RECENT GEOLOGIC MAPS

Geologic map of the Chokecherry Mountain quadrangle, Lincoln County, Nevada

Authors: Peter D. Rowley, Lawrence W. Snee, Ralph R. Shroba, W C Swadley, and F. William Simonds

Year: 2023
Series: Open-File Report 2023-09
Format: map sheet with cross sections: 36 x 28 inches, color; text: 31 pages, b/w
Scale: 1:24,000

This geologic map is one of two geologic quadrangles of the Caliente caldera complex to be published in 2023 by the Nevada Bureau of Mines and Geology (NBMG); five more quadrangles are anticipated. These result from mapping and related petrologic, geochemical, and isotopic studies by the authors that were funded by the U.S. Geological Survey (USGS) in the late 1980s to middle 1990s. The mapping was part of a large USGS project named the Basin and Range to Colorado Plateau Transition (BARCO) study in southeastern Nevada, southwestern Utah, and northwestern Arizona. Mapping was to be published by the USGS at detailed (1:24,000) scale, then compiled in 1:100,000-scale quadrangles. The project ended in early 1995 during the USGS Reduction in Force (RIF).

One of the subprojects of BARCO was a study of the Caliente caldera complex and its gold deposits, led by the senior author. Mapping at 1:24,000 scale began at the western end of the caldera complex, but only three quadrangles were published (Rowley and Shroba, 1991; Rowley et al., 1994; Swadley and Rowley, 1994). Abstracts cited here and summary reports (e.g., Rowley et al., 1992, 1995, 2001; Best et al., 1993; Hudson et al., 1995, 1998; Nealey et al., 1995; Unruh et al., 1995; Scott et al., 1995a, b) also were prepared before the RIF, with some published after. The seven quadrangles we intend to complete were mapped but never published. We also intend to publish with NBMG many 40Ar/39Ar dates by L.W. Snee, most of them from rocks in the caldera complex, that were never released in final form (e.g., Snee et al., 1990; Snee and Rowley, 2000). Funding from the USGS STATEMAP program awarded to NBMG has permitted synthesis and completion of our research in the area and publication of these quadrangles.

The physiography of the Chokecherry Mountain quadrangle consists mostly of the central to northern Delamar Mountains, with the central Burnt Springs Range in the northwestern part of the map area. Southern Dry Lake Valley and northern Delamar Valley lie west of the quadrangle. The other map to be published this year, the Caliente NW quadrangle to the north (Rowley et al., 2023), contains the northern Delamar Mountains, the northern Burnt Springs Range, and several small unnamed ranges. The Caliente quadrangle to the east of the map area consists of the eastern Delamar Mountains and magnificent south-flowing Rainbow Canyon that forms the eastern edge of the Delamar Mountains. The railroad town of Caliente lies in the northern end of Rainbow Canyon, where Newman Canyon joins Rainbow Canyon from the west and Clover Creek joins Rainbow Canyon from the east. North and northeast of the Caliente quadrangle, the areas of the eastern Antelope Canyon basin, Chief Range, and southern Panaca basin were mapped by Rowley and Shroba (1991) and Rowley et al. (1994). West of the map area, the western Dry Lake Valley, southern Burnt Springs Range, and part of the western Delamar Mountains were mapped by Swadley and Rowley (1994).

Geologic map of the Chokecherry Mountain quadrangle, Lincoln County, Nevada [MAP AND TEXT]

Geologic map of the Caliente NW quadrangle, Lincoln County, Nevada

Authors: Peter D. Rowley, Ralph R. Shroba, W C Swadley, F. William Simonds, Lawrence W. Snee, and Gary J. Axen

Year: 2023
Series: Open-File Report 2023-10
Format: map sheet with cross sections: 37 x 30 inches, color; text: 25 pages, b/w
Scale: 1:24,000

This geologic map is one of two geologic quadrangles of the Caliente caldera complex to be published in 2023 by the Nevada Bureau of Mines and Geology (NBMG); five more are anticipated. These result from mapping and related petrologic, geochemical, and isotopic studies by the authors that were funded by the U.S. Geological Survey (USGS) in the late 1980s and early 1990s. The mapping was part of a large project named the Basin and Range to Colorado Plateau Transition (BARCO) study in southeastern Nevada, southwestern Utah, and northwestern Arizona. Mapping was to be published at detailed (1:24,000) scale, then compiled in 1:100,000-scale quadrangles. The project ended in early 1995 during the USGS Reduction in Force (RIF).

One of the subprojects of BARCO was a study of the Caliente caldera complex and its gold deposits, led by the senior author. Mapping at 1:24,000 scale began at the western end of the caldera complex, but only three quadrangles were published (Rowley and Shroba, 1991; Rowley et al., 1994; Swadley and Rowley, 1994). Abstracts cited here and summary reports (e.g., Rowley et al., 1992, 1995, 2001; Best et al., 1993; Hudson et al., 1995, 1998; Nealey et al., 1995; Unruh et al., 1995; Scott et al., 1995a, b) also were prepared before the RIF, with some published after. The seven quadrangles we intend to complete were mapped but never published. We also intend to publish with NBMG many 40Ar/39Ar dates by L.W. Snee, most of them from rocks in the caldera complex, that were never released in final form (e.g., Snee et al., 1990; Snee and Rowley, 2000).

The physiography of the Caliente NW quadrangle consists of the northern end of the Delamar Mountains and several small ranges to the north, the Burnt Springs Range on the west and unnamed ranges east of it. In the Caliente NW quadrangle, west of these mountain clusters is the eastern edge of broad Dry Lake Valley, and east of the mountain clusters is the western part of the Antelope Canyon basin. The other map to be published in 2023, the Chokecherry Mountain quadrangle to the south (Rowley et al., 2023), contains the central to northern Delamar Mountains and the central Burnt Springs Range. East of the Caliente NW map area, the Chief Range and eastern Antelope Canyon basin were mapped by Rowley et al. (1994). Southwest of the map area, the western Dry Lake Valley, southern Burnt Springs Range, and western Delamar Mountains, including the western edge of the Delamar caldera, were mapped by Swadley and Rowley (1994).

