Kilometre-scale compartmentalization of fluid sources to a fossil hydrothermal system
Kilometre-scale compartmentalization of fluid sources to a fossil hydrothermal system
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DOI：
10.1016/j.oregeorev.2019.103207
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发表时间：
2020-01
影响因子：
3.3
通讯作者：
J. Armstrong;J. Parnell;A. Boyce;L. Bullock;L. Bullock
中科院分区：
文献类型：
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作者：
J. Armstrong;J. Parnell;A. Boyce;L. Bullock;L. Bullock
硫同位素数据证明，西坎布里亚铁矿田表现出公里级的流体源分区。重晶石伴生赤铁矿矿石来自 13 个矿山，沿走向宽度为 5km，其 δ34S(VCDT) 同位素组成范围为 +7.9 至 +23.6‰。巨大的变化受到NNW-SSE断层的强烈控制，其中北部成分最重，南部成分最轻。重成分和轻成分分别与石炭纪和二叠纪蒸发岩相当，这两种蒸发岩都产于西坎布里亚，被认为是重晶石硫的主要来源，尽管石炭纪煤黄铁矿的氧化输入可能提供了少量成分。来自地层不同来源的硫的推导表明，断层在局部范围内隔离了隔室中的流体流动。已发布的塞拉菲尔德潜在废物处理场附近断块中重晶石的数据更加明显，表明主要黄铁矿来源。这些数据强调，流体源可以在故障系统中高度划分，并且需要支持证据来确认它们是否可以相关。
The West Cumbria iron ore field exhibits kilometre-scale compartmentalization of fluid sources, as evidenced by sulphur isotope data. Barite accompanying haematite ore from 13 mines in an along-strike width of 5 km has δ34S(VCDT)isotopic compositions ranging from +7.9 to +23.6‰. The large variation is strongly controlled by NNW-SSE faulting, in which the heaviest compositions are to the north and lightest in the south. The heavy and light compositions are comparable with those of Carboniferous and Permian evaporites respectively, both of which occur in West Cumbria and are the assumed primary sources of the barite sulphur, though input from the oxidation of Carboniferous coal pyrite may have provided a minor component. The derivation of sulphur from stratigraphically distinct sources shows that faults isolated fluid flow in compartments on a local scale. Published data for barite from an adjacent fault block in a potential waste disposal site at Sellafield are further distinct, indicative of a primary pyrite source. These data emphasize that fluid sources can be highly compartmentalized in a faulted system and require supporting evidence to confirm if they can be correlated.