USGS Science⌕ Search
Home/Archive/USGS

USGS · 70206635

Igneous activity in the Comstock District, Nevada

F. C. Calkins
View original source ↗Export metadata ↓

Abstract

The oldest igneous rocks in the Comstock District are amphibolites probably derived from basalts and of Triassic age. These are intruded by pre‐Tertiary quartz monzonlte and by granodiorite of Sierran facies, the latter not being exposed on the surface but found on mine‐dumps. Igneous activity recorded mainly in volcanic rocks was almost continuous throughout the Tertiary. Its products, in order of age, were as follows: Eocene—Rhyolitic flows aggregating a few hundred feet in thickness: One intrusive plug of rhyolite occurs. Eocene or Miocene—Hornblende‐auglte andesite intrusive into the rhyolite, type locality American Ravine. ©1938. American Geophysical Union. All Rights Reserved.

Explore related subjects

Eos, Transactions, American Geophysical UnionArticle
90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 35.002085° to 42.002207° latitude; -120.005746° to -114.039648° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

F. C. Calkins. 2014-08-18. Igneous activity in the Comstock District, Nevada. https://doi.org/10.1029/tr019i001p00262-1

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2019

Better approaches to managing drought in the American Southwest

The second in a series of USGS Southwest Region (SWR) “Science Exchange” annual workshops, focused on USGS drought science. The participants considered how extreme drought conditions are evolving in much of the American southwest, with an emphasis on integrated drought science planning at the USGS bureau and program levels. The increased need for interdisciplinary science to support resource-management decisions systems, was highlighted. The workshop brought together scientists and program managers from USGS with Bureau of Land Management, National Oceanic and Atmospheric Administration, US Bureau of Reclamation and state water management departments. Key objectives of the workshop were to improve awareness of ongoing drought-science work within the region, highlight the capabilities of USGS-SWR science centers in drought science, and build new relationships to advance best approaches in drought science. Topics covered in presentations and demonstrations were broad-ranging and included monitoring for drought early warning; water use and water production associated with petroleum production; paleo perspectives on drought, and ecological consequences of drought to native fish.

Eos, Transactions, American Geophysical Union↗
USGS2017

Defining opportunities for collaboration across data life cycles

Monitoring natural resources - water, forests, and animal populations—is required to support effective management of natural resources. However, because monitoring activities are often specific to a discipline, issue, or agency, it is typically difficult to integrate data to answer questions that transcend geopolitical and jurisdictional boundaries. How do we reach the better data integration we need?

Eos, Transactions, American Geophysical Union↗
USGS2014

Coastal fog, climate change, and the environment

Coastal marine fog, a characteristic feature of climates generated at the eastern boundaries of ocean basins worldwide, evokes different feelings in those who experience it (see Figure 1). Authors and poets use fog to represent mystery, bleakness, and confusion. Film directors seek out fog to shroud scenes in eerie gloominess. Tourists visiting beaches bemoan the cool and damp conditions that create a striking contrast to the sunny warm conditions typically found less than a few kilometers inland. Airline passengers delayed by fog impatiently wait for the skies to clear. Residents get used to the Sun “rising” in midday after fog dissipates.

Eos, Transactions, American Geophysical Union↗