Geologic map of the Caliente NW quadrangle, Lincoln County, Nevada [MAP AND TEXT]

Geologic map of Rhyolite Ridge and the northern Silver Peak Range, Esmeralda County, Nevada

Authors: Izabella Ogilvie, Michael H. Darin, John T. Reynolds, Daniel A. Chafetz, and Matthieu Harlaux

Year: 2023
Series: Open-File Report 2023-11
Format: map sheet with cross sections: 41 x 29.5 inches, color; text: 35 pages, color
Scale: 1:24,000

Rhyolite Ridge is located in the northern Silver Peak Range of southwestern Nevada and contains significant sediment-hosted lithium and boron deposits that are nearing development. Despite the economic importance of these resources, the primary source of lithium, deformation history, and the relative influences of structural, stratigraphic, and magmatic controls on lithium enrichment are uncertain. This report presents new 1:24,000-scale geologic mapping, whole-rock geochemistry, and a sub-regional compilation of Cenozoic geochronologic data to support the evaluation and assessment of these critical minerals through the U.S. Geological Survey (USGS) Earth Mapping Resources Initiative (Earth MRI). Most of the economic lithium and boron mineralization occurs in the upper Miocene to lower Pliocene Cave Spring formation, which is composed of interbedded lacustrine claystone, marl, limestone, volcaniclastic rocks, and tuffs. Anomalously high concentrations of lithium (up to 2,620 ppm; Reynolds and Chafetz, 2020) are bound in marl, smectite, and mixed illite-smectite clays, while boron is primarily associated with searlesite. The Cave Spring formation is mostly contained within a single structural basin in the study area and was deposited in an alluvial-lacustrine environment on top of ~6.1–5.8 Ma rhyolitic tuffs and lavas of the Rhyolite Ridge and Argentite Canyon formations. Geochemical data from these pre-basin volcanic rocks contain exceptionally high whole-rock lithium concentrations up to 451 ppm, though with notable spatial heterogeneity. The high lithium (and boron) concentrations and considerable spatial extent and volume of these rhyolites implicate them as a probable source for the mineralization in the Cave Spring formation. The White Hill and Cave Spring faults are a pair of conjugate normal faults that controlled deposition of the Cave Spring formation in an internally drained, alluvial-lacustrine basin that experienced WNW-directed extension since latest Miocene time (Ogilvie, 2023). Field relations, subsurface well data, airborne electromagnetic surveys, and our synthesis of geochronologic constraints indicate a similar style of extension across the study area associated with both NW- and SE-dipping normal faults. Active faulting and basin subsidence continues today near the western map boundary along the Emigrant Peak fault zone that bounds northern Fish Lake Valley.

Geologic map of Rhyolite Ridge and the northern Silver Peak Range, Esmeralda County, Nevada [MAP AND TEXT]

Geologic map of the Calavera Canyon quadrangle, Humboldt County, Nevada

Authors: Christopher D. Henry, Joseph A. Laravie, William A. Starkel, Ben S. Ellis, John A. Wolff, and Stephen B. Castor

The Calavera Canyon 7.5-minute quadrangle covers the western margin of the 16.4 Ma McDermitt caldera, one of the oldest expressions of the Yellowstone hotspot and site of major lithium-clay deposits, and the eastern part of the adjacent Kings River Valley, a significant agricultural center. The ~800-m-high topographic scarp between the two areas exposes the caldera ring-fracture zone, extensive pre- caldera rocks, and a complete section of intracaldera tuff. The oldest pre-caldera rocks are a diverse suite of Jurassic intrusive rocks (table 1) that mostly consists of granodiorite but spans from high-Si felsite, aplite, and pegmatite to gabbro (table 2). Two major pulses of Eocene volcanism at 46–47 Ma and 39–41 Ma (table 3) produced dacite to rhyolite lavas and andesite-dacite(?) lavas, respectively (table 2). The lavas and volcaniclastic rocks coeval with the younger pulse filled a west-trending paleovalley cut into the Jurassic intrusive rocks. After a hiatus until ~17 Ma, intensive volcanic activity resumed with eruption of basalt and basaltic andesite lavas that are some of the southernmost expressions of Columbia River Basalt magmatism. Volcanism became more silicic with time, initially with anorthoclase-bearing rhyolite lavas, followed by biotite rhyolite lava domes, and peralkaline rhyolite lavas. Volcanism culminated with ~16.4 Ma eruption of ~1000 km3 of McDermitt Tuff, which is zoned from aphyric, peralkaline, high-Si rhyolite to abundantly anorthoclase-phyric trachydacite and icelandite (Fe-rich andesite). Eruption induced collapse of the ~40 x 22–30 km McDermitt caldera. Collapse along the western margin in the Calavera Canyon quadrangle was accommodated by an as much as 1 km wide zone of east-dipping, high-angle faults and monoclinal downwarps into the caldera. A lake that formed within the caldera was subsequently filled with tuffaceous sediments until ~15.7 Ma.

Normal faulting that probably began about 11–12 Ma in the McDermitt region (Colgan et al., 2006) cut through the western edge of the caldera, exposing the considerable intracaldera sequence in the quadrangle. The resulting, west-dipping Montana Mountains fault zone separates bedrock in the eastern part of the quadrangle from thick Quaternary and latest Cenozoic deposits in Kings River Valley. An as much as ~8-m-high scarp demonstrates that faulting has continued to the present. Quaternary deposits include alluvium, alluvial-fan deposits, and extensive colluvium and talus in drainages and slopes in bedrock and extending out into the valley. A pluvial lake occupied the valley into the Holocene, deposited both fine sediments in the lake bottom and gravel along shorelines and spits, and generated numerous shorelines during lake recession.

