CAREER: Linking the stable isotope record of Earth's surface and interior across the Great Oxidation Event

职业：将大氧化事件期间地球表面和内部的稳定同位素记录联系起来

• 批准号: 1943629
• 负责人: Claire Bucholz
• 金额: $ 66.45万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1943629&HistoricalAwards=false
• 关键词: CAREER; Linking; stable; isotope; record

Oxygen levels in Earth’s atmosphere have risen throughout its ~4.5 billion-year history in two major transitions. The first, known as the Great Oxidation Event (GOE), occurred circa 2.3-2.4 billion years ago when atmospheric oxygen levels increased to 1-10% of present day levels. This rise in oxygen levels left an indelible imprint on the sedimentary rock record through the onset of oxidative weathering and shifts in stable isotope compositions. During this same time interval, the igneous (or magmatic) rock record underwent significant chemical and isotopic changes. The proposed research will investigate whether the changes in the sedimentary and igneous rock records are linked through studying the stable isotopes of a unique suite of igneous rocks known as strongly peraluminous granites (SPGs). SPGs form when sedimentary rocks are metamorphosed and partially melted to form granitic melts. SPGs therefore represent an endmember igneous archive of a pure sedimentary contribution (through partial melting and assimilation) to the igneous rock record. Through analyzing the isotopes of SPGs on either side of the GOE, this study will determine if and how changing sedimentary compositions affected the igneous rock record across this critical transition in Earth’s history. The PI will lead an integrated research and education plan designed to encourage participation and retention of under-represented minorities in OFW-based research through a multi-tiered mentoring system. This project supports one female or minority graduate student at Caltech, 3 undergraduate summer fellows, 3 high-school student and teacher interns from the Pasadena Unified School District (PUSD), and annual classroom lessons and field trips for PUSD middle schoolers to the local San Gabriel Mountains. The proposed research in this CAREER project will explore how the GOE influenced the O, S, and Fe isotope record of igneous rocks through partial melting or assimilation of sediments. The research examines Archean and Proterozoic strongly peraluminous granites, which represent pure partial melts of metasedimentary rocks. This research has three main objectives. First, it will shed light on the underlying causes for shifts observed in the stable isotope record of igneous rocks across the GOE. For example, the increase in O isotope ratios in magmatic zircon has been variably ascribed to the onset of plate tectonics and recycling of sedimentary rocks or to the rise of oxidative, subaerial weathering generating heavier O isotope ratios in sediments. If the latter is true, a shift in the oxygen isotope ratios of zircon from Archean and Proterozoic SPGs should be observed. Second, this research will explore in detail how Fe and S isotopes are transferred from sediments to igneous rocks through detailed field studies of two “focus” localities which preserved representative source metasedimentary rocks, as well as, the derivative SPG. Third, the SPGs provide an alternative archive to the sedimentary record in that they homogenize large volumes of sedimentary rocks and thus can yield information on average sedimentary compositions. Importantly, this work will establish a “reference collection” of SPGs, which will be curated at Caltech and made available to external researchers to investigate other aspects of their chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在两个主要的过渡中，地球的氧气水平在其约45亿年的历史上增加了在氧气中，在同一时间间隔内，氧气上的烙印记录了稳定的同位素组成的发作。岩石岩石的变化通过粘性的岩石稳定的同位素，被称为强烈的花岗岩（SPG），并部分融化，以形成花岗岩熔体。这项研究的任何一侧都将确定在地球历史上的批判性过渡中，沉积物的成分是否以及如何影响火成岩。该项目的多态指导系统在加州理工学院（Caltech），帕萨迪纳（Pasadena）统一学区（PUSD）的3个本科生的夏季研究生，以及PUSD中学生的年度课堂课程和现场圣加布里埃尔（San Gabriel）山该职业生涯中的拟议研究将探讨GOE如何通过部分融化或同化沉积物来影响火成岩的O，S和Fe同位素记录。 。或氧化度的氧化型氧化氧化物比率的升高，即较重的o同位素比率。两个“焦点”位置保留了衍生物的重新定位岩石，第三，SPG是spgs arternative to sedimentard的，因为它们均质化了大量的沉积岩石，因此在平均沉积物中获得了收益率信息工作将建立SPGS的“参考集合”，该奖项将在Caltech上策划，以调查其化学的其他方面。该奖项反映了NSF'Sf'story M Ission，并被认为值得通过评估的Toundation's Toundation's Toundation's Toundation's Toundation's Toundation's Supporty提供支持。智力优点和更广泛的影响审查标准。

项目成果

Sulfur isotope behavior during metamorphism and anatexis of Archean sedimentary rocks: A case study from the Ghost Lake batholith, Ontario, Canada

• DOI: 10.1016/j.epsl.2020.116494
• 发表时间: 2020-11
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: C. Bucholz;J. Biasi;P. Beaudry;S. Ono

Emergence of continents above sea‐level influences sediment melt composition

• DOI: 10.1111/ter.12531
• 发表时间: 2021-04
• 期刊: Terra Nova
• 影响因子: 2.4
• 作者: J. Liebmann;C. J. Spencer;C. Kirkland;C. Bucholz;X. He;M. Santosh;X. Xia;Martín L.;N. Evans

Coupling sulfur and oxygen isotope ratios in sediment melts across the Archean-Proterozoic transition

• DOI: 10.1016/j.gca.2021.05.045
• 发表时间: 2021-05
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: J. Liebmann;C. Spencer;C. Kirkland;C. Bucholz;X. Xia;L. Martin;N. Kitchen;L. Shumlyanskyy

Coevolution of sedimentary and strongly peraluminous granite phosphorus records

• DOI: 10.1016/j.epsl.2022.117795
• 发表时间: 2022-09-09
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Bucholz, Claire E.

Secular variability in zircon phosphorus concentrations prevents simple petrogenetic classification

锆石磷浓度的长期变化阻碍了简单的岩石成因分类

• DOI: 10.7185/geochemlet.2240
• 发表时间: 2022
• 期刊: Geochemical Perspectives Letters
• 影响因子: 4.9
• 作者: Bucholz, C.;Liebmann, J.;Spencer, C.J.
• 通讯作者: Spencer, C.J.