Hydrothermal recharge and discharge across 50 km guided by seamounts on a young ridge flank
Hydrothermal recharge and discharge across 50 km guided by seamounts on a young ridge flank
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DOI：
10.1038/nature01352
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发表时间：
2003-02-06
期刊：
影响因子：
64.8
通讯作者：
Becker, K
中科院分区：
文献类型：
--
作者：
Fisher, AT;Davis, EE;Becker, K
海底热液循环通过超过 100 万年 (Myr) 的岩石圈，造成了板块冷却释放的 30% 的能量，以及 70% 的全球热流异常（观测到的热输出与传导冷却模型预测的热输出之间的差异）(1,2)。热液从海洋岩石圈带走大量热量，对于板块来说通常可达 65 Myr 老(3,4)。但鉴于覆盖大多数山脊侧面的相对不渗透的沉积物(5)，很难解释这些流体如何将热量从地壳传输到海洋。在这里，我们展示了胡安德富卡海岭年轻东侧的测绘带测绘、热流、地球化学和地震勘测结果，这些结果表明，穿过厚厚沉积物的孤立基底露头引导着相距超过 50 公里的地点之间的热液排放和补给。我们的分析揭示了邻近充注和排放露头的海底存在明显的热模式。我们发现，根据独立观测和建模研究的报告，这种通过基底露头的循环可以在压力差和地壳特性的情况下持续下去。
Hydrothermal circulation within the sea floor, through lithosphere older than one million years (Myr), is responsible for 30% of the energy released from plate cooling, and for 70% of the global heat flow anomaly (the difference between observed thermal output and that predicted by conductive cooling models)(1,2). Hydrothermal fluids remove significant amounts of heat from the oceanic lithosphere for plates typically up to about 65 Myr old(3,4). But in view of the relatively impermeable sediments that cover most ridge flanks(5), it has been difficult to explain how these fluids transport heat from the crust to the ocean. Here we present results of swath mapping, heat flow, geochemistry and seismic surveys from the young eastern flank of the Juan de Fuca ridge, which show that isolated basement outcrops penetrating through thick sediments guide hydrothermal discharge and recharge between sites separated by more than 50 km. Our analyses reveal distinct thermal patterns at the sea floor adjacent to recharging and discharging outcrops. We find that such a circulation through basement outcrops can be sustained in a setting of pressure differences and crustal properties as reported in independent observations and modelling studies.