Three types of mineralization are present in the quadrangle. 1. Lithium-rich clays in the intracaldera sedimentary deposits, first recognized in the 1970s (Rytuba and Glanzman, 1979), are currently most important because of demand for Li for Li-ion batteries. The deposits also contain significant K, Rb, Mo, As, Sb, Mg, and F (Castor and Henry, 2020). The uncertain origin of these deposits involves diagenesis of the host tuffaceous sediments and possibly hydrothermal activity during the waning stages of caldera magmatism (Castor and Henry, 2020; Benson et al., 2017a, 2023). 2. U-Zr mineralization in pre-caldera volcanic rocks in and along caldera collapse faults at the Moonlight Mine and in Horse Canyon formed from hydrothermal solutions immediately following collapse (table 1; Castor and Henry, 2000). These deposits mostly consist of U-rich zircon, are accompanied by As, Sb, and Hf; minor amounts of Cu, Zn, Y, Hg, and Pb; and locally Mo, Ag, and Tl (table 4). 3. Quartz-sulfide veins in the Jurassic granitic rocks produced an unknown but probably small amount of Au and Ag in the early 1900s (Willden, 1964; Minor et al., 1988). Analyses of two vein samples for this study show minor enrichment in Co, Cu, As, Mo, Ag, Sb, Hg, and Bi (Au not analyzed; table 4).

Geologic map of the Calavera Canyon quadrangle, Humboldt County, Nevada [MAP AND TEXT]

NBMG Job Announcement – Professor/Director, Nevada Bureau of Mines and Geology

Job Description

Applications are invited for the Professor/Director of the Nevada Bureau of Mines and Geology (NBMG) role at the University of Nevada, Reno. NBMG serves as the geological survey for the state of Nevada.  This tenure-track faculty position at Full Professor level reports directly to the Dean of the College of Science.  The Director of the NBMG serves as the Nevada State Geologist and will lead a strong research organization focused on the geologic framework, natural resources, and geologic hazards of Nevada. The successful candidate should have the vision and initiative to enhance innovative research and educational programs within NBMG in collaboration with other departments at UNR and other institutions in the Nevada System of Higher Education. NBMG has programs in economic geology, geothermal energy, Quaternary geology, geological mapping, structural geology, geodesy, GIS-cartography, and data management. 

The primary responsibilities of this position will be to 1) manage the overall operations of NBMG, including leading a diverse team of academic and administrative faculty, research scientists, technical and support staff, and graduate students, 2) contribute to and facilitate new research opportunities related to the geologic framework, natural resources (e.g., minerals, geothermal, and groundwater), and geologic hazards (e.g., earthquakes and floods) of Nevada, 3) facilitate and enhance external funding opportunities for important components of NBMG, including the Great Basin Science Sample and Records Library (the state repository for geologic information and specimens), GIS-Cartography, and geological mapping, 4) serve as spokesperson for the amazing geology of Nevada through outreach and effective media engagements, and 5) promote diversity and inclusion in all aspects of NBMG’s activities, creating a welcoming and supportive environment for all members of the NBMG community. The position could also involve occasionally teaching courses in the applicant’s area of expertise and advising graduate students. We seek geoscientists with interest in both applied and basic research on the geology of Nevada, experience in leading and securing major external funding for research programs relevant to state geological surveys (e.g., natural resources, geologic hazards, geological mapping, and data management-preservation), and enhancing/developing partnerships with other state and federal organizations. Candidates who appreciate and can promote the value of all NBMG programs will be particularly valued.

Required Qualifications

• Ph.D. in geology or a related field, with significant experience in research, education, and/or organizational leadership. 
• Valid Driver’s License.

Preferred Qualifications (optional):

• Excellent communication and interpersonal skills, with the ability to build strong relationships with internal and external stakeholders.
• Extensive experience in program development and project management, including building collaborations and partnerships with academia, state and federal agencies, and industry.
• Collaborative leadership skills that foster a culture of teamwork and innovation among NBMG faculty and staff.
• Broad background in the geosciences.
• Knowledge of the primary mission of state geological surveys, including societally relevant applied research on natural resources, geologic hazards, and the regional geologic framework.

Compensation Grade

Professor, 9-month

To view the salary schedule for this position, please visit: Salary Schedules and select Academic Faculty (Nine-month), Assistant Professor or Professor. Salary is competitive and commensurate with related education and experience.

Application Review

Qualified individuals are encouraged to apply immediately with an initial review of applications starting March 11, 2024.

This posting is open until filled

Qualified individuals are encouraged to apply immediately. This search will close without notice when a sufficient number of applications are received or a hiring decision has been made.

For more information and to apply, visit:

https://nshe.wd1.myworkdayjobs.com/UNR-external/job/University-of-Nevada-Reno—Main-Campus/Professor-Director–Nevada-Bureau-of-Mines-and-Geology_R0140564

NBMG IN THE NEWS

KOLO-TV: Cortez Masto looking to strengthen domestic green energy, rare-earth elements supply chain dominated by China   CREG Director and Associate Professor, Simon Jowitt, was recently interviewed by KOLO-TV regarding critical minerals in Nevada. View the full interview here.

ESRI ArcNews: GIS-Based Predictions Advance Geothermal Energy Exploration   The GBCGE Subsurface Database Explorer web app was featured by ESRI’s ArcNews. NBMG’s Elijah Mlawsky and Cary Lindsey share their impressive work with the Great Basin Center for Geothermal Energy (GBCGE) INGENIOUS project. View the full article here.

WILD NEVADA: Episode 612: Mount Rose and Peavine Peak   Join Wild Nevada and NBMG Director and State Geologist, Jim Faulds, on day hikes to Mount Rose and Peavine Peak and learn more about the geology of these mountainous landmarks. Watch the full episode here.

IUGG Berlin 2023: Nevada Geodetic Laboratory’s, Geoff Blewitt, spoke during the Plenary Union Lecture at the 28th General Assembly of the International Union of Geodesy and Geophysics in Berlin last July. View the full talk, “Geodesy: It’s About Time”, here.

