During exploration for oil and gas, a technical drilling fluid is used to lubricate the drill bit, maintain hydrostatic pressure, transmit sensor readings, remove rock cuttings and inhibit swelling of unstable clay based reactive shale formations. Increasing environmental awareness and resulting legislation has led to the search for new, improved biodegradable drilling fluid components. In the ...

Clay rocks are being considered for radioactive waste disposal, but relatively little is known about the impact of microbes on the long-term safety of geological repositories. Thus, a more complete understanding of microbial community structure and function in these environments would provide further detail for the evaluation of the safety of geological disposal of radioactive waste in clay roc...

Introduction: Over 13 years after landing at Meridiani Planum and in her 10 extended mission, Mars Exploration Rover Opportunity continues to explore the rim of ~22 km diameter Endeavour crater [1]. The rim exposes material that is older than the S-rich, layered sedimentary rock covering the Meridiani plains and filling much of the interior of Endeavour. Clay mineral exposures at the rim have b...

[1] To understand the role of hydrated clay minerals in active fault systems, a humidity chamber connected to an X-ray diffractometer was used to determine the adsorption of water onto and/or into the crystal structure of smectite. This new type of analysis was carried out under specific temperature and humidity conditions, using powdered clay size fractions (< 2 mm) of rock samples from the Sa...