Bermuda hotspot

The Bermuda hotspot is a supposed midplate hotspot swell in the Atlantic Ocean 500–1,000 km (310–620 mi) southeast of Bermuda,[1] proposed to explain the extinct volcanoes of the Bermuda Rise as well as the Mississippi Embayment[2][3][4] and the Sabine Uplift southwest of the Mississippi Embayment.[5]

A 2002 paper proposes that the Bermuda hotspot generated the Mississippi Embayment in the Early Cretaceous Epoch, when the hotspot strengthened and uplifted the present-day Mississippi Valley. The resulting highland eroded over time, and when North American Plate motion moved the valley away from the hotspot, the resulting thinned lithosphere subsided, forming a trough. The seismic zones centered on New Madrid, Missouri, and Charleston, South Carolina, and the volcanic kimberlite pipes in Arkansas are cited as evidence.[4]

Other published reports[6][7] argue that the lack of a chain of age-progressive seamounts (as in the Hawaiian-Emperor seamount chain), the absence of present-day volcanism, and the elongation of the Bermuda Rise oblique to plate motion are evidence against a hotspot origin for the Bermuda Rise. Others[6] alternatively attribute the Bermuda Rise to a reorganization of plate tectonics associated with the closing of the Tethys Sea, though noting that shallow processes may not explain the source of the magmatism. A more recent paper[7] finds a thinning in the mantle transition zone under Bermuda, apparently consistent with mantle upwelling and a hot lower mantle below Bermuda. A still more recent paper,[8] based on geochemical analysis of a drill core, suggests that Bermuda volcanism sampled a transient mantle reservoir in the mantle transition zone that was formed by chemical recycling related to subduction during the formation of Pangaea.

  1. ^ Vacher, H.L.; Rowe, Mark (1997). Vacher, H.L.; Quinn, T. (eds.). Geology and Hydrogeology of Bermuda, in Geology and Hydrogeology of Carbonate Islands, Developments in Sedimentology 54. Amsterdam: elsevier Science B.V. pp. 35–90. ISBN 9780444516442.
  2. ^ Cox, Randel T.; Roy B. Van Arsdale (January 2007). "The Mississippi's Curious Origins". Scientific American. 296 (1): 76–82B. Bibcode:2007SciAm.296a..76V. doi:10.1038/scientificamerican0107-76. PMID 17186836.
  3. ^ Cox, Randel T.; Roy B. Van Arsdale (1997). "Hotspot origin of the Mississippi embayment and its possible impact on contemporary seismicity". Engineering Geology. 46 (3–4): 201–216. Bibcode:1997EngGe..46..201C. doi:10.1016/S0013-7952(97)00003-3.
  4. ^ a b Cox, Randel T.; Roy B. Van Arsdale (2002). "The Mississippi Embayment North America: A First Order Continental Structure Generated by the Cretaceaous Superplume Mantle Event". Journal of Geodynamics. 34 (2): 163–176. Bibcode:2002JGeo...34..163C. doi:10.1016/S0264-3707(02)00019-4.
  5. ^ Nunn, Jeffrey A. (1990). "Relaxation of Continental Lithosphere: an Explanation for Late Cretaceous Reactivation of the Sabine Uplift of Louisiana-Texas". Tectonics. 9 (2): 341–359. Bibcode:1990Tecto...9..341N. doi:10.1029/TC009i002p00341.
  6. ^ a b Vogt, Peter R.; Woo-Yeol Jung (2007). Origin of the Bermuda volcanoes and the Bermuda Rise: History, observations, models, and puzzles (PDF). Vol. 430. pp. 553–591. CiteSeerX 10.1.1.484.2851. doi:10.1130/2007.2430(27). ISBN 978-0-8137-2430-0. Retrieved 12 August 2008. {{cite book}}: |journal= ignored (help)
  7. ^ a b Benoit, Margaret H.; Maureen D. Long; Scott D. King (2013). "Anomalously thin transition zone and apparently isotropic upper mantle beneath Bermuda: Evidence for upwelling". Geochemistry, Geophysics, Geosystems. 14 (10): 4282. Bibcode:2013GGG....14.4282B. doi:10.1002/ggge.20277.
  8. ^ Mazza, Sarah E.; Esteban Gazel; Michael Bizimis; Robert Moucha; Paul Béguelin; Elizabeth A. Johnson; Ryan McAleer; Alexander V. Sobolev (2019). "Sampling the volatile-rich transition zone beneath Bermuda". Nature. 569 (7756): 398–403. Bibcode:2019Natur.569..398M. doi:10.1038/s41586-019-1183-6. PMID 31092940. S2CID 155103393.