Tag: 一品楼上海宝山

Shallow marine sedimentation within an active margin basin, James Ross Island, Antarctica

first_imgThe Santa Marta Formation exposed on northern James Ross Island, Antarctica, represents shallow marine shelf sedimentation within an active margin basin. The formation is approximately 1000 m thick, is of uppermost Santonian to Campanian age and represents part of a 5000–6000 m thick sedimentary sequence forming the Larsen Basin. The Larsen Basin represents either a back-arc basin, or a half-graben basin, developed on the extending margin of the Weddell Sea. Twelve sedimentary facies have been recognised, which can be subdivided into two groups: those which are controlled by shelf processes and those which are related to active arc volcanism. Background shelf processes include fair-weather suspension sedimentation, storm sands and rare tidal current reworking. Active arc processes include direct settling of airfall detritus and rapid resedimentation of volcaniclastic detritus by sandy debris-flows and both high- and low-concentration turbidity currents. In addition sheet conglomerates represent debris flows that evolved from syn-sedimentary slumps. Two facies associations representing a mid to outer shelf and an inner shelf depositional setting respectively can be distinguished, with an apparent regression in the ?mid to late Campanian.last_img read more

The role of Raman spectroscopy as an astrobiological tool in the exploration of Mars

first_imgWe describe how the exploration of the Martian environment would be considerably enhanced through the use of Raman spectroscopy. Furthermore, Raman spectroscopy is particularly suited for both mineralogical analysis of Martian rock and soil and for the detection of fossilised biota from former Martian microorganisms. We outline astrobiologically relevant features of the Martian environment and issues related to the detection of biotic residues. We further discuss the possibility of the emergence of photosynthetic bacteria on early Mars which may have left fossil evidence. We describe how Raman spectroscopy may be deployed for both astrobiological and mineralogical investigation, particularly in search of pigmented biomolecules, and describe the requirements for a spaceflight-qualified version of a Raman spectrometer for deployment on Mars.last_img read more

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