Post-depositional mobility of platinum, iridium and rhenium in marine sediments

Article Abstract:

The high levels of platinum-group-elements (PGEs) found in some sediments may have resulted from prolonged distributive processes that are part of diagenesis rather than from meteoric impact. Some scientists have postulated that the elevated concentrations of iridium, platinum, rhenium and other PGEs at the Cretaceous/Tertiary boundary and at other boundaries in the geological record were caused by meteors striking the Earth. However, geochemical analysis of abyssal marine sediments indicates that redox processes may have produced the high concentrations at some of these boundaries.

Research, Composition, Marine sediments, Geochemistry, Platinum group, Platinum group metals, Diagenesis, Diagenesis (Geology)

---

Stratified prokaryote network in the oxic-anoxic transition of a deep-sea halocline

Article Abstract:

The Bannock brine lake-seawater interface is revealed to be a deep-sea microbial oasis. It consists of a biomass-dense, metabolically active microbial ecosystem that receives methane from the hypersaline brine below and organic particulates sedimenting through the water column from above, recycles this organic matter and interconverts diverse ionic species, which are used and reused as electron acceptors and donors.

Environmental aspects, Prokaryotes, Microbial ecology, Saline waters, Salt water

---

Variability of the North Atlantic thermohaline circulation during the last interglacial period

Article Abstract:

Natural climate variability studies are used to evaluate future evolution. Ice cores in Greenland indicated that the Holocene period has been stable for 9,000 years. High-resolution ocean sediment records from the Bermuda Rise, covering the last interglacial period, are presented. Deep-water chemical changes appear to coincide with changes in surface climate.

Observations, Climatic changes, Climate change

Similar abstracts:

• Abstracts: A three-dimensional photonic crystal operating at infrared wavelengths. Three-dimensional control of light in a two-dimensional photonic crystal slab
• Abstracts: Modeling the sustainability of subsistence farming and hunting in the Ituri forest of Zaire. Income and price elasticities of bushmeat demand in lowland Amerindian societies
• Abstracts: Wandering across time. Implications of Deltatheridium specimens for early marsupial history. Epipubic bones in eutherian mammals from the Late Cretaceous of Mongolia
• Abstracts: Frequency variations of the Earth's obliquity and the 100-kyr ice-age cycles. Stabilization of the Earth's obliquity by the Moon
• Abstracts: The catalase-peroxidase gene and isoniazid resistance of Mycobacterium tuberculosis. Receptor-associated Mad homologues synergize as effectors of the TGF-beta response

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.