Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1992 The yH drothermal System of Nevado Del Ruiz Volcano, Colombia. Dina Areli larios Lopez Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Lopez, Dina Areli larios, "The yH drothermal System of Nevado Del Ruiz Volcano, Colombia." (1992). LSU Historical Dissertations and Theses. 5331. https://digitalcommons.lsu.edu/gradschool_disstheses/5331 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 3 0 0 North Z eeb Road. Ann Arbor, Ml 481 0 6 -1 3 4 6 USA 313/761-4700 800/521-0600 Order Number 9301079 The hydrothermal system of Nevado del Ruiz Volcano, Colombia Lopez, Dina Arelf Larios, Ph.D. The Louisiana State University and Agricultural and Mechanical Col., 1992 UMI 300 N. ZeebRd. Ann Arbor, MI 48106 THE HYDROTHERMAL SYSTEM OF NEVADO DEL RUIZ VOLCANO, COLOMBIA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Geology and Geophysics by Dina Areli Larios Lopez B. Sc., Universidad de El Salvador, 1975 M. Sc., Virginia Polytechnic Institute and State University, 1979 May 1992 ACKNOWLEDGMENTS It is my great pleasure to express my appreciation and gratitude to my co-major professors, Stanley N. Williams and Jeffrey S. Hanor. Dr. Williams invaluable advice, guidance, continuous encouragement, and support have been essencial for me in this long journey. I am particularly grateful to Dr. Hanor for his guidance and careful revision of this work. I want to acknowledge the other members of my Committee: Jeffrey A. Nunn, Andrew Schedl, Gary Byerly, and Adam T. Bourgoyne for their interest and time. I wish to acknowledge the help of Ray Ferrell with the X-ray diffraction analysis. I am also grateful to Wanda Leblanc and Lynda Williams for their help with the X-ray diffraction sampling preparation techniques. I want to thank my friends, Nemesio Miguel Perez, Martha Lucia Calvache, and Karen Graber, and all my classmates for the day-to-day interactions, encouragement and enriching discussions that we have shared. I want to thank Steve Schaefer for helping with the collection of the samples for mineral alteration during his field trip to Nevado del Ruiz in 1990. I appreciate the help of Rick Young in preparing thin sections and X-ray samples. I am especially grateful for the scholarship support provided over the period 1988-1990 by the Organization of American States. I want to express my gratitude to the American Association of University Women for the fellowship support over the year 1990-1991. I also want to thank the Department of Geology and Geophysics for the teaching assistantship support during the period 1988-1991. I want to thank my friend, Esther Marin, my brother, Jose Carlos, my sister in law, Norma Palomo, and all my brothers and sisters for all their support and concern. Finally, I want to dedicate this work to my beloved ii children, Mauricio, Dinita, and Erny, and to my husband Moris in recognition for all their help and encouragem ent during these difficult years. This research was supported in part by a grant (EAR-871206) to Stanley N. Williams from the National Science Foundation. TABLE OF CONTENTS Page ACKNOWLEDGMENTS ii LIST OF TABLES viii LIST OF FIGURES x ABSTRACT xix CHAPTER 1. INTRODUCTION 1 SCOPE AND PURPOSE OF THIS STUDY 1 PHYSICAL AND CHEMICAL PROCESSES IN VOLCANIC HYDROTHERMAL SYSTEMS APPROACH OF THIS STUDY 10 CHAPTER 2. GEOLOGY OF NEVADO DEL RUIZ HYDROTHERMAL SYSTEM GEOLOG ICAL SETTING 14 CHARACTERISTICS OF NEVADO DEL RUIZ ROCKS 16 Metamorphic Rocks 16 Intrusive Igneous Rocks 20 Volcanic Rocks 21 Glacier Cap 22 S oils 23 STRUCTURAL GEOLOGY AND MASS WASTING PROCESSES AT NEVADO DEL RUIZ VOLCANO 24 GEOPHYSICAL STUDIES 26 Seismicity at Nevado del Ruiz 27 SPATIAL DISTRIBUTION OF HYDROTHERMAL SITES AT NEVADO DEL RUIZ 28 SUMMARY 30 CHAPTER 3. WATER CHEMISTRY 34 INTRODUCTION 34 DATA BASE 34 PREVIOUS GEOCHEMICAL MODELS OF NEVADO DEL RUIZ HYDROTHERMAL SYSTEM 39 a) Alkali-Chloride water 39 b) Bicarbonate-Sulfate water. 