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The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy(More)
[1] Biomass burning in the Amazon provides strong input of aerosols into the atmosphere, with potential effects on precipitation, cloud properties, and radiative balance. However, few studies to date have systematically examined these effects at the scale of the Amazon Basin, over an entire burning season, using available data sets. We empirically study the(More)
1. Introduction: Impacts of planetisimals on early Earth have been considered to affect the origin and evolution of life and atmosphere (1). We suggest an importance of organic synthesis due to catalytic reaction like Fischer-Tropsch catalysis over the hot iron condensates. When condensed particles, formed in an expanding impact vapor plume, reenter into(More)
High-velocity (-• 2 to-• 5 km/sec) impacts into octahedrite iron meteorites (Gibeon, El Sampal, and Arispe), steel, and iron targets were made at the NASA-Ames Vertical Gun Facility. The experiments clearly revealed the brittle behavior of meteorites at very low temperatures (<200 ø K) as indicated by spallation of the crater rim and the development of(More)
Cyanide compounds are amongst the most important molecules of the origin of life. Here, we demonstrate the importance of mid-size (0.1–1 km in diameter) hence frequent meteoritic impacts to the cyanide inventory on the early Earth. Subsequent aerodynamic ablation and chemical reactions with the ambient atmosphere after oblique impacts were investigated by(More)
Introduction: Hypervelocity impacts on the surface of growing planets may generate impact-induced vapor clouds and many chemical species are produced within such vapor clouds. These species may control the surface environments of the planets, such as temperature and redox state of the atmosphere. It is, thus, important to understand the composition of gases(More)
Introduction: Fischer-Tropsch catalysis, which converts CO (and CO 2) and H 2 into CH 4 on the surface of transition metals such as iron and nickel, is believed to play important roles in astrophysical environments. In addition to producing large quantities of water in some circumstellar envelopes [1], it has also been showed as a mean to produce(More)
Electrical properties of PECVD produced poly-Si photovoltaic layers on the various textured substrates showing the light trapping effect have been investigated using an AC-conductivity technique. From temperature dependence of electron (hole) conductivities using n-i-n (p-i-p) structures, the Fermi level of the poly-Si layer on the slightly textured(More)
Forsterite (Mg2SiO4) is one of the major planetary materials, and its behavior under extreme conditions is important to understand the interior structure of large planets, such as super-Earths, and large-scale planetary impact events. Previous shock compression measurements of forsterite indicate that it may melt below 200 GPa, but these measurements did(More)
[1] This study assesses near surface lapse rates and temperatures over the past decade at two heights from the Oklahoma Mesonet. A statistically significant change in lapse rate was detected of À0.21 ± 0.09°C (10 m) À1 per decade. The trend of nighttime lapse rate was about three times larger than the magnitude of trend of the daytime lapse rate. The lapse(More)
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