Major mines of Nevada 2013: Mineral industries in Nevada’s economy, by Rich Perry and Mike Visher, 2014
This is the twenty-fifth of an annual series of summary reports on major mines of Nevada. Sand and gravel operations are not included. Information on employment and production for the calendar year 2013 was provided by the individual mine operators. The Nevada Division of Minerals maintains a complete register of Nevada mines. For further information, contact them at 400 W. King, Suite 106, Carson City, Nevada 89703 or call (775) 684-7040, fax (775) 684-7052, or visit their website at http://minerals.nv.gov.
Map locations of all major mines are shown and an overview of mineral production and its effect on Nevada’s economy is presented.
P-25, $5.00 for a paper copy or available free on the Web:
Article in Geology—by Kreemer and Gordon: Pacific plate deformation from horizontal thermal contraction
This article was recently published in the journal Geology:
Pacific plate deformation from horizontal thermal contraction
By Corné Kreemer (Nevada Bureau of Mines and Geology, and Seismological Laboratory, University of Nevada, Reno) and Richard G. Gordon (Department of Earth Science, Rice University)
Geology, October 2014, v. 42, p. 847-850, first published on August 15, 2014, doi:10.1130/G35874.1
Abstract: The central approximation of plate tectonics is that the plates are rigid, which gives the theory its rigor and predictive power. Space geodetic measurements are consistent with the rigidity of stable plate interiors, but some failures of plate-circuit closure, in particular of oceanic plates, indicate that plates may be measurably non-rigid. We explore the hypothesis that horizontal thermal contraction causes deformation of oceanic plates. Here we show significant expected displacement fields due to thermal contraction for the Pacific plate based on a previously proposed relationship between seafloor age and strain rate and on two end-member assumptions on how strain compatibility is enforced. The predicted maximum 2.2 mm/yr southeastward motion of the northeastern part of the plate relative to the Pacific-Antarctic Rise may contribute to a large part of the non-closure of the Pacific–North America plate motion circuit. Our predicted displacement rates cannot (yet) be confirmed by current space geodetic data and will require seafloor geodesy with 1 mm/yr accuracy. The spatial distribution of predicted moment rate agrees reasonably well with that of intraplate earthquake epicenters, similar to what is observed for plate boundary zones. Our results suggest that plate-scale horizontal thermal contraction is significant, and that it may be partly released seismically.
Both this new article by Kreemer and Gordon listed above and a 2009 article by Chris Henry listed below were on GSA’s “Most-Read Articles during September 2014.”
Uplift of the Sierra Nevada, California
By Christopher D. Henry (Nevada Bureau of Mines and Geology)
Geology, June 2009, v. 37, p. 575-576, doi:10.1130/focus062009.1
Geoff Blewitt has been awarded the Vening Meinesz Medal for 2015.
The medal was established by the European Geosciences Union Division of Geodesy and is the highest award offered in Europe that recognizes distinguished research in Geodesy.
The official announcement of the medal recipients was posted on October 13, 2014 at http://www.egu.eu/news/126/egu-announces-2015-awards-and-medals/ .
A description of the medal and a list of past recipients is given at http://www.egu.eu/awards-medals/vening-meinesz/ .
Congratulations to Geoff!
A message from Craig dePolo: Take a moment to sign up for the ShakeOut, check out the website, and practice protecting yourself on Thursday. There is an old saying that “You Can’t Learn to Dance the Night of the Ball” and this applies to earthquakes. We need all Nevadans to effectively know how to Drop, Cover, and Hold and to have practiced doing this.
A message from the Great Nevada ShakeOut: GET READY! The International ShakeOut Day of Action is Thursday, October 16! Most participate on this day, though your drill may be on any day through the end of the year. More than 560,000 Nevadans have registered so far (24.3 million worldwide). Nevada is tied with last year’s record total, and many more will still register!
If you have not yet done so, please log in to your profile to register for 2014.
