Award Date

5-1-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geoscience

First Committee Member

Wanda J. Taylor

Second Committee Member

Ganqing Jiang

Third Committee Member

Pamela C. Burnley

Fourth Committee Member

Craig M. dePolo

Fifth Committee Member

Paul Forster

Number of Pages

267

Abstract

The study of fault origin, development and interactions is critical to understanding structural deformation models and the associated seismic hazards. The Basin and Range province, western United States, provides opportunities to assess and develop structural deformation models especially the less studied cases of differential compaction, and dip-slip and strikeslip fault interactions. Because the region is tectonically active, it also allows assessment of how each deformation influences the seismic hazard. This study addresses two cases of fault development and interaction in southern Nevada: the origin of the Las Vegas Valley Fault System (LVVFS), Las Vegas Valley, and the interaction between three Quaternary-active faults: the Kane Springs Wash Fault (KSWF), the Coyote Spring Fault (CSF), and the Wildcat Wash Fault (WWF) near Kane Springs Wash, southeastern Nevada. The LVVFS provides an example of the interaction between tectonism and differential compaction to shape fault offset patterns and address the controversy surrounding fault origins. The KSWF, CSF, and WWF lie along the boundary zone between the northern and the central Basin and Range subprovinces of the Basin and Range and provide an example of the role of transverse strikeslip deformation in limiting and influencing the geometry of the propagation of dip-slip faults between the subprovinces as well as transferring slip between linked fault networks. Geophysical and geological well logs, subsurface rock samples, and thin sections are used to delineate the effect of differential compaction on the development of the surface scarps of the LVVFS; while field mapping, and aerial image analyses are used to map the deformation geometry in the interaction zone between the KSWF, CSF, and WWF. The new differential compaction model for Las Vegas Basin showed that compaction was hindered by early cementation in fine-grained sediments influencing a compaction pattern that is opposite to the dip direction of the faults suggesting that tectonism was required for fault development. The measured scarp offset was decreased by higher compaction of the less cemented footwalls. In the case of the KSWF, CSF, and WWF, syndeformational fault curving, linkage, splaying, and development of process zones are among the processes that determine the geometry and degree of interaction between the propagating fault tips. The three faults were synchronously active in the Middle to Late Pleistocene in the southwestern part of Kane Springs Wash. These faults formed a hard-linked fault network where the CSF and WWF abut the KSWF. That geometry suggests that the propagation of the CSF and the WWF is limited by the presence of the left-lateral KSWF at a high angle to their N-S strike; nonetheless slip can be transferred between the two faults by slip along the KSWF. The same relationship can be observed elsewhere along the boundary zone between the northern and the central Basin and Range suggesting that the segmentation of the Basin and Range into distinct structural domains is facilitated by strain and slip-transfer along interacting active normal and left-lateral strike-slip faults within the boundary zone as in the case of the KSWF, CSF, and WWF presented in this study.

Keywords

Differential Compaction; Fault Interaction; Fault offset; Rift Segmentation; Strain transfer; The Basin and Range

Disciplines

Geology | Geophysics and Seismology

File Format

pdf

File Size

7800 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Decompaction.csv (1040 kB)
decompaction spreadsheet

Map of Kane Springs Wash.pdf (48258 kB)
map of Kane Springs Wash

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Available for download on Tuesday, May 15, 2029


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