Explosive subaqueous eruptions: edifices and deposits

为期四年的研究补助金题为“水下爆炸性喷发：建筑物和沉积物”，是一项关于古代水下喷发及其火山的面向过程的研究。这项研究的适用部分将利用观察到的火山碎屑沉积组织来指导可能的多金属火山块状硫化物矿床，这些矿床是古代水下火山固有的。研究区域包括魁北克Abitibi绿岩带的太古界(约2.7Ga)布莱克河群、安大略省Wabigoon子省的2.9Ga陡岩地区，以及新西兰南岛的第三纪Oamaru火山杂岩。主要的重点是识别和表征原生水下火山碎屑岩，并将它们与重新加工的对应岩石区分开来。所研究的喷发类型是通常与火山口有关的大到中等体积的火山碎屑流和沉降物沉积，这是火山坍塌结构，以及小体积的喷泉和火山碎屑锥喷发出来的小体积喷发。这些火山建筑物发生在水下的事实使我们能够更好地了解水下爆炸的形成和分布。输沙过程以泥沙重力流为主，其中周围的介质水起着突出的作用。常见的三种爆炸产物是火山碎屑流、坠落和涌浪，后者在水下领域可能是不可能的。学生将直接从这个研究项目中获得资金，该项目包括一个博士学位论文和两个硕士学位论文。学生将使用基本的制图技术，但也使用详细的相分析来识别各种岩石套件，在一年的1-3个月的时间内在野外进行。学生津贴和现场后勤是这项研究项目的主要成本。

The four-year research grant entitled "Explosive subaqueous eruptions: edifices and deposits" is a process-oriented study concerning ancient subaqueous eruptions and their volcanoes. The applicable part of the study will use the observed pyroclastic deposit organization to vector possible polymetalic volcanic massive sulfide deposits that are inherent to ancient subaqueous volcanoes. The study areas include the Archean (ca. 2.7 Ga) Blake River Group of the Abitibi greenstone belt, Quebec, the 2.9 Ga Steep Rocks area  Wabigoon Subprovince, Ontario, and the Tertiary Oamaru volcanic complex, South Island, New Zealand. Major emphasis is placed on identifying and characterizing primary subaqueous pyroclastic rocks and differentiating them form their reworked counterparts. The type of eruptions studied are large- to moderate-volume pyroclastic flows and fallout deposits commonly associated with calderas, which are volcanic collapse structures, and small-volume fountaining and Surtseyan eruptions emanating from cinder and pyroclastic cones. The fact that these volcanic edifices occur under water allow us to better understand how subaqueous explosions form and distribute. The principal transport process is that of sediment gravity flows, in which the surrounding medium water plays a prominent role. The three prevalent types of explosive products are pyroclastic flow, fall and surge, with the latter probably not possible in the subaqueous realm. The students will be directly funded from this research project, which consists of one PhD and two MSc-level theses. Students will use basic mapping techniques but also use detailed facies analysis to identify the various rocks suites over a period of 1-3 months per year in the field. The student stipendium and field logistics represent the major costs of this research project.