Numerical simulation of cool hydrothermal processes in the upper volcanic crust beneath a marine sediment pond: North Pond, North Atlantic Ocean

Low temperature hydrothermal systems hosted in the volcanic oceanic crust are responsible for ~20% of Earth's global heat loss. Marine sediment ponds comprise an important type-setting on young ridge flanks where hydrothermal circulation advectively extracts lithospheric heat, but the nature of coupled fluid-heat transport in these settings remains poorly understood. Here we present coupled (fluid-heat) numerical simulations of ocean crustal hydrogeology in and below North Pond, a sediment pond on ~8 Ma seafloor of the North Atlantic Ocean. Two- and three-dimensional simulations show that advective transport beneath North Pond is complex and time-varying, with multiple spatial and temporal scales, consistent with seafloor and borehole observations. A unidirectional, single-pass flow system is neither favored nor needed to match the spatial distribution of seafloor heat flux through North Pond sediments. When the permeability of the crustal aquifer is relatively high (10-10 to 10-9 m2), ...

赋存于火山洋壳中的低温热液系统，约贡献了地球全球总热散失量的20%。海洋沉积盆地是年轻洋脊侧翼上一类典型的赋存环境，热液循环通过对流作用带走岩石圈热量，但这类环境中流体与热量的耦合输运本质仍有待深入认知。本文针对北池（North Pond）——位于北大西洋约8 Ma海床之上的沉积盆地——内部及其下方的洋壳水文地质体系，开展了流体-热量耦合数值模拟研究。二维与三维模拟结果显示，北池下方的对流输运过程复杂且随时间动态变化，具备多尺度时空特征，与海底及钻孔观测结果相符。若要匹配北池沉积物的海底热通量空间分布，单向单程流系统既非合理的物理图景，也并非必要条件。当壳层含水层的渗透率处于较高水平（10^-10 至 10^-9 平方米）时，……