Paleomagnetic data bearing on the origin of arcuate structures in the French Peak--Massachusetts Mountain area of southern Nevada

Journal Article · Fri May 01 04:00:00 EDT 1992 · Geological Society of America, Bulletin

DOI:https://doi.org/10.1130/0016-7606(1992)104<0581:PDBOTO>2.3.CO;2· OSTI ID:518415

Hudson, M R ^[1]

---

1. Geological Survey, Denver, CO (United States)

The eastern margin of the Yucca Flat basin, in southern Nevada, is bounded by north-northwest-striking tilted fault blocks of the Halfpint Range whose strikes curve as much as 90{degrees} clockwise into east-northeast strikes in the French Peak-Massachusetts Mountain (FPMM) area. This pattern of arcuate structures has been attributed to clockwise drag along a postulated northwest-trending, right-lateral shear zone. The flexure model implies that rocks within the FPMM area were rotated strongly clockwise about a vertical axis. Directions of remanent magnetization of the middle Miocene Ammonia Tanks and Rainier Mesa Members of the Timber Mountain Tuff and of the Topopah Spring Member of the Paintbrush Tuff indicate no systematic vertical-axis rotation in the FPMM area and disprove the flexure model. After tilt correction, declinations of 29 site means obtained from the three ash-flow sheets in the FPMM area are not systematically different than declinations of 17 site means from the Halpint Range or declinations of 16 site means from little-deformed mesa areas to the west. The paleomagnetic data thus indicate that structures in the FPMM area initiated with arcuate trends and were not originally straight elements that were rotated by right-lateral drag. The structures probably formed under the influence of spatially variable stress fields. The FPMM area lies in an accommodation zone between domains of oppositely tilted extensional fault blocks. Interaction between stress fields associated with propagating normal-fault zones may have been responsible for the arcuate structures in the FPMM area. 64 refs., 11 figs., 2 tabs.

• OSTI ID: 518415
• Journal Information: Geological Society of America, Bulletin, Journal Name: Geological Society of America, Bulletin Journal Issue: 5 Vol. 104; ISSN BUGMAF; ISSN 0016-7606
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
GEOLOGIC FAULTS
GEOLOGY
NEVADA
NEVADA TEST SITE
PALEOMAGNETISM
PLATE TECTONICS
SITE CHARACTERIZATION