Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Original Horizontality

Skip navigational links
Loading
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: 01:49 - 03:08 (01:19)
Source: Annenberg/CPB Resources - Earth Revealed - 8. Earth's Structures
Keywords: "Nicholas Steno", "Principle of Original Horizontality", deformation, strata, sedimentation

Our transcription: Geologic structures are patterns in the arrangement of rock inside the Earth.
Among the most common patterns is parallel layering seen in sedimentary strata and some volcanic deposits.
One of the key insights leading to the birth of Geology as a modern science concerned the nature of this layering.
In the early Seventeenth Century, Nicholas Steno, a Danish military engineer living in Italy, published an important observation.
He noted that in most places at the bottom of water bodies sediment settles to form continuous flat lying layers.
This explains why young sedimentary strata tend to be horizontal with the youngest layer on top and the oldest at the bottom.
Steno's observation became known as the "Principle of Original Horizontality."
Geologists find this principle useful as a basis for measuring how much deformation has occurred in ancient strata.
If layers are folded, geologists assume that they layers were once nearly horizontal, and that the folding came later.

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 USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/infobank/programs/html/school/moviepage/07.01.03.html
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:28:19 PDT 2013  (chd)