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Cratering Rates in the Outer Solar System
- K. Zahnle
- Geology, Physics
- 1 September 1999
Biogenic Methane, Hydrogen Escape, and the Irreversible Oxidation of Early Earth
- D. Catling, K. Zahnle, C. McKay
- PhysicsScience
- 3 August 2001
TLDR
Carbon dioxide cycling and implications for climate on ancient Earth
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,…
Annihilation of ecosystems by large asteroid impacts on the early Earth
- N. Sleep, K. Zahnle, J. Kasting, H. Morowitz
- Environmental Science, PhysicsNature
- 9 November 1989
TLDR
The loss of mass‐independent fractionation in sulfur due to a Palaeoproterozoic collapse of atmospheric methane
- K. Zahnle, M. Claire, D. Catling
- Environmental Science
- 1 December 2006
We use a 1‐D numerical model to study the atmospheric photochemistry of oxygen, methane, and sulfur after the advent of oxygenic photosynthesis. We assume that mass‐independent fractionation (MIF) of…
Photochemistry of methane and the formation of hydrocyanic acid (HCN) in the Earth's early atmosphere
- K. Zahnle
- Environmental Science
- 20 February 1986
The photochemistries of methane and HCN are discussed in the context of the primitive terrestrial atmosphere, using a detailed numerical model. In the absence of abundant O2, absorption of solar EUV…
Nitrogen-enhanced greenhouse warming on early Earth
- C. Goldblatt, M. Claire, T. Lenton, A. Matthews, A. Watson, K. Zahnle
- Geology, Environmental Science
- 1 December 2009
Early in Earth’s history, the Sun provided less energy to the Earth than it does today. However, the Earth was not permanently glaciated, an apparent contradiction known as the faint young Sun…
Why O2 is required by complex life on habitable planets and the concept of planetary "oxygenation time".
- D. Catling, C. Glein, K. Zahnle, C. McKay
- PhysicsAstrobiology
- 7 June 2005
TLDR
Environmental Perturbations Caused by the Impacts of Asteroids and Comets
- O. Toon, K. Zahnle, D. Morrison, R. Turco, C. Covey
- Geology, Physics
- 1 May 1997
We review the major mechanisms proposed to cause extinctions at the Cretaceous-Tertiary geological boundary following an asteroid impact. We then discuss how the proposed extinction mechanisms may…
Habitable zone limits for dry planets.
- Y. Abe, A. Abe‐Ouchi, N. Sleep, K. Zahnle
- Geology, PhysicsAstrobiology
- 27 June 2011
TLDR
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