Detailed geochemical and mineralogical analyses of naturally occurring arsenic in the Hawthorn ...

141 Pages·2015·3.15 MB·English

University of South Florida
Scholar Commons
Graduate Theses and Dissertations Graduate School
11-2-2004
Detailed Geochemical and Mineralogical Analyses
of Naturally Occurring Arsenic in the Hawthorn
Group
Olesya Lazareva
University of South Florida
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Lazareva, Olesya, "Detailed Geochemical and Mineralogical Analyses of Naturally Occurring Arsenic in the Hawthorn Group" (2004).
Graduate Theses and Dissertations.
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Detailed Geochemical and Mineralogical Analyses of Naturally Occurring Arsenic in

the Hawthorn Group

by

Olesya Lazareva

A thesis submitted in partial fulfillment
of the requirements for the degree of
Master of Science
Department of Geology
College of Arts and Sciences
University of South Florida

Major Professor: Thomas Pichler, Ph.D.
Thomas Scott, Ph.D.
Jonathan Arthur, Ph.D
Peter Harries, Ph.D.

Date of Approval:
November 2, 2004

Keywords: phosphate, mining, pyrite, aquifer, trace metal, florida

© Copyright 2004, Olesya Lazareva
ACKNOWLEDGEMENTS

First and foremost, I would like to gratefully acknowledge the help, support
and encouragement of my advisor Dr. Thomas Pichler, who presented me with this
wonderful opportunity, and assisted me with developing the research topic and with
completing and revising the paper. His contribution to my development as a
geochemist cannot be underestimated. I am extremely thankful for his endless effort
to provide invaluable assistance and inspired ideas. It was my luck to work with Dr.
Thomas Pichler as my advisor.
I would like greatly appreciate Southwest Florida Water Management District
(SWFWMD) and Mr. Greg Jones, Director of Resource and Conservation
Development for SWFWMD, for financial support of this project
I would like to thank my Thesis Committee, Dr. Thomas Scott, Dr. Jonathan
Arthur, and Dr. Peter Harries, for supporting me throughout my academic career,
reviewing the manuscript and providing very valuable and helpful suggestions.
I am also grateful to Dr. Chuck Connor, Department of Geology Chair, for his
support in my efforts to study statistics.
I want to express my gratitude to a great colleague and a good friend, Roy
Price, for his incredible help during field work and throughout the entire academic
period.
I would like to thank faculty, staff and students in the Department of Geology,
University of South Florida for their support and guidance throughout this work.
Finally I am grateful to my family, my lovely boyfriend Dmitri Prokhorov,
and his wonderful parents for their constant inspiration, advice, support, and wisdom.
Without their help, patience, and love this work would never happen.
TABLE OF CONTENTS

LIST OF TABLES iv

LIST OF FIGURES v

ABSTRACT viii

CHAPTER ONE: INTRODUCTION 1
Problem Statement 2
Purpose of Research 3
Research Plan 4

CHAPTER TWO: GEOLOGY AND HYDROGEOLOGY 9
Arcadia Formation 11
Tampa Member 11
Nocatee Member 13
Peace River Formation 13
Origin of Florida’s Phosphate Deposits 17
Possible Arsenic in the Hawthorn Group 18
Francolite (Carbonate Fluorapatite) 19
Sulfide Minerals 19
Clay and Organic Material 20
Hydrous Ferric Oxides (HFO) 20

CHAPTER THREE: METHODS 22
Sample Collection and Preparation 22
Petrography and Mineralogy 23
Stereo and Petrographic Microscopy 23
Scanning Electron Microscopy 24
Chemistry 24
Inductively Coupled Plasma – Optical Emission Spectrometry
and Hydride Generation- Atomic Fluorescence Spectrometry 24
Electron-Probe Microanalyser – Wave Dispersive Spectrometry 26
Statistics 26

CHAPTER FOUR: RESULTS 28
Petrography and Mineralogy 28
Stereo and Petrographic Microscopy 28
Arcadia Formation 28
i
Peace River Formation 30
Scanning Electron Microscopy 30
Bulk Chemical Composition 32
Hawthorn Group (All samples) 32
Hawthorn Group (Interval Samples) 35
Undifferentiated Arcadia Formation 36
Tampa Member 38
Nocatee Member 40
Peace River Formation 42
Electron-Probe Microanalyser – Wave Dispersive Spectrometry 45
Hawthorn Group (All samples) 45
Undifferentiated Arcadia Formation 46
Tampa Member 49
Nocatee Member 49
Peace River Formation 50
Probability Analysis 53

CHAPTER FIVE: DISCUSSION 63
Abundance of Arsenic in the Hawthorn Group 63
Sources of Arsenic in the Hawthorn Group 71
Francolite (Carbonate Fluorapatite) 71
Pyrite 72
Clay and Organic Matter 73
Hydrous Ferric Oxides (HFO) 74
Quantified Role of Pyrite 74
Mobilization of Arsenic during Phosphate Mining 77
Mobilization of Arsenic during Aquifer Storage and Recovery (ASR) 79

CHAPTER FIVE: CONCLUSIONS 81

REFERENCES 83

APPENDICES 90
APPENDIX A: Detailed Lithological Descriptions of the Arcadia
Formation Core Samples 91

APPENDIX B: Detailed Lithological Composition of the Tampa
Member of the Arcadia Formation Core Samples 97

ii
APPENDIX C: Detailed Lithological Composition of the Nocatee
Member of the Arcadia Formation Core Samples 100

