Prepared in cooperation with the New Mexico Office of the State Engineer Geophysical Interpretations of the Southern Española Basin, New Mexico, That Contribute to Understanding Its Hydrogeologic Framework Professional Paper 1761 U.S. Department of the Interior U.S. Geological Survey Geophysical Interpretations of the Southern Española Basin, New Mexico, That Contribute to Understanding Its Hydrogeologic Framework By V.J.S. Grauch, Jeffrey D. Phillips, Daniel J. Koning, Peggy S. Johnson, and Viki Bankey Prepared in cooperation with the New Mexico Office of the State Engineer Professional Paper 1761 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2009 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Grauch, V.J.S., Phillips, J.D., Koning, D.J., Johnson, P.S., and Bankey, Viki, 2009, Geophysical interpretations of the southern Española Basin, New Mexico, that contribute to understanding its hydrogeologic framework: U.S. Geological Survey Professional Paper 1761, 88 p. iii Contents Executive Summary .......................................................................................................................................1 Introduction.....................................................................................................................................................3 Objectives, Approach, and Hydrogeologic Significance ........................................................................3 Elements of the Basin Floor ................................................................................................................5 Elements of Basin Fill ...........................................................................................................................9 Structure.................................................................................................................................................9 Geologic Setting .............................................................................................................................................9 Data Types and Descriptions .....................................................................................................................12 Physical Properties.............................................................................................................................12 Aeromagnetic Data.............................................................................................................................13 Gravity Data .........................................................................................................................................18 Other Data ............................................................................................................................................18 Methods of Data Analysis ..........................................................................................................................20 Edge Detection ....................................................................................................................................20 Magnetic Anomaly Separation ........................................................................................................21 Magnetic Depth Estimation ..............................................................................................................21 Model Construction .....................................................................................................................................24 Gravity Inversion .................................................................................................................................24 Profile Models .....................................................................................................................................27 Integrated Three-Dimensional Model .............................................................................................31 Interpreted Elements of the Basin Floor ..................................................................................................35 Precambrian Basement .....................................................................................................................35 Pre-Rift Sedimentary Section ...........................................................................................................41 Intrusions..............................................................................................................................................44 Older Volcanic Rocks .........................................................................................................................50 Interpreted Elements of Basin Fill .............................................................................................................52 Santa Fe Group Sediments ................................................................................................................52 Younger Volcanic Rocks ....................................................................................................................57 Interpreted Structure ..................................................................................................................................57 Summary........................................................................................................................................................65 Description of Digital Products .................................................................................................................66 Acknowledgments .......................................................................................................................................66 References Cited..........................................................................................................................................67 Appendix 1. Well Data Used to Constrain Three-Dimensional Integrated Model and Gravity Inversion.............................................................................................................................77 Appendix 2. Well Data Used to Guide Three-Dimensional Integrated Model ................................82 Appendix 3. Magnetic Depth Estimation Methods Used in This Study ...........................................84 Appendix 4. Other Point-Located Data .................................................................................................86 iv Plates 1. Composite of Selected Geophysical Interpretations at 1:100,000 Scale (in pocket and on CD) 2. Geologic Units Inferred to Directly Underlie the Santa Fe Group at 1:100,000 Scale (on CD) Figures 1–3. Maps showing: 1. Española Basin and areas used for various analyses ....................................................4 2. Key basin elements addressed by geophysical interpretation ......................................6 3. Generalized geology and geography of the study area ................................................11 4. Diagrams showing magnetic property information for geologic units in study area ......14 5–9. Maps showing: 5. Coverage of high-resolution aeromagnetic surveys .....................................................17 6. Isostatic residual gravity and station locations for area of gravity analyses ...........19 7. First vertical derivative of reduced-to-pole aeromagnetic data .................................22 8. Broad magnetic anomalies enhanced by lowpass filters ............................................23 9. Data coverage and types of independent constraining data used for gravity inversion ................................................................................................................................26 10. Diagram showing simplified density-depth functions developed from borehole density logs in the Albuquerque and Española Basins ........................................................27 11–13. Maps showing: 11. Elevation of base of basin fill derived from gravity inversion ......................................28 12. Bedrock gravity map derived from gravity inversion ....................................................29 13. Section lines and data used to construct three-dimensional integrated model ......30 14. Two sections demonstrating three-dimensional model and forms of input .....................34 15. Aeromagnetic map showing labels on interpreted sources of selected features ..........36 16. Isostatic residual gravity map for study area ........................................................................37 17. Two-dimensional gravity and magnetic model for Tesuque profile ...................................38 18. Geologic map and aeromagnetic image of southeastern part of study area ...................39