Oxidation of manganese (II) to manganese (III,IV) demands oxidants with very high redox potentials; consequently, manganese oxides are both excellent proxies for molecular oxygen and highly favorable electron acceptors when oxygen is absent. The first of these features results in manganese-enriched sedimentary rocks (manganese deposits, commonly Mn ore deposits), which generally correspond to t...

no-bahar watershed is located, south of khorasan razavi province. geologically, the study area is a part of central iran zone. the rock units are late mesozoic and cenozoic in age in this watershed. no-babhar watershed includes several channels, which among them, only two main channels, motr-abad and solh-abad, have been studied. these rivers are mostly, braided channel in style, with high grad...

We view the structures and features described in this atlas as sedimentary structures, albeit of a complex organo-physico-chemical origin. Just like their physical sedimentary structure counterparts (e.g., Pettijohn and Potter, 1964), they can be of great assistance in unravelling depositional palaeoenvironments inferred for ancient rock successions. Pettijohn and Potter (1964) included stromat...

published in: Lunar and Planetary Science XL, CD-ROM, Lunar and Planetary Institute, Houston (2009). 1073.pdf 40th Lunar and Planetary Science Conference (2009)

Widespread sedimentary rocks on Mars preserve evidence of surface conditions different from the modern cold and dry environment, although it is unknown how long conditions favorable to deposition persisted. We used 1-meter stereo topographic maps to demonstrate the presence of rhythmic bedding at several outcrops in the Arabia Terra region. Repeating beds are approximately 10 meters thick, and ...

Backscatter SEM imaging and small-angle neutron scattering (SANS) data are combined within a statistical framework to quantify the microstructure of a porous solid in terms of a continuous pore-size distribution spanning over five orders of magnitude of length scale, from 10 A to 500 microm. The method is demonstrated on a sample of natural sandstone and the results are tested against mercury p...

[1] Understanding the mechanical behavior of rock is critical for researchers and decision-makers in fields from petroleum recovery to hazardous waste disposal. Traditional continuum-based numerical models are hampered by inadequate constitutive relationships governing fracture initiation and growth. To overcome limits associated with continuum models we employed a discrete model based on the f...

A high-resolution, three-dimensional (3D) image of the interior of the sedimentary rock was obtained by means of nano-focus X-ray computer tomography (X-ray CT). Using computational methods to analyze the 3D microstructure of the rock, we presented the tortuosity and geometrical constrictivity. We also presented results on the tritiated water (HTO) diffusion tests and a mercury intrusion porosi...

New mapping, geochronology, and geochemistry of the supracrustal enclave and associated orthogneisses at Akilia, West Greenland, support a >3825 6 Ma age for the sequence and a chemical sedimentary origin for the controversial Fe-rich quartz-pyroxene gneisses. Lithologies of the enclave comprise laterally continuous, mappable units of mafic amphibolite, ultramafic rocks, and two Fe-rich quartzp...

Introduction: Individual grains and small lithic clasts in thin-sectioned suevitic breccia samples from the International Continental Scientific Drilling Program (ICDP) Bosumtwi impact crater drillcore LB07A were examined petrographically to evaluate the occurrence , abundance, and characteristics of unshocked and shock-metamorphosed quartz. The analyzed samples were taken across a ~42-m-long (...