Below the Neon: Reno’s Bare Earth Recent Reno–Sparks–Carson City Lidar Acquisition Project

Story maps provide an excellent means for NBMG staff to share information about programs and activities throughout Nevada with the public. NBMG Cartography and GIS group members Irene Seelye and Rachel Micander have created a story map documenting the recent lidar acquisition in the greater Reno–Sparks–Carson City area. This story map, titled “Reno’s Bare Earth: Below the Neon,” documents the differences between various quality levels of lidar data, air photos, and the bare earth data that are obtained with lidar. This recent lidar acquisition was made possible with matching funds from the Office of the Vice President of Research and Innovation at the University of Nevada, Reno and through partnerships with the Washoe Regional Basemap Committee, the US Forest Service, Lyon County, and Storey County. Read more about the plan, collaborators, and the final products here: https://nbmg.maps.arcgis.com/apps/Cascade/index.html?appid=d56cc0a4bb4c425093f63cb43550e720

Revealing our dynamic landscape through new high-resolution topographic data: Nevada Bureau of Mines and Geology’s regional-scale lidar mapping provides novel insights into earthquake, flood and glacial history
Nevada Today, 12/18/2018, by: Jane Tors
https://www.unr.edu/nevada-today/news/2018/nbmg-lidar-mapping-project

The complete article is copied below.

If you could pull back the vegetation and man-made structures and have a high definition view from above, what would you learn about the landscapes and valleys below? A lot, it turns out.

A significant recent effort by the Nevada Bureau of Mines and Geology at the University of Nevada, Reno and the United States Geological Survey (USGS) utilized airborne lidar technology to produce high-resolution topographic maps of the Reno–Sparks–Carson City area. The data will benefit a number of in-progress Nevada Bureau of Mines and Geology studies to understand earthquake and flood hazards, as well as natural resources.

Preliminary project findings include:

  • The discovery of more than two dozen, previously unknown earthquake faults, plus better understanding of many previously identified faults.
  • The extent of large and geologically young landslide deposits at the mouth of Ophir Creek in Washoe Valley.
  • Evidence for a large lake during the end of the last ice age in Lemmon Valley.
  • The size and geologic history of ice-aged glaciers on Mount Rose.

Using Light Detection and Ranging technology, or lidar, the project collected data by bouncing light pulses off the surface of the earth. The result is a high-resolution, three-dimensional topographic map that allows improved identification of geologic features such as flood plains, glacial deposits and earthquake faults. This can also support the assessment of ecological systems, infrastructure planning and the identification of geothermal reserves to support clean-energy production.

The Nevada Bureau of Mines and Geology created an online story map, titled Reno’s Bare Earth: Below the Neon, to document the project and share examples of lidar images. Visit the story map at http://www.unr.edu/nbmg/bare-earth

A Collaborative Effort

Under the direction of Nevada Bureau of Mines and Geology Director Jim Faulds and spearheaded by faculty member and Geologic Mapping Specialist Seth Dee, the project received initial funding through the USGS and Research & Innovation at the University of Nevada, Reno.

The many significant implications of this high quality dataset were quickly evident. Several entities and agencies recognized this potential and extended financial support to allow the lidar data to be expanded in areal coverage and acquired at a greater level of resolution. The Washoe County Regional Basemap Committee, the U.S. Forest Service, Lyon County, Storey County, City of Reno, City of Sparks and NV Energy are among those that provided additional support for the project and are now using the data for planning or hazard mitigation.

Exploring Nevada’s Wide-Open Spaces

Through the USGS’s 3D Elevation Program (3DEP), lidar mapping has been completed in many other states, though typically concentrated in urban or well-populated settings. The USGS 3DEP program requires a 1:1 funding match, which is easier to obtain for more populated areas with large amounts of private land. In the wide-open spaces of Nevada, where approximately 86 percent of the state is owned by the federal government, it is more difficult to obtain this match and thus lidar acquisitions have progressed more slowly compared to other regions. This presents opportunities for future work in the region and adds the element of discovery to nearly any lidar acquisition in the state.

