Bolide Impact on Evaporite Terrane: Sulfur Gas Emission, Aerosol Formation, and Ejecta Dispersal

白垩纪/第三纪（K/T）界线处高硫撞击玻璃球的地球化学证据表明，蒸发岩沉积物地层发生了一次火流星撞击，并向大气中大量排放。pi将研究火流星撞击这些地面的后果，由此产生的含硫气体向大气脱气，硫酸气溶胶的形成，以及对大气和陆地的影响。硫酸气溶胶和酸雨可能是K/T边界全球灭绝的关键因素。因此，灭绝的严重程度可能在很大程度上是目标地层不寻常的地质作用。在第一年，项目监督员将通过实验确定硬石膏和石膏沉积物脱气的过程以及所排放的硫气体的形态。第二年，pi将模拟撞击引起的硫酸气溶胶对环境的影响。这些影响可能包括：(a)由硬石膏解离产生的CaO沉降引起的碱度危机，(b)由平流层硫酸盐气溶胶引起的全球变冷，以及(c)硫酸盐气溶胶沉降引起的酸雨。

Geochemical evidence from high-sulfur impact glass spherules at the Cretaceous/Tertiary (K/T) boundary indicates that a bolide impact occurred on evaporite sediment terrane, resulting in major emission to the atmosphere. PIs will study the consequences of bolide impact on such terrane, the resulting degassing of sulfurous gases to the atmosphere, formation of sulfuric acid aerosol, and effects on the atmosphere and land. Sulfuric acid aerosol and possibly acid rain may have been key factors in the global extinction at the K/T boundary. The severity of the extinctions may thus be largely a function of the unusual geology of the target terrane. During the first year PIs will determine experimentally the processes of degassing of anhydrite and gypsum sediments and the speciation of sulfur gases emitted. In the second year PIs will model the environmental effects of an impact-induced sulfuric acid aerosol. These effects may include: (a) alkalinity crisis due to the fallout of CaO derived from dissociation of anhydrite, (b) global cooling due to stratospheric sulfate aerosol, and (c) acid rain from fallout of sulfate aerosol.