How long can a hydrothermal system be sustained by a single intrusive event?
How long can a hydrothermal system be sustained by a single intrusive event?
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DOI：
10.2113/gsecongeo.92.7-8.766
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发表时间：
1997-11-01
期刊：
影响因子：
--
通讯作者：
Barrie, T
中科院分区：
文献类型：
--
作者：
Cathles, LM;Erendi, AHJ;Barrie, T
已发表的数值计算表明，产生近地表地热系统或矿床的对流系统可能在最多几万年的时间内冷却其侵入热源，即使侵入量很大。一般认为，热液环流、近地表地热活动和岩浆侵入在时间和空间上应紧密联系在一起。长时间的（类似于1毫秒）热液活动通常表明有多个侵入脉冲和相关的热液循环脉冲。然而，如果侵入环境的渗透率刚好高于常规渗透率，并且侵入的体积非常大，则本文的计算表明，单次侵入可以维持类似80万年的热液循环和近地表地热活动。这些异常长寿的热液系统可以通过几个非常分散的排放点排放，并有可能产生异常大尺寸的孤立块状硫化物矿床。
Published numerical calculations show that the convective systems which produce near-surface geothermal systems or ore deposits are likely to cool their intrusion heat source in at most a few tens of thousands of years, even if the intrusion is large. Generally, hydrothermal circulation, near-surface geothermal activity, and magmatic intrusion should be closely tied in time and space. Long-lived (similar to 1 m.y,) hydrothermal activity normally suggests multiple pulses of intrusion with associated pulses of hydrothermal circulation. However, if the permeability of the intruded environment is just above that which allows convention, and the volume of the intrusion is very large, calculations presented here show that a single episode of intrusion can sustain hydrothermal circulation and near-surface geothermal activity for similar to 800,000 yr. For a deep sill heat source, these unusually long-lived hydrothermal systems can vent through a few very widely separated discharge sites and have the potential to produce isolated massive sulfide deposits of unusually large size.