Chemical cycles in the oceanic crust

海洋地壳中的热液循环在控制世界海洋成分方面起着关键作用，为极端微生物提供能量和营养，并产生具有重要经济意义的矿床。在一个海洋板块的整个生命周期中，从它在洋中脊的形成到它在俯冲带的再循环回到地幔中，热量和质量在岩石圈和海洋之间交换。我提出的研究计划侧重于了解是什么驱动了这种交换，无论是在高温热液系统活跃的洋中脊，还是在海底风化占主导地位的离轴洋脊。在这两种环境中，我们将地质约束与地球化学示踪剂的见解结合起来，以评估控制化学反应和元素迁移的环境条件。对于洋中脊环境，我们将通过研究一种新型深海钻探所回收的岩心来研究海水进入下洋壳的条件和后果。我们还将通过海王星网络分析记录胡安德富卡山脊奋进号部分活跃热液系统高温流体特性的仪器的实时数据流。我们在离轴环境中的重点是通过探索与海水化学和气候的联系来推进我们对海底风化如何响应外部强迫的理解。我们将对海底风化产物进行深入研究，利用国际钻探项目的广泛核心收集和盆地尺度数据集，开发预测模型，评估地壳年龄与气候状态和海水化学对海底风化地球化学通量的相对重要性。

Hydrothermal circulation in the oceanic crust plays a critical role in controlling the compositions of the world's oceans, provides energy and nutrients for extremophile organisms and generates ore deposits of economic importance. Heat and mass are exchanged between the lithosphere and oceans throughout the lifecycle of an ocean plate, from its creation at mid-ocean ridges to its recycling back into the mantle at subduction zones. My proposed research program focuses on understanding what drives this exchange, both at mid-ocean ridges where high temperature hydrothermal systems are active and in the off-axis where seafloor weathering dominates. In both environments, we integrate geological constraints with insights from geochemical tracers to assess what environmental conditions control chemical reactions and element mobility. For the mid-ocean ridge setting, we will examine the conditions and consequences of seawater ingress into the lower ocean crust by studying drill cores recovered by a novel deep-sea drill. We will also analyze the real-time data stream from instruments recording high temperature fluid properties from active hydrothermal systems at the Endeavour segment of the Juan de Fuca Ridge through the NEPTUNE network. Our focus in the off-axis environment is to advance our understanding of how seafloor weathering responds to external forcing by exploring linkages with seawater chemistry and climate. We will conduct an in depth study of the products of seafloor weathering using the extensive core collection of international drilling programs and basin-scale datasets to develop predictive models that assess the relative importance of crustal age versus climate state and seawater chemistry for seafloor weathering geochemical fluxes.