COLLABORATIVE RESEARCH: Calibrating the Cryogenian in the Yukon

合作研究：校准育空地区的低温层

• 批准号: 1148499
• 负责人: Mark Schmitz
• 金额: $ 11.3万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-15 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1148499&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Calibrating; Cryogenian; Yukon

COLLABORATIVE RESEARCH: Calibrating the Cryogenian in the YukonFrancis MacDonald.1148499, Harvard University; Mark Schmitz.1148058, Boise State UniversityABSTRACTThe Snowball Earth hypothesis has galvanized broad interest in Neoproterozoic geology; however, the hypothesis remains controversial largely due to uncertainty about the timing, duration, and initiation mechanism of global glaciation. With previous and preliminary studies, we have demonstrated that the age of Sturtian glacial deposits in the Yukon is indistinguishable from the age of the Franklin large igneous province (LIP), which was emplaced on the eastern margin of Laurentia, in the tropics, in an ideal position for being chemically weathered. This is intriguing, because basalt is more weatherable than average continental crust, and it has been proposed that Snowball Earth events were initiated by an increase in weatherbility and a concomitant increase in CO2 consumption. However, the age range and error bars on the Franklin LIP are still too large to determine if the volcanism was long- or short-lived, and if the glaciation occurred during, before or after the main pulse of volcanism. With the proposed research PIs intend to constrain the timing and duration of the Sturtian glaciation and the Franklin LIP in the Yukon with high resolution U-Pb ID-TIMS dating of magmatic zircons and LA-ICPMS dating of detrital zircons that bracket the glacial deposits.

合作研究：校准育空地区的低温层Francis MacDonald.1148499，哈佛大学； Mark Schmitz.1148058，博伊西州立大学摘要雪球地球假说激起了人们对新元古代地质学的广泛兴趣；然而，由于全球冰川作用的时间、持续时间和起始机制的不确定性，这一假说仍然存在争议。通过之前的初步研究，我们已经证明，育空地区斯图尔特冰川沉积物的年龄与富兰克林大火成岩省（LIP）的年龄没有区别，后者位于热带劳伦西亚东部边缘，在化学风化的理想位置。这很有趣，因为玄武岩比普通大陆地壳更耐风化，并且有人提出雪球地球事件是由耐风化性的增加和随之而来的二氧化碳消耗的增加引发的。然而，富兰克林 LIP 上的年龄范围和误差线仍然太大，无法确定火山活动是长期还是短暂，以及冰川作用是否发生在火山活动的主脉冲期间、之前或之后。通过拟议的研究，PI 打算通过岩浆锆石的高分辨率 U-Pb ID-TIMS 测年和冰川沉积物碎屑锆石的 LA-ICPMS 测年来限制育空地区斯图尔特冰川和富兰克林 LIP 的时间和持续时间。

项目成果

A robust age model for the Cryogenian Pocatello Formation of southeastern Idaho (northwestern USA) from tandem in situ and isotope dilution U-Pb dating of volcanic tuffs and epiclastic detrital zircons

• DOI: 10.1130/ges02437.1
• 发表时间: 2022-02
• 期刊: Geosphere
• 影响因子: 2.5
• 作者: V. Isakson;M. Schmitz;C. Dehler;F. Macdonald;W. Yonkee