Detrital-zircon (DZ) U-Pb data show that Appalachian-affiliated sediment was transported to western Laurentia by the Carboniferous, yet additional DZ U-Pb data from the eastern United States suggest that sediment-routing systems were oriented south toward the Ouachita deepwater sink. Within this context, this study presents DZ U-Pb ages from the Lower Pennsylvanian Caseyville Formation of Illinois, and U-Pb ages and εHf values from the coeval Pottsville Formation of Alabama as well as sandstone petrographic data from the Caseyville Formation, the Pottsville Formation, and the Jackfork Group of the Ouachita Basin to document provenance, delineate drainage divides in the Appalachian foreland-basin system, and comment on the unlikelihood of transcontinental sediment routing from the eastern United States to western United States at this time.Two DZ U-Pb age distributions from quartz arenite sandstones of the Caseyville Formation display prominent ca. 1250–950 Ma, 1550–1300 Ma, 1800–1600 Ma, and 3500–3000 Ma ages, consistent with ultimate derivation from Grenville, Midcontinent granite–rhyolite, Yavapai–Mazatzal, and Superior provinces, as well as minor contributions from ca. 500–400 Ma and 2000–1800 Ma grains. Two DZ U-Pb age distributions from sublitharenite sandstones of the Pottsville Formation display prominent ca. 500–400 Ma, 1250–950 Ma, 1550–1300 Ma, and 1800–1600 Ma ages, consistent with ultimate derivation from Appalachian, Grenville, Midcontinent granite–rhyolite, and Yavapai–Mazatzal provinces, as well as minor contributions from ca. 2000–1800 Ma and 3500–3000 Ma grains. The Pottsville Formation samples demonstrate a greater percentage of Appalachian and Grenville ages relative to the Caseyville Formation samples, whereas the Caseyville Formation samples have elevated Yavapai–Mazatzal and Superior percentages relative to the Pottsville. We interpret these differences to suggest parallel fluvial systems in the foredeep and back-bulge depozones of the Appalachian foreland-basin system.Like DZ studies of modern deep-sea fans that demonstrate an affinity to feeder fluvial systems, this study demonstrates fidelity between endmember segments of ancient fluvial-to-deepwater systems. Multidimensional scaling (MDS) analysis shows that DZ samples from the Pottsville and Caseyville formations cluster with deepwater Jackfork Group samples, and we infer a source-to-sink relationship from these two distinct source areas to the Ouachita terminal sink. One example of large-scale inclined strata thickness from the Caseyville Formation also suggests a drainage basin area of > 105 km2. Contextualized with these observations, we suggest that the foredeep and backbulge depozones of the Appalachian foreland-basin system steered distinct Early Pennsylvanian rivers across emergent continental shelves during periods of low sea-level, which discharged to distinct slope canyons and sourced > 100-km-long deep-sea fans. Clearly circumscribed, southward- or southwestward-oriented paleodrainage areas provide a template of the Appalachian foreland-basin system, and as such the central and southern Appalachians were an unlikely source for the Appalachian signature observed in the western United States at this time.

中文翻译：

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基于碎屑-锆石U-Pb和Hf分析的阿巴拉契亚前陆-盆地系统沉积层早期宾夕法尼亚期古河谷划分

碎屑锆石 (DZ) U-Pb 数据显示，阿巴拉契亚附属沉积物被石炭纪运送到劳伦蒂亚西部，但来自美国东部的额外 DZ U-Pb 数据表明，沉积物路线系统向南朝向 Ouachita 深水下沉。在此背景下，本研究展示了伊利诺伊州下宾夕法尼亚州 Caseyville 组的 DZ U-Pb 年龄、阿拉巴马州同时期 Pottsville 组的 U-Pb 年龄和 εHf 值，以及 Caseyville 组、Pottsville 组的砂岩岩相数据, 和 Ouachita 盆地的 Jackfork 小组来记录物源，描绘阿巴拉契亚前陆盆地系统中的排水分水岭，并评论此时从美国东部到美国西部的横贯大陆沉积物路线的可能性。来自 Caseyville 组石英砂岩砂岩的两个 DZ U-Pb 年龄分布显示出显着的 ca。1250-950 Ma、1550-1300 Ma、1800-1600 Ma 和 3500-3000 Ma 年龄，与 Grenville、Midcontinent 花岗岩-流纹岩、Yavapai-Mazatzal 和苏必利尔省的最终推导一致，以及来自 ca。500-400 Ma 和 2000-1800 Ma 晶粒。来自 Pottsville 组的次岩屑砂岩的两个 DZ U-Pb 年龄分布显示出显着的 ca。500-400 Ma、1250-950 Ma、1550-1300 Ma 和 1800-1600 Ma 年龄，与阿巴拉契亚、格伦维尔、中大陆花岗岩-流纹岩和亚瓦派-马萨扎尔省的最终推导一致，以及来自 ca。2000-1800 Ma 和 3500-3000 Ma 晶粒。相对于 Caseyville 组样品，Pottsville 组样品显示出更大百分比的阿巴拉契亚和 Grenville 年龄，而相对于 Pottsville 组，Caseyville 组样品具有较高的 Yavapai-Mazatzal 和高级百分比。我们将这些差异解释为表明阿巴拉契亚前陆盆地系统的前深和后隆起沉积带中的平行河流系统。就像现代深海扇的 DZ 研究表明对支线河流系统的亲和力一样，这项研究证明了端元段之间的保真度古代河流到深水系统。多维尺度 (MDS) 分析表明，来自 Pottsville 和 Caseyville 地层的 DZ 样本与深水 Jackfork Group 样本聚集在一起，我们从这两个不同的源区域到 Ouachita 终端接收器推断出源到接收器的关系。Caseyville 组大规模倾斜地层厚度的一个例子也表明流域面积 > 105 平方公里。结合这些观察，我们认为阿巴拉契亚前陆盆地系统的前深和后隆起沉积带在低海平面期间引导不同的早期宾夕法尼亚河流穿过新兴大陆架，这些河流排放到不同的斜坡峡谷并源出 > 100-km-长深海迷。界限分明、南向或西南向的古排水区提供了阿巴拉契亚前陆盆地系统的模板，