Tag Archive | publications

Deal of the Week—April 30 through May 6

Deal of the Week
http://pubs.nbmg.unr.edu/dealoftheday.asp

Geology of Northern Nye County, Nevada
http://pubs.nbmg.unr.edu/Geol-northern-Nye-Co-p/b099a.htm

Mineral Resources of Northern Nye County, Nevada
http://pubs.nbmg.unr.edu/Mineral-northern-Nye-Co-p/b099b.htm

Free delivery to the University of Nevada, Reno campus.

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NBMG

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Publication Sales and Information Office – Closed December 22–29, 2017

The Publication Sales and Information Office at Great Basin Science Sample and Records Library will be closed the week of December 22–29, 2017.

Please note the additional day of closure on Friday December 22.

No orders will be filled during this time period. If you will need any publications before January 2, 2018, please place those orders by December 19 to give us time to fill them before the week that we are closed.

Order online by December 19:
http://pubs.nbmg.unr.edu/

or

Order by phone by December 19:
775-682-8766 (Tues-Fri, 8-4, PST)

If you need to visit the Geological Society of Nevada office during the closure, please contact Laura Ruud:
gsn@gsnv.org
775-323-3500

The NBMG 2018 Nevada Geology Calendar is also available for sale at these locations in Reno—in case you need a last-minute gift during the times that our office is closed:

Wolf Store at UNR
Sundance Books and Music
The Flag Store

Many NBMG publications are available for viewing/downloading on our website:
http://www.nbmg.unr.edu
http://pubs.nbmg.unr.edu
http://www.nbmg.unr.edu/Maps&Data/index.html

You can view/download topo maps free on these pages:
USGS
http://store.usgs.gov
https://ngmdb.usgs.gov/topoview/

National Geographic—FREE Printable USGS PDF TOPO! Maps
http://www.natgeomaps.com/trail-maps/pdf-quads

We will be open our normal hours again on Tuesday January 2, 2018. We apologize for this inconvenience.

New USGS Professional Paper 1832 – Eruptive History, Geochronology, and Post-Eruption Structural Evolution of the Late Eocene Hall Creek Caldera, Toiyabe Range, Nevada

Authors: Joseph P. Colgan[usgs.gov] (USGS) and Christopher D. Henry (NBMG)
Year: 2017
Series: U.S. Geological Survey (USGS) Professional Paper 1832
Format: Report: viii, 43 p.; figure; data release
ISSN: 2330-7102 (online)
View/download here: https://pubs.er.usgs.gov/publication/pp1832[pubs.er.usgs.gov]
http://pubs.nbmg.unr.edu/Eruptive-Hall-Creek-caldera-p/usgs-pp1832.htm

hallcreekcaldera

Abstract: The magmatic, tectonic, and topographic evolution of what is now the northern Great Basin remains controversial, notably the temporal and spatial relation between magmatism and extensional faulting. This controversy is exemplified in the northern Toiyabe Range of central Nevada, where previous geologic mapping suggested the presence of a caldera that sourced the late Eocene (34.0 mega-annum [Ma]) tuff of Hall Creek. This region was also inferred to be the locus of large-magnitude middle Tertiary extension (more than 100 percent strain) localized along the Bernd Canyon detachment fault, and to be the approximate location of a middle Tertiary paleodivide that separated east and west-draining paleovalleys. Geologic mapping, 40Ar/39Ar dating, and geochemical analyses document the geologic history and extent of the Hall Creek caldera, define the regional paleotopography at the time it formed, and clarify the timing and kinematics of post-caldera extensional faulting. During and after late Eocene volcanism, the northern Toiyabe Range was characterized by an east-west trending ridge in the area of present-day Mount Callaghan, probably localized along a Mesozoic anticline. Andesite lava flows erupted around 35–34 Ma ponded hundreds of meters thick in the erosional low areas surrounding this structural high, particularly in the Simpson Park Mountains. The Hall Creek caldera formed ca. 34.0 Ma during eruption of the approximately 400 cubic kilometers (km3) tuff of Hall Creek, a moderately crystal-rich rhyolite (71–77 percent SiO2) ash-flow tuff. Caldera collapse was piston-like with an intact floor block, and the caldera filled with thick (approximately 2,600 meters) intracaldera tuff and interbedded breccia lenses shed from the caldera walls. The most extensive exposed megabreccia deposits are concentrated on or close to the caldera floor in the southwestern part of the caldera. Both silicic and intermediate post-caldera lavas were locally erupted within 400 thousand years of the main eruption, and for the next approximately 10 million years sedimentary rocks and distal tuffs sourced from calderas farther west ponded in the caldera basin surrounding low areas nearby. Patterns of tuff deposition indicate that the area was characterized by east-west trending paleovalleys and ridges in the late Eocene and Oligocene, which permitted tuffs to disperse east-west but limited their north-south extent. Although a low-angle fault contact of limited extent separates Cambrian and Ordovician strata in the southwestern part of the study area, there is no evidence that this fault cuts overlying Tertiary rocks. Total extensional strain across the caldera is on the order of 15 percent, and there is no evidence for progressive tilting of 34–25 Ma rocks that would indicate protracted Eocene–Oligocene extension. The caldera appears to have been tilted as an intact block after 25 Ma, probably during the middle Miocene extensional faulting well documented to the north and south of the study area.