“Nevada is still the wild west,” said Rachel Micander, a geographic information system analyst in the Nevada Bureau of Mines and Geology. “There’s a lot going on in this state from the geographic and geologic perspectives. Nevada is the second most mountainous state and the state with the most named mountain ranges.”

“Nevada is still relatively unexplored; we are still figuring it out,” said Faulds. “We don’t know as much about our flood hazards compared to many other parts of the country, and we continue to find new earthquake faults. There’s a whole element of discovery here that isn’t happening in other areas.”

Seth Dee remarked that the new lidar data acquisition for the area “is the equivalent of getting a much better lens on a telescope. The best topography widely available 20 years ago was from contours every 40 feet on a topographic map. With lidar we get a grid of data with elevation measurements spaced at least every meter (~3 ft), accurate to 10 cm (4 inches) vertically. We can now quickly map sub-meter geologic features, in addition to countless applications in other disciplines.”

Understanding Hazards

It’s well known that Nevada is a seismically active state. Faulds noted that understanding the geologic setting and finding new faults should not be a cause for concern, but rather recognized as valuable information in the effort to monitor seismic activity, mitigate hazards, aid in the planning of infrastructure and development, and guide future geologic exploration.

“These data can help us focus in on where to conduct our geologic work,” he said. “We see there is a fault scarp at a certain location; we now know we need to go there to learn more.”

The mapping data also informs flood planning by accurately defining what land could be inundated when flood waters rise. The Reno’s Bare Earth: Below the Neon online story map, which was developed by Micander and her fellow geographic information system analyst, Irene Seelye, shows the example of the Carson River near Dayton, Nevada.

The Nevada Bureau of Mines and Geology team is understandably proud of the project and deeply appreciative of the support and engagement behind it.

“This demonstrates the University’s public service role and the role of statewide programs that are out there doing things for the public good,” said Faulds.  “This is a great example of partnership and what we strive to do to achieve really broad benefits.”

 

Researchers made 3D laser maps of northern Nevada and the data is available to anyone online
Reno Gazette Journal, 12/21/18, by Benjamin Spillman
https://www.rgj.com/story/life/outdoors/2018/12/21/laser-data-creates-most-detailed-maps-ever-reno-carson/2387823002/

This story includes a video interview: “Researcher Seth Dee of University of Nevada explains how recently made LiDAR maps of Reno and Carson City will help Nevadans for years to come.”

New NBMG Publication – Geologic Map of the Humboldt Peak Quadrangle, Elko County

Geologic Map of the Humboldt Peak Quadrangle, Elko County
By Allen J. McGrew, University of Dayton
Year: 2018
Series: Map 186
Format: plate: 43 x 37 inches, color; text: 23 pages, color
Scale: 1:24,000
View/purchase: http://pubs.nbmg.unr.edu/Geol-Humboldt-Peak-quad-p/m186.htm
GIS files: http://pubs.nbmg.unr.edu/CDP-Geol-Humboldt-Peak-quad-p/m186z.htm

