EAGER: Exploring the potential for the 1.1 Ga Copper Harbor Conglomerate to yield information on terrestrial environments during the rise of the eukaryotes

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The evolution of marine environments during the Proterozoic is the subject of intense investigation because of dramatic changes in oxygenation linked to the origin of complex eukaryotic life. In contrast, little is known about terrestrial environments or ecosystems. A lack of data and suitably unaltered successions means that intense speculation surrounds the few hypotheses that exist regarding environmental conditions on land at this time. The investigators wish to study rocks that are situated in a unique time and place in the history of Earth and life, and are ideally placed for exploring the terrestrial biosphere during the rise of crown group eukaryotes and the composition of the ancient atmosphere. If the datasets are not compromised by diagenesis (a question this study will address directly using clumped isotope paleothermometry), then this succession has the potential to answer several outstanding questions about the evolution of life and climate. The project has numerous societal benefits. It will support the career development of at least two women scientists, the raining of a postdoctoral researcher, and new collaborations including with an international collaborator. It will be used to broaden participation and to promote diversity, including outreach activities to under-represented students. Project participants will conduct outreach to K-12 students. It will also support education as results will be included in lectures to undergraduate and graduate students. The investigators propose a brief initial exploratory investigation to determine the potential of an unburied 1 billion year old succession from Michigan for the study of terrestrial environments during the rise of the eukaryotes. Carbonates in the 1.09 Ga Copper Harbor conglomerate of northern Michigan represent a potentially transformative archive of paleoclimatic and geobiological information. The succession contains terrestrial stromatolites that developed on an ancient alluvial fan, as well as lacustrine stromatolites. Researchers will conduct preliminary analyses of a suite of pilot samples from both facies to explore preservation and collect pilot data on proxy signatures, including on clumped isotopes and redox sensitive proxies. This work will allow to assess preservation and the utility of future in depth study of these rocks to provide proxy data for a crucial period in Earth's geobiological evolution. If successful, researchers will follow up with a collaborative, in-depth study of the succession. The potential rewards from future research are huge - but the risks of trying to find and identify unaltered rocks from this time period would preclude a study of this nature from being funded through traditional NSF programs until a suite of pilot data is collected.