Deformational features, such as faults, strongly affect the pathways, rates, and length-scales of fluid flow in sedimentary basins. The hydrologic properties of faults vary greatly, allowing them to exhibit hydrologic behaviors spanning the gamut from open and conductive pathways for fluid flow to closed barriers to fluid flow. As a result, determining the role of faults with respect to fluid flow and their impact on geologic fluid migration throughout the life cycle of sedimentary basins remains challenging. Previous studies interrogate fault behavior using structural characteristics of fault cores and damage zones or the geochemistry of fluid inclusions and mineral veins associated with these features. Here, we evaluate the utility of crustal noble gases as tracers of fluid flow in fault systems by examining the composition of a well-constrained fault system in the Northern Appalachian Basin. The Seneca Stone Thrust fault, located near Seneca Falls, NY, USA, displays ~5 m of offset in the Onondaga Limestone and Marcellus Shale. Significant loss of ⁴He and ²¹Ne* near the fault appears to occur prior to basin exhumation, likely resulting from compactive dewatering or hydrocarbon generation and migration. Subsequent cooling shifted fault function from acting as a conduit to acting as a barrier, allowing accumulation of crustal noble gases for extended geologic time (~140 Myr) apparently in a closed-system. We identify significantly lower [⁴He] and ⁴He/²¹Ne* in a discrete zone that includes the fault core and extends ~30 cm into the intensely fractured portion of the fault damage zone as compared to the rest of the fault damage zone (~5 m in width) and other nearby samples from the Marcellus Fm. in the quarry pavement. These results imply that the Seneca Stone Thrust fault has reverted to behaving like a localized conduit in recent geological time. We interpret the discrete zone of extreme ⁴He loss near the fault plane as evidence of recent focused fluid flow within the fault core at temperatures below 94 °C, possibly within the past ~45,000 years. Our data suggest that crustal noble gases can be used to evaluate the timing of crustal isolation and/or hydraulic communication in fault zones locally in the Marcellus Shale and potentially in other geological settings. Future work can further develop this approach to examine the long-term suitability of geological formations for permanent subsurface storage of CO₂, other gases (e.g., H₂), or nuclear waste, as well as to determine if various subsurface intervals represent zones of hydrocarbon accumulation and/or loss over geological time.

断层等变形特征强烈影响沉积盆地中流体流动的路径，速率和长度尺度。断层的水文特性变化很大，使它们表现出的水文行为涵盖了从流体流动的开放和传导路径到流体流动的封闭屏障的整个范围。因此，确定断层在流体流中的作用及其在沉积盆地整个生命周期中对地质流体迁移的影响仍然具有挑战性。先前的研究使用断层岩心和破坏带的结构特征或与这些特征相关的流体包裹体和矿脉的地球化学来询问断层行为。这里，我们通过检查北部阿巴拉契亚盆地中受约束良好的断层系统的组成，评估了地壳稀有气体在断层系统中作为流体流动示踪剂的效用。位于美国纽约州塞尼卡福尔斯附近的塞尼卡石阶断层在奥南达加石灰岩和马塞勒斯页岩中显示约5 m的偏移量。重大损失断层附近的⁴ He和²¹ Ne *似乎是在盆地发掘之前发生的，很可能是由于压实脱水或碳氢化合物的产生和运移所致。随后的冷却将断层作用从充当管道转变为充当屏障，从而使地壳稀有气体在明显的封闭系统中积聚了更长的地质时间（约140 Myr）。我们鉴定出明显较低的[ ⁴ He]和⁴ He / ²¹Ne *在包括断层核心的离散区域中，与其余断层破坏区域（宽度约5 m）和其他来自马塞勒斯附近的样本相比，延伸到断层破坏区域的强烈断裂部分约30 cm调频。在采石场的人行道上。这些结果表明，在最近的地质时期中，塞内卡石块断层已恢复为局部导管状。我们解释极端⁴的离散区域他在断层平面附近损失，这是最近温度低于94°C（可能在过去的45,000年之内）在断层岩心中集中流体的最新证据。我们的数据表明，地壳稀有气体可用于评估马塞勒斯页岩局部断层带中和潜在地在其他地质环境中地壳隔离和/或水力连通的时机。未来的工作可以进一步开发这种方法，以检查地质构造对地下CO ₂，其他气体（例如H ₂）或核废料的永久地下存储的长期适用性，以及确定各种地下层段是否代表了地下区域。在地质时期内碳氢化合物的积累和/或损失。