Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Volcanoes Die With Changes In Plate Boundaries

Skip navigational links
Dictionaries: Our Mapping Systems   The USGS and Science Education   USGS Fact Sheets   Topics   Keywords   Data Dictionary   Metadata Dictionary   Computer Terminology   Digital Formats  
InfoBank Terms: Activity ID   activity overview   crew   digital data   formal metadata   lines   metadata   NGDC   port stops   project/theme   region   ship   stations   time   virtual globe   year  
Data Types: bathymetry   biological   geochemical   gravity   ground penetrating radar   imaging   LIDAR   logs   magnetics   metering equipment   navigation   samples   seismic   total station   definitions disclaimer  
Data Formats: ARC coverage   E00   FGDC metadata   gridded/image   imaging   material   scattered/swath   Shapefile   vector/polygon  
Comment: 13:20 - 14:07 (00:47)
Source: Annenberg/CPB Resources - Earth Revealed - 13. Volcanism
Keywords: "James Sadd", volcano, "convergent plate margin", "Panam Crater", gas, eruption, crater, pumice, magma, vent, plug, dome, obsidian, viscosity, silica

Our transcription: Belts of volcanoes have grown, shifted, and died with changes in plate boundaries.
The history of individual volcanoes themselves can be quite complex.
A volcano can look very different at different stages in its development.
Here at Panam Crater, for example, the initial eruptions were gas charged explosions.
They produced this shallow crater surrounded by the rim of pumice that I'm standing on.
Having lost most of its gases, the remaining magma grows slowly out of the vent in the next eruption.
This magma plugged the vent by forming this dome composed of volcanic glass.
This glass known as "obsidian" is the product of an extremely viscous magma.
It is composed almost entirely of silica.

Geology School Keywords
Skip footer navigational links

Coastal and Marine Science Centers:  Pacific   St. Petersburg   Woods Hole  
InfoBank   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:26:36 PDT 2013  (chd)