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Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
- R. Firestone, A. West, W. Wolbach
- Environmental Science, GeographyProceedings of the National Academy of Sciences
- 9 October 2007
It is proposed that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling, which contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.
The Organic Content of the Tagish Lake Meteorite
Analysis of the Tagish Lake meteorite has shown this carbonaceous chondrite to contain a suite of soluble organic compounds that provides insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.
Impact Event at the Permian-Triassic Boundary: Evidence from Extraterrestrial Noble Gases in Fullerenes
Fullerenes from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites, implying that an impact event accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.
Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia
The Bedout High, located on the northwestern continental margin of Australia, has emerged as a prime candidate for an end-Permian impact structure and the identification of melt rocks and impact breccias from drill cores located on top of Bedout are consistent with the presence of a buried impact crater.
Chondritic Meteorite Fragments Associated with the Permian-Triassic Boundary in Antarctica
In one sample, the meteoritic fragments are accompanied by more abundant discrete metal grains, which are also found in an end-Permian bed at Meishan, southern China, and the implications for a suggested global impact event at the Permian-Triassic boundary are discussed.
Extraterrestrial Helium Trapped in Fullerenes in the Sudbury Impact Structure
The 3He/4He ratios in the Sudbury fullerenes are similar to those found in meteorites and in some interplanetary dust particles, suggesting that the helium within the C60 molecules at Sudbury is of extraterrestrial origin.
Astrophysical and astrochemical insights into the origin of life
Stellar nucleosynthesis of heavy elements such as carbon allowed the formation of organic molecules in space, which appear to be widespread in our Galaxy. The physical and chemical…
New insights into deformation and fluid flow processes in the Nankai Trough accretionary prism: Results of Ocean Drilling Program Leg 190
The Nankai Trough accretionary prism is considered an “end‐member” prism accreting a coarse terrigenous sediment section in a setting with structural simplicity, unparalleled resolution by seismic…
Fullerenes in the 1.85-billion-year-old Sudbury impact structure.
The oxidation of the fullerenes during the 1.85 billion years of exposure was apparently prevented by the presence of sulfur in the form of sulfide-silicate complexes associated with the fulrerenes.
Fullerenes: an extraterrestrial carbon carrier phase for noble gases.
It is determined that both the Allende and Murchison fullerene cage structure and the KTB fullerenes contain trapped noble gases with ratios that can only be described as extraterrestrial in origin.