Lithospheric drip

A lithospheric drip is a geological phenomenon in which a dense and relatively cold mass of lithosphere sinks into the more fluid upper mantle. The regions of descending material have been detected by seismic tomography methods and modeled as near vertically oriented cylindrical masses within the upper mantle. The lithospheric drip discovered below the Great Basin in central Nevada has dimensions of 100 km diameter by 500 km vertical length.[1][2]

Another area underlain by a descending cylindrical mass of dense lithosphere has been reported in the southwestern Sierra Nevada and portions of the San Joaquin Valley of California. Here a 100 km by 225 km mass of relatively high density (fast p wave velocity) has been discovered below an area of anomalous topography.[3]

References

  1. ↑ National Science Foundation (May 27, 2009). "Dripping 'Blob' Under Western U.S.: A Hidden Drip, Drip, Drip Beneath Earth's Surface". Science Daily. Retrieved January 12, 2016.
  2. ↑ West, John D.; Fouch, Matthew J.; Roth, Jeffrey B.; Elkins-Tanton, Linda T. (2009). "Vertical mantle flow associated with a lithospheric drip beneath the Great Basin" (PDF). Nature Geoscience 2 (6): 439–444. doi:10.1038/ngeo526. ISSN 1752-0894. Retrieved January 12, 2016.
  3. ↑ Saleeby, Jason; Foster, Zorka (2004). "Topographic response to mantle lithosphere removal in the southern Sierra Nevada region, California". Geology 32 (3): 245. doi:10.1130/G19958.1. ISSN 0091-7613. Retrieved January 12, 2016.


This article is issued from Wikipedia - version of the Wednesday, January 13, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.