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Evaluation of radiometric ages pertaining to rocks hypothesized to have been derived by hotspot activity, in and around the Atlantic, Indian, and Pacific Oceans

By
Ajoy K. Baksi
Ajoy K. Baksi
1
Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Published:
January 01, 2005

Hotspot activity has been invoked to explain a number of geological observations and phenomena. The genetic relationship between hotspots and continental flood basalts, as well as “tracks” in many oceans, appears to be commonly accepted by Earth scientists. One critical test that must be applied to such connections or hypotheses is that the pertinent radiometric data must be robust. Herein I critically reexamine some sets of data in this regard. The pertinent 40Ar/39Ar step-heating data must (1) satisfy rigorous statistical tests for validity and (2) be based on material that can be shown to be fresh or minimally altered. I show that most age data published recently for the Isle of Mull (British Tertiary Igneous Province) are invalid as proper estimates of the crystallization age. I apply a similar mode of examination to rocks thought to represent the tracks of (1) the Yellowstone hotspot, Pacific Northwest, USA, (2) the Tristan da Cunha and Great Meteor hotspots, Atlantic Ocean, and (3) the Kerguelen and Ré-union hotspots, Indian Ocean. Few, if any, valid crystallization ages were recovered. These hotspot tracks cannot be temporally defined. Conclusions based on the data rejected herein, in particular those pertaining to the extrapolated paths of such tracks and the calculation of plate velocities, should be subject to critical scrutiny.

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GSA Special Papers

Plates, plumes and paradigms

Gillian R. Foulger
Gillian R. Foulger
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James H. Natland
James H. Natland
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Dean C. Presnall
Dean C. Presnall
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Don L. Anderson
Don L. Anderson
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Geological Society of America
Volume
388
ISBN print:
9780813723884
Publication date:
January 01, 2005

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