The existence of unusually large fluctuations in the Neoproterozoic (1,000-543 million years ago) carbon-isotopic record implies strong perturbations to the Earth's carbon cycle. To analyze these fluctuations, we examine records of both the isotopic content of carbonate carbon and the fractionation between carbonate and marine organic carbon. Together, these are inconsistent with conventional, ...

The Neoproterozoic was an era of great environmental and biological change, but a paucity of direct and precise age constraints on strata from this time has prevented the complete integration of these records. We present four high-precision U-Pb ages for Neoproterozoic rocks in northwestern Canada that constrain large perturbations in the carbon cycle, a major diversification and depletion in t...

[1] Simulations of frigid Neoproterozoic climates have not considered the tendency of thick layers of floating marine ice to deform and spread laterally. We have constructed a simple model of the production and flow of marine ice on a planetary scale, and determined ice thickness and flow in two situations: when the ocean is globally icecovered (‘‘hard snowball’’) and when the tropical waters r...

We report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Lithostratigraphic correlations with the relatively well-dated Mackenzie Mountains Supergroup constrain Shaler deposition to approximately 770-880 Ma, a range corroborated by 723 +/- 3 Ma lavas that disconformably overlie Shaler carbonates and by Late Ri...

The Saharan Metacraton is a poorly known tract of pre-Neoproterozoic continental crust that occupies the area between juvenile Arabian Nubian Shield, in east, and Tuareg Shield to west. Neoproterozoic orogenesis (i.e. Oubanguides East African orogenies) affect west, south east metacraton, respectively, which led deformation, emplacement igneous bodies, localised episodes rift-related magamatism...

Oxygenation has widely been viewed as a major factor driving the emergence and diversification of animals. However, links between early animal evolution and shifts in surface oxygen levels have largely been limited to extrapolation of paleoredox conditions reconstructed from unfossiliferous strata to settings in which contemporaneous fossils were preserved. Herein, we present a multi-proxy pale...

The Luís Alves Terrane in southern Brazil is one of the largest expositions Archean to Paleoproterozoic units that acted as basement for development Neoproterozoic Pan-African/Brasiliano orogenic belts Mantiqueira Province, South America. Combined field observations, petrography, Hf and U-Pb LA-ICP-MS zircon titanite isotopic data are presented this terrane. dataset spans a large time range wit...