Forwarded from Laura Ruud at GSN:
James E. Faulds, State Geologist and Director of NBMG, will be giving a two-part talk at October’s Geological Society of Nevada meeting in Reno.
Part 1. Nevada Bureau of Mines and Geology: Analyzing and Educating for Nevada’s Future
Nevada is richly endowed with natural resources and stunning landscapes, ranging from high alpine mountains to enchanting deserts. It has more mountain ranges, gold, and geothermal resources than any other state. It has some of the largest gold deposits in the world, and its vast geothermal potential could one day be harnessed to produce enormous quantities of electricity. Nevada owes its unique setting to its location within the Pacific-North American plate boundary, where tectonic stresses drive crustal blocks to slide past one another along major faults, akin and related to the San Andreas Fault in California, and also to crustal stretching in the horizontal dimension. These motions make Nevada literally the fastest growing state in the country, as the stretching adds new land at the rate of two acres every decade. Some models predict that the San Andreas fault will eventually shift inland in a few million years and make Nevada home, ultimately allowing the Gulf of California to grow northward and create beachfront property near Reno. All of this activity makes Nevada the third most seismically active state after California and Alaska, with a number of large M 7 earthquakes in our recent past. So large earthquakes are a looming natural hazard that Nevada will continue to face in the coming years.
Studies of Nevada’s geology are therefore important for both public safety in its large dynamic cities (Las Vegas and Reno) and rural communities and to support economic development throughout the state, especially for its mining and renewable energy industries.
The Nevada Bureau of Mines and Geology is responsible for understanding Nevada’s geology and landscapes, assessing its natural resources, and analyzing its earthquake potential and other natural hazards. NBMG is Nevada’s state geological survey. Every state has a geological survey, with 1/3 of them residing at a major university. In Nevada, NBMG resides in the College of Science at the University of Nevada, Reno. The university relationship allows us to be intimately involved in both cutting edge research and education of the next generation of geoscience experts.
Although NBMG resides at UNR, we are a statewide agency that applies its expertise to all corners of the state, including the burgeoning city of Las Vegas in the south, the major gold resources of the northeast, and the earthquake hazards and geothermal resources of the west and northwest within and near the Reno-Carson City urban corridor. Thus, NBMG is relevant to nearly every Nevada citizen, and its work is making Nevada a safer and more attractive home for its people and industries.
Part 2. Favorable Structural Settings of Active Geothermal Systems in the Great Basin Region: Implications for Fluid Flow, Normal Faulting Mechanisms, and Geothermal and Epithermal Mineral Exploration
Active amagmatic geothermal systems of the Great Basin, USA are used to generate electricity and have temperatures overlapping formation of some epithermal mineral deposits (up to and >200°C). We recently completed an inventory of structural settings of known geothermal systems (426 total) in the extensional Great Basin region. Of ~250 categorized fields, step-overs or relay ramps in normal fault zones are the most favorable setting, hosting ~32% of the systems. Such areas have overlapping fault strands, increased fracture density, and thus enhanced permeability. Other common settings include a) normal fault tips (25%), where horse-tailing generates closely-spaced faults and increased permeability; b) fault intersections (22%), where multiple minor faults typically connect major faults and fluids can flow readily through highly fractured, dilational quadrants; and c) accommodation zones (9%), where oppositely dipping normal fault systems intermesh in belts of multiple fault tips and intersections. 3D modeling indicates subvertical conduits of high fracture density in these settings. The primary segments of major faults only host ~1% of the geothermal fields. Quaternary faults lie within or near most fields.
The paucity of geothermal systems along primary fault segments may result from reduced permeability in thick clay gouge and periodic stress release in major earthquakes. Step-overs, terminations, intersections, and accommodation zones represent critically stressed areas, where fluid pathways more likely remain open in breccia-dominated fracture networks. Because stress is not relieved by major earthquakes, abundant microseismicity characterizes fault interaction areas, which precludes pervasive healing of fractures and thus facilitates fluid flow. Increased pore-pressure may also provide a positive feedback mechanism that promotes more frequent but lesser magnitude earthquakes. The association of some young (
The GSN October Membership meeting is this Friday, October 17th at the Reno Elks Lodge, 597 Kumle Lane, Reno, Nevada. Drinks begin at 6 p.m., Dinner at 7 p.m., and Talk begins at 8 p.m.
