Arroyo formation impacts on an early dryland agricultural community in Northeastern Utah, USA
Arroyo formation impacts on an early dryland agricultural community in Northeastern Utah, USA
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DOI：
10.1002/gea.21942
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
J. Finley;E. Robinson;R. Justin DeRose
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文献类型：
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作者：
J. Finley;E. Robinson;R. Justin DeRose
Cub Creek是犹他州东北部恐龙国家保护区的一部分，从公元300年到1300年，当地的弗里蒙特农民占据了北美西部玉米种植的北方生态边缘。丘伯溪的农业是对几十年降水变化的回应，但当降水在公元750年至1050年之间稳定下来时，农业条件得到改善，人口扩大，形成了沿着当地旱地河流漫滩的村庄。在相同的条件下（即，降水量的变化减少），使农业社会的增长，使他们同时容易受到阿罗约形成，一个关键的地貌风险，洪泛平原农业？Cub Creek的初步结果表明，过去2000年的特征是快速沉积，间歇性的阿罗约形成。我们使用贝叶斯年龄模型中形式化的地层和年代学证据来开发一组工作假设，即在公元1020年或公元1275年之前形成了一个2.5米深的不连续河沟。早期的年龄与占领的幼崽溪村，而后期的年龄与弗里蒙特农业在幼崽溪结束，并展示了区域同步性与整个科罗拉多高原的阿罗约形成。公元1490年之前形成了第二条河沟，表明幼仔溪的冲积循环非常迅速。我们的结论是，洪泛区的不稳定性和形成结合的主导几十年降水变率制度的回报开始于公元1050年是当地人口的增长潜力的一个关键制约因素。这些发现对整个北美西部内陆地区早期土著旱地农业系统的发展具有潜在的影响。
Indigenous Fremont farmers in Cub Creek, a part of northeastern Utah's Dinosaur National Monument, occupied the northern ecological margin of maize cultivation in western North America from A.D. 300 to 1300. Agriculture in Cub Creek was a response to multidecadal precipitation variability, but when precipitation stabilized between A.D. 750 and 1050, agricultural conditions improved and populations expanded to form villages along the floodplains of local dryland streams. Did the very same conditions (i.e., decreased precipitation variability) that allowed the growth of agricultural societies make them simultaneously vulnerable to arroyo formation, a key geomorphic risk to floodplain agriculturalists? Preliminary results from Cub Creek show that rapid sedimentation punctuated by episodic arroyo formation characterized the last 2000 years. We use stratigraphic and chronological evidence formalized in a Bayesian age model to develop a set of working hypotheses that a 2.5 m‐deep discontinuous arroyo formed before either A.D. 1020 or A.D. 1275. The earlier age corresponds with occupation of the Cub Creek village, while the later age corresponds with the end of Fremont agriculture in Cub Creek, and demonstrates regional synchronicity with arroyo formation across the Colorado Plateau. A second arroyo formed before A.D. 1490, indicating rapid alluvial cycling in Cub Creek. We conclude that floodplain instability and arroyo formation combined with the return of the dominant multidecadal precipitation variability regime beginning at A.D. 1050 was a key constraint on the growth potential of local populations. These findings have potential implications for the development of early Indigenous dryland agricultural systems throughout the interior of western North America.