Rapid emplacement of the Kerguelen plume–related Sylhet Traps, eastern India: Evidence from 40Ar-39Ar geochronology

We report for the first time 40Ar‐39Ar plateau ages for the Sylhet Traps of eastern India. Our results provide concordant ages for two samples, vertically separated by ∼200 m, from a tholeiite lava flow sequence. The ages are indistinguishable at 2σ confidence level indicating a rapid emplacement of...

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Bibliographic Details
Published in:Geophysical research letters 2005-05, Vol.32 (10), p.L10303-n/a
Main Authors: Ray, Jyotiranjan S., Pattanayak, S. K., Pande, Kanchan
Format: Article
Language:English
Subjects:
Cretaceous
Effusive volcanism
Geochemistry
Information Related to Geologic Time
Intra-plate processes
Mineralogy and Petrology
Volcanology
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Summary:We report for the first time 40Ar‐39Ar plateau ages for the Sylhet Traps of eastern India. Our results provide concordant ages for two samples, vertically separated by ∼200 m, from a tholeiite lava flow sequence. The ages are indistinguishable at 2σ confidence level indicating a rapid emplacement of these lavas. The weighted mean of the plateau ages associated with least errors, 116.0 ± 3.5 Ma, most likely represents the age of eruption. Clearly, the Sylhet Traps are contemporaneous with the Kerguelen plume generated Rajmahal and Bengal Traps. Our results in conjunction with the existing age data in the Rajmahal‐Bengal‐Sylhet igneous province suggest that the latter experienced widespread, and rapid emplacement of flood basalts at ∼118 ± 2 Ma. Such a large‐scale volcanism would have required a direct involvement of the Kerguelen plume, suggesting that the Kerguelen hotspot was located close to the eastern Indian margin during its initiation.
ISSN:0094-8276
1944-8007
DOI:10.1029/2005GL022586