Recently Identified Mesoproterozoic Strata in South‐Central Idaho Document Late‐Stage Rifting of the Nuna Supercontinent in Western Laurentia

Author:

Lever J. P.1ORCID,Sundell K. E.1ORCID,Pearson D. M.1ORCID,Brennan D.T.2

Affiliation:

1. Department of Geosciences Idaho State University Pocatello ID USA

2. Montana Bureau of Mines and Geology Butte MT USA

Abstract

AbstractSedimentary basins are valuable archives of tectonic processes involved in continental rifting. The northern Rocky Mountains preserve the Belt Supergroup, one of the most complete records of Mesoproterozoic strata on Earth; however, debate remains about its tectonic origin. We investigated a recently identified package of Mesoproterozoic strata at Leaton Gulch near Challis, Idaho, using a combination of traditional and newer sedimentological tools. Results suggest that the Leaton Gulch stratigraphic section was deposited in a fluvial setting ca. 1,380–1,317 Ma, spanning the poorly documented interval between late Belt Supergroup deposition at ∼1,370 Ma and recently characterized Deer Trail Group strata that are less than 1,300 Ma. Detrital zircon age distributions from Leaton Gulch demonstrate a similar provenance signature to Missoula Group rocks of the upper Belt Supergroup; however, Leaton Gulch strata are up to ∼70 Ma younger than most prior age constraints on Belt Supergroup rocks. Regional metabentonites (interpreted as metamorphosed reworked tuffs) found within Leaton Gulch and Missoula Group strata show dominantly radiogenic εHf(t), with a range of −8 to +15, interpreted as a mix of primary mantle and remelted metasedimentary sources. Zircon trace element data of the metabentonite from Leaton Gulch suggest a 1,450–1,300 Ma geochemically consistent and moderate–high silica melt source. Collectively, the strata of Leaton Gulch record basin sedimentation during a critical window of Mesoproterozoic time. We speculate that sedimentation during late‐stage Belt Supergroup deposition thickened and stepped westward, abandoning the main Belt basin, culminating with breakup of the Nuna Supercontinent.

Publisher

American Geophysical Union (AGU)

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3