USGS News: USGS Partners with Nevada to map critical mineral potential with cutting-edge data in Nevada   The U.S. Geological Survey (USGS) will invest more than $1 million in a new airborne geophysical survey to map critical mineral resources in western and central Nevada in partnership with the Nevada Bureau of Mines and Geology.   View the full article featuring quotes from NBMG Director, Jim Faulds.

RECENT NEWS ARTICLES

SIERRA NEVADA ALLY Nevada a hot bed in the search for critical minerals NBMG Director and State Geologist, Jim Faulds is quoted in this article on the USGS and NBMG’s collaboration on mapping projects across the state.   Read more

SCIENCE.ORG Treasure Hunt: The first U.S. nationwide geological survey in a generation could reveal badly needed supplies of critical minerals NBMG’s Carolina Muñoz-Saez and Jim Faulds are quoted in this article on lithium and critical minerals.   Read more

RENO GAZETTE JOURNAL Is the price too steep for renewable energy? A tiny Nevada town hopes it never finds out. *This article requires a subscription NBMG Director and State Geologist, Jim Faulds is quoted in this article.   Read more

The new and improved GBCGE Subsurface Database Explorer web app

NBMG’s Great Basin Center for Geothermal Energy (GBCGE) Subsurface Database Explorer web application has recently undergone redevelopment to deliver much improved performance. This application allows users to browse, filter, and download public-domain data and documents from the GBCGE PostgreSQL Subsurface Database. This living database warehouses over 300,000 wells, springs, geothermal plants, and relational data points such as temperature, aqueous geochemistry, and log documents for the Great Basin region – with additional datasets frequently being added. An updated Quick Start Guide provides the ability for users at any level of background to dig in and use the data for professional or personal use and learn more about the Earth and geothermal resources within the Great Basin.

View the application in your browser at gbcge.org/subsurface. For questions and feedback, please contact emlawsky@unr.edu. 

Nevada Petroleum and Geothermal Society (NPGS) May Meeting

NPGS Dinner Meeting – Speaker: Vincent Ramirez – 3PL Operating
Wednesday, May 3, 2023, 6:30pm

Come join us for dinner, drinks, and a presentation.

Presentation Title:

Distribution of salts, lithium, boron and other metals in Railroad Valley, Nevada

Speaker: Vincent Ramirez – 3PL Operating

3PL Operating explores and develops locatable minerals, and lithium is a primary target. Earth scientists dominate the workforce and collectively have 200 years of prior work experience with major companies. In 2017 3PL filed for the largest mining claim block yet assembled in the State of Nevada. This acquisition followed several years of research in the western USA studying basin development, stratigraphy, and lithium concentration processes.

Location: 13101 S Virginia St, Reno, NV 89511.

Register Now

AEG Southern Nevada Chapter: April Meeting

Meeting Announcement Tuesday – April 11, 2023 – 6:00 P.M.   “The Stillwater Scarp, Central Nevada – Coseismic Gravitational Failure on a 1,200-M-High Range-Front Escarpment”   By: Dr. James McCalpin President, GEO-HAZ Consulting, Inc. (Winner of the 2022 AEG Publication Award) Join us Tuesday, April 11, 2023, for an AEG Southern Nevada Chapter In-person Dinner at the Embassy Suites located at 4315 University Center Drive in Las Vegas, Nevada     Check-in and Socialize 6:00 to 6:30 pm Dinner: 6:30 pm Presentation: 7:15 to 8:00 pm   Members: $35.00 Non-members: $40.00 Student Members: $17.00 (Do not Pay in Advance) Student Non-members: $20.00 (Do not Pay in Advance) Walk-ins: $45.00  Linguine with marinara and meatballs / vegetarian meat, steamed seasonal vegetables, Caesar salad, garlic bread, and dessert will be served. Just let us know when you register if you prefer the vegetarian option.   Abstract of the presentation and speaker’s bio are available on our website.     Please Register (By April 4th Preferred) at https://www.aegsnv.org/rsvp     Please save the date and time!     Thank you to this month’s sponsors. Click on the logos to learn more about this month’s sponsors.

Eleventh Annual Great Basin Rendezvous: Save the Date! September 8-10, 2023

Eleventh Annual Great Basin Rendezvous  Save the Date! September 8 – 10, 2023   Come join your fellow geologists, drillers, consultants, and their families at Camp Lamoille in the beautiful Ruby Mountains of Elko County for our Eleventh time around!!   Mark your calendars now for the 2023 Great Basin Rendezvous (GBR) being held September 8 through 10, 2023! This year, we return to Camp Lamoille in the beautiful, glaciated Ruby Mountains metamorphic core complex. After the devastating 2018 fire that destroyed the Whipple Lodge building and scorched the camp, the GBR was moved to the Wilson family’s Royal Peacock Opal Mine in the Virgin Valley where Julie Wilson (mine owner) spoiled us for the last three years. While the enclosed Whipple Lodge was consumed in the fire, the original stone foundation and chimney survived to support the building of the current open-air pavilion with ten tables. A restroom/shower house is newly remodeled and has three showers per side (men/women), with ADA-accessible toilets. There are plenty of camping areas for tents and there are 14 RV spaces with power and water hookups.         Upper Left: From the ashes survives the foundation and chimney. Upper right: New pavilion built on old foundation. Lower left: Pavilion from the SE. Lower right: Grill, small refrigerator, and sink in pavilion.      This year’s field trips, hikes, and/or other activities are still being worked out, but we do have a comittment from the Celtic folk band Southwind to entertain us Saturday night, as in the previous three years at the Camp Lamoille GBRs. Southwind has always gotten us up kicking and clogging!   We have always had excellent suppport from our sponsors and contractors. This year, we are again looking for support for Friday and Saturday night dinners, Sunday morning breakfast, and rental support for the camp. All sponsors will have their logos prominantly displayed at the camp. As previously mentioned, we have been spoiled the last several years by Julie Wilson and her crew cooking and serving the dinners. Since we are back at Camp Lamoille this year, the dinner sponsor will be responsible for either personally preparing the dinners (with many volunteer helpers) or finding a caterer.     Please contact Catherine Lee  (clee@westlandresources.com) or JoAnn Newbury (jnewbury.consulting@yahoo.com) if you desire to sponsor an event.   Please contact Warren Thompson at wfthompson@frontiernet.net for further information. We look forward to having you join us this September! – NMEC