APPENDIX D: Detailed Lithological Descriptions of the Peace
River Formation Core Samples 102

APPENDIX E: ICP-OES Results for the Arcadia Formation 105

APPENDIX F: ICP-OES Results for the Tampa Member of the
Arcadia Formation 113

APPENDIX G: ICP-OES Results for the Nocatee Member of the
Arcadia Formation 117

APPENDIX H: ICP-OES Results for the Peace River Formation 120

APPENDIX I: Electron –Probe Microanalysis of Pyrites 122

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LIST OF TABLES

Table 1a. List of 16 core wells chosen for this research (English units) 7

Table 1b. List of 16 cores chosen for this study (Metric units) 8

Table 2. Maximum, Minimum, Mean and Standard Deviation of arsenic
concentrations in ppm for the Hawthorn Group and its
Formations/Members 33

Table 3. Correlation matrix for the Hawthorn Group (all samples) 35

Table 4. Correlation matrix for the Hawthorn Group (interval samples) 36

Table 5. Correlation matrix for the undifferentiated Arcadia Formation 38

Table 6. Correlation matrix for the Tampa Member of the Arcadia Formation 39

Table 7. Correlation matrix for the Nocatee Member of the Arcadia Formation 42

Table 8. Correlation matrix for the Peace River Formation 44

Table 9. Electron microprobe results for arsenic in pyrites for the Formation/
Member of the Hawthorn Group (in ppm) 46

Table 10. Electron microprobe results for arsenic in pyrites and phosphate
matrix in sample 5-1-235 for the undifferentiated Arcadia Formation
(wt. %) 48

Table 11. Electron microprobe results for arsenic in pyrites and hydrous ferric
oxides in sample 4-1-501 for the undifferentiated Arcadia Formation
(in weight percent) 49

Table 12. Probability of arsenic concentrations being larger than corresponding
values throughout the Hawthorn Group 62

Table 13. Measured bulk arsenic concentrations and calculated arsenic in pyrite 75

iv
LIST OF FIGURES

Figure 1. Map of the research area including the ROMP locations, numbers,
names, and the FGS well numbers of the 16 cores that were sampled 5

Figure 2. Lithostratigraphic and hydrogeologic units of the study area 12

Figure 3. Geological cross sections of southwestern Florida 15

Figure 4. Geological cross sections of southwestern Florida Hillsborough and
Manatee Counties 16

Figure 5. Backscattered images of framboidal pyrite (py) in carbonate
matrix (carb) from sample 20-143 (Arcadia Formation) 29

Figure 6. Scanning electron micrograph of framboidal pyrite (py)
onto kaolinite (kaol) in sample 22-170 from the Tampa Member
(arsenic concentration is 14.0 ppm) 31

Figure 7. Scanning electron micrograph of euhedral pyrite (py) in sample
4-1-599 from the Arcadia Formation (arsenic concentration is
7.5 ppm) 31

Figure 8. Diagrams showing correlation between Fe and S in the Hawthorn
Group all data (A) and without the outlier (B) 34

Figure 9. Correlation between Fe and S for the Hawthorn Group interval
samples 35

Figure 10. Correlation between Fe and S for the Undifferentiated Arcadia
Formation 37

Figure 11. Correlation between Fe and S for the Tampa Member 39

Figure 12. Correlation between As and S for the Tampa Member 40

Figure 13. Correlation between Fe and S for the Nocatee Member 41

Figure 14. Diagrams showing correlation between Fe and S in the
Peace River Formation for all data set (A) and with removed
outlier (B) 44
v
Figure 15. Elemental mapping of phosphorite in sample 5-1-235
(Arcadia Formation) 47

Figure 16. (A) Photograph of sample 4-1-501 (undifferentiated Arcadia
Formation); (B) Backscattered image of pyrites (py), hydrous
ferric oxides (HFO), and carbonate matrix (carb) 48

Figure 17. (A) Photograph of sample 12 – 125 (Peace River Formation)
composed of clays (1 = 12 – 125(1)) and pyrite – phosphate
matrix (2 = 12-125(2)); (B) Photomicrograph of contact between
sample (1) and (2); (C) Backscattered image of pyrite (py), clay
(cl) and phosphate (ph) 51

Figure 18. Elemental mapping of pyrite in sample 12-125
(Peace River Formation) 52

Figure 19. Frequency histogram and normal P-P plot of log-transformed
arsenic concentrations from the Hawthorn Group 53

Figure 20. Frequency histogram and normal P-P plot of log-transformed
sulfur concentrations from the Hawthorn Group 54

Figure 21. Frequency histogram and normal P-P plot of log-transformed
iron concentrations from the Hawthorn Group 54

Figure 22. Cumulative distribution function of log-transformed arsenic
concentrations for the all Hawthorn Group 55

Figure 23. Frequency histogram and normal P-P plot of log-transformed
arsenic concentrations from the Hawthorn Group interval samples 56

Figure 24. Cumulative distribution function of log-transformed arsenic
concentrations for the interval Hawthorn samples 56

Figure 25. Survivor probability functions of log-transformed (A) and actual
(B) arsenic concentrations for the Arcadia Formation 58

Figure 26. Survivor probability functions of log-transformed (A) and actual
(B) arsenic concentrations for the Tampa Member of the Arcadia
Formation 59

Figure 27. Survivor probability functions of log-transformed (A) and actual
(B) arsenic concentrations for the Nocatee Member of the Arcadia
Formation 60
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