Meeting details from Laura Ruud, GSN Office Manager:
- Dinner cost is $25/each and reservations are due by 4:00 p.m. on WEDNESDAY, OCTOBER 15TH!
- Please email your reservation to Laura at: firstname.lastname@example.org or call 775-323-3500.
- Any Nevada GSN Student member can eat for free if they make a reservation by the deadline of 4 pm on October 15th.
- The Bar Sponsor for OCTOBER is RUEN DRILLING INC.
Friends of NBMG,
You are invited to join us at the NBMG Open House at Great Basin Science Sample and Records Library on October 15 and 16.
Hope to see you there!
Discover Nevada with Experts from Nevada Bureau of Mines and Geology
Lectures, Displays, and Tours—each night from 5:00 p.m. to 8:30 p.m.
The open house is hosted by the Nevada Bureau of Mines and Geology (NBMG) at the Great Basin Science Sample and Records Library (GBSSRL). It is an opportunity for the general public to discover Nevada and learn more about our dynamic landscapes and unique geology. Nevada is richly endowed with natural resources and has more gold and geothermal resources than any other state. But our evolving landscapes also make Nevada prone to natural hazards, including earthquakes, floods, and landslides. The Nevada Bureau of Mines and Geology is the state’s geological survey and charged with assessing our mineral, geothermal, and oil-gas resources while also analyzing natural hazards to mitigate their effects. The GBSSRL houses vast collections of reports and rock and mineral specimens on Nevada’s geology, resources, and geologic hazards. We welcome the public to our first annual open house on October 15 and 16 to learn more about our unique environment. Informal presentations will address Nevada’s gold deposits (Nevada is America’s True Golden State), geothermal resources (Why is Nevada in Hot Water), and earthquakes (Nevada is Earthquake Country: How to Protect Life and Property). In addition, a field trip on October 11 and 12 will explore the geologic wonders in the Carson City area.
Wednesday, October 15: Nevada Gold
Silver and gold mining began in Nevada in 1859 with the discovery of the Comstock Lode at Virginia City. Although Nevada is well known for the Comstock, Goldfield, Tonopah, and other historic mining camps, the state is currently in the midst of the biggest gold boom in the history of America. More gold has been mined in Nevada in the last 35 years than was ever mined in California. Ironically settlers trekked over most of Nevada’s gold as they rushed to find gold California. We’ll discuss why this gold was missed, how it forms, how one explores for it, and what the Nevada Bureau of Mines and Geology does to help maintain this amazing modern day gold rush.
Nevada: America’s True Golden State (John Muntean)—6:30 p.m.
Why is Nevada in Hot Water: Overview of Nevada’s Vast Geothermal Resources (Jim Faulds)—7:30 p.m.
Displays: Ongoing displays will include samples of ore, geologic maps of mining districts, and maps showing major mines and mineral and geothermal resource potential across the state. Expert geologists will be on hand to answer questions about gold and geothermal deposits and exploration activities in Nevada.
Door Prizes: Gold ore samples, Geologic Map of Nevada, Geologic Map of Virginia City
Thursday, October 16: Nevada is Earthquake Country
Nevada resides in a tectonically active setting, with our landscapes evolving through periodic earthquakes. Nevada is the third most seismically active state in the country and also the fastest growing state, as we add a few acres every decade due to these tectonic events. These events have created Nevada’s beautiful and varied landscapes, endowing it with more mountain ranges than any other state, with environments ranging from high alpine settings to low sandy deserts. We’ll discuss the story behind the scenery, including 1) how tectonic forces are continuously working to modify and enrich our landscapes, 2) why these forces also periodically trigger earthquakes, 3) how we analyze faults to understand their earthquake history and potential, 4) how we measure tectonic strains across the region, and 5) how we can prepare and mitigate the effects of earthquakes.
