How complex nucleic acids originally formed, despite dilution and degradation reactions, is not clear. Thermal gradients in rock pores have now been shown to be capable of trapping and thermo-cycling genetic polymers during replication. In this system long oligonucleotide strands are seen to outcompete short strands — a prerequisite for the evolution of replicating systems towards increasing complexity.
Geologists from the University of Cambridge uncover hidden magnetic messages from the early solar system in meteorites measured at BESSY II.
A team of scientists led by Dr. Richard Harrison from the University of Cambridge, has captured information stored inside tiny magnetic regions in meteorite samples using the PEEM-Beamline at BESSY II.
The Kos-Nisyros volcanic centre is a long-active, Plio-Pleistocene magmatic system in the subduction zone along the easternmost edge of the active Hellenic volcanic arc in the Aegean Sea. Although today there are signs of relative quiescence in volcanic activity, active onshore fumaroles and shallow-sea hydrothermal vents persist on, amongst others, the island of Kos. The present study explores the large-scale imprint of hydrothermally sourced heavy metals and nutrients on the island’s coastal marine environment, based on geochemical data collected from hydrothermal waters and surficial nearshore sediments (<10 m water depth) at several vents in the Bros Thermi and Kephalos Bay hydrothermal fields.
Geomicrobiologists say that the first oxygen-producing bacteria were poisoned by abundant iron in ancient oceans. Three billion years ago, Earth's atmosphere contained less than 0.0001 percent oxygen. Today's atmosphere has around 20 percent oxygen -- and that is due to the work of tiny microorganisms in Earth's primeval oceans.
The authors investigated the speciation and distribution of Fe and As in flocs collected from low-flow streams (pH 5.3–6.3) of the naturally As-enriched peatland Gola di Lago (Switzerland) using 57Fe Mössbauer spectroscopy and Synchrotron X-ray techniques.
The goal of this study was to investigate the Hg stable isotope signatures of sediments in San Carlos Creek downstream of the former Hg mine New Idria, CA, USA and to relate the results to previously studied Hg isotope signatures of unroasted ore waste and calcine materials in the mining area.
DCO’s Patrick Allard and colleagues first demonstrated in 2005 that by measuring the chemical composition of the driving magmatic gas phase they could discriminate between these two potential mechanisms. In a new paper, La Spina et al., report on the largest data set ever obtained for the magmatic gas phase powering lava fountains; see: http://www.sciencedirect.com/science/article/pii/S0012821X14007997
Chemical analysis of some of the world's oldest rocks has provided the earliest record yet of Earth's atmosphere. The results show that the air 4 billion years ago was very similar to that more than a billion years later, when the atmosphere -- though it likely would have been lethal to oxygen-dependent humans -- supported a thriving microbial biosphere that ultimately gave rise to the diversity of life on Earth today.
Nitrogen may have arrived on Earth in ancient meteorites after the planet had already formed, according to a new study.
Ath Godelitsas's insight:
The authors used an electron microscope to study crystals from two ancient carbonaceous chondrite meteorites named Yamato-791198 and Yamato-793321 which were recovered from Antarctica in 1979.
They discovered an unusual mineralised form of nitrogen which matched Earth's nitrogen. "We found nitrogen with a similar isotopic composition to nitrogen found in people and in Earth's atmosphere, in a very unusual mineral which was detected in two meteorites," says Harries. "This mineral shows us that there was another type of nitrogen in the early solar system billions of years ago, and this molecule was probably responsible for making the building blocks of life and bringing the nitrogen of our atmosphere to Earth."
"The discovery of this mineralized form of nitrogen is telling us something about how Earth got its nitrogen."
The authors explore the isotopic characteristics of the global uranium cycle. They show that the subducted flux of uranium is isotopically distinct, with high 238U/235U ratios, as a result of alteration processes at the bottom of an oxic ocean. They also find that mid-ocean-ridge basalts (MORBs) have 238U/235U ratios higher than does the bulk Earth, confirming the widespread pollution of the upper mantle with this recycled uranium.
Bob got his B.S. and M.S. degrees from the University of Michigan, and his Ph.D. from Harvard. He did a postdoc at the Scripps Institution of Oceanography before moving to the University of Chicago as an Assistant Professor in 1963. He came to Yale in 1965, and stayed here for the rest of his career.
Ath Godelitsas's insight:
We extend our deepest, heartfelt condolences to his family at this most difficult time.
On the last day of 2014, the Taiwan Photon Source (TPS) has delivered its first synchrotron light at 13:58, an exciting news released by the National Synchrotron Radiation Research Center (NSRRC) in Hsinchu, Taiwan.
Are REEs best understood as simple commodities, or as strategic resources that can be used as tools of statecraft? And can Australia play a part in the development of alternative reliable sources of rare earths? To help understand the strategic importance of REEs the National Security College and Crawford School of Public Policy welcome two global experts in the field.