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Title: Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life
Authors:  Marie-Laure Pons, Ghylaine Quitté, Toshiyuki Fujii, Minik T. Rosing, Bruno Reynard, Frederic Moynier, Chantal Douchet, and Francis Albarède

The Isua Supracrustal Belt, Greenland, of Early Archean age (3.81-3.70 Ga) represents the oldest crustal segment on Earth. Its complex lithology comprises an ophiolite-like unit and volcanic rocks reminiscent of boninites, which tie Isua supracrustals to an island arc environment. We here present zinc (Zn) isotope compositions measured on serpentinites and other rocks from the Isua supracrustal sequence and on serpentinites from modern ophiolites, midocean ridges, and the Mariana forearc. In stark contrast to modern midocean ridge and ophiolite serpentinites, Zn in Isua and Mariana serpentinites is markedly depleted in heavy isotopes with respect to the igneous average. Based on recent results of Zn isotope fractionation between coexisting species in solution, the Isua serpentinites were permeated by carbonate-rich, high-pH hydrothermal solutions at medium temperature (100-300 °C). Zinc isotopes therefore stand out as a pH meter for fossil hydrothermal solutions. The geochemical features of the Isua fluids resemble the interstitial fluids sampled in the mud volcano serpentinites of the Mariana forearc. The reduced character and the high pH inferred for these fluids make Archean serpentine mud volcanoes a particularly favorable setting for the early stabilisation of amino acids.

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Volcanic rock rafts 'could have been cradles of life'
 
Volcanic rock rafts could have played a key role in the origins of life on Earth, a team of scientists suggests.
Researchers say the buoyant rock pumice has the right properties to have provided the conditions for early life to emerge more than 3.5bn years ago.
Pumice "rafts" are found today on shores of islands such as the volcanic Greek island of Santorini (Thera).
The team, from Oxford University and the University of Western Australia, calls for more research on the idea.

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Origins of Life
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Title: Life might be rare despite its early emergence on Earth: a Bayesian analysis of the probability of abiogenesis
Authors: David S. Spiegel (1), Edwin L. Turner (1, 2), ((1) Princeton, (2) IPMU, University of Tokyo)

Life arose on Earth sometime in the first few hundred million years after the young planet had cooled to the point that it could support water-based organisms on its surface. The early emergence of life on Earth has been taken as evidence that the probability of abiogenesis is high, if starting from young-Earth-like conditions. We revisit this argument quantitatively in a Bayesian statistical framework. By constructing a simple model of the probability of abiogenesis, we calculate a Bayesian estimate of its posterior probability, given the data that life emerged fairly early in Earth's history and that, billions of years later, sentient creatures noted this fact and considered its implications. We find that, given only this very limited empirical information, the choice of Bayesian prior for the abiogenesis probability parameter has a dominant influence on the computed posterior probability. Thus, although life began on this planet fairly soon after the Earth became habitable, this fact is consistent with an arbitrarily low intrinsic probability of abiogenesis for plausible uninformative priors, and therefore with life being arbitrarily rare in the Universe.

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Stinky Origins to Life? New Analysis Yields Clues

A new NASA-funded study demonstrates how a chemical that smells like rotten eggs -- hydrogen sulfide -- may have played a role in the formation of life on Earth. The study authors, including Andrew Aubrey of NASA's Jet Propulsion Laboratory, re-examined old test tubes from classic experiments performed in the 1950s by Stanley Miller, who was a graduate student at the University of Chicago.
The team analysed samples from another variant of the experiment performed in 1958 in which Miller used carbon dioxide and hydrogen sulfide gas in the mixture. It was "lost" for decades because, for unknown reasons, Miller never reported his analysis of the results.

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Oil droplets mimic early life

Oil droplets that creep purposefully through their watery environment, metabolise fuel, sense their surroundings and perhaps even replicate - could these be precursors to life? That's the claim of a chemist with a controversial approach to modelling how Earth's first organisms scraped themselves together.
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Scientists debate life's origins

Renowned scientists in fields ranging from astrobiology to genetics disputed the origin of life on Earth as we know it and the definition of life itself during a panel discussion titled "The Great Debate: What is Life?" at Arizona State University on Feb. 12.
Many of the debaters agreed that the key to understanding our own origins and life itself was to find another example of life that evolved separate from our own. Although we may grasp how life has evolved on Earth, it is difficult to recognize how "non-life" became "life" when we have only one known example - our own - to study, according to Paul Davies, an ASU physicist and astrobiologist.

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A Romp Into Theories of the Cradle of Life

Darwin speculated that life began in a warm pond on the primordial Earth. Lately other scientists have suggested that the magic joining of molecules that could go on replicating might have happened in an undersea hot spring, on another planet or inside an asteroid. Some astronomers wonder if it could be happening right now underneath the ice of Europa or in the methane seas of Titan.
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