carbon dioxide
; ice
; air temperature
; atmosphere
; biogenesis
; environmental temperature
; freezing
; geography
; greenhouse effect
; mathematical analysis
; model
; oceanic regions
; priority journal
; review
; steady state
; thawing
英文摘要:
Without sufficient greenhouse gases in the atmosphere, the early Earth would have become a permanently frozen planet because the young Sun was less luminous than it is today. Several resolutions to this faint young Sun- frozen Earth paradox have been proposed, with an atmosphere rich in CO2 being the one generally favored. However, these models assume that there were no mechanisms for melting a once frozen ocean. Here we show that bolide impacts between about 3.6 and 4.0 billion years ago could have episodically melted an ice-covered early ocean. Thaw-freeze cycles associated with bolide impacts could have been important for the initiation of abiotic reactions that gave rise to the first living organisms.
Bada, J.L., Scripps Institution of Oceanography, Univ. of California at San Diego, San Diego, CA 92093-0212, United States; Bigham, C., Scripps Institution of Oceanography, Univ. of California at San Diego, San Diego, CA 92093-0212, United States; Miller, S.L., Department of Chemistry, Univ. of California at San Diego, San Diego, CA 92093-0317, United States
Recommended Citation:
Bada J.L.,Bigham C.,Miller S.L.. Impact melting of frozen oceans on the early Earth: Implications for the origin of life[J]. Proceedings of the National Academy of Sciences of the United States of America,1994-01-01,91(4)