Abstract The Upland Complex is a widespread terrace of the ancestral Mississippi River. It has played a central role in studies of the Pliocene Mississippi River drainage, as well as uplift and seismicity in the central Mississippi River Valley. Previous efforts to date the Upland Complex have yielded a range of age estimates spanning the Miocene through Pleistocene. We dated gravels and Fe-oxide cements from quarries of the Upland Complex in Arkansas, Kentucky, Mississippi, and Tennessee using 26Al/10Be burial dating and (U Th)/He geochronology. Our 26Al/10Be burial dates revealed possible Pliocene-to-Pleistocene depositional ages, while (U Th)/He dating showed that the onset of weathering dates to at least the Pliocene. Taken together, the 26Al/10Be and (U Th)/He age constraints demonstrate that the Upland Complex is at least Pliocene in age, and likely formed during a prolonged period of base level stability that preceded Pleistocene glaciations.

中文翻译：

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新的 26Al/10Be 和 (U Th)/He 对密西西比河谷中部高地复合体年龄的限制

摘要 高地复合体是祖先密西西比河的一个广泛的阶地。它在上新世密西西比河排水系统以及密西西比河谷中部的隆起和地震活动的研究中发挥了核心作用。之前对 Upland Complex 进行测年的努力已经产生了一系列跨越中新世到更新世的年龄估计。我们使用 26Al/10Be 埋藏年代学和 (U Th)/He 年代学对来自阿肯色州、肯塔基州、密西西比州和田纳西州的 Upland Complex 采石场的砾石和氧化铁水泥进行了年代测定。我们的 26Al/10Be 埋藏年代揭示了上新世至更新世可能的沉积年龄，而 (U Th)/He 年代测定表明风化的开始至少可以追溯到上新世。综合起来，26Al/10Be 和 (U Th)/He 年龄限制表明，高地复合体的年龄至少是上新世，