Collaborative Research: The Thermal State of 20-25 Ma Lithosphere Subducting at the Costa Rica Margin, Implications for Hydrogeology, Fluxes, and the Seimogenic Zone

建议的项目是对哥斯达黎加边缘近海俯冲岩石圈的热状态进行多学科调查。 热流测量将在两次航行中进行，覆盖尼科亚半岛近海的海洋岩石圈部分，这些部分在构成和构造样式上不同，北方部分形成于东太平洋隆起，而南部部分被地形突变分开，形成于科科斯-纳斯卡扩张中心。 这些测量将伴随地震和条带测深研究，以及一个取芯方案，该方案将检查与地壳上覆沉积物中流体流动有关的孔隙水化学变化。 这些现场项目将伴随着两个数值模拟练习，将检查俯冲带的热状态，因为这两个部分的岩石圈俯冲。 目标将是确定这些地区俯冲岩石圈的相对热状态，负责俯冲板片热状态的相关热量和流体通量，以及这些变量如何影响俯冲带过程，包括化学通量率。

Recommended project is for a multidisciplinary investigation of the thermal state of the subducting lithosphere offshore of the Costa Rica margin. Heat flow measurements will be undertaken in two cruises covering oceanic lithosphere portions offshore of the Nicoya Peninsula that differ in makeup and tectonic style, with the northern portion formed at the East Pacific Rise and the southern portion, separated by an abrupt change in relief, formed at the Cocos-Nazca spreading center. These measurements will be acompanied by seismic and swath bathymmetric study, as well as a coring program that will examine changes in porewater chemistry associated with fluid flow in the sediments overlying the crust. These field programs will be accompanied by two numerical modeling exercises that will examine the thermal state of the subduction zone as these two portions of lithosphere subduct. The goals will be to determine the comparative thermal state of the subducting lithosphere in these regions, the associated heat and fluid fluxes responsible for the subducting slab thermal states, and how these variables affect subduction zone processes, including chemical flux rates.***