperative effo...

New SHRIMP U-Pb zircon ages for the Portalegre and Alcáçovas orthogneisses document a complex pre- Variscan history for the Iberian basement in Portugal. The available geochemical and geochronological data for the Alcáçovas orthogneiss (ca. 540 Ma) tend to favor its involvement in a Cadomian orogenic event. This is consistent with the development of an active continental margin setting at the e...

One radiograph of Hunsrück slate shows the presence of a drop-shaped "worm". This image resembles an acoel platyhelminth in the presence of an apparently eversible pharyngeal structure, but no trace can be tound of the complex reproductive structures of platyhelminths, making full identification impossible. Another more elongate worm-like image shows the presence of anterior perforations into a...