STRATIGRAPHIC RECORD OF A DISTRIBUTARY FLUVIAL SYSTEM, PALEOSOLS, SOILS, AND THEIR PALEOCLIMATIC IMPLICATIONS DURING THE MIOCENE TO EARLY PLIOCENE, NORTHWESTERN ARGENTINA A Dissertation Presented to the Faculty of the Graduate School of Cornell University In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Geological Sciences by José Juan Rosario May 2017 © 2017 José Juan Rosario STRATIGRAPHIC RECORD OF A DISTRIBUTARY FLUVIAL SYSTEM, PALEOSOLS, SOILS, AND THEIR PALEOCLIMATIC IMPLICATIONS DURING THE MIOCENE TO EARLY PLIOCENE, NORTHWESTERN ARGENTINA José Juan Rosario, Ph. D. Cornell University 2017 Abstract The Andean topography influences regional climates on both sides of its physical structure. Sedimentary environments and climate might have evolved along the growth of the orographic barrier caused by the topographic uplift as the result of the interaction between the Nazca and South America tectonic plates. This study present evidence of the history of the sedimentary environments evolution and the paleoclimate response and sensitivity of the uplift of the Andes during the Miocene to Early Pliocene. To determine if environmental and climatic changes occurred during the geologic record three main subjects were studied: (1) The sedimentary record of three stratigraphic columns that produced a west-east profile; (2) Paleosols that were compared with the modern soils in order to establish correlations between past and modern sedimentary environment; (3) and the study of pedogenic calcium carbonates deposits through the analyses of Carbon and Oxygen stable isotope ratios. The sedimentary record exhibits an overall upward coarsening sequence that can be sub-divided in three main sedimentary cycles. These cycles are formed by alternations between sandstones and mudstones with the sandstones presenting different geometries. The paleosols identified during the field work are present across the three stratigraphic columns. Most paleosols contain pedogenic calcium carbonate and were rich in clay, silt, amnd fine sand. The last set of analyses presented by carbon and oxygen resulted with isotopic values similar to today’s rainfall values in the area for oxygen, and a consistent δ13C values through time for carbon isotopes. The results from the sedimentary record represent a distributary fluvial system that has been progressing to the east that is correlated with tectonic events. The sub-cycles are representative of the lateral migration of the fluvial system. Paleosols present similar physical and mineralogical properties compared with modern soils. The range of values of stable isotopes suggest a climate history similar as todays. The sedimentary record presents a constant or a low variable climate of the Eastern Andean belt throughout the Miocene-Early Pliocene geologic time. BIOGRAPHICAL SKETCH I am the oldest son of a total of five siblings, a single mother and 2 grandparents that gave me love and most of the principles and values that I still hold until this day. We didn’t have much, but what we had we valued, and I personally always have valued that that life has gave me for free. Since a child, my curiosity for nature and my enjoyment in school inspired me to be a scientist and my family always encourage us to pursue our dreams. Growing in a tropical island and be surrounded by so much vegetation and animals, I took the decision to study biological sciences to learn how are living things made, how living things interact with each other, and how we human being became humans. While finishing my undergraduate at the University of Puerto Rico at Cayey Campus, the field of ecology, physics, and organic chemistry made me want to pursue a scientific field that was integhrated at the same time that give me the opportunity to be in direct touch with nature besides the four walls of a laboratory. This is when I decided to answer the call to study geology. I was part of the graduate program of geology at the University of Puerto Rico at Mayaguez Campus, participate in teaching programs where I had the opportunity to instruct college students and school teachers in the fields of geology and ecology feeding my curiosity and inspiration to chase a carreer where I could acquire knowledge on a common base. Short after those experiences I applied to the Department of Earth & Atmospheric Sciences at Cornell University to start my training and career as a researcher. My studies at Cornell University open my life not only to a great academic experience but to have friends for all over the world including Russia, China, Chile, and so many other places where I have good and close friends. After several years at Cornell University and started to write my dissertations, I felt the urge to open my experiences outside the academia. One