在美国密西西比-密苏里河高度变化的河流系统中测试锆石 U-Pb 测年作为一种物源方法的适用性,Basin Research

当前位置： X-MOL 学术 › Basin Res. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

在美国密西西比-密苏里河高度变化的河流系统中测试锆石 U-Pb 测年作为一种物源方法的适用性
Basin Research ( IF 2.8 ) Pub Date : 2021-09-30 , DOI: 10.1111/bre.12618
Brittney Gregory ₁ , Achim D. Herrmann ₁ , Thomas Ireland ₂ , Peter D. Clift _{1,

3}

Affiliation

穿过密西西比河的泥沙运输影响了沿线数百万人的生活和经济，因此了解对这一过程的控制具有科学和社会重要性。由粒度和主要元素数据支持的碎屑 U-Pb 年代学可以成为限制碎屑沉积系统中沉积物源的强大工具，已应用于密西西比河。然而，沉积物的储存和改造会使解释复杂化，而通过修建堤坝、水坝、船闸和河流改道工程的人为改变会进一步加剧这种情况。在这项研究中，我们对来自现代密西西比河的锆石进行了测定，并将它们与先前获得的数据进行比较，以说明从同一流域采集的样本之间的差异，以便更好地了解现代碎屑锆石信号的下游传播。现代密西西比河和支流系统显示出明显的相似性，并且在样本相距不太远（<100 公里）的研究之间具有可比性。我们估计阿肯色河比之前提出的更重要，至少在沙子供应方面，供应了总负荷的 7%–11%。密西西比河最大的沉积物供应商是密苏里河 (33%–43%)，其大部分沉积物来自 Sevier 和 Laramide 事件期间沉积的前深层沉积岩。现代河流系统的人为改变可以在“河流控制结构”建设后红河截止信号的下游传播中看到，这意味着缓慢的锆石运输速度（<2.8公里/年）。由采样位置和少量谷物引起的回收程度的差异给混合计算带来了很大的不确定性。

"点击查看英文标题和摘要"

Testing the applicability of zircon U‐Pb dating as a provenance method in a highly altered river system, Mississippi‐Missouri River, USA

Sediment transport through the Mississippi River affects the lives and economies of millions of people along its course, so that understanding the controls on this process is of scientific and societal importance. Detrital U-Pb geochronology, supported by grain size and major element data, can be a robust tool for constraining sediment provenance in clastic sedimentary systems that has been applied to the Mississippi. However, sediment storage and reworking can complicate interpretation, and this can be further exacerbated by anthropogenic alteration via the construction of levees, dams, locks and river diversion projects. In this study, we date zircons from the modern Mississippi River and compare them to previously acquired data to illustrate the difference between samples taken from the same catchment in order to better understand the downstream propagation of the modern detrital zircon signal. The modern Mississippi River and tributary systems show distinct similarities and are comparable between studies when samples are not too far separated (<100 km). We estimate that the Arkansas River is more important than previously proposed, at least in terms of sand supply, supplying 7%–11% of the total load. The largest supplier of sediment to the Mississippi is the Missouri River (33%–43%), which derives much of its sediment from sedimentary rocks in the foredeep deposited during the Sevier and Laramide events. Anthropogenic alteration of the modern river system can be seen in the downstream propagation of a Red River cut-off signal following construction of the “River Control Structure”, implying slow zircon transport rates (<2.8 km/year). Differences in the degree of recycling caused by sampling locations and low numbers of grains introduce significant uncertainties to mixing calculations.

更新日期：2021-09-30

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南

全部期刊列表>>