This publication was prepared in cooperation with the Nevada Bureau of Mines and Geology.

Nevada Active Mines and Energy Producers

Authors: John L. Muntean and David A. Davis
Year: 2017
Series: Open-File Report 2017-01
Version: supersedes Open-File Report 2014-01 (second edition)
Format: 31 x 34.5 inches, color
Scale: compilation at 1:1,000,000
View/download here: http://pubs.nbmg.unr.edu/NV-active-mines-and-energy-2017-p/of2017-01.htme60
Site locations and information on this map were obtained from a variety of published and non-published sources with the last updates made in January 2017. All sites shown on this map have had some form of production activity during 2016.

The map includes the names of the mining districts shown with a symbol marking the center of the district polygon—which does not necessarily represent the center of mining activity in that district. Mining district locations are taken from NBMG Report 47, Mining Districts of Nevada.

This map was prepared in cooperation with the Nevada Division of Minerals.

New Geologic Maps in Northern Nevada: Mount Rose NW and Herder Creek Quadrangles

 

mrnw

Preliminary Geologic Map of the South Half of the Mount Rose NW Quadrangle, Washoe County, Nevada

 Authors: Nicholas H. Hinz and Alan R. Ramelli
Year: 2016
Series: Open-File Report 16-6
Format: plate: 35 x 29 inches, color; text: 3 pages, b/w
Scale: 1:24,000
View/Download/Buy: http://pubs.nbmg.unr.edu/Geol-south-half-Mount-Rose-NW-p/of2016-06.htm

This quadrangle straddles the north end of the Carson Range directly west-southwest of Reno and abuts the Nevada-California border. The Truckee River and Interstate 80 transect the northwest quarter of this quadrangle. This quadrangle also encompasses part of the rural community along Thomas Creek in the southeast quarter, and segments of the Steamboat irrigation ditch and part of the City of Reno urban area fall within the northeast corner.

The bedrock exposures in the quadrangle consist of Mesozoic granitic basement and Tertiary volcanic and sedimentary rocks. The Tertiary section includes a complex section of lavas, intrusions, and volcanic sedimentary rocks. Many of these volcanic and sedimentary rocks were derived from a ~6-7 Ma ancestral Cascades volcanic center in the Mount Rose quadrangle, directly south of this quadrangle. Plio-Pleistocene basaltic andesite lavas and rhyolite domes locally rest on the late Miocene volcanic rocks in the middle part of the quadrangle. Principal surficial deposits include late Pliocene to modern alluvial fan and fluvial deposits, Quaternary glacial deposits, and late Quaternary mass wasting deposits. Notable deep-seated landslide complexes reside in all major drainages—including Thomas Creek, Hunter Creek, Bronco Creek, and the smaller catchments along the west edge of the quadrangle. Most of the Carson Range is west-tilted with west-dipping Cenozoic strata. However, within the Mount Rose NW quadrangle, the dip domain flips and most all the Cenozoic strata dips east with numerous west-dipping normal faults. These west-dipping normal faults are cut by younger east-dipping normal faults of the Mount Rose fault zone on the east side of the range.  East-facing Quaternary fault scarps were observed on the east side of the range and west-facing Quaternary fault scarps were observed on the west side of the range.

This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G15AC00240, 2016.

 herdercreek

Preliminary Geologic Map of the Herder Creek Quadrangle, Elko County, Nevada
Author: Seth Dee and Michael W. Ressel
Year: 2016
Series: Open-File Report 16-5
Format: plate: 33 x 29 inches, color; text: 5 pages, b/w
Scale: 1:24,000
View/Download/Buy: http://pubs.nbmg.unr.edu/Prel-geol-Herder-Creek-quad-p/of2016-05.htm

The map area covers part of Starr Valley, the upper reaches of the Humboldt River, and the northwest part of the East Humboldt Range.

