Date:8/23/2012

sing the slope of the river system, for instance by tectonic uplift, or by increasing the water discharge into the river system, for instance by a climatic shift. The sedimentary and geomorphic impact of these two competing roles should, in principal, be distinguishable in the sedimentary record, however this still remains challenging. A grasp of this is important because Earth scientists rely on landscape features and the sedimentary record, in combination with analytical datasets, to make inferences about past geological events and future landscape scenarios. Nowhere else has the issue of "tectonics" versus "climate" been as contentious as in the Rocky Mountains-Great Plains region of the United States. Building upon the plethora of data and concepts in the region, we contribute new data from key sedimentary units and paleo-surfaces, and add a different perspective on landscape evolution in the Rocky Mountains-Great Plains region. Crucially we constrain the timing of potential phases of surface uplift and landscape development and offer a more integrative model of the competing roles of that "tectonics" and "climate" might play in the region.

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Early diagenesis of sulfur in a tropical upwelling system, Cabo Frio, southeastern Brazil
R. Diaz et al., Projeto Ressurgencia Team, Programa de Geoqumica Ambiental, Universidade Federal Fluminense, Outeiro So Joo Baptista s/n., Niteri RJ 24020-150, Brazil. Posted online ahead of print 9 Aug. 2012; doi: 10.1130/G33111.1.

R. Diaz and colleagues investigated the behavior of inorganic of sulfur species, including sulfate, dissolve sulfide, iron monosulfide and pyrite (FeS2) to evaluate the sulfur redox cycling in sediments sampled across the upwelling area of Cabo Frio, southeastern Brazil. The pyrite formation was limited by availability of reduced sulfur species, since there were oxidizing conditions, as indicated by a low degree of iron pyritization. Textural analysis of pyrite was c
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Contact: Kea Giles kgiles@geosociety.org Geological Society of America Source:Eurekalert

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