Abstract In the Rocky Mountain region of the western United States, upper Mississippian and Pennsylvanian stratigraphy in central Montana and northern Utah preserve a poorly documented, paleotropical stratigraphic record that spans the Carboniferous interval of the Late Paleozoic Ice Age (LPIA). Sedimentologic and stratigraphic investigation of the Otter Formation (Visean) to the Alaska Bench (Bashkirian) in central Montana, and the Humbug Formation (Visean) to the Weber Formation (Gzhelian) in northern Utah, facilitated an appraisal of paleotropical environmental change preserved in these successions. Paleoclimate records of central Montana and northern Utah that were documented during this investigation were compared with previously derived records throughout paleotropical Laurentia to elucidate the mechanisms responsible for preserved paleoclimate trends. From the Serpukhovian through the Pennsylvanian, paleoclimate records from tropical western Laurentia preserve a broad first-order trend of progressive aridification driven by northern plate migration through increasingly arid paleoclimate belts. Current biostratigraphic indicators suggest that discrete excursions in humidity (

中文翻译：

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来自西劳伦西亚上密西西比和宾夕法尼亚地层记录的古热带气候振荡：板块迁移和冈瓦纳冰动力学的卷积

摘要 在美国西部的落基山脉地区，蒙大拿州中部和犹他州北部的密西西比河上游和宾夕法尼亚州地层保留了一份记录不足的古热带地层记录，其跨越晚古生代冰河时代 (LPIA) 的石炭纪区间。对蒙大拿州中部的 Otter 组 (Visean) 到阿拉斯加台地 (Bashkirian) 以及犹他州北部的 Humbug 组 (Visean) 到 Weber 组 (Gzhelian) 的沉积学和地层学调查，促进了对这些地区保存的古热带环境变化的评估继承。将本次调查期间记录的蒙大拿州中部和犹他州北部的古气候记录与之前在整个古热带劳伦蒂亚派生的记录进行比较，以阐明导致古气候趋势得以保存的机制。从塞尔普霍维纪到宾夕法尼亚纪，热带劳伦西亚西部的古气候记录保留了由北板块迁移通过日益干旱的古气候带驱动的广泛的一级干旱化趋势。当前的生物地层学指标表明湿度的离散偏移（