Nevada is Earthquake Country: How to Protect Life and Property (Craig dePolo)—6:30 p.m.
Tectonic Forces that Shape Nevada: Nevada’s Mini-San Andreas Fault (Bill Hammond, Jim Faulds, and others)—7:30 p.m.
Displays: Ongoing displays will include samples of faults; maps showing earthquake distribution and history; earthquake animations; instruments that record earthquakes and tectonic forces (seismometer and GPS stations); and a “find that fault” exercise. Experts from both the Nevada Bureau of Mines and Geology and Nevada Seismological Laboratory will be on hand to answer questions about Nevada’s earthquakes and evolving landscapes.
Door prizes: Earthquake maps of Nevada, geodetic strain map of Nevada
Other ongoing activities on each day:
- GBSSRL tours
- Rock ID, meet the scientists (3 scientists minimum per night), earthquake movie on a loop, latest maps on display
- Kids rocks and minerals: 5:30-6:30 p.m., teach 5 rocks and 5 minerals to kids and visit the rock garden
This annual Earth Science Week field trip is hosted by the Nevada Bureau of Mines and Geology.
Carson Rocks! – A Sesquicentennial Celebration of Some of our Capital City’s Geological High Points
2014 Earth Science Week Field Trip
October 11 or 12, 2014
Click here to sign up:
National Earth Science Week (ESW) 2014 encourages people everywhere to explore the natural world and learn about the geosciences. The Nevada Bureau of Mines & Geology (NBMG) welcomes you to participate in its seventeenth annual Earth Science Week field trip. In keeping with the National ESW theme, “Earth’s Connected Systems,” this year’s trip will explore geological features in the Carson City area. This year NBMG is partnering with Dr. Winnie Kortemeier of Western Nevada College, who has offered her expertise on interesting geologic sites around Carson City. Also Nevada Division of Minerals geologic staff will participate in the field trip.
The complete field trip guide is available at this site: http://www.nbmg.unr.edu/dox/e56.pdf
Field trip participants should meet at 8:00 a.m. in the parking lot of the Nevada Division of Minerals (NDOM) offices at 400 West King Street in Carson City. The field trip will leave from NDOM at 8:30 a.m.
The trip is free and open to the public. Be sure to bring your own water, lunch, sunscreen, hat, first-aid kit, walking stick, gloves, camera, binoculars, bag or bucket for collecting samples, safety glasses if you use a hammer, and a GPS receiver (optional).
The day’s activity will involve hiking and climbing around rocks so wear appropriate outdoor clothing and sturdy shoes or hiking boots.
This year’s field trip will appeal to people of all ages. Please sign up to attend on either Saturday, Oct 11th, or Sunday, Oct 12th (the same field trip is repeated on two consecutive days). You must sign up online prior to the trip and sign a waiver form. Please print out a paper copy, sign and date, and submit prior to the field trip or bring to the field trip meeting place.
There will be several geologists in attendance to help answer your questions about geology and identify a variety of rocks. There will also be an opportunity to learn more about geocaching and EarthCaching—a high-tech treasure hunting game using GPS devices. If you have a hand-held GPS unit, bring it.
Questions about the field trip? Call D.D. at 682-8772.
For more information about educational activities during Earth Science Week, go to the national Earth Science Week website at: http://www.earthsciweek.org/.
UNR News Story Features ESW Field Trips—October 11 and 12
Nevada geologists host interactive field trip in northern Nevada–Public invited to join a one-day excursion in the Carson City area for Earth Science Week
by Mike Wolterbeek
You may read the story here:
FOR IMMEDIATE RELEASE: October 7, 2014 from University of Nevada Media Newsroom