Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 3-29-2018 Identifying the Origins of Volcanic Ash Deposits Using Their heC mical and Physical Compositions Emmanuel Soto Florida International University, [email protected] DOI: 10.25148/etd.FIDC006542 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Geochemistry Commons, Geology Commons, and the Volcanology Commons Recommended Citation Soto, Emmanuel, "Identifying the Origins of Volcanic Ash Deposits Using Their heC mical and Physical Compositions" (2018). FIU Electronic Theses and Dissertations. 3650. https://digitalcommons.fiu.edu/etd/3650 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida IDENTIFYING THE ORIGINS OF VOLCANIC ASH DEPOSITS USING THEIR CHEMICAL AND PHYSICAL COMPOSITIONS A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in GEOSCIENCE S by Emmanuel Soto 2018 i To: Dean Michael R. Heithaus College of Arts, Sciences and Education This thesis, written by Emmanuel Soto Esguerra, and entitled Identifying the Origins of Volcanic Ash Deposits Using Their Chemical and Physical Compositions, having been approved in respect to style and intellectual content, is referred to you for judgment. We have read this thesis and recommend that it be approved. _________________________________________ Laurel Collins _______________________________________ Grenville Draper _______________________________________ Rosemary Hickey-Vargas, Major Professor Date of Defense: March 29, 2018 The thesis of Emmanuel Soto Esguerra is approved. _______________________________________ Dean Michael R. Heithaus College of Arts, Sciences and Education _______________________________________ Andrés G. Gil Vice President for Research and Economic Development and Dean of the University Graduate School Florida International University, 2018 ii © Copyright 2018 by Emmanuel Soto Esguerra All rights reserved. iii DEDICATION I dedicate this Thesis to my parents, for all their love and support. iv ACKNOWLEDGMENTS First, I would like to thank my academic advisor, Dr. Rosemary Hickey-Vargas for her kindness, wisdom, and guidance from the very beginning to the end. I will forever be grateful you chose me as your student. Secondly, to the members of my committee for accepting their role and for challenging my work whenever necessary. Lastly, I would like to thank my life partner Adhly Huertas, for her understanding, patience, and motivation throughout this journey. Without her contribution, this work might have never been finished. I also thank Tom Beasley, of FIU's Florida Center for Analytical Electron Microscopy, and Dr. Sarah Jantzi, of FIU's Trace Evidence Analysis Facility, for instruction and assistance with chemical analyses. I have found my coursework throughout the Curriculum and Instruction program to be stimulating and thoughtful, providing me with the tools with which to explore both past and present ideas and issues. v ABSTRACT OF THE THESIS IDENTIFYING THE ORIGINS OF VOLCANIC ASH DEPOSITS USING THEIR CHEMICAL AND PHYSICAL COMPOSITIONS by Emmanuel Soto Florida International University, 2018 Miami, Florida Professor Rosemary Hickey-Vargas, Major Professor Pleistocene-Recent ocean sediments collected offshore Chile by Ocean Drilling Program Leg 202 contained layers of volcanic ash of unknown origin. These deposits may have originated from sources in the Southern Volcanic Zone (SVZ) within the Andean Volcanic Belt to the east, or from explosive volcanoes in the southwestern Pacific transported by westerly prevailing winds. In this study, mineral and glass textures and compositions of Leg 202 ashes were evaluated to try to determine the sources of the ash layers. Ash fragments were imaged and analyzed for major elements using an SEM with X-Ray detector and for trace elements using LA-ICPMS. Results show that the ash samples are rhyolitic and that they formed in a subduction zone setting or a continental margin. The ash samples have distinct physical and geochemical features that can be used in the future to identify their source(s) by comparison to databases of Pleistocene- Recent explosive volcanic eruptions. vi TABLE OF CONTENTS CHAPTER PAGE INTRODUCTION .............................................................................................................. 1 Expedition 202 of the Oceanic Drilling Program............................................................ 3 Geologic Setting ............................................................................................................. 6 OBJECTIVE OF PROJECT ............................................................................................. 10 METHODOLOGY ........................................................................................................... 10 Sample collection and selection .................................................................................... 10 Laboratory Procedures .................................................................................................. 13 Sample Preparation .................................................................................................... 13 Chemical Analysis of Glass Fragments ..................................................................... 15 Ash Identification .......................................................................................................... 18 DATA AND RESULTS ................................................................................................... 19 Physical characteristics of samples: .............................................................................. 19 Major element results: ................................................................................................... 20 Trace element results:.................................................................................................... 23 Interpretations based on physical characteristics of samples ........................................ 27 Interpretations based on the major element composition of the samples ...................... 29 Interpretations based on trace element patterns in the samples .................................... 30 DISCUSSION ................................................................................................................... 32 Conclusions ................................................................................................................... 35 REFERENCES ................................................................................................................. 36 APPENDICES .................................................................................................................. 42 vii LIST OF TABLES TABLES PAGES Table 1. Data of volcanic eruptions in Chile from the Pleistocene epoch to recent. .........48 Table 2. Data of volcanic eruptions in Indonesia from the Pleistocene epoch to recent. ..49 Table 3. Data of volcanic eruptions in NZ from the Pleistocene epoch to recent .............50 Table 4. Concentrations in Parts Per Million (PPM) of trace elements. Raw values collected from the LA ICP-MS. A. Site 1232 B. Site 1234 C. Site 1235. .........................51 Table 5a. Concentrations of La and Y for sites 1232, 1234, and 1235. .............................52 Table 5b. Concentrations of Ti and Zr for sites 1232, 1234, and 1235. ............................52 Table 5c. Concentrations of Sr and Y for sites 1232, 1234, and 1235. .............................52 Table 5d. Cocentrations of La and Y for sites 1232, 1234, and 1235. ..............................52 Table 5e. Concentrations of La and Yb for sites 1232, 1234, and 1235. ...........................52 Table 5f. Concentrations of La and Nb for sites 1232, 1234, and 1235. ...........................52 Table 5g. Concentrations of Zr and Nb for sites 1232, 1234, and 1235. ...........................53 Table 5h. Concentrations of Zr and Y for sites 1232, 1234, and 1235. .............................53 Table 5i. Concentrations of Ba and La for sites 1232, 1234, and 1235. ............................53 viii Table 5j. Concentrations of Ba and Th for sites 1232, 1234, and 1235 .............................53 Table 5k. Concentrations of Th and La for sites 1232, 1234, and 1235. ...........................53 Table 5l. Concentrations of Zr and Hf for sites 1232, 1234, and 1235. ............................53 Table 5m. Concentrations of Zr and La for sites 1232, 1234, and 1235. ..........................54 Table 5n. Concentrations of Zr and Nd for sites 1232, 1234, and 1235. ...........................54 Table 5o. Concentrations of La and Gd for sites 1232, 1234, and 1235. ..........................54 Table 5p. Concentrations of Gd and Yb for sites 1232, 1234, and 1235. ..........................54 Table 5q. Concentrations of Dy and Yb for sites 1232, 1234, and 1235. ..........................54 Table 6a. Concentrations of SiO2 and Zr, La, Nb, Ba, and Nd for Site 1232. ...................55 Table 6b. Concentrations of SiO2 and Zr, La, Nb, Ba, and Nd for Site 1234. ...................55 Table 6c. Concentrations of SIO2 and Zr, La, Nb, Ba, and Nd for Site 1235. ...................56