Between ;750 and 635 million years ago, during the Neoproterozoic era, the earth experienced at least two significant, possibly global, glaciations, termed ‘‘Snowball Earth.’’ While many studies have focused on the dynamics and the role of the atmosphere and ice flow over the ocean in these events, only a few have investigated the related associated ocean circulation, and no study has examined ...

Investigation of climatic conditions prior to the Sturtian glaciations is critical to understanding the trigger mechanism for the series of Neoproterozoic global glaciations. In this study, we report high-resolution chemical index of alteration (CIA) records in the sediments of South China prior to the Sturtian glaciation (820~720 Ma). Our results showed there occurred multiple climate cooling ...

During the latest Neoproterozoic to Mid-Cambrian time (580–505 Ma ago), the Earth underwent significant changes in palaeogeography that included rifting of a possible supercontinent and the near simultaneous formation of a second, slightly smaller supercontinent. It is against this tectonic backdrop that the Cambrian radiation occurred. Although the general tectonic setting during this interval...

The distribution of major phosphate deposits in the Precambrian sedimentary rock record is restricted to periods that witnessed global biogeochemical changes, but the cause of this distribution is unclear. The oldest known phosphogenic event occurred around 2.0 Ga and was followed, after more than 1.3 billion years, by an even larger phosphogenic event in the Neoproterozoic. Phosphorites (phosp...

Abstract In the paleogeographic configuration of Neoproterozoic supercontinent Rodinia, Tarim craton (northwestern China), traditionally seen as a single block, is placed either on periphery near northern Australia or India in central position between and Laurentia. To distinguish these possibilities, we present here new primary paleomagnetic results from ca. 900 Ma volcanics Aksu region northw...

The results of a geochemical study organic matter found in carbonate deposits typical section the Minyar formation Upper Riphean, exposed within Karatau structural complex western part Bashkir meganticlinorium, are presented.
 Analytical methods gas chromatography and chromato-mass spectrometry extracted hydrocarbons have been used to diagnose diamantanes, alkanes specific biomarkers – tri...

ONE of John Shergold’s abiding research interests, and an area in which he made fundamental contributions to the fields of palaeontology and geology, was the study of Cambrian arthropods in general, and trilobites in particular (e.g., Shergold 1977, 1988, 1991; Shergold et al. 1990; Shergold & Laurie 1997). Here we focus on what Cambrian arthropods, including trilobites, can tell us about the n...

The Ross orogen of Antarctica is one of Earth’s great Phanerozoic mountain belts. It is thought from igneous geochemistry, deformation patterns, and sedimentation history to be the result of late Neoproterozoic and early Paleozoic plate-margin convergence between paleo-Pacifi c oceanic lithosphere and continental lithosphere represented by the composite East Antarctic shield. Convergence along ...