Evidence for life on Earth before 3,800 million years ago
- S. Mojzsis, G. Arrhenius, K. McKeegan, T. Harrison, A. Nutman, C. Friend
- GeologyNature
- 7 November 1996
IT is unknown when life first appeared on Earth. The earliest known microfossils (˜3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a…
Methane-Consuming Archaea Revealed by Directly Coupled Isotopic and Phylogenetic Analysis
- V. Orphan, C. House, K. Hinrichs, K. McKeegan, E. Delong
- Biology, Environmental ScienceScience
- 20 July 2001
These results demonstrate the feasibility of simultaneous determination of the identity and the metabolic activity of naturally occurring microorganisms and indicate assimilation of isotopically light methane into specific archaeal cells.
Multiple archaeal groups mediate methane oxidation in anoxic cold seep sediments
- V. Orphan, C. House, K. Hinrichs, K. McKeegan, E. Delong
- Biology, Environmental ScienceProceedings of the National Academy of Sciences…
- 14 May 2002
The results provide direct evidence for the involvement of at least two distinct archaeal groups (ANME-1 and ANME-2) in AOM at methane seeps and indicate that the microbial species and biotic interactions mediating anaerobic methanotrophy are diverse and complex.
Prolonged residence times for the youngest rhyolites associated with Long Valley Caldera:230Th—238U ion microprobe dating of young zircons
- M. Reid, C. Coath, T. Harrison, K. McKeegan
- Geology
- 1 July 1997
Origin and episodic emplacement of the Manaslu Intrusive Complex
- T. Harrison, M. Grove, P. Lefort
- Geology
- 1999
decompression to achieve the same result appear to require extreme The Manaslu granite is the most studied of the dozen or so plutons conditions not permitted by available geological constraints.…
The Oxygen Isotopic Composition of the Sun Inferred from Captured Solar Wind
- K. McKeegan, A. Kallio, D. Burnett
- Physics, GeologyScience
- 24 June 2011
It is concluded that essentially all rocky materials in the inner solar system were enriched in 17O and 18O, relative to 16O, by ~7%, probably via non–mass-dependent chemistry before accretion of the first planetesimals.
Detection of inherited monazite in the Manaslu leucogranite by 208Pb232Th ion microprobe dating: Crystallization age and tectonic implications
- T. Harrison, K. McKeegan, P. Lefort
- Geology
- 1 July 1995
Early formation of the Moon 4.51 billion years ago
- M. Barboni, P. Boehnke, K. McKeegan
- Geology, PhysicsScience Advances
- 1 January 2017
Data on lunar zircons indicate differentiation of the lunar crust by 4.51 billion years, indicating the formation of the Moon within the first ~60 million years after the birth of the solar system.
Mass-independent isotope effects in Archean (2.5 to 3.8 Ga) sedimentary sulfides determined by ion microprobe analysis
- S. Mojzsis, C. Coath, J. Greenwood, K. McKeegan, T. Harrison
- Geology, Environmental Science
- 1 May 2003
Mass-Independent Sulfur of Inclusions in Diamond and Sulfur Recycling on Early Earth
- J. Farquhar, B. Wing, K. McKeegan, J. Harris, P. Cartigny, M. Thiemens
- GeologyScience
- 20 December 2002
Populations of sulfide inclusions in diamonds from the Orapa kimberlite pipe in the Kaapvaal-Zimbabwe craton, Botswana, preserve mass-independent sulfur isotope fractionations. The data indicate that…
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