Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: No Evidence For An Expanding Earth

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: 12:56 - 13:54 (00:58)
Source: Annenberg/CPB Resources - Earth Revealed - 5. The Birth of a Theory
Keywords: "Harry H. Hess", "sea floor spreading", "mid-oceanic ridge", Earth, crust, trench, subduction, "Alfred Wegener", data, geopoetry, paleomagnetism

Our transcription: If mid-ocean ridges were continuously creating new sea floor, it would seem that the Earth must be growing, swelling along the ocean ridges like a ball slowly being inflated.
But scientists saw no convincing evidence for an expanding Earth.
How, then could the excess oceanic crust be explained?
Hess suggested that the ocean floor simply sinks back into the planet at deep marine trenches.
He claimed that this process, now called subduction, destroys the surface formed by sea floor spreading.
Just as Wegener's hypothesis was weakened by lack of data, so, too, was the model of sea floor spreading.
Hess cautiously referred to his own theory as "Geopoetry," but supporting evidence would come from the emerging field of paleomagnetism.

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 04:25:40 PDT 2013  (chd)