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Oxidation of the Ediacaran Ocean
High-resolution carbon isotope and sulphur isotope records from the Huqf Supergroup, Sultanate of Oman, that cover most of the Ediacaran period indicate that the ocean became increasingly oxygenated after the end of the Marinoan glaciation and allow us to identify three distinct stages of oxidation. Expand
Stromatolites in Precambrian carbonates: evolutionary mileposts or environmental dipsticks?
Application of a process-based approach has shown that stromatolites were originally formed largely through in situ precipitation of laminae during Archean and older Proterozoic times, but that younger ProTerozoic strom atolites grew largely through the accretion of carbonate sediments, most likely through the physical process of microbial trapping and binding. Expand
Biostratigraphic and Geochronologic Constraints on Early Animal Evolution
Two distinct evolutionary pulses, represented by the Vendian Ediacaran fauna and Cambrian small shelly faunas, are generally thought to characterize the emergence of macroscopic animals at the end ofExpand
Geochronologic constraints on the chronostratigraphic framework of the Neoproterozoic Huqf Supergroup, Sultanate of Oman
The Huqf Supergroup, Sultanate of Oman, contains an important record of Neoproterozoic history, including evidence for two glaciations, a massive reorganization of the global carbon cycle, and theExpand
Extinction of Cloudina and Namacalathus at the Precambrian-Cambrian boundary in Oman
Biostratigraphic, carbon isotope, and U-Pb zircon geochronological data from the Ara Group of Oman indicate an abrupt last appearance of Cloudina and Namacalathus coincident with a large-magnitude,Expand
Paleoclimate of Mars as captured by the stratigraphic record in Gale Crater
A kilometers-thick sedimentary sequence in Gale Crater exhibits stratigraphic changes in lithology that are consistent with transitions in aqueous and climatic conditions purported to be global inExpand
In Situ Evidence for an Ancient Aqueous Environment at Meridiani Planum, Mars
The geologic record at Meridiani Planum suggests that conditions were suitable for biological activity for a period of time in martian history. Expand
New Constraints on Precambrian Ocean Composition
The Precambrian record of carbonate and evaporite sedimentation is equivocal, and it is possible that Archean, Paleoproterozoic, and to a lesser extent, Meso to Neopropperozoic seawater favored surplus abiotic carbonate precipitation, as aragonite and calcite, in comparison to younger times. Expand
Mars Science Laboratory Mission and Science Investigation
AbstractScheduled to land in August of 2012, the Mars Science Laboratory (MSL) Mission was initiated to explore the habitability of Mars. This includes both modern environments as well as ancientExpand
Fossil steroids record the appearance of Demospongiae during the Cryogenian period
It is suggested that shallow shelf waters in some late Cryogenian ocean basins contained dissolved oxygen in concentrations sufficient to support basal metazoan life at least 100 Myr before the rapid diversification of bilaterians during the Cambrian explosion. Expand