UC Santa Barbara UC Santa Barbara Electronic Theses and Dissertations Title Probing the relationship between extension and magmatism in the lower Colorado River Extensional Corridor: Field, geochronological, and geochemical studies of Miocene volcanic rocks in the vicinity of the Whipple Mountains, CA and AZ Permalink https://escholarship.org/uc/item/6kc9p3wz Author Fidler, Mary Katherine Publication Date 2018 Supplemental Material https://escholarship.org/uc/item/6kc9p3wz#supplemental Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA Santa Barbara Probing the relationship between extension and magmatism in the lower Colorado River Extensional Corridor: Field, geochronological, and geochemical studies of Miocene volcanic rocks in the vicinity of the Whipple Mountains, CA and AZ A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Geological Sciences by Mary Katherine Fidler Committee in charge: Professor Phillip B. Gans, Chair Professor Bradley Hacker Professor Matt Jackson January 2018 The dissertation of Mary Katherine Fidler is approved. ____________________________________________ Bradley Hacker ____________________________________________ Matthew Jackson ____________________________________________ Phillip B. Gans, Committee Chair December 2017 The relationship between extension and magmatism in the Lower Colorado River Extensional Corridor: Field, geochronological, and geochemical studies of Miocene volcanic rocks in the vicinity of the Whipple Mountains, CA and AZ Copyright © 2018 by Mary Katherine Fidler iii I dedicate this dissertation to the fiery women who raised me, my mom, Kathleen Fidler, and my grandmothers (by blood and in practice), Eugenia Taylor and Donna Kearney iv ACKNOWLEDGEMENTS Throughout graduate school, I have been the lucky recipient of help, mentorship, advice, and teaching from a great number of individuals. First, I would like to thank my advisor, Phil Gans, who has been a great mentor, colleague, and friend. Through his teaching and by watching his example, I have gained innumerable skills as a researcher, writer, and field geologist. But most importantly, Phil is an exemplary teacher, and his care and passion for teaching carries over into his student advising and has greatly inspired the development of my own teaching philosophy. He encouraged me to pursue every teaching opportunity available to me. Thank you for your patience and unwavering support of my academic growth and career goals. I would also like to thank Brad Hacker, Matt Jackson, and John Cottle for serving on my committees throughout graduate school, particularly Brad and Matt for serving on my dissertation committee. Their advice, ideas, and insightful questions have greatly improved this dissertation and promoted my growth as a scientist. I owe a debt of gratitude to several people and organizations who provided financial support for my education and for this research. I would like to especially thank Rachel Haymon and Ken MacDonald for their support through the UCSB Earth Science Department Graduate Student Opportunity Award. Their generosity gave this project a kick-start at a time when funds were tight and hope was desperately needed! Funding for tuition expenses were provided by the Earth Science Department at UCSB through the Harry Glicken Memorial Fellowship and by Shawn Byers through her generous donation to the STEM Student Support Fund. The Geological Society of America and EdMap (a component of the v USGS National Cooperative Geologic Mapping Program) also provided generous financial support for this research. I have greatly benefited from my interactions and close friendships with a number of graduate students, particularly those in the Gans, Cottle, Hacker, Spera, and Simms research groups. I am especially thankful for the friendship and support of my housemates and colleagues, Will Junkin, Sophie Briggs, Elisabeth Steel, Josh Garber, Tyson McKinney, Alex Wrobel, and Diane Seely. Their friendship created a sense of family for me at UCSB that has carried me through every new challenge. Finally, I would like to thank my family for their encouragement and support. My parents have always encouraged me to pursue my passions and goals with abandon. Their words of love and support have comforted and empowered me throughout my life, but especially during these five years of graduate school. vi VITA OF MARY KATHERINE FIDLER January 2018 EDUCATION: Doctor of Philosophy in Geology University of California Santa Barbara, January 2018 Certificate of College and University Teaching University of California Santa Barbara, January 2018 Bachelor of Science in Environmental Geoscience University of Notre Dame, May 2012 (Cum Laude) PROFESSIONAL