of the reasons for this was to test not neccesarily my knowledge in the field of geological sciences, but my new set of critical and creative thinking tools. I spent four years at the v US Geological Survey at Menlo Park in California. I applied my knowledge, promote research ideas in the field of paleoclimate and environmental sciences that I still working today as a member of a team of scientists that wake up everyday looking for new ways to learn the history of our planet and to live in harmony with nature. Once I came back to complete my degree at Cornell University, I never felt more happy about my decision to pursue a career as a researcher and be a geologist. I am in a stage where every btime that I look back to my life, I know that I have been heading in the right direction, including some bumps and stumbles along the way that now seem far away as lessons that help me to recognize not only what is the purpose of life, but that we as humans can create and give almost any purpose to our life as long as we are willing to step into the right road and start walking toward our destination. vi DEDICATION I dedicate my thesis to four outstanding human beings that have taught me three valuable life lessons, not with words, but by example. My mother Vilma Díaz Rodríguez that besides gave me the gift of life showed me what love and good will can accomplish. My grandparents Amelia Rodríguez and José Díaz for showed me that doesn’t matter the circumstances I must always hold my dignity and integrity, never let the circumstances define me. Lastly but not less important, my advisor Professor Teresa E. Jordan for taught me that perseverance and good work ethics can take you anywhere. I am grateful for these magnificent beings been in my life and for always believe in me. It is up to me now to take these teachings forward. vii ACKNOWLEDGMENTS I would like to thank my thesis committee, Professors Teresa (Terry) E. Jordan, Louise A. Derry, and Johannes Lehmann for all the scientific and academic education that they had provided me during my studies and research at Cornell University. I would also like to show my appreciation to Professors Carmala N. Garzione and Pennilyn (Penny) Higgins at the University of Rochester for their immense collaboration in this project and the exciting scientific discussions that made possible the completion of this dissertation. I am also very thankful for our collaborators and friends in Salta, Argentina that are part of the XR-Geomap, especially to Roberto M. Hernández, Juan I. Hernández, Alejandra Dalenz Farjat, Luis A. Gonzalez, Andrés F. Alvararez, Edgar D. Gonzalez, Mario (Chopi) Aguilar, and Manolo. Their willingness to move forward the geological knowledge and education is one to be emulated. Finally, I would like to thank my colleagues and friends that not only gave me support, but share their scientific knowledge. This includes Dr. Greg Hoke, Dr. Peter Nester, and Dr. Cornelius Uba, all of which taught me a big deal about geology, critical thinking, and work ethics during our field trips in Chile and Argentina. Financial support provided it by National Science Foundation grant EAR 0635677 and Cornell University Fellowships. viii TABLE OF CONTENTS List of Figures………………………………………………………………………….ix List of Tables…………………………………………………………………………xiii Dissertation Abstract…………………………………………………………………...1 Chapter1………………………………………………………………………………..3 Abstract………………………………………………………………….….….4 Introduction…………………………….………………………………………6 Background…………………………………………………………………...15 Pedogenesis, Soils and Paleosols………………………….…………..15 Area of Study………………………………………………………….18 Modern Soils…………………………………………………………..23 Methodology………………………………………………………….34 Results………………………………………………………………………...36 Paleosol Profiles and Composition……………………….………….36 Mineralogy and Microstructures……………………………………..47 Paleosol Frequency…………………………………………………..55 Discussion……………………………………………………………………56 Environmental Processes Involved in Paleosol Development………..56 Temporal Characteristics of Paleosol Development and Preservation…………………………………………………………...59 Modern Depositional Setting as an Analogue for the Ancient Deposits and Paleosols…………………………………………………………63 Relationships of Paleosols to Thrust Belt Activity…………………..70 Test of Hypothesis that Climate Changed in Response to Miocene Andean Uplift………………………………………………………..77 Conclusions…………………………………………………………………...78 References…………………………………………………………………….80 Chapter 2……………………………………………………………………………...83 Abstract……………………………………………………………………….84 ix Introduction…………………………………………………………………...87 Area of Study………………………………………………………………….94 Stratigraphy of the Foreland Basin……………………………………………97 Methods……………………………………………………………………...102 Chronostratigraphy…………………………………………………………..105 U-Pb Ages of Zircons………………………………………………..105