Located in central Elko County, Nevada, the Humboldt Peak quadrangle exposes the central and highest part of the East Humboldt Range (EHR). It is flanked to the east by Clover Valley and a northerly trending line of hills. The central East Humboldt Range probably represents the structurally deepest part of the Ruby Mountains–East Humboldt Range metamorphic core complex. The high-grade core of the EHR consists of migmatitic upper amphibolite facies rocks that achieved peak P-T conditions during Late Cretaceous metamorphism up to 8 kb and 775°C. The deepest structural levels, exposed in Lizzies Basin in the west-central part of the quadrangle, form a migmatite complex with >67% leucogranitic rock. In the northwest part of the quadrangle, this migmatite complex is overlain in the cirque wall above Winchell Lake by a southward-closing, kilometer-scale recumbent fold known as the Winchell Lake fold-nappe (WLN). The WLN folds a sequence of intensely metamorphosed, migmatized and profoundly attenuated Neoproterozoic to Mississippian metasedimentary rocks. Farther north in the adjacent Welcome quadrangle the WLN is cored by Nevada’s oldest rocks—Neoarchean to early Paleoproterozoic orthogneiss and paragneiss that were thrust over the Neoproterozoic to Mississippian metasedimentary sequence before peak metamorphism and WLN-related folding. Overprinting this assemblage at higher structural levels is a WNW-directed, kilometer-scale mylonitic shear zone that diachronously exhumed this high-grade terrain during extensional tectonism bracketed between late Eocene and Miocene. Together, the mylonitic shear zone and the detachment fault that forms its roof probably accommodated much more than 15 km of extensional displacement. Cutting through the metamorphic core along the steep, eastern face of the East Humboldt Range is a younger, post-Miocene normal fault that remained active into the Quaternary. In the northern part of the quadrangle this normal fault uplifts and juxtaposes the high-grade core against moderately east-dipping Middle Miocene volcanic and hypabyssal intrusive rocks (rhyolitic quartz porphyry). A single exposure of flat-lying vitric tuff, also of Miocene age, lies to the east of the east-dipping rhyolite-bearing sequence, but it is unclear at present whether the flat-lying strata are faulted down against the rhyolitic rocks or overlie them in angular unconformity. The line of hills in the northeastern part of the quadrangle consists of Paleozoic sedimentary rock that probably represents the down-faulted “cover” of the metamorphic core complex. Finally, the late Quaternary basin fill to the east of this line of hills was faulted down against the Paleozoic sedimentary rocks along the Clover Valley fault, which strikes northward through the adjacent Welcome quadrangle toward the town of Wells where it may correlate with the fault that produced the Mw 6.0 Wells earthquake in 2008.

New GIS Files are Now Available

GIS files are now available for the following NBMG publications. Please click on links below for details.

Surficial geology, hydrology, and late Quaternary tectonics of the IXL Canyon area, Nevada, as related to the 1954 Dixie Valley earthquake
http://pubs.nbmg.unr.edu/CDP-IXL-Canyon-1954-Dixie-Valle-p/b102z.htm

Geologic map of the McCoy mining district, Lander County, Nevada
http://pubs.nbmg.unr.edu/CDP-Geol-McCoy-mining-district-p/m103z.htm

Geologic map of the Caetano caldera, Lander and Eureka counties, Nevada
http://pubs.nbmg.unr.edu/CDP-Geol-Caetano-caldera-p/m174z.htm

Geology and geophysics of White Pine and Lincoln counties, Nevada, and adjacent parts of Nevada and Utah: the geologic framework of regional groundwater flow systems
http://pubs.nbmg.unr.edu/Geol-geophys-White-Pine-Lincoln-p/r056z.htm

New Geologic Map – Kinsley Mountains

Preliminary Geologic Map of the Kinsley Mountains, Elko and White Pine Counties, Nevada
Authors: John L. Muntean, Seth Dee, Tyler J. Hill, Randall L. Hannink, Moira Smith, Gene Urie, and Ken Raabe
Year: 2017
Series: Open-File Report 2017-07
Version: first edition, September 2017; supersedes Open-File Report 15-9
Format: plate: 41 x 54.5 inches, color; text: 5 pages, b/w
Scale: 1:12,000
View/Download/Purchase:

This detailed geologic mapping of the Kinsley Mountains in eastern Nevada investigates the time-space relationships between an Eocene intrusive complex centered on a granitic stock, proximal intrusion-related polymetallic skarn and carbonate replacement mineralization, disseminated Carlin-style gold deposits 3 km north of the stock, Eocene magmatism, and Eocene through Quaternary faulting. Previous detailed mapping of the northern Kinsley Mountains by geologists of Pilot Gold was compiled, field checked, and refined, along with new mapping during the summers of 2015 and 2017. Pilot Gold is exploring for more Carlin-style mineralization in the center of the range and map area, where gold ore was previously mined in the late 1990s. The mapping revealed: 1) a significant amount of extensional faulting occurred prior to Eocene magmatism and mineralization, similar to what NBMG mapping documented recently in the Eureka mining district. Eocene intrusions cut faults or fill faults, and Eocene volcanic rocks unconformably overlie Paleozoic rocks as old as Ordovician and as young as Permian, 2) Eocene dikes, gossans, and quartz veins, and jasperoid formation are focused within a 1-km-wide corridor that extends 3 km northward from the stock to the area of carbonate-hosted Carlin-like gold deposits, where dikes in drill core have locally high gold grades, 3) significant Eocene extension is demonstrated by a southwest-dipping fault that dropped Permian rocks against metamorphosed and mineralized Cambrian rocks proximal to the Eocene stock; the fault is overlapped by Eocene volcanic rocks that are a few million years younger than the stock, suggesting the intrusive complex was rapidly exhumed nearly 3 km, and 4) detailed mapping of the Quaternary range front fault on the east side of the mountains demonstrates offset of alluvial-fan deposits of likely mid-Pleistocene age with no faulting in younger Quaternary deposits.

