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Strike-Slip Faulting Along the Wassuk Range of the Northern Walker Lane, Nevada

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Strike-Slip Faulting Along the Wassuk Range of the Northern Walker Lane, Nevada Origin and Evolution of the Sierra Nevada and Walker Lane themed issue Strike-slip faulting along the Wassuk Range of the northern Walker Lane, Nevada Shaopeng Dong1,2,*, Gulsen Ucarkus3,*, Steven G. Wesnousky2,*, Jillian Maloney3,*, Graham Kent4,*, Neal Driscoll3,*, and Robert Baskin5,* 1Key Laboratory of Active Tectonics and Volcanoes, Institute of Geology, China Earthquake Administration, Beijing 100029, China 2Center for Neotectonics Studies, University of Nevada Reno, Reno, Nevada 89557, USA 3Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, USA 4Nevada Seismological Laboratory, University of Nevada Reno, Reno, Nevada 89557, USA 5U.S. Geological Survey, West Valley City, Utah 84119, USA ABSTRACT tions begin to reconcile what was a mismatch (e.g., Wesnousky, 2005). Based on geodesy, as between geodetically predicted deformation much as one-fi fth of the right-lateral relative A strike-slip fault is present outboard rates and geological fault slip rate studies plate motion between the Pacifi c and North and subparallel to the Wassuk Range front along the Wassuk Range front, and pro- America plates is accommodated east of the within the central Walker Lane (Nevada, vide another example of strain partitioning Sierra Nevada, with the majority localized USA). Recessional shorelines of pluvial Lake between predominantly normal and strike- within the Walker Lane (Bennett et al., 1999; Lahontan that reached its highstand ca. slip faults that occurs in regions of oblique Hammond and Thatcher, 2007; Thatcher et al., 15,475 ± 720 cal. yr B.P. are displaced ~14 m extension such as the Walker Lane. 1999). The eastern escarpment of the Wassuk and yield a right-lateral slip-rate estimate Range is steep, abrupt, and bounded by a normal approaching 1 mm/yr. The strike-slip fault INTRODUCTION fault just west of Walker Lake (Fig. 2; e.g., Wes- trace projects southeastward toward the east- nousky, 2005). Here we present both terrestrial ern margin of Walker Lake, which is ~15 km The Wassuk Range (Nevada, USA) is a and lacustrine observations that place bounds to the southeast. The trace is obscured in this north-trending ~80-km-long mountain block on the late Pleistocene rate of uplift due to dis- region by recessional shorelines features that within the central Walker Lane (Figs. 1 and 2), placement on the range-bounding normal fault record the historical dessication of the lake which is an ~100-km-wide zone of discontinu- and document the presence of an active strike- caused by upstream water diversion and con- ous active faults and disrupted topography that slip fault system outboard and subparallel to the sumption. High-resolution seismic CHIRP trends along the east fl ank of the Sierra Nevada range front. The observations begin to reconcile (compressed high intensity radar pulse) pro- fi les acquired in Walker Lake reveal ~20 k.y. of stratigraphy that is tilted westward ~20– 30 m to the Wassuk Range front, consistent W ~200KM ? E S with ~1.0–1.5 mm/yr (20–30 m/20 k.y.) of T E vertical displacement on the main range- W R bounding normal fault. Direct evidence of a N Figure 1. Tectonic map show- l the northwest-trending right-lateral strike- S k G ing the location of the Wassuk A e Wassuk R N r E slip fault is not observed, although a set of Sierra Nev Range Range within the Walker Lane A folds and faults trending N35°E, conjugate to A T (shaded). The range-bounding N D the trend of the strike-slip fault observed to B fault of the Wassuk Range is 38°N R the north, is superimposed on the west-dip- E A A shown as a thick black line with S ping strata. The pattern and trend of folding S ad IN hachures on the hanging wall. F L and faulting beneath the lake are not simply A a a The majority of ~50 mm/yr U n explained; they may record development of L e of northwest-directed Pacific T 36°N Nevada Riedel shears in a zone of northwest-directed S Californi plate motion is taken up by the Y strike slip. Regardless of their genesis, the ~50 mm/yr S San Andreas and Walker Lane T faults and folds appear to have been inactive EM fault systems (adapted from a during the past ~10.5 k.y. These observa- Wesnousky, 2005). *Emails: Shaopeng Dong: dshaopeng@ gmail .com; Ucarkus: gucarkus@ucsd .edu; Wesnousky: PACIFIC wesnousky@unr .edu; Maloney: jmaloney@ucsd .edu; Kent: gkent@unr .edu; Driscoll: ndriscoll@ PLATE 114°W ucsd.edu; Baskin: rbaskin@usgs .gov 120°W Geosphere; February 2014; v. 10; no. 1; p. 40–48; doi:10.1130/GES00912.1; 8 fi