The Ruby Mountains–East Humboldt Range metamorphic core complex is exposed in the high-relief range front in the southeast part of the quadrangle. In this area, the core complex is comprised of intensely metamorphosed and highly attenuated Neoarchean through Mississippian(?) strata, thought to be part of the platform facies of the Proterozoic through Paleozoic passive margin. Contractional structures exposed in the map area are complex and difficult to discern due to overprinted extensional deformation but are likely part of the Winchell Lake nappe (WLN), a kilometer scale, southward-closing recumbent fold-nappe mapped in adjacent quadrangles to the east. Overturned Devonian to Neoproterozoic(?) meta-sedimentary strata exposed at the highest structural levels are interpreted to be in thrust contact with an underlying, upright sequence of Cambrian to Neoproterozoic(?) paragneiss and Paleoproterozoic to Neoarchean(?) orthogneiss in the core of the fold. This structural interpretation matches those from the adjacent Welcome quadrangle (McGrew and Snoke, 2015; NBMG Map 184). Rocks in the upper part of the metamorphic core complex are pervasively overprinted by a WNW-directed mylonitic shear fabric, which records middle to late Cenozoic extensional exhumation from mid-crustal depths. Abundant sills and lenses of less deformed Oligocene to Cretaceous garnet-muscovite leucogranite and biotite monzogranite intrude all metamorphic rocks in the quadrangle.

The west side of the East Humboldt Range is bound by the active, W-dipping Ruby Mountains frontal fault zone, which extends for more than 60 km to the southwest. A west step-over in the Ruby Mountains fault south of the Herder Creek drainage results in a broad, hanging wall uplift underlain by middle-Miocene to Pliocene strata comprised of NE-dipping to flat-lying tuffaceous sandstone, shale, and conglomerate of the Humboldt Formation and younger units. A tephra in the uppermost exposed section yielded a 40Ar/39Ar age on feldspar of 5.15 ± 1.82 Ma.

Repeated late Quaternary surface-rupturing earthquakes along active traces of the frontal fault are recorded by increased uplift and dissection of Quaternary surfaces as a function of relative age. Fault scarps in Holocene deposits have up to 2.5 m of vertical separation while glacial outwash deposits from the two most recent Pleistocene glacial advances have scarp heights ranging from 6 to 32 m. The upper reaches of several drainages have well-preserved glacial moraine deposits that record the Angel Lake and Lamoille glacial advances. Adjacent to the Humboldt River, in the northwest corner of the quadrangle, 3 sets of abandoned terrace surfaces are preserved, including a broad surface comprised of gravel-rich alluvium that was likely deposited during a period of increased discharge during the latest Pleistocene.

This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G15AC00240, 2016.

New Geologic Maps in Clark County: Boulder City and Apex Quadrangles

bc

Preliminary Geologic Map of the Boulder City Quadrangle, Clark County, Nevada

Authors: Seth Dee, Nicholas H. Hinz, R. Ernie Anderson, and Racheal Johnsen
Year: 2016
Series: Open-File Report 16-4
Format: plate: 39 x 29 inches, color; text: 6 pages, some color
Scale: 1:24,000
View/Download/Buy: http://pubs.nbmg.unr.edu/Prel-geol-Boulder-City-quad-p/of2016-04.htm

 A 1:24,000 scale preliminary geologic map of the Boulder City 7.5-minute quadrangle in Clark County, Nevada. This quadrangle covers portions of the southeastern River Mountains, the northern Eldorado Mountains and straddles a segment of the drainage divide between the hydrologically closed Eldorado Valley and the through-flowing Colorado River Basin. Boulder City is located in the northern part of the quadrangle, as is the in-progress Interstate 11, Boulder City Bypass. This publication includes a combination of new mapping and integration with existing mapping by Ernie Anderson.

