Quaternary Faults within Intermontane Basins of Northwest Trans-Pecos Texas and Chihuahua, Mexico. Digital Download

RI0245D. Quaternary Faults within Intermontane Basins of Northwest Trans-Pecos Texas and Chihuahua, Mexico, by E. W. Collins and J. A. Raney. 59 p., 31 figs., 2 tables, 1997. doi.org/10.23867/RI0245D. Downloadable PDF.

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About This Publication
This report details the occurrence, geometries, scarp morphology, and paleorupture histories of Quaternary faults of northwest Trans-Pecos Texas and northern Chihuahua, Mexico.

ABSTRACT
This study area encompasses a part of the east margin of the Southern Basin and Range-Rio Grande rift tectonic province. Pre-Cenozoic tectonism and its influence on the Cenozoic structural history is also reviewed. Basins studied include the Hueco, Red Light, Northwest and Southeast Eagle Flat, Green River, Salt, Wild Horse, Lobo Valley, and Ryan Flat Basins. Aerial photographs and outcrops were analyzed in conjunction with borehole and seismic data to evaluate the region's structural and stratigraphic framework and the attributes of the Quaternary faults.

Regional Cenozoic extension produced northwest- and north-northwest-trending, fault-bounded basins and adjacent mountain ranges that were superimposed upon preexisting Tertiary, Mesozoic, and older tectonic features. Similar strikes of pre-late Cenozoic structures and the superimposed late Cenozoic basins and faults indicate that the preexisting structural grain influenced geometries of the late Cenozoic basins and associated faults.

The Hueco Bolson, the most tectonically active Cenozoic basin of the region, locally contains as much as 3 km of fill. Other basins contain less than 900 m of Cenozoic basin fill. Evidence of Quaternary tectonism is recorded by displacement of middle and upper Pleistocene deposits across range-bounding and intrabasinal faults. Middle Pleistocene displacement varies from less than 1 to 32 m. The larger displacement faults vertically offset upper Pleistocene deposits between 1 and 6 m. For some of these faults, early Holocene fault movement is likely, although not precisely dated. Even on the most active faults, average slip rates since the middle Pleistocene are low, at less than or equal to 0.1 mmlyr. Maximum vertical displacements during large surface rupture events were between 0.5 and 3 m. Average recurrence intervals since the middle Pleistocene of large surface ruptures are relatively long--15,000 to 160,000 yr, although faulting events are probably episodic.

Knowledge of structural setting and Quaternary tectonism of these basins and associated faults provides clues about these basins' structural development, as well as the structural history of the southeast margin of this extensional tectonic province. These studies are also useful in seismic risk studies related to designing critical facilities such as the proposed Eagle Flat low-level radioactive waste repository.

Keywords: faults, neotectonics, paleotectonics, Quaternary, seismic risk, Southern Basin and Range-Rio Grande rift, tectonics, Trans-Pecos Texas

CONTENTS

Abstract

Introduction

            Location and Methods

            Previous Work

            Geologic Setting

            Quaternary Stratigraphy

            Historical Earthquakes

Cenozoic Basins and Quaternary Faults

            Hueco Bolson

                        East Franklin Mountain Fault

                        Hueco Fault Zone

                        Campo Grande Fault Zone

                        Arroyo Diablo Fault

                        Caballo Fault Zone

                        Amargosa Fault Zone

                        Acala Fault

                        Arroyo Macho Fault

                        Ice Cream Cone Fault

                        Schroeder Fault

            Red Light Bolson

                        West Eagle Mountains-Red Hills Fault

                        West lndio Mountains Fault

                        Nick Draw Fault

            Northwest Eagle Flat Basin

            Southeast Eagle Flat Basin

                        West Van Horn Mountains Fault

                        East Eagle Mountains Fault

            Green River Basin

                        lndio Fault

                        China Canyon Fault

                        Green River Fault

            Salt Basin Graben System

                        Border Fault Zone

                        West Delaware Mountains Fault Zone.

                        Dell City Fault

                        East Flat Top Mountains Fault

                        North Sierra Diablo Fault

                        East Sierra Diablo Fault...

                        East Carrizo Mountains-Baylor Mountain Fault

                        Fay Fault

                        Neal Fault

                        Mayfield Fault

                        Sierra Vieja Fault

                        West Wylie Mountains Fault

                        Deep Well Fault

            Possible Quaternary faults in Chihuahua, Mexico

Summary

                        Pre-Cenozoic Structural Grain and Cenozoic Basins

                        Quaternary Fault Occurrence and Rupture Attributes

Acknowledgments

References

Figures

1. Regional map of Cenozoic basins and Quaternary faults, northwestern Trans-Pecos Texas and adjacent Chihuahua, Mexico

2. Map showing major regional tectonic features of West Texas and adjacent areas of New Mexico and Mexico

3. Generalized map of Paleozoic tectonic setting

4. Generalized map of Mesozoic-Laramide tectonic setting

5. Map showing location and basin-fill thicknesses of Cenozoic basins, northwestern Trans-Pecos Texas

6. Chart showing Quaternary stratigraphy, northwestern Trans-Pecos Texas and south-central New Mexico

7. Map showing Quaternary faults, northwest Hueco Bolson

8. Map showing Quaternary faults, southeast Hueco Bolson

9. Photograph of scarp of East Franklin Mountains fault

10. Photograph of probable scarp of North Caballo fault

11. Photograph of South Caballo fault

12. Photograph of outcrop view of Northwest Amargosa fault

13. Maps showing section boundaries of Northwest Amargosa fault, Central Amargosa fault, and Southeast Amargosa fault

14. Maps showing fault-strand boundaries along the Amargosa fault zone

15. Photograph of distinct scarp of Amargosa fault zone, aerial view

16. Southwest-northeast cross sections showing faulting of Quaternary gravel deposits at the Ice Cream Cone fault and structural relationship of the Schroeder fault, Ice Cream Cone fault, and South Caballo fault

17. Map showing Quaternary faults, Red Light Bolson

18. Photograph of landslide--slump faults of the Washboard Hills area, Red Light Bolson, aerial view

19. Log of trench excavated across the West Eagle Mountains-Red Hills fault

20. Photograph of scarp of West lndio Mountains fault

21. Map showing Quaternary and distinct, late Tertiary faults, northwest Eagle Flat, southeast Eagle Flat, and Green River Basins

22. Photograph of north part of West Van Horn Mountains fault (fault 9), aerial view

23. Map showing Quaternary faults, Salt Basin graben system

24. East-west scarp profiles and outcrop descriptions of the north strand of the East Sierra Diablo fault

25. Photograph of scarp of north part of East Sierra Diablo fault

26. Photograph of Neal fault, a range-bounding fault along the eastern base of the Van Horn Mountains, aerial view

27. Photograph of scarp of Neal fault

28. Photograph of scarp of Mayfield fault, where resistant limestone bedrock crops out along scarp face

29. Northeast-southwest profile and outcrop descriptions of Mayfield fault

30. Southwest-northeast cross sections of Lobo Valley basin and along Van Horn Creek valley showing local obsequent fault-scarp expression of Mayfield fault

31. Photograph of scarp of Sierra Vieja fault (fault 16c)

Appendix Tables

Table A-1. Geometric characteristics of faults that offset Quaternary deposits

Table A-2. Fault-displacement characteristics of faults that offset Quaternary deposits


Citation
Collins, E. W., and Raney, J. A., 1998, Quaternary Faults within Intermontane Basins of Northwest Trans-Pecos Texas and Chihuahua, Mexico: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 245, 59 p. doi.org/10.23867/RI0245D.