gures. Received 14 February 2013 ♦ Revision received 9 October 2013 ♦ Accepted 21 November 2013 ♦ Published online 19 December 2013 40 For permission to copy, contact [email protected] © 2014 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/10/1/40/3333427/40.pdf by guest on 27 September 2021 Strike slip along Wassuk Figure 2. The range-bounding An enlarged portion of a 1:40,000-scale fault along the Wassuk Range 119°W 118.5°W Nevada Bureau of Mines and Geology low- is shown as a dark line. Global sun-angle photo of the fault trace where it cuts positioning system (GPS) recessional shorelines of Lake Lahontan is measured displacement field 39°N shown in Figure 4A. The fault trace cuts from (reported in Wesnousky et al., Strike slip fault trace northwest to southeast across the central portion 2012) (red arrows emanating Reese River Canyon Figure 3a of the image. Several of the tonal bands result- from small white circle) is plot- ing from shadows cast by the recessional beach ted with respect to an assumed 0.2-0.4 ridges are offset right laterally across the trace. 0.9-1.0 stable Sierra Nevada block. Ori- Penrod Canyon To measure the amount of offset, the photo was entation and increasing length W 0.7-1.3 georeferenced to existing U.S. Geological Sur- Location of two seismic of arrows to northeast show a vey digital raster graphics and orthophotoquads Walker Lake Walker reflection profiles that shear is oriented oblique to s s encompassing the site. The dashed line pairs in the Wassuk Range. White boxes u Figure 4B are along interpreted piercing point k are geologically determined lines that follow the three most distinct tonal R values of fault-normal exten- a contrasts. The right-lateral offset of the tonal sion (black—upper text), geo- n g lineaments across the fault range from 11.7 to detic estimates of fault-normal Rose Creek e 0.5-0.8 15.2 m with an average of 13.5 m. In addition, extension (magenta—middle 0.4-0.7 38.5°N we used a backpack global positioning system text), and geodetic estimates of 1.2-1.6 (GPS) to survey along our interpretation by eye fault-parallel strike slip (blue— of the crests and swales of a number of beach North Canyon lower text) (rates reported in ridges (dotted line pairs in Fig. 4C). The range Wesnousky et al., 2012). Two- of 4 offsets measured in this way range from headed arrows schematically 12.3 m to 14.3 m, with an average of 13.9 m. show ranges of the same values Figure 4D shows the Lidar image at the same and correspond in arrange- 5 mm/yr scale as Figures 4B and 4C. In this case, the ment and color to the values in offsets observed in the low-sun-angle image are boxes. The geologically deter- not clearly evident in the Lidar image. mined extension-rate arrows The offset shorelines postdate the highstand are placed adjacent to the sites of pluvial Lake Lahontan (15,475 ± 720 yr B.P.). of studies. The dashed white box Dividing the ~14 m offset of the shorelines by shows the extent of Figure 3A. The dashed blue line approximates the 1252 m historical high- the age of the highstand yields a minimum fault stand shoreline of Walker Lake documented by Adams (2007) and marked in Figure 3A. slip rate equal to ~0.9 mm/yr. The approximate fault slip rate assumes the total offset is due to multiple earthquakes. an existing mismatch between geodetically pre- vation of ~1330 m ca. 13,070 ± 60 14C B.P. (e.g., dicted deformation rates compared to geologi- Adams and Wesnousky, 1998), or ~15,475 ± Submarine CHIRP Survey cally determined slip rates reported from studies 720 cal. yr B.P. (Briggs and Wesnousky, 2004). along the range-bounding fault (Bormann et al., Below the ~1330 m pluvial highstand and above Methods 2012; Wesnousky et al., 2012). The study also the ~1262 m latest Holocene highstand of the Approximately 200 line-km of seismic provides another example of the partitioning of lake mapped by House and Adams (2009, 2010), CHIRP (compressed high intensity radar pulse, slip between primarily normal and strike-slip the lineament cuts wave-washed surfaces of acoustic variant) data were acquired in Walker faults that occur in regions of oblique extension pluvial Lake Lahanton and alluvial fan depos- Lake in 2012 and 2013 (Fig. 5). The survey (e.g., Wesnousky and Jones, 1994). its developed since that time. The fi eld expres- employed Scripps Institution of Oceanogra- sion of the lineament is characterized by the phy’s Edgetech SUBSCAN CHIRP profi ler and OBSERVATIONS presence of alternate facing scarps along strike, was operated with a 50 ms swept pulse of 1–15 which are typically associated with strike-slip kHz, which provides decimeter vertical reso- Terrestrial displacement (e.g., Wallace, 1991).
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