42 c) Acid Sulfate-Chloride waters 43 d) Acid Sulfate water 43 CLASSIFICATION OF WATERS IN THIS STUDY 47 SPATIAL DISTRIBUTION OF MAJOR WATER TYPES 48 COMPOSITIONAL VARIATION WITHIN MAJOR WATER TYPES 52 iv Page Cation vs. Sum anions diagrams 52 Bicarbonate waters 56 Acid sulfate waters. 56 Neutral chloride waters 56 Chloride versus Boron 57 Cations versus Chloride 63 Boron versus Sulfate 70 Cations versus Sulfate 70 Cations versus Bicarbonate 76 Cations versus Silica 76 ISOTOPIC COMPOSITION 76 SUMMARY 90 CHAPTER 4.- MINERAL ALTERATION PRODUCTS AT THE DISCHARGE SITES OF NEVADO DEL RUIZ HYDROTHERMAL SYSTEM. 93 INTRODUCTION 93 OVERVIEW OF THE VOLCANIC ROCKS AT NEVADO DEL RUIZ 93 X-RAY ANALYSES 94 Sample Preparation 94 RESULTS 97 PETROG RAPH 1C ANALYSES 102 CHAPTER 5. WATER-ROCK INTERACTIONS 107 INTRODUCTION 107 GIGGENBACH DIAGRAMS FOR NEVADO DEL RUIZ 108 SILICA SYSTEMATICS 110 Silica Concentration versus Discharge Temperature 110 Silicate Mineral Equilibria 116 CARBONATE MINERAL EQUILIBRIA 129 SULFATE MINERAL EQUILIBRIA 133 LINEAR TRENDS IN PHASE DIAGRAMS OF NEVADO DEL RUIZ WATERS 141 Dilution of a Concentrated Solution. 141 Rock Dissolution 142 SUMMARY 147 CHAPTER 6 . REACTION PATH MODELING AT NEVADO DEL RUIZ HYDROTHERMAL SYSTEM. 149 INTRODUCTION 149 THE COMPUTER PROGRAMS CHILLER AND SOLVEQ 151 SOLVEQ 152 n u n i c n 1 REACTION SIMULATIONS 153 Acid sulfate waters 153 Bicarbonate waters 165 v Page DISCUSSION 172 CHAPTER 7. GAS THERMODYNAMICS 175 INTRODUCTION 175 Composition of volcanic-hydrothermal gases 175 Redox reactions in volcanic-hydrothermal gases 178 DATA BASE 185 PREVIOUS WORK 189 COMPOSITIONAL TRENDS AND REDOX PROCESSES AT NEVADO DEL RUIZ VOLCANO HYDROTHERMAL SYSTEM 196 Compositional Trends 198 Redox Reactions 203 Carbon Reactions 207 Sulfur and Iron Reactions 210 Oxygen Fugacities 215 CHAPTER 8 . FLOW REGIME 219 INTRODUCTION 219 PHYSICAL AND CHEMICAL PROPERTIES OF THE FLOW REGIME AT MOUNTAINOUS TERRAINS 219 THE FLOW REGIME AT NEVADO DEL RUIZ HYDROTHERMAL SYSTEM 225 CHAPTER 9. SYNTHESIS 227 INTRODUCTION 227 WATER TYPES 227 AREAL VARIATION IN COMPOSITION AND ITS RELATION WITH FLOW REGIME 229 SURFACE ALTERATION PRODUCTS 231 SOURCES OF H20 231 Acid Sulfate Waters 231 Bicarbonate and Neutral Chloride Waters 232 SOURCES AND SINKS OF CHEMICAL SPECIES AT NEVADO DEL RUIZ 232 Sulfate 233 Chloride 233 Bicarbonate 233 Alkaline elements 235 Alkaline earth elements 235 Aluminum 236 Silica 236 CONTROLS ON MAJOR CATIONS 236 Acid Sulfate Waters 236 Bicarbonate Waters 240 Comparison between the two water types 241 MIXING, ROCK DISSOLUTION, AND MINERAL EQUILIBRIA AT NEVADO DEL RUIZ 242 Page GAS AND REDOX STATE 244 COMPARISON OF WATER-ROCK INTERACTION AT RUIZ WITH OTHER AREAS. 246 Comparison with other active systems 246 Fossil systems 257 A NEW MODEL FOR NEVADO DEL RUIZ HYDROTHERMAL SYSTEM 258 CHAPTER 10. CONCLUSIONS 263 IMPORTANCE OF THIS STUDY 263 SUGGESTIONS FOR FUTURE WORK 264 REFERENCES 266 APPENDIX 1. DESCRIPTION OF SAMPLES FOR X-RAY DIFFRACTION ANALYSES 273 APPENDIX 2. EFFECT OF TEMPERATURE AND USE OF CONCENTRATIONS IN PHASE DIAGRAMS 275 APPENDIX 3. GIGGENBACH DIAGRAMS AND THEIR CONSTRUCTION 288 VITA 296 LIST OF TABLES Page Table 3.1. Water chemistry of Nevado del Ruiz hydrothermal system 35 Table 3.2. Geothermometry of alkali-chloride waters 41 Table 3.3. H, O, C, and S isotopic composition of Nevado del Ruiz volcano hydrothermal system 85 Table 4.1. Minerals of hydrothermal alteration identified by X ray diffraction analyses in samples from waters of brackish acid sulfate type hot springs at Nevado del Ruiz 99 Table 4.2. Minerals of hydrothermal alteration identified by X ray diffraction analyses in samples from the waters of brackish bicarbonate and neutral chloride type hot springs at Nevado del Ruiz hydrothermal system 100 Table 4.3. Concentration of minerals identified in sample D 6 100 Table 5.1. Composition of average crustal rocks, and typical andesite and dacite from Nevado del Ruiz 144 Table 6.1. Composition of hydrothermal gases discharged at Nevado del Ruiz crater one day before the eruption of November 1985 155 Table 6.2.