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Secular Change in the Precambrian Silica Cycle: Insights from Chert Petrology
(Geological Society of America, 2005)
Chert deposits preserve a record of secular change in the oceanic silica cycle. The evolutionary radiation of silica-secreting organisms resulted in a transition from abiological silica deposition, characteristic of the ...
Stable Isotopic Compositions of Carbonates from the Mesoproterozoic Bangemall Group, Northwestern Australia
(Elsevier, 1995)
Marine carbonate rocks from the Mesoproterozoic Bangemall Group of northwestern Australia show little deviation (+/- 1.3 parts per thousand) in whole-rock delta(13)C(carb)-values about a mean of -0.5 parts per thousand. ...
Middle and Late Cambrian Sponge Spicules from Hunan, China
(Society of Economic Paleontologists and Mineralogists, 1996)
Abundant and well-preserved assemblages of disarticulated sponge spicules occur in Middle and Late Cambrian platform carbonates of western Hunan, China. Assemblages recovered from 11 stratigraphic horizons include calcisponges, ...
An Emerging Picture of Neoproterozoic Ocean Chemistry: Insights from the Chuar Group, Grand Canyon, USA
(Elsevier, 2009)
Detailed iron, sulfur and carbon chemistry through the > 742 million year old ChuarGroup reveals a marine basin dominated by anoxic and ferrous iron-rich (ferruginous) bottom waters punctuated, late in the basin's development, ...
Deep-Water Incised Valley Deposits at the Ediacaran-Cambrian Boundary in Southern Namibia Contain Abundant Treptichnus Pedum
(Society for Sedimentary Geology, 2012)
Valley-filling deposits of the Nama Group, southern Namibia, record two episodes of erosional downcutting and backfill, developed close together in time near the Ediacaran-Cambrian boundary. Geochronological constraints ...
Si Isotope Variability in Proterozoic Cherts
(Meteoritical Society, 2012)
We report Si-isotopic compositions of 75 sedimentologically and petrographically characterized chert samples with ages ranging from ~2600 to 750 Ma using multi-collector inductively coupled plasma mass spectrometry. ...
Eukaryotic Skeletal Formation
(Wiley, 2012)
What is Geobiology?
(John Wiley & Sons, 2012)
The Fossil Record of Microbial Life
(Wiley-Blackwell, 2012)
Ancient Impact and Aqueous Processes at Endeavour Crater, Mars
(American Association for the Advancement of Science, 2012)
The rover Opportunity has investigated the rim of Endeavour Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at ...