Effect of bolide impacts on Earth's surface environment Analysis of chemical reactions within a giant vapor plume

火流星撞击对地球表面环境的影响巨大蒸气羽流内的化学反应分析

• 批准号: 14340167
• 负责人: IGARASHI George
• 金额: $ 9.6万
• 依托单位: Tohoku University (2004)The University of Tokyo (2002-2003)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340167/
• 关键词: Hypervelocity Impacts; Impact vapor plume; K; T event; Mass extinction; Sulfur oxides; Chemical reaction kinetics; Environmental perturbation; Earth History

In this research project we conducted a series of laser ablation experiments simulating the thermodynamic state in the vapor loud induced by K/T impact event in order to understand the basic chemical processes involved in SO_x reactions. We constructed a new laser irradiation system with a X-Y stage to ensure that each laser pulse can ablate fresh target (CaSO4) surface. Also we incorporated a new high-performance quadruple mass spectrometer to enhance the signal-to-noise ratio of our mass measurements. Furthermore, we used a high power Nd:YAG Laser (15J/pulse) to generate a large high-temperature plumes. Combining this laser facility with the existing small Nd:YAG laser, we could cover more than 10^3 of dynamic range of laser energy. This allows us to obtain a very reliable data on SO_x reactions. Finally, we conducted high-speed spectroscopic measurements of laser-induced vapor plumes. The results of experiments show that the terminal SO_3/SO_2 ratio in vapor clouds increases sharply as size of laser plume increases. This increase is caused by lowering the quenching temperature of SO_x redox reactions in the laser vapor clouds.Kinetic analysis of the above experimental results indicate that SO_3 formation rate found in our laser experiments is 100 to 3000 times the rate estimated based on extrapolation from literature data measured at much lower and higher temperatures than the temperature range in this study. This result suggests that there is a new reaction pathway to form SO_3 in a high-temperature vapor cloud, such as catalytic reaction on the surface of CaO. If such catalytic reaction exists, the conversion of SO2 to SO3 in the K/T impact is also much faster than previously thought. This will decrease the duration of sulfuric acid aerosol winter following the K/T impact and may enhance greatly the intensity of acid rain fall after the K/T impact.

本研究计划通过激光烧蚀实验模拟K/T碰撞产生的蒸汽云中的热力学状态，以了解SO_x反应的基本化学过程。我们构造了一种新的激光辐照系统，该系统具有X-Y工作台，以确保每个激光脉冲都能烧蚀新鲜的靶（CaSO 4）表面。此外，我们采用了一种新的高性能四重质谱仪，以提高我们的质量测量的信噪比。此外，我们还利用高功率Nd：YAG激光器（15 J/脉冲）产生了大的高温羽流。将该激光设备与现有的小型Nd：YAG激光器相结合，我们可以覆盖超过10^3的激光能量动态范围。这使我们获得了一个非常可靠的SO_x反应数据。最后，我们进行了高速光谱测量的激光诱导蒸汽羽流。实验结果表明，随着激光羽流尺寸的增大，水汽云中的SO_3/SO_2终末比急剧增大。对上述实验结果的动力学分析表明，我们在激光实验中发现的SO_3生成速率是根据文献数据外推的速率的100 ~ 3000倍。这一结果表明，在高温蒸汽云中存在一种新的生成SO_3的反应途径，如CaO表面的催化反应。如果存在这样的催化反应，那么在K/T撞击中SO2向SO 3的转化也比以前认为的要快得多。这将减少K/T冲击后硫酸气溶胶冬季的持续时间，并可能大大增强K/T冲击后的酸雨强度。

项目成果

Interaction between Impact-Induced Vapor Clouds and the Ambient Atmosphere 1 : Spectroscopic Observation

撞击引起的蒸气云与环境大气之间的相互作用 1：光谱观测

• 发表时间: 2003
• 期刊: Journal of Geophysical Research 108・E6
• 作者: S.Sugita;P.H.Schultz
• 通讯作者: P.H.Schultz

Intensities of atomic lines and molecular bands observed in impact-induced luminescence

• DOI: 10.1029/2003je002156
• 发表时间: 2003-12
• 期刊: Journal of Geophysical Research
• 作者: S. Sugita;P. Schultz;S. Hasegawa

Real-time detector for hypervelocity microparticles using piezoelectric material

使用压电材料的超高速微粒实时探测器

• 发表时间: 2004
• 期刊: Advances in Space Research 34
• 作者: Miyachi;T.;N.Hasebe;H.Ito;T.Masumura;H.Okada;H.Yoshioka;K.Nogami;T.Iwai;H.Shibata;Y.Hamabe;S.Sasaki;S.Sugita;S.Hasegawa;H.Yano;H.Ohashi.K.Muranaga;M.Sato;T.Tou
• 通讯作者: T.Tou

S.Sugita, P.H.Schultz: "Initiation of Run-Out Flows on Venus by Oblique Impacts"Icarus. 155. 265-284 (2002)

S.Sugita、P.H.Schultz：“金星上倾斜撞击引发的流出流”伊卡洛斯。

Ohno, S., S.Sugita, S.Hasegawa, T.Kadono, G.Igarashi: "Sulfur chemistry in laser-simulated impact vapor clouds : implications for the K/T impact event"Earth Planetary Science Letters. 218・3-4. 347-361 (2004)

Ohno, S., S.Sugita, S.Hasekawa, T.Kadono, G.Igarashi：“激光模拟撞击蒸气云中的硫化学：对 K/T 撞击事件的影响”地球行星科学快报 218・3-。 4. 347-361 (2004)