Chapter 5 Chemical environments of submarine hydrothermal systems
Chapter 5 Chemical environments of submarine hydrothermal systems
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第五章海底热液系统的化学环境
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发表时间：
2005
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通讯作者：
E. Shock
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作者：
E. Shock
也许是因为冒着黑烟的烟囱成为杂志封面的巨大主题，海底热液系统参与生命起源的提议使许多调查人员将注意力集中在引人注目的热液喷口上。就像游客们争先恐后地观看老忠实间歇泉壮观的喷发，而很少考虑黄石盆地的水文一样，人们的注意力集中在壮观的高温热液喷口上，几乎排除了巨大的地下热液系统。然而，地质结构、热流和水文参数的规模和复杂性也是黄石国家公园间歇泉盆地的特征，也是海底热液系统的特征。然而，在潜艇系统中，规模可以大得多。像老忠实泉一样，海底热液喷口具有壮观的品质，但它们只是在所有海洋盆地的海底扩张中心运作的巨大地质系统的一个迷人方面。对热液过程在生命起源中可能发挥的作用进行的批判性研究应包括可能存在的各种环境。本章的目标是综合有关海底热液系统的无机地球化学的各种信息，汇编这些系统的基本物理和化学属性的描述，并考虑高温，流体驱动的有机合成过程的影响。关于海底热液系统的信息来自许多方面。直接对排气流体进行的测量提供了有用的，但非常有限的，关于深度过程的线索。大洋地壳已被钻到约2.0公里深，提供了许多其他信息，但钻井技术还不允许钻孔和岩心样本达到含水流体在大洋地壳中循环的最大深度。这种确定依赖于对诸如沿着西南印度洋脊等构造力抬升的深海地壳块的研究，或对称为蛇绿岩序列的更完整的洋壳部分的研究，这些部分由于构造侵位而目前暴露在大陆上。人们认为海底热液系统中发生的许多事情都是从蛇绿岩序列的研究中推断出来的，特别是从暴露较好的蛇绿岩序列中推断出来的。
Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to ~ 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such determinations rely on studies of pieces of deep oceanic crust uplifted by tectonic forces such as along the Southwest Indian Ridge, or more complete sections of oceanic crust called ophiolite sequences which are presently exposed on continents owing to tectonic emplacement. Much of what is thought to happen in submarine hydrothermal systems is inferred from studies of ophiolite sequences, and especially from the better-exposed ophi-