The dynamic floor of Yellowstone Lake, Wyoming, USA: The last 14 k.y. of hydrothermal explosions, venting, doming, and faulting
The dynamic floor of Yellowstone Lake, Wyoming, USA: The last 14 k.y. of hydrothermal explosions, venting, doming, and faulting
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美国怀俄明州黄石湖的动态湖底：过去 14 年
DOI：
10.1130/b36190.1
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Best, J.L.
中科院分区：
文献类型：
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作者：
Morgan, L.A.;Shanks, W.C.P.;Pierce, K.L.;Iverson, N.;Schiller, C.M.;Brown, S.R.;Zahajska, P.;Cartier, R.;Cash, R.W.;Best, J.L.
热液爆炸是美国怀俄明州黄石国家公园的重大潜在危险。北方黄石湖地区拥有地球上已知的三个最大的热液爆炸陨石坑，这些陨石坑由黄石最高的热流值和活跃的地震活动和变形所赋予。18个湖底岩芯的地质和地球化学研究首次提供了多个热液爆炸矿床的时代，沉积相和成因的详细综合。新的火山灰年代学和放射性碳结果提供了一个四维视图，最近的地质活动，因为在约衰退。15-14.5 ka>1 km厚的派恩代尔冰盖。黄石湖的沉积记录包含多个热液爆炸沉积物，年龄从大约。13 ka ~~1860 CE。热液爆炸需要压力突然下降，导致高温流体迅速膨胀，造成碎片，喷射和火山口形成;爆炸可能由地震活动，断层，变形或快速的湖平面变化引发。喷出物的沉降和搬运形成了水下热液爆炸沉积的不同相。黄石热液系统的特点是碱性氯和/或蒸汽为主的流体，分别产生蚀变为主的硅蒙脱石-蒙脱石或高岭石。碱性氯液体闪蒸汽在热液爆炸，产生更多的精力充沛的事件比简单的蒸汽膨胀在蒸汽为主的系统。两个巨大的爆炸事件在黄石湖触发完全不同：埃利奥特的火山口爆炸是由一个主要的地震事件（8 ka），打破了不透水的热液圆顶，而玛丽湾爆炸（13 ka）是由一个突然下降的湖平面由地震事件，海啸和出口通道侵蚀刺激触发。
Hydrothermal explosions are significant potential hazards in Yellowstone National Park, Wyoming, USA. The northern Yellowstone Lake area hosts the three largest hydrothermal explosion craters known on Earth empowered by the highest heat flow values in Yellowstone and active seismicity and deformation. Geological and geochemical studies of eighteen sublacustrine cores provide the first detailed synthesis of the age, sedimentary facies, and origin of multiple hydrothermal explosion deposits. New tephrochronology and radiocarbon results provide a four-dimensional view of recent geologic activity since recession at ca. 15–14.5 ka of the >1-km-thick Pinedale ice sheet.The sedimentary record in Yellowstone Lake contains multiple hydrothermal explosion deposits ranging in age from ca. 13 ka to ~1860 CE. Hydrothermal explosions require a sudden drop in pressure resulting in rapid expansion of high-temperature fluids causing fragmentation, ejection, and crater formation; explosions may be initiated by seismicity, faulting, deformation, or rapid lake-level changes. Fallout and transport of ejecta produces distinct facies of subaqueous hydrothermal explosion deposits. Yellowstone hydrothermal systems are characterized by alkaline-Cl and/or vapor-dominated fluids that, respectively, produce alteration dominated by silica-smectite-chlorite or by kaolinite. Alkaline-Cl liquids flash to steam during hydrothermal explosions, producing much more energetic events than simple vapor expansion in vapor-dominated systems. Two enormous explosion events in Yellowstone Lake were triggered quite differently: Elliott’s Crater explosion resulted from a major seismic event (8 ka) that ruptured an impervious hydrothermal dome, whereas the Mary Bay explosion (13 ka) was triggered by a sudden drop in lake level stimulated by a seismic event, tsunami, and outlet channel erosion.