University of New Mexico UNM Digital Repository Earth and Planetary Sciences ETDs Electronic Theses and Dissertations Fall 12-10-2019 Interpreting amalgamation processes of a fluvial sandstone of the Nacimiento Formation in the San Juan Basin, New Mexico Keely Elizabeth Miltenberger University of New Mexico - Main Campus Follow this and additional works at: https://digitalrepository.unm.edu/eps_etds Part of the Geology Commons, and the Sedimentology Commons Recommended Citation Miltenberger, Keely Elizabeth. "Interpreting amalgamation processes of a fluvial sandstone of the Nacimiento Formation in the San Juan Basin, New Mexico." (2019). https://digitalrepository.unm.edu/ eps_etds/277 This Thesis is brought to you for free and open access by the Electronic Theses and Dissertations at UNM Digital Repository. It has been accepted for inclusion in Earth and Planetary Sciences ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected]. i Keely E. Miltenberger Candidate Earth and Planetary Sciences Department This thesis is approved, and it is acceptable in quality and form for publication: Approved by the Thesis Committee: Dr. Gary Weissmann, Chairperson Dr. Peter Fawcett Dr. Louis Scuderi ii INTERPRETING AMALGAMATION PROCESSES OF A FLUVIAL SANDSTONE OF THE NACIMIENTO FORMATION IN THE SAN JUAN BASIN, NM by KEELY MILTENBERGER BACHELOR OF SCIENCE IN EARTH AND PLANETARY SCIENCES THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Earth and Planetary Sciences The University of New Mexico Albuquerque, New Mexico May, 2020 iii ACKNOWLEDGEMENTS I would like to sincerely thank the many people that helped me with my research. My family has been very patient and supported me through the last two years, thank you to my husband Luke, and sons Addison and Quentin. A huge thank you to my advisor, Dr. Weissmann and the remainder of my graduate committee, Dr. Fawcett, and Dr. Scuderi. Many thanks to Wade, Karen, Quentin, and Dustin who helped me immensely with field work. I would also like to thank the administration, we would be lost without Faith, Paula, Mabel, and Cecilia! Thank you to Jed Frescette for taking the time to meet with me and for introducing me to Houdini. Thank you to my fellow graduate students and best friends, Jessica, Christina, and Johanna for moral and friendly support!! Thank you to all of my fellow coworkers and friends at the United States Geological Survey for supporting me through my degree(s)! Lastly, I would like to thank the New Mexico Geological Society for a generous graduate student grant to help offset research costs. iv Interpreting amalgamation processes of a fluvial sandstone of the Nacimiento Formation in the San Juan Basin, NM Keely Miltenberger Bachelor of Science in Earth and Planetary Sciences Master of Science in Earth and Planetary Sciences ABSTRACT Outcrop studies of fluvial sand bodies are important for the study of fluid transport and storage capabilities because the deposits are heterogeneous. 3-D photogrammetry was used to evaluate the amalgamation processes of a multi-storey sheet sandstone in the San Juan Basin, NM. The Angel Peak member was deposited in the proximal-medial transition of a distributive fluvial system by a meandering river during the Paleocene. Within the study area, amalgamation occurred by avulsion and reoccupation of channel-belts to produce five storeys of the multi- storey sheet sandstone. Within each storey is evidence of processes that are internal to a channel-belt, such as bar migrations, small scour surfaces, and chute deposits. Vertical truncation by subsequent channel-belts has occurred to each storey. Miocene to present erosion has also removed portions of the uppermost storeys within the detailed study area. The multi- storey sheet sandstone of the Angel Peak member was deposited as the San Juan Basin was almost full, thus has many characteristics of amalgamation during low accommodation space. v LIST OF FIGURES Figure 1. Three end-member possibilities for amalgamation ...............................................3 Figure 2. Planview and cross-sectional DFS ........................................................................8 Figure 3. Geologic map of the San Juan Basin .....................................................................10 Figure 4. Stratigraphic column for San Juan Basin ..............................................................12 Figure 5. Map of detailed study area ....................................................................................14 Figure 6. Storey edge classifications ....................................................................................17 Figure 7. Interpolated 3-D storey bases ................................................................................18 Figure 8. Initial 3-D bounding surface projections ...............................................................19 Figure 9. Sedimentary structures ..........................................................................................20 Figure 10. Lateral accretion sets ...........................................................................................21 Figure 11. Clay clast conglomerates .....................................................................................22 Figure 12. Floodplain and overbank deposits .......................................................................23 Figure 13. Storey bases on 3-D outcrop................................................................................24 Figure 14. East wall- Adobe Illustrator bounding surfaces ..................................................25 Figure 15. Features of internal processes ..............................................................................25 Figure 16. Rose diagrams for crossbedding ..........................................................................26 Figure 17. Surface erosion of west wall................................................................................27 Figure 18. Storey-scale scours ..............................................................................................28 Figure 19. Storey B covered floodplain deposits ..................................................................29 Figure 20. Petrified log concretion .......................................................................................30 Figure 21. Storey C- additional Rose diagrams ....................................................................30 Figure 22. Lateral accretion sets of chute channel ................................................................31 Figure 23. Crevasse splay deposits .......................................................................................31 Figure 24. Storey E- additional Rose diagram ......................................................................33 Figure 25. Storey E- compound bars ....................................................................................33 Figure 26. Storey E- crossbedding variability ......................................................................34 Figure 27. Storey edges.........................................................................................................35 vi Figure 28. Smooth MSSS bounding surface .........................................................................36 Figure 29. Interpolated surfaces in 3-D with paleocurrents ..................................................37 Figure A1. All Adobe Illustrator bounding surfaces ............................................................48-49 vii LIST OF TABLES Table 1. ................................................................................................................................26 Table A1. Camera types used in study..................................................................................46 Table A2. Agisoft image processing parameters ..................................................................46 Table A3. Paleocurrent measurements .................................................................................46-47 viii TABLE OF CONTENTS ACKNOWLEDGEMENTS ...................................................................................................iii ABSTRACT ...........................................................................................................................iv LIST OF FIGURES ...............................................................................................................v-vi LIST OF TABLES .................................................................................................................vii INTRODUCTION .................................................................................................................1 AMALGAMATION PROCESSES .......................................................................................2 HYPOTHESES ......................................................................................................................6 BACKGROUND ...................................................................................................................6 STUDY AREA ......................................................................................................................9 METHODS ............................................................................................................................14 3-D Storey distribution analysis.................................................................................18 RESULTS