Emplacement of the 1991 Ignimbrite at Mount Pinatubo, Philippines: Evaluation of Present Ideas on Deposition from Pyroclastic Flows

9419111自本研究是映射，采样，并通过粒度和碎屑形态分析的各种相的1991年在皮纳图博山，菲律宾的熔结凝灰岩。 还将利用磁化率各向异性对熔结凝灰岩的主体进行组构研究。 其主要目的是更好地了解存款的岩相和相组合，其定位机制和火山碎屑流的性质。 这些信息将被放入3.5小时长的高潮的严格限制的时间框架中，将为火山学目前关于火山碎屑流的性质和沉积机制谱的辩论提供急需的光线。 这项研究还将提供有关1991年火山爆发期间产生的共熔凝灰岩灰量的资料。 如果不对熔结凝灰岩进行详细研究，火山碎屑流侵位的模型将继续超过从已详细探索的实际实例中获得的信息量，在这方面，不应失去新的大型皮纳图博存款成果的价值。

9419111 Self This study is to map, sample, and analyze by both granulometry and clast morphology the various facies of the 1991 ignimbrite at Mount Pinatubo, Philippines. Fabric studies of the main body of the ignimbrite by anisotropy of magnetic susceptibility (AMS) will also be undertaken. The main aim is to better understand the lithofacies and facies association of the deposit, its emplacement mechanisms, and the nature of the pyroclastic flows. The information, which will be put into the well-constrained temporal framework of the 3.5-hour-long climax, will shed much-needed light on the current debate in volcanology concerning the nature of, and the spectrum of deposition mechanisms from, pyroclastic flows. The study will also provide information on the amount od co-ignimbrite ash generated during the 1991 eruption. Without detailed studies of ignimbrites, models of pyroclastic flow emplacement will continue to outstrip the amount of information available from actual examples that have been explored in detail, and in this regard the value of results from the new, large Pinatubo deposit should not be lost.