The bedrock exposures in the quadrangle are dominated by Tertiary plutonic, volcanic, and sedimentary rocks with lesser Proterozoic metamorphic rocks and Paleozoic sedimentary rocks. In the northern Eldorado Mountains the basal volcanic section includes the early to middle Miocene, intermediate to felsic composition Patsy Mine volcanics. The Patsy Mine volcanics are locally intruded by the composite, middle Miocene Boulder City pluton. This pluton is variably hydrothermally altered with actinolite present in altered groundmass and fracture-fill veins. Both the Boulder City pluton and the Patsy Mine volcanics are locally overlain by the middle Miocene Mount Davis volcanics which consist of a syn-extensional, bimodal sequence of lavas and tuffaceous sediments. In the southeastern River Mountains, the Tertiary strata are dominated by the middle Miocene, intermediate to felsic composition Red Mountain volcanics. These rocks are intruded by a middle Miocene granitic stock, which is probably related to widespread hydrothermal alteration of the Red Mountain volcanics. Locally overlying the Red Mountain volcanics are the less altered, intermediate to silicic, volcanics of Bootleg Wash, and unaltered Mount Davis volcanics.

The bedrock in the northern Eldorado Mountains is faulted by numerous north-striking, down-to-east and down-to-west normal faults. The northeast-striking, sinistral Hemenway Wash fault transects the northwest quarter of the quadrangle, separating the Eldorado Mountains from the River Mountains. The Hemenway Wash fault is one of the faults that makes up the >100 km-long, Lake Mead Fault System. In the northernmost Eldorado Mountains, fault strikes curve from N-S to NW and to E-W as they approach the Hemenway Wash fault zone, possibly due to oroclinal flexure. Provisional analysis of new geochronologic and geochemical data acquired in this study indicate that the plutonic and volcanic strata exposed in the southeastern River Mountains may correlate directly to strata in the northern Eldorado Mountain, providing a means to evaluate a range of possible displacements across the Hemenway Wash fault.

Surficial sediments in the quadrangle are largely alluvial fan and pediment deposits ranging from historic to Pliocene in age. Early Pleistocene to late Pliocene surficial deposits are characterized by 2+ m thick pedogenic carbonate horizons, which form resistant geomorphic surfaces on the east side of the Eldorado basin and cap many of the bedrock highlands in the Eldorado range. Fan deposits eroded from altered Boulder City plutonic rocks or from Miocene basin sediments may contain redistributed actinolite-bearing clasts. One possible fault scarp was observed in a late to middle Pleistocene aged fan. No other evidence for Quaternary faulting was recognized in the quadrangle.

This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program under STATEMAP award number G15AC00240, 2016.

apexPreliminary Geologic Map of the Apex Quadrangle, Clark County, Nevada

Author: Robert G. Bohannon
Year: 2016
Series: Open-File Report 16-3
Format: plate: 31 x 32 inches, color; text: 5 pages, color
Scale: 1:24,000
View/Download/Buy: http://pubs.nbmg.unr.edu/Prelim-geol-Apex-quad-p/of2016-03.htm

The Apex quadrangle (1:24,000 scale) is centered approximately 22.5 km northeast of downtown Las Vegas in Clark County, Nevada. Rocks in the quadrangle are exclusively sedimentary and include a mostly conformable sequence of Paleozoic continental shelf and platform rocks in its north half. The south half of the quadrangle is mostly Miocene interior-continental-basin deposits. Dissected alluvial deposits of Quaternary and latest Tertiary age, only the oldest of which are consolidated, discontinuously cover large lowland parts of the quadrangle. The Paleozoic rocks are deformed and in some places overturned by Mesozoic thrust faults associated with the Late Cretaceous Sevier Orogenic disturbance. A large east-vergent thrust fault with a northeast orientation, the Dry Lake Thrust, cuts the eastern half of the quadrangle, where it is mostly concealed by post-Cretaceous deposits. The thrust juxtaposes lower Paleozoic shelf rocks in the hanging wall above upper Paleozoic continental platform rocks in the footwall. Tertiary normal faults are also common and are mostly oriented northeast where they cut Paleozoic rocks. The Miocene beds, most of which post-date the northeast normal faults, are deformed by a few east-west or east-northeast-oriented faults and numerous small folds that are associated with them. The younger faults might be associated with very late-stage movement on the Las Vegas Valley shear zone which projects into the quadrangle from beneath Las Vegas Valley to the east, but the shear zone is otherwise concealed by the Miocene deposits.

Publication Sales and Information Office Closed December 26–30, 2016

GBSSRL_March_2014_Jack_Hursh

NBMG’s Great Basin Science Sample and Records Library (aka “The Gold Building”) at 2175 Raggio Parkway in Reno.

The Publication Sales and Information Office at Great Basin Science Sample and Records Library will be closed the week of December 26–30, 2016.

No orders will be filled during this time period. If you will need any publications before January 3, 2017, please place those orders by December 20 to give us time to fill them before the week that we are closed.

We will be open our normal hours again on Tuesday January 3, 2017. We apologize for this inconvenience.