Collaborative Research: Geothermal heating of the Panama Basin and crustal evolution of the Costa Rica Rift

海洋地壳和深海之间的热量和质量传递对地球的冷却、关键生物地球化学物种的运动和海底生物群落的维持具有全球性的影响。此外，最近的研究表明，地热加热是深海环流的重要驱动力，深海环流是海洋-大气系统的主要组成部分。作为一个大型多学科和国际研究项目的一部分，该项目将开发第一个高分辨率模型，研究地壳热量和质量传递如何影响深海环流。拟议的工作将有助于更好地了解深海环流及其与全球海洋-大气系统的联系。这项提议的工作也将在理解地壳热和质量传递如何随着海洋地壳年龄的增长而演变方面取得重要进展。该项目支持研究生和本科生的培养。拟议的研究是由英国达勒姆大学领导的大型多学科、多机构项目的一个组成部分。本研究将使用最近收集的物理海洋学、地球物理和传导热流数据，以及赤道太平洋巴拿马盆地的现有数据集，构建从哥斯达黎加裂谷（CRR）轴到沉积物覆盖的600万年前地壳的热液和质量通量模型。目标是：(1)了解随着岩石圈年龄的增长，热液传热如何随地壳结构演变；(2)建立高分辨率模型，在区域尺度上显示热液热质传递对深海环流的影响。为了实现这些目标，在与多通道地震线重合的1.3 ~ 5.3 Ma沉积层地壳中获得了85个新的传导热流测量值。这些数据将与现有的热流数据以及英国主导的项目的地球物理和海洋学数据一起用于构建年轻沉积物覆盖地壳中热液传热的数学和数值模型。此外，关于轴向和近轴向区域熔体和部分熔体分布的其他地球物理数据，以及用于氦分析的水样和表征海底边界层和CRR热液柱结构的海洋学数据，将约束脊轴和近轴向区域热液环流模型。这些分析将提供CRR和近轴区域热液热输出的初步估计，并将指导未来CRR热液活动、地球化学运输和生物群落的探索。最后，热液模型将作为高分辨率海洋环流模型的输入，使用在英国主导的项目中收集的详细海洋学数据。

Heat and mass transfer between the oceanic crust and the deep ocean has global implications for the cooling of the earth, the movement of critical biogeochemical species, and the maintenance of ocean bottom biological communities. Moreover, recent studies show that geothermal heating is an important driver of deep ocean circulation, which is a major component of the ocean-atmosphere system. As a part of a large multidisciplinary and international research program, this project will develop the first high-resolution models of how crustal heat and mass transfer impact deep ocean circulation. The proposed work will lead to a better understanding of deep ocean circulation and its connection with the global ocean-atmosphere system. The proposed work also will yield an important advance in understanding how crustal heat and mass transfer evolves as the oceanic crust ages. The project supports the training of graduate and undergraduate students. The proposed research forms an integral component of the large multi-disciplinary, multi-institutional project led by the University of Durham, England. This research will use recently collected physical oceanographic, geophysical, and conductive heat flow data, together with existing data sets from the Panama Basin in the equatorial Pacific Ocean, to construct hydrothermal heat and mass flux models from the Costa Rica Rift (CRR) axis to sediment-covered, 6 million year old crust. The goals are: (1) to understand how hydrothermal heat transfer evolves with crustal structure as the lithospheric ages; and (2) to develop high resolution models that show how hydrothermal heat and mass transfer impacts deep ocean circulation on a regional scale. To achieve these goals, 85 new conductive heat flow measurements have been obtained in sediment-covered crust at ages between 1.3 and 5.3 Ma co-located with a multi-channel seismic line. These data will be used together with existing heat flow data, and the geophysical and oceanographic data from the British-led project, to construct mathematical and numerical models of hydrothermal heat transfer in young sediment-covered crust. In addition, other geophysical data on the distribution of melt and partial melt in axial and near-axial regions, coupled with water samples for helium analysis and oceanographic data characterizing the ocean bottom boundary layer and hydrothermal plume structure at the CRR, will constrain models of hydrothermal circulation at the ridge axis and in near-axial regions. These analyses will provide the first estimates of hydrothermal heat output at the CRR and near-axis region, and will guide future exploration of hydrothermal activity, geochemical transport, and the biological communities at the CRR. Finally, the hydrothermal models will serve as input to high-resolution models of ocean circulation using the detailed suite of oceanographic data collected during the British-led project.