Biomarkers heat up during earthquakes: New evidence of seismic slip in the rock record

Abstract

Research Article| February 01, 2014 Biomarkers heat up during earthquakes: New evidence of seismic slip in the rock record Heather M. Savage; Heather M. Savage 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Pratigya J. Polissar; Pratigya J. Polissar 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Rachel Sheppard; Rachel Sheppard 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Christie D. Rowe; Christie D. Rowe 2Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montréal, H3A 0E8 Quebec, Canada Search for other works by this author on: GSW Google Scholar Emily E. Brodsky Emily E. Brodsky 3Department of Earth and Planetary Sciences, University of California–Santa Cruz,1156 High Street, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Heather M. Savage 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Pratigya J. Polissar 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Rachel Sheppard 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA Christie D. Rowe 2Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montréal, H3A 0E8 Quebec, Canada Emily E. Brodsky 3Department of Earth and Planetary Sciences, University of California–Santa Cruz,1156 High Street, Santa Cruz, California 95064, USA Publisher: Geological Society of America Received: 02 Jul 2013 Revision Received: 24 Sep 2013 Accepted: 02 Oct 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (2): 99–102. https://doi.org/10.1130/G34901.1 Article history Received: 02 Jul 2013 Revision Received: 24 Sep 2013 Accepted: 02 Oct 2013 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Heather M. Savage, Pratigya J. Polissar, Rachel Sheppard, Christie D. Rowe, Emily E. Brodsky; Biomarkers heat up during earthquakes: New evidence of seismic slip in the rock record. Geology 2014;; 42 (2): 99–102. doi: https://doi.org/10.1130/G34901.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract During earthquakes, faults heat up due to frictional work. However, evidence of heating from paleoearthquakes along exhumed faults remains scarce. Here we describe a method using thermal maturation of organic molecules in sedimentary rock to determine whether a fault has experienced differential heating compared to surrounding rocks. We demonstrate the utility of this method on an ancient, pseudotachylyte-hosting megathrust at Pasagshak Point, Alaska. Measurements of the ratio of thermally stable to thermally unstable compounds (diamondoids/n-alkanes) show that the melt-bearing rocks have higher thermal maturity than surrounding rocks. Furthermore, the mineralogy of the survivor grains and the presence of any organic molecules allow us to constrain the temperature rise during the ancient earthquakes to 840–1170 °C above ambient temperatures of ∼260 °C. From this temperature rise, we estimate that the frictional work of the earthquake was ∼105–228 MJ/m2. Using experimental friction measurements as a constraint, we estimate that the minimum slip necessary for heating was ∼1–8 m. This paper demonstrates that biomarkers will be a useful tool to identify seismic slip along faults without frictional melt. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.