Accretion of Extraterrestrial Matter to the Earth: The Sedimentary Record

Kyte 9418303 建议继续开展基础广泛的研究方案，以便在了解地球沉积物中记录的地外物质对地球的化学和矿物学记录方面取得重大进展。 我们建议对来自三个不同撞击事件的碎片的矿物学和地球化学进行研究。 (1)在接下来的三年里，我们的主要目标将是对我们发现的独特存款进行重新调查。 它记录了上新世晚期小行星撞击深海盆地的情况。 将于1995年春季参加德国极地研究考察队，对撞击发生的区域进行地球物理和地质勘探。 将对回收的含有撞击碎片的沉积物岩心进行矿物学和地球化学分析，以了解这次撞击事件的物理和化学演变情况，并将其用作撞击-第三纪边界沉积物的模拟物。 (2)我们还将调查详细的地球化学的早期太古代（-3.4 Ga）球床，可能会记录一个主要的小行星的影响，以及在构造演化的巴伯顿绿岩带的重大变化。 我们将集中精力确定是否有地球化学证据来支持这一假设，即整个小球床的渐变反映了撞击产生的蒸汽云的化学和热演化。 (3)此外，我们还将描述大西洋和印度洋沉积物中第三纪边界撞击碎片的丰度、分布和组成。 这将使以这种方式研究的地球表面面积增加一倍，大大改进我们关于撞击碎片相对于希克苏鲁布结构的演变和分布的模型。 (4)我们还预计，我们将被要求为其他研究人员提供Ir分析。 如果我们的时间表允许，我们将在适当的情况下协助解决这些问题。

Kyte 9418303 It is proposed to continue the broad-based research program which is designed to make significant advances in the understanding of the chemical and mineralogical record of extraterrestrial matter to the Earth, as recorded in terrestrial sediments. We propose research into the mineralogy and geochemistry of debris from three distinct impact events. (1) In the next three years our principal objective will be a renewed investigation of a unique deposit that we discovered. It records an asteroid impact into a deep-ocean basin during the late Pliocene. Will join a German polar research expedition in Spring 1995 that will engage in a geophysical and geological exploration of the region in which the impact occurred. Sediment cores recovered that contain debris from the impact will be the subject of mineralogical and geochemical analyses to learn about the physical and chemical evolution of this impact event as well as to use it as an analog to Cretaceous-Tertiary boundary deposits. (2) We will also investigate the detailed geochemistry of an early Archean (-3.4 Ga) spherule bed which may record a major asteroid impact as well as a major change in the tectonic evolution of the Barberton Greenstone Belt. We will concentrate on determining whether there is geochemical evidence to support the hypothesis that gradations across the spherule bed reflect chemical and thermal evolution of an impact-generated vapor cloud. (3) Additionally we will characterize the abundance, distribution, and composition of Cretaceous-Tertiary boundary impact debris in sediments from the Atlantic and Indian Oceans. This will approximately double the portion of the Earth's surface studied in this way greatly improve our model of the evolution and distribution of impact debris relative to the Chicxulub structure. (4) We also anticipate that we will be requested to provide Ir analyses for other researchers. As our schedule permits, we will assist in such problems, if appropriate.