Reconstruction of paleoenvironments of the Great Salt Lake Basin during the late Cenozoic
Reconstruction of paleoenvironments of the Great Salt Lake Basin during the late Cenozoic
复制标题
大盐湖盆地新生代晚期古环境重建
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Cohen
中科院分区：
文献类型：
--
作者：
A. Kowalewska;A. Cohen
本文总结了美国犹他州大盐湖五口深井威尔斯岩屑的微体古生物学、沉积学和同位素地球化学分析结果。跨越过去的500万年，我们的大盐湖的环境历史区分四个区间的基础上古生物学和沉积学特征，使用以前开发的火山灰年代学年龄控制。在大盐湖盆地的大部分历史中，它是沼泽、浅湖和砂坪的混合体。相比之下，开放的湖泊条件，典型的邦纳维尔旋回和现代大盐湖显然只占主导地位的盆地在过去的0.6-0.8马。两个主要的构造盆地在研究区（北，南盆地）经历了不同的湖泊历史。约0.6 Ma后，北部盆地出现了大型但经常是盐湖的湖泊。在南部盆地，短暂的，盐湖条件开始于2.1马，并在0.3马发展到完整的湖泊条件。我们的古环境的解释是大致一致的水生孢粉记录从相同的威尔斯，以及与先前的核心和露头为基础的证据线。然而，南北盆地之间的湖泊历史的差异以前没有被认识到。
This study summarizes the results of micropaleontological, sedimentological, and isotope geochemical analyses of cuttings from five deep wells drilled in the Great Salt Lake (Utah, USA). Spanning the last 5.0 million yrs, our environmental history of the Great Salt Lake distinguishes four intervals based on paleobiological and sedimentological characteristics, using a previously developed tephrochronology for age control. For most of its history, the Great Salt Lake Basin has been occupied by a mixture of marsh, shallow lacustrine and sand flat conditions. In contrast, open lake conditions, typical of the Bonneville cycles and the modern Great Salt Lake apparently have only dominated the basin for the past 0.6-0.8 Ma. The two main structural basins in the study area (the North and South Basins) experienced different lacustrine histories. Large but frequently saline lakes occupied the North Basin after about 0.6 Ma. In the South Basin, ephemeral, saline lacustrine conditions started at 2.1 Ma and developed to full lacustrine conditions at 0.3 Ma. Our paleoenvironmental interpretations are broadly consistent with the aquatic palynological records from the same wells, as well as with the prior core- and outcrop-based lines of evidence. However, the differences in lake history between the North and South Basin have not been previously recognized.