Mineral studies applied to geological problems

地幔本质上是由无水矿物（不含水）组成的，但地质作用将水沿着俯冲带带带入地幔，主要以蛇纹岩的形式存在。水也可以沿着断裂系统进入地幔，这些断裂系统是地壳板块碰撞时地幔岩石向地壳岩石上倒转而形成的。我正在研究一系列被称为蛇绿岩复合体的地幔和上地壳岩石，这些岩石在英国康沃尔被推升。这些岩石以前曾被研究过，但没有人认识到这些岩石中复杂而广泛的脉系的重要性。这些裂缝使水进入蛇绿岩复合体的中心，改变了岩石，用新的矿物填满裂缝，润滑了岩石，使它们能够被引出到现在的位置。脉体的矿物学特征反映了它们形成时的降温状态：高温脉体含长石、角闪石和斜绿石，中温脉体含滑石、斜绿石和蛇纹石，低温脉体含斜绿石、皂石和海泡石。确定这些脉状矿物的矿物学和化学成分可以让我确定它们形成的条件和水的来源。

The Mantle is essentially composed of anhydrous minerals (contain no water) but geological processes carry water down into the Mantle along subduction zone mainly in rocks called serpentinites. Water can also have access to the Mantle along fracture systems that develop when Mantle rocks are obducted onto crustal rocks when tectonic plates collide. I am studying a series of mantle and upper crustal rocks called an ophiolite complex that has been thrust up in Cornwall, UK. These rocks have been studied before but no one has recognized the importance of a complex and extensive vein system in these rocks. These fractures have allowed water into the heart of the ophiolite complex altering the rocks, filling the fractures with new minerals and lubricating the rocks so that they could be obducted to their present position. The mineralogy of the veins reflects the falling temperature regime in which they form: high-temperature veins with feldspar, amphibole and clinochlore, medium-temperature veins with talc, clinochlore and serpentine and low-temperature veins with clinochlore, saponite and sepiolite. Determining the mineralogy and the chemical composition of these vein minerals will allow me to determine the conditions they formed under and the source of the water.