This map was prepared as a part of the STATEMAP component of the National Cooperative Geologic Mapping Program in cooperation with the U.S. Geological Survey under STATEMAP award number G16AC00186, 2017.

New Geologic Map – Independence Valley NW

Preliminary Geologic Map of the North Half of the Independence Valley NW Quadrangle and the Adjacent Part of the Independence Valley NE Quadrangle, Elko County, Nevada
Author: Seth Dee, Christopher D. Henry, Michael W. Ressel, and Andrew V. Zuza
Year: 2017
Series: Open-File Report 2017-06
Version: first edition, September 2017
Format: plate: 35 x 30.5 inches, color; text: 4 pages, b/w
Scale: 1:24,000
View/Download/Purchase:
http://pubs.nbmg.unr.edu/Prel-geo-Indep-Valley-NW-p/of2017-06.htm

The north half of the Independence Valley NW 7.5-minute quadrangle covers a part of the western Pequop Mountains and adjacent Independence Valley in eastern Elko County. The east-tilted Pequop Mountains have newly recognized Carlin-type gold deposits in a geographic and geologic setting distinct from similar deposits elsewhere in Nevada. Mapping in the quadrangle was done in the summer of 2017.

Southeast-dipping Cambrian through Ordovician sedimentary rocks are exposed in the range front along the eastern edge of the map area. Eocene rhyolite dikes and sills, and Cretaceous granitic sills and pods locally intrude the oldest Cambrian stratigraphy. The Eocene intrusions may be part of a magmatic system that produced the heat source for the nearby Carlin-type mineralization. The range front is bound on the west by two west-dipping normal fault systems that accommodated late Cenozoic exhumation. Exposed in the hanging wall of the eastern fault system are late Cenozoic basin deposits that uncomfortably overlie Cambrian through Ordovician sedimentary rocks. Logs from three boreholes drilled into the Paleozoic rocks of the hanging wall during mineral exploration were used to help develop cross section A–A’’. One of the boreholes encountered an approximately 60-m-thick zone of fault gouge and a fault sliver with repeated Ordovician stratigraphy. This fault zone is interpreted to place Permian Pequop Formation above Ordovician Fish Haven Dolomite and may be correlative with the enigmatic Pequop fault observed in the adjacent Pequop Summit and Independence Valley NE quadrangles and variably interpreted as a thrust (Thorman, 1970) or a low-angle normal fault (Camilleri, 2010). Another borehole was advanced through the eastern range-front fault and constrains the dip of the fault to 34° west. Correlation of stratigraphy across the eastern range-front fault suggests approximately 4 km of total dip-slip displacement during Cenozoic exhumation.

The oldest Cenozoic basin deposits exposed between the two range front fault systems are tuffaceous sediments with a maximum measured bedding dip of 34° east. The tuffaceous sediments are overlain by a megabreccia landslide deposit with individual bedrock blocks over 200 m long. The individual blocks have lithologic and textural characteristics similar to rocks exposed along the western flank of the modern Pequop Mountains, which may have been the source of these megabreccia deposits. The megabreccia is overlain by Pliocene(?) fanglomerate deposits with nearly horizontal bedding.

The western range-front fault, named the Independence Valley fault zone, has evidence for late-Quaternary activity. In the footwall of the fault, alluvial-fan deposits of probable middle Pleistocene age are beveled onto the Cenozoic sediments. Late Quaternary displacement along the Independence Valley fault zone has uplifted these fan deposits a minimum of 30 m. The youngest fan deposits offset by the fault zone are of probable latest Pleistocene age, and are displaced by fault scarps up to 3 m high.

