Shock-induced devolatilization of calcium sulfate and implications for K-T extinctions
Shock-induced devolatilization of calcium sulfate and implications for K-T extinctions
复制标题
冲击引起的硫酸钙脱挥发分及其对 K-T 灭绝的影响
DOI：
10.1016/0012-821x(94)90174-0
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发表时间：
1994
影响因子：
5.3
通讯作者：
T. Ahrens
中科院分区：
文献类型：
--
作者：
Guangqing Chen;J. Tyburczy;T. Ahrens
硫酸钙的脱挥发作用（存在于墨西哥撞击构造希克苏鲁布的目标岩石中）和所产生的硫酸气溶胶在平流层中的扩散被认为是第三纪碰撞的可能机制[1，2]。在实验室中测量了在42GPa压力下硫酸钙的两个冲击脱挥反应：CaSO4 + SiO2 → CaSiO3 + SO3 ↑ CaSO4 → CaO + SO2 ↑ +12O2 ↑的SO2生成量，发现两者的生成量都比平衡热力学计算的低得多。发现反应产物是平衡时计算值的10 - 2倍。通过对希克苏鲁布光刻切片中CaSO 4冲击脱挥发分脱气到大气中的硫氧化物量的模拟，得到了9 × 10 16~6 × 10 17 g（以硫质量计）比先前的上限估计值低10 - 100倍，由全球变冷和酸雨沉降引起的相关环境压力不足以解释广泛的KT抑制。
The devolatilization of calcium sulfate, which is present in the target rock of the Chicxulub, Mexico impact structure, and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions [1, 2]. We measured the amount of SO 2 produced from two shock-induced devolatilization reactions of calcium sulfate up to 42 GPa in the laboratory: CaSO 4+ SiO 2→ CaSiO 3+ SO 3↑ CaSO 4→ CaO+ SO 2↑+ 1 2 O 2↑ We found both to proceed to a much lower extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be∼ 10− 2 times those calculated for equilibrium. Upon modeling the quantity of sulfur oxides degassed into the atmosphere from shock devolatilization of CaSO 4 in the Chicxulub lithographic section, the resulting 9× 10 16 to 6× 10 17 g (in sulfur mass) is lower by a factor of 10–100 than previous upper limit estimates, the related environmental stress arising from the resultant global cooling and fallout of acid rain is insufficient to explain the widespread KT extinctions.