Abstract The Late Ordovician late Katian was a period of generally warm, transitional greenhouse to icehouse climate with sea-level oscillations dominated by moderate-amplitude eustasy. This study aims to improve the understanding of the climatic and sea-level fluctuations prior to the end-Ordovician glaciation, using a comprehensive core, wireline log, and thin-section dataset spanning the topmost Red River-Stony Mountain Formation within the subsurface of North Dakota, Williston Basin, North America. Eleven facies are identified, interpreted, and grouped into four facies associations, including salina to peritidal evaporative, restricted-marine subtidal, open-marine subtidal, and open-marine deeper water. Stratigraphic trends, basin-wide facies variations, and correlation of individual surfaces for ~380 km across the study area, suggest that the facies were deposited under different climatic and sea-level regimes as part of the long-term Stony Mountain sequence. The sequence (37–52 m) is bounded by anhydrites (basin center) and their correlative thin exposure-related breccias (updip proximal basin), and contains a set of high-frequency sequences (HFS; 2–26 m) that can be traced across the study area. The lowstand systems tract (LST) anhydrites formed in a shallow and well‑oxygenated setting under an arid climate during relatively short periods of the basin restriction. The sea-level rise during the early transgressive system tract (TST) resulted in a higher evapotranspiration rate and an increasingly humid climate that peaked during the late TST with the input of siliciclastics off the Transcontinental Arch. The increased precipitation and runoff resulted in quasiestuarine circulation. Return to semi-arid conditions characterizes the highstand systems tract (HST), with increasingly more restricted, shallow-marine and oxygenated setting with antiestuarine circulation. The work provides insight into the interaction of siliciclastic input, climate, and sea-level changes on depositional dynamics and sequence architecture of a mixed carbonate-siliciclastic-evaporite succession that formed in a tropical epicontinental basin setting prior to the end-Ordovician glaciation.

中文翻译：

---

美国威利斯顿盆地碳酸盐岩-硅质碎屑岩-蒸发岩混合岩相的晚奥陶世气候和海平面记录

摘要 晚奥陶世晚期卡蒂安是一个普遍温暖的、温室气候向冰库气候过渡的时期，海平面振荡以中等幅度的快感为主。本研究旨在利用涵盖北部亚表层最顶端红河-石山地层的综合核心、电缆测井和薄片数据集，提高对奥陶纪末期冰川作用之前的气候和海平面波动的理解。达科他州，威利斯顿盆地，北美。确定、解释了 11 个相，并将其分为四个相关联，包括盐沼到潮间带蒸发、受限海洋潮下带、开放海洋潮下带和开放海洋更深水。整个研究区约 380 公里的地层趋势、盆地范围的相变化以及各个地表的相关性，表明这些相沉积在不同的气候和海平面状况下，作为长期石山序列的一部分。该层序（37-52 m）以硬石膏（盆地中心）及其相关的薄暴露相关角砾岩（上倾近端盆地）为界，并包含一组高频层序（HFS；2-26 m），可以跟踪整个研究区域。低水位系统域 (LST) 硬石膏在相对较短的盆地限制期间在干旱气候下的浅层和充氧良好的环境中形成。早期海侵系统域 (TST) 期间海平面上升导致更高的蒸散率和日益潮湿的气候，在 TST 晚期随着横贯大陆拱门的硅质碎屑输入达到顶峰。降水和径流的增加导致了准水流环流。恢复到半干旱条件是高位系统域 (HST) 的特征，具有越来越多的限制、浅海和含氧环境，具有反河口循环。这项工作深入了解了硅质碎屑输入、气候和海平面变化对沉积动力学和碳酸盐-硅质碎屑-蒸发岩混合层序结构的相互作用的洞察，这些混合碳酸盐-硅质碎屑-蒸发岩在奥陶纪末期冰川作用之前形成于热带表陆盆地环境中。