In Independence Valley, lacustrine gravels are deposited on shorelines, beach bars, and spits recording the high-stand and recessional stages of latest Pleistocene Lake Clover (Munroe and Laabs, 2013). An older lacustrine gravel deposit with a well-developed pedogenic carbonate soil horizon was mapped topographically above the latest Pleistocene shorelines along the western edge of the map area.

This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G16AC00186, 2017.

New Geologic Map—Bateman Spring Quadrangle, Lander County

Geologic map of the Bateman Spring quadrangle, Lander County, Nevada

Authors: Alan R. Ramelli, Chester T. Wrucke, and P. Kyle House
Year: 2017
Series: Map 185
Version: supersedes Open-File Report 2000-08
Format: plate: 27 x 34 inches, color; text: 6 pages, b/w
Scale: 1:24,000
View/download/purchase:
http://pubs.nbmg.unr.edu/Geol-Bateman-Spring-quad-p/m185.htm

This 1:24,000-scale geologic map of the Bateman Spring 7.5-minute quadrangle in Lander County, Nevada contains descriptions of 24 geologic units and one cross section. Accompanying text includes full unit descriptions and references. This quadrangle includes lower Paleozoic siliciclastic sedimentary rocks of the Roberts Mountain allochthon, Miocene intrusive dikes, alluvial deposits of the northern Shoshone Range piedmont, and riverine deposits of the Reese and Humboldt rivers.

Significant findings include the following: refined age estimates for the Ordovician-Cambrian Valmy Formation and Devonian Slaven Chert, based on new fossil information; and detailed mapping of late Quaternary fault traces along the Shoshone Range fault system.

This map was funded in part by the USGS National Cooperative Geologic Mapping Program under STATEMAP agreement number 99-HQ-AG-0058.

A GIS zip file is also available separately:
http://pubs.nbmg.unr.edu/CDP-Geol-Bateman-Spring-quad-p/m185z.htm

New Geologic Map—Red Ridge Area, Churchill and Mineral Counties

Preliminary Geologic Map of the Red Ridge Area, Churchill and Mineral Counties, Nevada
Author: Chad W. Carlson
Year: 2017
Series: Open-File Report 2017-02
Format: plate: 35.5 x 28 inches, color; text: 7 pages, color
Scale: 1:24,000
Free download/purchase: http://pubs.nbmg.unr.edu/Prel-geol-Red-Ridge-area-p/of2017-02.htm

The Walker Lane accommodates dextral motion between the northwest translating Sierra Nevada microplate to the west and Basin and Range extension to the east. A significant portion of dextral shear in the central Walker Lane is accommodated on left-stepping, en echelon, northwest-striking fault systems that compose the Walker Lake domain. Northwest of these dextral faults, strain is transferred to sinistral faults accommodating oroclinal flexure and clockwise-rotation of blocks in the Carson domain of the northern Walker Lane. Positioned at the northern terminus of the Walker Lake domain, the Red Ridge area resides southeast and in right-lateral separation across the Benton Spring fault from the Terrill Mountains. The thick Oligocene to late Miocene volcanic strata of the Red Ridge area provide opportunity to examine Tertiary strata and styles of deformation and correlate to results of recent geologic mapping completed in the adjacent Terrill Mountains quadrangle. Detailed geologic mapping of the Red Ridge area was completed to help elucidate the Neogene styles of, and transitions in, strain accommodation for this region of the Walker Lane.

Geologic mapping of the Red Ridge area greatly elucidated the stratigraphic and structural framework of Red Ridge and expanded understanding of deformation at the northern termination of the Walker Lake domain. The Tertiary strata included late Oligocene ash-flow tuffs and Miocene volcanic rocks correlated to, and dextrally offset from, Terrill Mountains stratigraphy. Several ash-flow tuffs correlate with regionally extensive units and provide opportunity for future paleomagnetic study. Similar to the southern Terrill Mountains, northeasterly-striking normal faults appear kinematically linked to major northwest-striking dextral faults and accommodate diffusion of dextral strain and basin development. The detailed mapping of the Red Ridge area has provided a firm foundation for future structural analysis and paleomagnetic study of the region.

This map was partially funded by the National Science Foundation.