The University of Maine DigitalCommons@UMaine Electronic Theses and Dissertations Fogler Library 12-2015 Fluvial Deposition, El Nino and Landscape Construction in Northern Coastal Peru Paul M. Pluta University of Maine Follow this and additional works at: http://digitalcommons.library.umaine.edu/etd Part of the Climate Commons, and the Sedimentology Commons Recommended Citation Pluta, Paul M., "Fluvial Deposition, El Nino and Landscape Construction in Northern Coastal Peru" (2015). Electronic Theses and Dissertations. 2414. http://digitalcommons.library.umaine.edu/etd/2414 This Open-Access Thesis is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of DigitalCommons@UMaine. FLUVIAL DEPOSITION, EL NINO AND LANDSCAPE CONSTRUCTION IN NORTHERN COASTAL PERU By Paul M. Pluta B.A. Temple University, 2010 A THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Quaternary and Climate Studies) The Graduate School The University of Maine December 2015 Advisory Committee: Daniel H. Sandweiss, Professor of Anthropology and Quaternary and Climate Studies, Co-Advisor Alice R. Kelley, Assistant Research Professor of Quaternary and Climate Studies, Instructor of Earth and Climate Sciences, Co-Advisor Gregory Zaro, Associate Professor of Anthropology and Climate Change Daniel F. Belknap, Professor of Earth and Climate Sciences FLUVIAL DEPOSITION, EL NINO AND LANDSCAPE CONSTRUCTION IN NORTHERN COASTAL PERU By Paul M. Pluta Thesis Co-Advisors: Dr. Daniel H. Sandweiss and Dr. Alice R. Kelley An Abstract of the Thesis Presented in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Quaternary and Climate Studies) December 2015 The El Nino global climate anomaly is a major cause of weather variation that can have far-reaching effects on human populations around the world. Northern coastal Peru is an area of historically major impacts where strong El Nino events have resulted in catastrophic flooding and mass wasting, leading to significant social disruption. There is a growing body of literature on the prehistoric chronology of El Nino and how it affected human populations of the past, but more work is needed. In order to address the timing and characteristics of past El Nino events I investigated the alluvial sedimentary sequences at two archaeological sites of the Moche Period, San Jose de Moro and Huaca del Sol, to infer patterns of past El Nino flooding. Both sites are located adjacent to braided rivers and are constructed on floodplains composed of thick alluvial sequences that are reflective of some aspects of the region’s past climate. San Jose de Moro is located along the Chaman River, just north of the city of Chepen. Due to the limited size of the river’s drainage basin and the extremely dry nature of the regional environment, flooding is limited to periods of El Nino rainfall and all alluvial deposits at San Jose de Moro are thus thought to be El Nino related. The exposed sedimentary sequence at the site reveals a prominent shift from broad, relatively flat floodplain deposits to cross-bedded, channelized deposits, which may have resulted from several causes, including channel avulsion, a change in stream character related to vegetation stabilization, a change in river base level, stream capture, or a change in climate resulting in an increase in the intensity or frequency of precipitation events. An increase in precipitation may be related to an increase in El Nino activity. Huaca del Sol is located along the Moche River, near the city of Trujillo. The Moche River has a much larger drainage basin and extends much higher into the Andes Mountains than the Chaman River. Because of this, flooding may be caused by non-El Nino events but El Nino is still one of the major sources of flooding within the drainage. At Huaca del Sol the stratigraphic sequence has significant textural variation throughout, and is consistent with a pattern of regular shifting and avulsion characteristic of braided streams. There is thus no clear evidence of any environmental changes having a significant effect on the stratigraphic sequence at the site. Both San Jose de Moro and Huaca del Sol are located on floodplain surfaces created at least in part by El Nino-driven aggradation that produced broad, elevated areas with decreased risk of El Nino flooding. The presence of these sites on this landscape shows that this environment was attractive for both occupation and ceremonialism. These results demonstration that in addition to being a cause of weather variation and catastrophism, El Nino should also be seen as a constructor of favorable landscapes that is essential to understanding the physical setting of prehistoric human settlements in northern coastal Peru. ACKNOWLEDGEMENTS This thesis was made possible by financial support from the National Science Foundation Award ARC-1152156 to Jeffrey Quilter (Harvard University). I am greatly indebted to Dr. Quilter for allowing me to pursue my research under his grant. Thanks to Dr. Luis Jaime Castillo Butters and the rest of the crew at El Proyecto Arqueologico San Jose de Moro as well as Dr. Santiago Uceda Castillo and the crew at Huaca del Sol for welcoming me to their sites and providing assistance throughout the fieldwork process. Maria Claudia Herrera of El Proyecto Arqueologico San Jose de Moro was particularly helpful, offering her help in the field, as well as providing resources, information and moral support throughout the entirety of this project. I would also like to thank Ana Cecilia Mauricio and Sofya Yelizarova for their invaluable assistance in the field. Dr. Joseph Kelley, Dr. Martin Yates and Kara Jacobacci were all enormous help with various aspects of the laboratory analysis. Dr. David Keefer graciously offered his knowledge and advice in support of my thesis. Jessica Whelpley and Jamie Fomier Wren both provided assistance in the lab as well as intelligent feedback and greatly needed moral support throughout the writing process. My committee members, Dr. Gregory Zaro and Dr. Daniel Belknap were both excellent sources of support and advice. Greg always provided a smiling face and thoughtful guidance whenever I came to him with questions or issues. Dan’s help showing me my way around the Sedimentology Lab was key to the research of this thesis, and he was very helpful in assisting me in interpreting the results of my analysis. IV I am extraordinarily grateful to my advisors Dr. Daniel Sandweiss and Dr. Alice Kelley. Both Dan and Alice took the time out of their busy schedules to thoughtfully guide me in my education, and I learned an immense amount from both. They have shown great dedication to my success, patience with my shortcomings and made sure that I got the most out of my time at the University of Maine. Either Dan or Alice alone would have made an excellent advisor, to have both was more than any burgeoning scholar and scientist could hope for. Finally, thanks to my friends and family, especially my parents, for all of their love and support. v TABLE OF CONTENTS ACKNOWLEDGEMENTS.....................................................................................................iv LIST OF TABLES................................................................................................................ viii LIST OF FIGURES........................................................................................................................ ix CHAPTER 1. INTRODUCTION AND BACKGROUND...................................................... 1 Introduction....................................................................................................................1 Outline of Thesis........................................................................................................... 3 Background....................................................................................................................3 Depositional Influences............................................................................................... 7 El Nino...........................................................................................................................9 Cultural Context...........................................................................................................18 CHAPTER 2. METHODS......................................................................................................25 Field Methods............................................................................................................. 25 Laboratory Methods....................................................................................................29 CHAPTER 3. RESULTS: SAN JOSE DE MORO..............................................................33 Unit 1........................................................................................................................... 33 Unit 2...........................................................................................................................48 Botanical Analysis......................................................................................................54 CHAPTER 4. RESULTS: HUACA DEL SOL....................................................................57 vi CHAPTER 5. DISCUSSION AND CONCLUSIONS........................................................ 71 Human Occupation.....................................................................................................77