AEG Great Basin Chapter Student Night

AEG Great Basin Chapter Student Night Thursday, April 13th, 2023 Please join us in concluding the 2022-2023 meeting season and celebrating UNR’s undergraduate and graduate student research. This year we are introducing an expanded program featuring three oral presentations and four poster presentations. All poster presentations will be held in the hotel lounge from 5:15 pm to 6:00 pm. Oral presentations will take place in the meeting room promptly at 7:00 pm following our dinner service. The final judging and awards ceremony will follow shortly thereafter. Thank you again for another successful AEG Great Basin Chapter season. We will resume our monthly meetings in October 2023.  All student presenters and presentation titles are provided below:   Student Speakers Mohsen Takhtravan, UNR PhD Geology Student “Hydraulic Plucking of Fractured Rock” For Abstract: Click Here Wes Johns, UNR MS Geology Student “Middle Miocene Exhmation of Avawatz Mountains, Southern California: A Termination Thrust Belt at the Eastern Tip of the Garlock Fault” For Abstract: Click Here Izabella Ogilvie, UNR MS Geology Student “Lithium Source and Structural Development of Sediment-Hosted Lithium Deposits at Rhyolite Ridge, Silver Peak Range, Western Nevada: New Insights from Geologic Mapping” For Abstract: Click Here   Student Posters Caleb Ring, UNR MS Geology Student “The Relationship between Scoured Channel Width and Drainage Area for Runoff – and Landslide-Generated Debris Flows” Dominik Vlaha, UNR MS Geophysics Student “Testing Deep Burial of the Ruby Mountain-East Humboldt Range Metamorphic Core Complex, Northeast Nevada, via Structural and Thermal Reconstructions of the Adjacent Ranges” Justin Toller , UNR PhD Geology Student “Antarctic Ice Shelf and Ocean Temperatures From Distributed Temperature Sensing: Analysis and Annual Changes and Calibration Techniques”   LOCATION Courtyard by Marriott — Reno Downtown/Riverfront 1 Ballpark Ln Reno, Nevada, 89501 Link to Map SOCIAL HOUR: 5:15 PM (Sponsored) DINNER: 6:00 PM PRESENTATION: 7:00 PM Cost: Members: $25.00 ~ Non-Members: $30.00 ~ Students: $20.00 *Great Basin Chapter t-shirts and coffee mugs will be available for a nominal price at the meeting.    Please register by following the link below. The registration deadline is 10:00 am on April 11th. RSVP *Payment for meeting attendance is required at registration. Cancellations made less than 72 hours of the meeting will not be eligible for a refund.   If you are not feeling well or have been in close contact with someone that has COVID-19, we ask that you please stay home and take care of yourself, and we’ll see you at next month’s meeting.

Thank you to this month’s Sponsor!             We are currently seeking a sponsor for student dinners! AEG can provide an itemized receipt for student dinner sponsorship. Email an AEG officer if you or your company is interested.

ADDITIONAL ANNOUNCEMENTS The monthly chapter meetings are held on the 2nd or 3rd Thursdays of every month, unless notified otherwise.  Announcements may be forwarded to colleagues who wish to attend the meetings. If there are any questions about the meeting registration process you may contact any of the 2022-2023 AEG Great Basin Chapter officers listed below: CHAIRPERSON: Merrily Graham 360-606-1838 mkgraham75@gmail.com VICE CHAIRPERSON: Kathleen Rodrigues krodrigues@nevada.unr.edu TREASURER: Chris Betts chris@earthtechnv.com  SECRETARY: Ryan Berg rberg@newfields.com

RECENT GEOLOGIC MAPS

Geologic map of the Silver Zone Pass quadrangle, Elko County, Nevada

Author: David M. Miller and Linda L. Berg
Year: 2022
Series: Map 192
Format: 1 sheet: 37 x 27 inches, cross sections, color; text: 8 pages, color
Scale: 1:24,000

This 1:24,000-scale geologic map of the Silver Zone Pass quadrangle lies in the southern Toano Range in Elko County, Nevada. Metamorphic and sedimentary strata of the quadrangle range from Neoproterozoic to Permian in age. Important intrusions include the Late Jurassic (ca. 159 Ma) Silver Zone Pass pluton and Cretaceous Toano Spring pluton. In particular, the Silver Zone Pass pluton involves undeformed dikes that crosscut metamorphic foliations and the pluton is associated with pluton-margin anticlines. Interpretation of these characteristics suggests that the pluton was syn-kinematic with respect to metamorphism and strain, thus requiring a phase of Late Jurassic deformation. A Miocene rhyolite lava is of particular interest as one of the few topaz-bearing volcanic rocks in Nevada. A major detachment fault places non-metamorphosed Paleozoic rocks over low-grade Paleozoic and Proterozoic rocks. High-angle normal faults tilted the range in several blocks, and Miocene Humboldt Formation were deposited on, and faulted against, bedrock. Rocks of the Toano Range are bounded by broad valleys on the east and west, with the eastern basin being at much lower elevation than the western basin. Pleistocene lakes, which created distinctive beach deposits, occupied both basins, with Lake Bonneville on the east and Lake Waring on the west. Silver Zone Pass owes its low relief to the enhanced weathering and erosion of the rock within the pass, a granodiorite pluton. The weathering has created some unusual landforms such as tors.

