Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Metamorphism

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: 01:17 - 02:29 (01:12)
Source: Annenberg/CPB Resources - Earth Revealed - 18. Metamorphic Rocks
Keywords: "James Sadd", mountain, "plate tectonics", lithosphere, deformation, energy, orogeny, collision, crust, magma, fault, heat, pressure, metamorphism, mineral, composition, "radiometric age", atom, recrystallization, time

Our transcription: Most mountains are forming today in tectonically active regions where the movements of plates deform the rocks of the Earth's lithosphere.
The tremendous energy that's expended in the mountain building process often has a profound effect on the rocks.
The geologic events that accompany mountain building, such as the collisions between plates, deep subsidence of portions of the Earth's crust, moving masses of magma, and the displacement of rock bodies along fault zones focus heat and pressure on the rocks.
As the result, these rocks are changed dramatically.
This process of change by the effects of heat and pressure is called "metamorphism", a term derived from the Greek words "meta," which means "change" and "morph" meaning "form."
Metamorphism changes the appearance of rocks, their mineral composition, and even their age as measured by radiometric dating.
During metamorphism, atoms within the rock can dislodge themselves from mineral lattices and move about freely.
This atomic reshuffling causes the existing minerals to recrystallize and new minerals to form.
This process also resets the radioactive clock within the rock to the time of metamorphism.

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 04:27:12 PDT 2013  (chd)