AEG Monthly Meeting—Thursday, April 19

AEG Great Basin Chapter Student Night 2018
Thursday, April 19th, 2018

Emma McConville, Geology M.S.
Title: Geothermal Potential in Crescent Valley, Eureka County, Nevada

ABSTRACT: Crescent Valley received one of the highest favorability scores in phase I of the DOE-sponsored Nevada play fairway analysis project and was therefore selected for detailed study in phase II. As part of the detailed study, geological, geochemical and geophysical data were collected, synthesized, and analyzed to identify favorable structural settings for geothermal fluids in the basin. A total of nine favorable structural settings were identified. Two host known geothermal systems, and seven could potentially host blind geothermal systems. In phase II a predictive geothermal potential model was conducted for each favorable structural setting. The highest-ranking areas in Crescent Valley are in the Dann Hot Springs step-over (relay ramp), followed by the two northern step-overs along the Cortez Mountains front, as well as a fault intersection at Hot Springs Point.

Dustin Naphan, Geophysics M.S.
Title: Effect of Energy Directionality on ReMi Analysis

ABSTRACT: Seismic surveying methods used to determine shear wave velocities fall primarily into the category of either active or passive, in terms of their source. The purpose of such a survey is often to evaluate building site classification for earthquake shaking hazards, which requires Vs30 estimates at a minimum.  For this reason, practitioners often choose passive methods, due to the locations of survey sites within noisy urban areas. There is debate over the reliability of passive methods compared to those that depend on an active source.  The concern is that the overall directional origin of the source energy relative to array configuration is unknown, and may have the effect of overestimating velocity values in the raw analysis.  In the case of a linear array, some proportion of an omni-directional ambient energy field will allow correct analysis.  Refraction Microtremor (ReMi™) is a passive method that utilizes a linear array.  To explore this issue, we conducted 3D synthetic studies as well as field recordings using an “L” shaped array configuration, consisting of two ReMi™ lines connected at a 90° angle.  Such a geometry allows for analysis of effects from directionality.  The synthetic modeling, which included added noise, demonstrates reliable shear-velocity estimates from cases with as little as 15% omni-directional energy.  Several real-world examples collected from “L” arrays in the Reno-Sparks area demonstrate consistent results regardless of line orientation.  We compiled a large volume of statistical data from the 10,000 ReMi™ surveys collected by Optim SDS for the Las Vegas Earthquake Parcel Map, at various array orientations. A regional analysis resulted in similar hazard-classification statistical distributions among Vs30 estimates, regardless of predominant array orientation.

Co-Authored by: John Louie, Satish Pullammanappallil, Travis West, Aasha Pancha

Jason Craig, Geology M.S.
Title: Discovery and Analysis of a Potential Blind Geothermal System in Southern Gabbs Valley, Western Nevada

ABSTRACT: The southern Gabbs Valley geothermal prospect is a blind thermal anomaly located 5 km north of the Gabbs Valley Range and ~15 km southeast of the Don A. Campbell geothermal power plant in west-central Nevada. The discovery of this blind thermal anomaly was initiated from the development of a detailed geothermal potential map covering 96,000 km² of the Great Basin region. This map synthesized about 9 geologic and geophysical parameters and showed high geothermal potential in southern Gabbs Valley. Subsequent geologic reconnaissance identified areas of favorable structure for hosting a blind geothermal system. Areas displaying complex fault relationships were then targeted for further exploration utilizing a shallow 2-meter thermal survey. The first 2-meter survey incorporated 60 data points in the basin, with one anomalously high-temperature point located in the southern portion of the basin. Water samples were taken from the Diamond A ranch 6 km northwest of the thermal anomaly. These samples yielded a geothermometer of 130-140°C. Additional shallow temperature survey work has been completed constraining the extent of the thermal anomaly and establishing a 7 km² area with elevated 2-meter temperatures. Subsurface data generated from a new gravity survey show that the 2-meter thermal anomaly corresponds to a significant gravity gradient that probably reflects a subsurface fault and possible fault intersection. Exploration of the system is ongoing, and further detailed mapping of bedrock and Quaternary exposures in the area will aid in understanding the structural controls of this potential geothermal system. The integration of geochemical, geophysical, and geologic datasets in this area will elucidate the probability of a commercial-grade geothermal system and produce a conceptual model to be used in the selection of drill targets.

James Ingraffia, Geology M.S. with a Graduate Minor in Business
Title: Lithium and the Lithium Clays of McDermitt Caldera, Nevada

ABSTRACT: The renewable energy revolution has taken off with the advent of lightweight, rechargeable lithium-ion batteries. The demand for lithium used in these batteries has increased exponentially over the last decade and is expected to continue as electric automotives become mainstream and nations such as Germany transition entirely to renewable energy. To supply future lithium demand, mineral exploration has turned to lithium clay deposits like that of McDermitt Caldera, Nevada. Lithium is hosted in the caldera lake sediments, specifically in smectite and illite clays. Estimates of the resource are 2*10^9 million tons of lithium. Current research efforts are aimed at answering the question of origin for the clays: are they hydrothermal or diagenetic, or a combination of the two? Answering this question will have us taking ages of the deposit stratigraphy, examining the deposit mineral assemblages for information of lake conditions, and understanding the dynamics of the McDermitt Caldera lake such that lithium clays could form. These answers will help guide exploration for more caldera-hosted lithium lake sediments.

Members: $27.00
Non-Members: $30.00
Students: $20.00

Phone 360-606-1838
Please give us a 48-hour cancellation notice if you are not able to attend.

Student Sponsors:
Wood Rodgers & Resource Concepts Inc.

We are providing complementary dinners to the first three students who submit RSVP’s. Any additional students will be charged $20.

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.

Selected wine and beer will be served in the meeting room following the Social Hour, compliments of Merrily Graham. The lounge is available for early arrivals at reduced Happy Hour prices.

This is the last meeting of the season, and the Fall/Winter speaker roster will be complete by the end of summer.

Ballots will be sent to members. Gary Luce is relocating to Arizona, and the following positions need to be filled: Vice-Chairperson, Treasurer, and Secretary. I will gladly serve another year to insure an easy transition.

Thank you to all who assisted Gary and myself, those who attended the meetings, the speakers, as well as the sponsors who generously contributed.  A special thank you to Vivi-Anne Brock for her assistance with the meeting announcements.

I also wish to acknowledge Dr. John Louie’s many contributions, including student sponsorships. His guidance as the UNR AEG Campus Advisor has been invaluable in planning “Student Night.”

Sincerely yours,
Merrily Graham
AEG Great Basin Chairperson

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