Geologic map of the Silver Zone Pass quadrangle, Elko County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the Soldier Peak quadrangle, Elko County, Nevada

Author: Arthur W. Snoke, Keith A. Howard, and Seth Dee
Year: 2022
Series: Map 191
Format: 1 sheet: 31 x 35 inches, cross sections, color; text: 31 pages, color
Scale: 1:24,000

The Soldier Peak quadrangle exposes evidence of a complex structural and metamorphic history involving a long stratigraphic record that ranges from the Neoproterozoic to the Holocene. The quadrangle exposes major elements of the architecture of the Ruby Mountains metamorphic core complex in the northern Ruby Mountains and East Humboldt Range. Mapped stratigraphic units ranging from Neoproterozoic to Upper Devonian are metamorphosed to amphibolite facies and intruded by myriad granitic to gabbroic bodies of Cretaceous to Oligocene age. The metamorphosed stratigraphic units trace out large recumbent folds in the infrastructure of the complex. An Oligocene to Miocene mylonitic shear zone, hundreds of meters thick, overprints the upper part of the complex. The Ruby Mountains–East Humboldt detachment-fault zone in turn is superposed on the mylonitic shear zone. The detachment-fault zone includes fault slices of the upper part of the stratigraphic sequence (Ordovician to Devonian), metamorphosed to greenschist facies and commonly brittlely faulted. A plexus of higher low-angle-fault slices of unmetamorphosed Upper Devonian to Permian formations defines the upper plate of the detachment fault and forms the upper tier of the core complex.

Pleistocene glacial moraine deposits are present in the mountains, and alluvial-fan and glacial-outwash deposits occur in Lamoille Valley west of the mountains. Vitric fallout ash originally correlated to the 2.1-Ma Huckleberry Ridge Tuff in the Yellowstone Plateau volcanic field occurs low in the exposed alluvial basin sequence. A new ⁴⁰Ar/³⁹Ar date on sanidine yielded an age of 2.35±0.07 Ma, somewhat older than the Huckleberry Ridge Tuff. Normal faults bounding the west side of the Ruby Mountains show offset as young as late Pleistocene and project toward seismically imaged subsurface listric faults.

Geologic map of the Soldier Peak quadrangle, Elko County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the Nevada part of the Boulder Canyon quadrangle, Clark County, Nevada

Author: Michael H. Darin and Barbaros Demircan
Year: 2023
Series: Open-File Report 2023-03
Version: first edition, March 2023; supersedes Open-File Report 2022-01
Format: map sheet: 30.5 x 41 inches, color; text: 10 pages, b/w
Scale: 1:24,000

The Boulder Canyon 7.5-minute quadrangle is located east of Las Vegas, Nevada and almost entirely within the boundary of the Lake Mead National Recreation Area. The south half of the quadrangle overlaps the Nevada-Arizona state line along the north shore of Lake Mead and rugged topography at the northern end of the Black Mountains. The only access to this area is via Northshore Road (Nevada State Road 167), which intersects the north half of the quadrangle, or by boat. New detailed geologic mapping for this report was conducted by the authors between April 2021 and June 2022, and builds on various M.S. theses completed at Northern Arizona University (San Filippo, 2008; Winston, 2016; Demircan, 2019) and the University of Nevada, Las Vegas (Naumann, 1987; Eschner, 1989), as well as detailed geologic mapping in adjacent quadrangles (Anderson, 2003; Duebendorfer, 2003). This report and the accompanying geologic map provide useful insights into the geologic framework of the western Lake Mead structural domain, its complex deformation and magmatic evolution, and the potential for recent Quaternary faulting and seismic hazards proximal to the rapidly expanding Las Vegas urban area and within the Lake Mead National Recreation Area.

Geologic map of the Nevada part of the Boulder Canyon quadrangle, Clark County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the Como quadrangle, Lyon County, Nevada

Author: Michael C. Say and Andrew V. Zuza
Year: 2022
Series: Open-File Report 2022-09
Format: 1 sheet: 39.5 x 27.5 inches, cross section, color; text: 7 pages, color
Scale: 1:24,000

This 1:24,000-scale geologic map of the Como 7.5-minute quadrangle covers part of the northern Pine Nut Mountains in Lyon County, Nevada. The northern Pine Nut Mountains consist of Mesozoic plutonic and sedimentary rocks unconformably overlain by west-tilted Oligocene tuff and a thick-package of Miocene volcanic and sedimentary strata. The range was tilted westward by Miocene east-dipping normal and left-oblique faulting along the middle and eastern flanks of the Pine Nut Mountains.

The map area consists mostly of parallel and conformable west-tilted Miocene volcanic and sedimentary rocks that are ~2 km thick. The volcanic sequence consists of mostly dacite to andesite, with some basaltic andesite. Some dacite-andesite dikes intrude the volcanic rocks. New 40Ar/39Ar dates bracket main volcanic sequence to 14.2–6.8 Ma, with most dates between 8.2 and 6.8 Ma. Miocene strata were deposited on sparse Oligocene ash-flow tuff and the Jurassic Gardnerville Formation. The Miocene sequence was tilted 30°–36° west by several north-striking east-dipping normal faults that must have initiated after ca. 6.8 Ma based on the parallel nature of the volcanic section. Restoration of the faulted strata suggests >14% extensional strain.

The Como mining district is located in the northern Pine Nut Mountains and hosts gold and silver mineralization. Active exploration projects are currently underway throughout the range including the Hercules project. Mineralization is thought to be a low-sulfidation volcanic-hosted epithermal gold and silver deposit. Abundant northeast-striking quartz veins are exposed throughout the Como, Hercules, and eastern flank areas. Large halos of hydrothermally altered volcanic rock envelope quartz veins. Alteration is not observed in the hanging wall of the main eastern fault block.