EMPLOYMENT: 2018-present Lecturer, Department of Environmental Engineering and Earth Science, Clemson University 2016-2017 Graduate Student Researcher, Department of Earth Science, University of California, Santa Barbara 2015-2017 Associate Instructor, Department of Earth Science, University of California, Santa Barbara 2012-2016 Teaching Assistant, Department of Earth Science, University of California, Santa Barbara 2009-2012 Undergraduate Student Researcher, University of Notre Dame TEACHING EXPERIENCE Winter 2017 and 2016 Associate Instructor, Structural Geology, Department of Earth Science, University of California, Santa Barbara Summer 2015 Associate Instructor, Physical Geology, Department of Earth Science, University of California, Santa Barbara PUBLICATIONS: M.K. Fidler, P.B. Gans, J.S. Lackey (2016). Geologic map of the western Whipple Mountains and the eastern Mopah Range, southeast California: unraveling the eruptive and structural history of a synextensional Miocene volcanic province. Abstracts with Programs - Geological Society of America, 48(7), Abstract no. 266-6 vii M.K. Fidler, P.B. Gans (2016). Exploring the link between crustal melting and extensional collapse; field, geochemical, and Sr-Nd isotopic evidence from pre-, syn-, and post- extensional lavas of the Whipple Mountains region, lower Colorado River extensional corridor, CA and AZ. American Geophysical Union Fall Meeting, 2016, Abstract V53D- 3161. M.K. Fidler, P.B. Gans (2014). Magmatic trigger for extensional collapse? Character and significance of pre-extensional volcanic activity in the Whipple Mountains region, lower Colorado River Extensional Corridor. American Geophysical Union Fall Meeting, 2014, Abstract V31E-4812 E. Steel, L. Reynolds, L. Simkins, M.K. Fidler (2014). Characterization of the Elephant Trees Formation, Anza Borrego with implications for determining the depositional environments of conglomeratic debris flows. Abstracts with Programs – Geological Society of America, 46(6), 147 M.K. Fidler & P.B. Gans (2013). Spatiotemporal patterns in the inception of Miocene volcanism and upper plate extensional block rotation in the vicinity of the Whipple Mountains, CA and AZ. Abstracts with Programs - Geological Society of America,45(7), 171. C. Ohlin, S. Harley, J. McAlpin, R. Hocking, B. Mercado, R. Johnson, E. Villa, M.K. Fidler, M. Olmstead, L. Spiccia, R.D. Britt, and W.H. Casey (2011). Rates of water exchange for two cobalt(II) heteropolyoxotungstate compounds in aqueous solution, Chemistry - a European Journal,17(16), 4408-4417. ACADEMIC HONORS: 2013 Harry Glicken Memorial Graduate Fellowship, UC Santa Barbara 2014 Preston Cloud Award, UC Santa Barbara 2014 Global Field Travel Award, UC Santa Barbara 2015 Alumni Graduate Award for Research Excellence, UC Santa Barbara 2016 Global Field Travel Award, UC Santa Barbara 2016 Lloyd and Mary Edwards Field Studies Fellowship in Earth Science, UC Santa Barbara 2016 Special Fellowship in the Stem Disciplines, UC Santa Barbara 2016 3rd place in the Best Student Geologic Mapping Competition, Geological Society of America, Fall Meeting 2017 Alumni Graduate Award for Research Excellence 2017 Muckers’ Coterie Lifetime Achievement Award viii GRANTS: M.K. Fidler. Geological Society of America Graduate Student Research Grant: Using isotopes and trace element chemistry to understand source of magmatism in the vicinity of the Whipple Mountains, CA & AZ. $1777. 3/15-3/16. P.B. Gans, M.K.Fidler, and B. Gentry. EDMAP, United States Geological Survey (USGS): Geologic Mapping of the Southwestern Whipple Mountains and Eastern Mopah Range, Southeastern California: Unraveling the Eruptive and Structural History of a Synextensional Miocene Volcanic Center. $25,677. 4/14-4/15. M.K. Fidler. UCSB Earth Science Dept., Graduate Student Opportunity Award: Exploring the temporal and spatial relationships between extension and magmatism in the lower Colorado River extensional corridor, CA and AZ. $3,880. 6/13-6/16. E. Steel, L. Reynolds, L. Miller, and M.K. Fidler. UCSB Earth Science Dept., Graduate Student Opportunity Award: Characterization of deep and shallow marine conglomerates with implications for determining the depositional environments of the Matilija Formation, southern California. $2,066. 6/13-6/14. ix ABSTRACT Probing the relationship between extension and magmatism in the lower Colorado River Extensional Corridor: Field, geochronological, and geochemical studies of Miocene volcanic rocks in the vicinity of the Whipple Mountains, CA and AZ by Mary Katherine Fidler New geologic mapping, 40Ar/39Ar geochronology, and whole rock major and trace element and Sr-Nd isotopic data of pre-, syn-, and post-extensional volcanic rocks shed