The Quaternary Coso volcanic field (CVF) is a compositionally bimodal volcanic field located within a releasing bend along the eastern range-front Sierra Nevada fault zone in California's southern Owens Valley. The erupted products of CVF silicic magmatism since ~1 Ma comprise 38 high-silica rhyolite domes, with the volumetric majority (~99%) of rhyolite emplaced within the past ~300 ka. The CVF hosts an economically important geothermal field driven by heat associated with a shallow (~5 km) igneous intrusion. The CVF is potentially an immature analog to the nearby Long Valley system, which culminated in generation and eruption of the voluminous and widespread Bishop Tuff. As such, the CVF represents a considerable volcanic hazard, making a detailed understanding of the eruptive history and pre-eruptive conditions of the system critically important. We present uranium-series isochron dates from zircon ± allanite crystal surfaces and zircon trace element geochemical data on the youngest 17 rhyolite domes at Coso, which represent ~60% (by volume) of the silicic magma erupted by the system. These data suggest: (1) a shorter emplacement duration than previously recognized for these domes, with a duration of 20 ± 5 ka; (2) 4 shorter-duration eruption pulses within this interval, all of which occur during the marine isotope stage (MIS) 5 interglacial period; (3) an uptick in the volume of CVF magma erupted between ~200 ka and ~ 78 ka relative to that emplaced over the lifetime of the system; (4) near-coeval eruption of geochemically distinct magma in close geographic proximity, either sourced from different portions of the same magma system at depth or from discrete, uncommunicating bodies; (5) ambiguity with respect to whether or not CVF magmatism is time-predictable, as previously suggested, or erupted as a series of punctuated episodes; (6) no rhyolite volcanism in the past ~78 kyr.

第四纪科索火山场 (CVF) 是一个成分双峰火山场，位于加利福尼亚州南部欧文斯山谷东部山脉前缘内华达山脉断层带的释放弯内。自~1 Ma 以来 CVF 硅质岩浆活动的喷发产物包括 38 个高硅质流纹岩圆顶，其中大部分（~99%）流纹岩在过去~300 ka 内发生。CVF 拥有一个具有重要经济意义的地热场，由与浅层（~5 公里）火成岩侵入相关的热量驱动。CVF 可能是附近长谷系统的一个不成熟的类比，后者最终产生和喷发了大量且广泛的 Bishop Tuff。因此，CVF 代表了相当大的火山危害，详细了解系统的喷发历史和喷发前条件至关重要。我们提供了来自 Coso 最年轻的 17 个流纹岩圆顶的锆石 ± 花岗岩晶体表面的铀系列等时线日期和锆石微量元素地球化学数据，它们代表了系统喷发的硅质岩浆的约 60%（按体积计）。这些数据表明：（1）这些圆顶的就位持续时间比以前认为的要短，持续时间为 20 ± 5 ka；(2) 该区间内的 4 个较短持续时间的喷发脉冲，均发生在海洋同位素阶段 (MIS) 5 间冰期；(3) CVF 岩浆在系统生命周期内喷发的体积增加了~200 ka 到~ 78 ka；(4) 地球化学性质不同的岩浆在地理上很近的近代喷发，要么来自同一岩浆系统深处的不同部分，要么来自离散的、不连通的物体；(5) 关于 CVF 岩浆活动是否是时间可预测的，如先前所建议的，或作为一系列间断的事件爆发的模糊性；(6) 过去没有流纹岩火山活动~78 kyr。