Geologic map of the Como quadrangle, Lyon County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the eastern flank of the northern Cortez Mountains, Eureka County, Nevada

Author: Russell V. Di Fiori and Sean P. Long
Year: 2022
Series: Open-File Report 2022-06
Format: sheet: 24 x 27.5 inches, color; text: 7 pages, color
Scale: 1:20,000

The Cortez Mountains are located in north-central Nevada, southwest of Carlin (fig. 1). Previous geologic mapping in this region (Smith and Ketner, 1978) and previous stratigraphic studies (e.g., Smith and Ketner, 1976; Suydam, 1988) have defined an extensive exposure of the Early Cretaceous Newark Canyon Formation (NCF) on the eastern flank of the northern Cortez Mountains. In this region of Nevada, there have been differing interpretations of the timing and style of contractional deformation associated with construction of the Cordilleran mountain belt, as well as the potential relationship of the NCF to this deformation. Smith and Ketner (1977) did not observe evidence for contractional deformation in the NCF, and interpreted that regional Mesozoic contractional deformation must have taken place prior to NCF deposition.

Alternatively, Vandervoort (1987) and Suydam (1988) interpreted that the NCF was deposited in isolated basins that formed in response to regional tectonism along the ‘Eureka thrust belt’ (also known as the Central Nevada thrust belt of Taylor et al. [1993, 2000]). The goal of this study is to present map data that illustrate field relations between the NCF and surrounding rock units. We present a new 1:20,000-scale geologic map of the eastern flank of the northern Cortez Mountains that covers ~42 km2 (a ~13 km north–south by ~4 km east–west distance), which covers the extent of exposure of the NCF (fig. 1). To illustrate the deformation geometry of the NCF relative to underlying and overlying rock units, we also present two retro-deformable cross sections. This report is meant to accompany Di Fiori et al. (2021), which characterizes the stratigraphic architecture, deposition timing, and deformation history of three NCF exposures in central Nevada, including the Cortez Mountains exposure. The following report provides descriptions of all rock and surficial units in the map area, with a focus on intraformational members of the NCF that we defined in our mapping, as well as the structural framework and geologic history of the map area and surrounding region.

Geologic map of the eastern flank of the northern Cortez Mountains, Eureka County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the southern Fish Creek Range, Eureka and Nye counties, Nevada

Author: Russell V. Di Fiori and Sean P. Long
Year: 2022
Series: Open-File Report 2022-05
Format: sheet: 33 x 22 inches, cross sections, color; text: 9 pages, color
Scale: 1:15,000

The southern part of the Fish Creek Range is located in central Nevada, ~40 km south of the town of Eureka (fig. 1). Previous studies in the Fish Creek Range (e.g., Merriam, 1967; Hose, 1983; Sans, 1986) have presented differing interpretations of the tectonic significance of Paleozoic, Mesozoic, and Cenozoic rock units exposed in the southern part of the range, including using different naming schemes for Paleozoic sedimentary rock units (e.g., Hose, 1983; Poole et al., 1983) and varying interpretations of the depositional age range and nature (i.e., stratigraphic versus structural) of the upper and lower contacts of the Cretaceous Newark Canyon Formation (NCF) and Paleogene Sheep Pass Formation (e.g., Hose, 1983; Sans, 1986). These Cretaceous and Paleogene sedimentary units are only sparsely exposed in eastern Nevada, and therefore the southern Fish Creek Range is an important field locality that offers a rare opportunity to bracket the timing of Mesozoic and early Cenozoic depositional events. In addition, the southern Fish Creek Range also has been interpreted to lie within the central Nevada thrust belt (CNTB), a system of north-striking, east-vergent thrust faults and folds that branch northward off the Sevier thrust in southern Nevada (fig. 1; e.g., Taylor et al., 1993, 2000). However, to date there have been vastly differing interpretations presented for the geometry, timing, and tectonic significance of contractional structures in the southern Fish Creek Range (e.g., Hose, 1983; Sans, 1986).

The purpose of this study is to present an updated structural and stratigraphic interpretation of rock units in the southern Fish Creek Range. Here, we present a new 1:15,000-scale geologic map, which covers an area of ~21.5 km² and focuses on the outcrop extent of the NCF and Sheep Pass Formation. This technical report, which is meant to accompany the geologic map, presents revisions to the Paleozoic stratigraphy as mapped by Hose (1983), divides the NCF into four mappable members, and presents an updated view of the structural framework of the range, including documenting a previously unmapped thrust fault. In addition, new U-Pb zircon geochronology presented in Di Fiori et al. (2021) provides additional depositional age constraints on both the NCF and the Sheep Pass Formation.

Geologic map of the southern Fish Creek Range, Eureka and Nye counties, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the southern Diamond Mountains, Eureka and White Pine counties, Nevada

Author: Russell V. Di Fiori and Sean P. Long
Year: 2022
Series: Open-File Report 2022-04
Format: sheet: 58.5 x 38.5 inches, color, cross sections; text: 10 pages, color
Scale: 1:24,000

The Diamond Mountains are located in east-central Nevada, east and northeast of the town of Eureka (fig. 1). Early geologic mapping in the surrounding region by Nolan et al. (1962, 1971) revealed exposures of several thrust faults and folds, which have since been interpreted as part of the central Nevada thrust belt (CNTB), a system of N-striking contractional structures that branch northward off of the Sevier fold-thrust belt in southern Nevada (e.g., Taylor et al., 2000; Long, 2012, 2015; Long et al., 2014; Di Fiori et al., 2021). The southern part of the Diamond Mountains have been important for this interpretation, as they contain exposures of the Cretaceous Newark Canyon Formation (NCF), which has long been hypothesized to have been deposited during regional contractional deformation (e.g., Nolan et al., 1956; Vandervoort and Schmitt, 1990; Long et al., 2014; Long, 2015). However, there have been significant variations in interpretations of the style, timing, and magnitude of contractional deformation in the southern Diamond Mountains across multiple generations of studies (e.g., Nolan, 1962; Nolan et al., 1971; Druschke et al., 2011; Long et al., 2014). In addition, several generations of Late Cretaceous to Cenozoic normal faults have extensionally dismembered the region (Long et al., 2015), which further complicates the regional structural architecture.

