@article {711,
	title = {H2-rich fluids from serpentinization: geochemical and biotic implications},
	journal = {Proc Natl Acad Sci U S A},
	volume = {101},
	year = {2004},
	note = {Sleep, N HMeibom, AFridriksson, ThColeman, R GBird, D KengResearch Support, U.S. Gov{\textquoteright}t, Non-P.H.S.2004/08/25 05:00Proc Natl Acad Sci U S A. 2004 Aug 31;101(35):12818-23. Epub 2004 Aug 23.},
	month = {Aug 31},
	pages = {12818-23},
	abstract = {Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth{\textquoteright}s mantle. For the rest of Earth{\textquoteright}s history, serpentinites covered only a small fraction of the Earth{\textquoteright}s surface but were an important prebiotic and biotic environment. Extant methanogens react H2 with CO2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produced complex organic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate. Conversely, inorganic catalysis of methane by FeNi3 competes with nascent and extant life.},
	issn = {0027-8424 (Linking)},
	doi = {10.1073/pnas.0405289101},
	author = {Sleep, N. H. and Meibom, A. and Fridriksson, T. and Coleman, R. G. and Bird, D. K.}
}
@article {768,
	title = {Carbon dioxide cycling and implications for climate on ancient Earth},
	journal = {Journal of Geophysical Research-Planets},
	volume = {106},
	year = {2001},
	note = {395tjTimes Cited:185Cited References Count:101},
	month = {Jan 25},
	pages = {1373-1399},
	abstract = {The crustal Urey cycle of CO2 involving silicate weathering and metamorphism acts as a dynamic climate buffer. In this cycle, warmer temperatures speed silicate weathering and carbonate formation, reducing atmospheric CO2 and thereby inducing global cooling. Over long periods of time, cycling of CO2 into and out of the mantle also dynamically buffers CO2. In the mantle cycle, CO2 is outgassed at ridge axes and island arcs, while subduction of carbonatized oceanic basalt and pelagic sediments returns CO2 to the mantle. Negative feedback is provided because the amount of basalt carbonatization depends on CO2 in seawater and therefore on CO2 in the air. On the early Earth, processes involving tectonics were more vigorous than at present, and the dynamic mantle buffer dominated over the crustal one. The mantle cycle would have maintained atmospheric and oceanic CO2 reservoirs at levels where the climate was cold in the Archean unless another greenhouse gas was important. Reaction of CO2 with impact ejecta and its eventual subduction produce even lower levels of atmospheric CO2 and small crustal carbonate reservoirs in the Hadean. Despite its name, the Hadean climate would have been freezing unless tempered by other greenhouse gases.},
	issn = {0148-0227},
	doi = {10.1029/2000je001247},
	author = {Sleep, N. H. and Zahnle, K.}
}
