Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Nonconformity

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: 19:30 - 20:30 (01:00)
Source: Annenberg/CPB Resources - Earth Revealed - 8. Earth's Structures
Keywords: "Dee Trent", nonconformity, unconformity, "geologic structure", erosion, "sea level change", "tectonic activity", deposition, "metamorphic rock", "igneous rock", "sea level change", erosion, "sedimentary rock", contact

Our transcription: Another kind of unconformity is a nonconformity.
This is the one that represents the greatest lapse of time between the formation of the underlying rocks and the overlying rocks.
Nonconformities are those in which crystalline rocks, either metamorphic or igneous rocks, primarily plutonic rocks, are overlain by sedimentary rocks.
Plutonic rocks and metamorphic rocks form deep in the Earth 10, 15 kilometers deep.
And in order for them to be at the surface, there has to have been the removal of all the overlying rocks.
So this takes many millions of years, and maybe tens of millions of years, and eventually those rocks reach a surface where they're exposed to erosion.
Then, a return of the oceans will result in sedimentary rocks being deposited on top of them.
So the time lapse there is immense, and the advance in the number of events that have occurred are really phenomenal.
Whole mountain ranges are built, and then worn away, and then covered over.

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 04:28:24 PDT 2013  (chd)