In this study, our goal is to present an updated view of the structural geometry and deformational and depositional history of this complex region of central Nevada, by presenting a new 1:24,000-scale geologic map of the southern Diamond Mountains that covers an area of ~235 km², including the exposed extent of the NCF (fig. 1). Our field work consisted of new geologic mapping focused on two main exposures of the Newark Canyon Formation, accompanied by compilation and field-checking of key localities on the 1:31,680-scale geologic map of the Eureka 15′ quadrangle (Nolan et al., 1971) and the 1:12,000-scale map of the Eureka mining district (Nolan, 1962). We also present three retro-deformable cross sections, which illustrate the deformation geometry both above and below the modern erosion surface. This map and technical report are meant to accompany Di Fiori et al. (2020), which presents details on the stratigraphy, deposition timing, and deformational history of the NCF in the southern Diamond Mountains. This report presents detailed descriptions of members of the NCF that we defined in our mapping, as well as descriptions of Paleozoic sedimentary rock units, and explains revisions to the older structural interpretations that we have performed in our new work.

Geologic map of the southern Diamond Mountains, Eureka and White Pine counties, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the McClure Spring syncline, central Pancake Range, Nye County, Nevada

Author: Russell V. Di Fiori and Sean P. Long
Year: 2022
Series: Open-File Report 2022-03
Format: map: 29.5 x 29 inches, color, two cross sections; text: 9 pages (one page in color)
Scale: 1:24,000

Documenting the style, geometry, and timing of contractional deformation is critical to understanding how orogenic systems evolve. In the Jurassic-Paleogene Cordilleran orogenic belt, many questions remain regarding the timing and geometry of crustal shortening, particularly within the hinterland region of the Sevier fold-thrust belt in Nevada, where Cenozoic extension has complexly overprinted Cordilleran contractional deformation (e.g., Gans and Miller, 1983; Taylor et al., 1993; 2000; Colgan and Henry, 2009; Long, 2012, 2015, 2019). In particular, the geometry and timing of deformation in the central Nevada thrust belt (CNTB), a system of east-vergent thrust faults and folds that branches northward off of the Sevier thrust belt in southern Nevada (fig. 1), have yet to be resolved along much of the along-strike length of this province (e.g., Bartley and Gleason, 1990; Vandervoort and Schmitt, 1990; Taylor et al., 1993, 2000; Long, 2012, 2015; Long et al., 2014). Near Eureka, Nevada (fig. 1), deformation in the CNTB has been interpreted to be coeval with deposition and folding of the Early Cretaceous Newark Canyon Formation, a sparsely preserved fluvio-lacustrine rock unit (Long et al., 2014; Di Fiori et al., 2020). However, south of Eureka, the timing of motion of the CNTB structures can, in most places, only be bracketed between the Pennsylvanian and Oligocene (Taylor et al., 2000).

The central Pancake Range, located ~50 km southeast of Eureka, lies near the eastern limit of the CNTB (fig. 1). 1:250,000-scale reconnaissance geologic mapping in this range by Kleinhampl and Ziony (1985) revealed the presence of a broad-scale (~10 km minimum north-south length, ~3 km minimum east-west width), N-trending, overturned fold: the McClure Spring syncline. An aerially restricted exposure, the Cretaceous Newark Canyon Formation has been mapped within its hinge zone; however, there is disagreement over whether the Newark Canyon Formation is folded or whether it overlaps the fold (Perry and Dixon, 1993). The existing 1:250,000-scale mapping does not permit evaluation of this important field relationship, which warrants investigation at a more detailed scale. To address this issue, we performed 1:24,000-scale geologic mapping of the full extent of exposed Paleozoic bedrock that defines the McClure Spring syncline (fig. 1). Our map encompasses a north-south extent of ~16 km and an east-west extent of ~5.5 km.

Geologic map of the McClure Spring syncline, central Pancake Range, Nye County, Nevada [MAP AND TEXT] (unr.edu)

Geologic map of the Parran quadrangle, Churchill County, Nevada

Author: James E. Faulds, Richard D. Koehler, Nolan P. Dellerman, and Heather L. Green
Year: 2022
Series: Open-File Report 2022-02
Format: 1 sheet: 38.5 x 28 inches, cross sections, color; text: 6 pages, b/w
Scale: 1:24,000

NBMG geologists James Faulds, Richard Koehler, Nolan Dellerman, and Heather Green completed a detailed geologic map of the Parran 7.5ꞌ quadrangle. The quadrangle is located in the eastern Hot Springs Mountains of Churchill County, Nevada about 80 km northeast of Reno. This area contains the Desert Queen geothermal system, which is a hidden geothermal system (no surface expressions such as hot springs) with temperatures >140°C at depths as shallow as ~150 m. The map area includes the western part of a large composite basin, the Desert Queen basin, and adjacent parts of the Hot Springs Mountains. The detailed mapping has revealed the stratigraphic and structural framework of the area, which is critical to developing a conceptual model for the geothermal system.

In the Desert Queen area, Tertiary volcanic and sedimentary strata rest nonconformably on Mesozoic metasedimentary-metavolcanic and plutonic basement. Quaternary sediments onlap the bedrock units. The Mesozoic basement is exposed directly west of the quadrangle in the footwall of the east-dipping Desert Queen fault zone. An erosional surface of moderate relief (i.e., hundreds of meters) is developed on the Mesozoic rocks, above which rests the Tertiary section. The Tertiary section is a heterogeneous mix of volcanic and sedimentary rocks, with a total of thickness of ~2–3 km. Only middle to late Miocene rocks are exposed in the quadrangle, but Oligocene units have been observed in deep wells in the area and altered sedimentary rocks of probable Eocene age crop out directly west of the map area. Although significant lateral variations exist, the Tertiary section exposed within the quadrangle can be grouped into several discrete packages.

Geologic map of the Parran quadrangle, Churchill County, Nevada [MAP AND TEXT] (unr.edu)