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Summary: JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 94, NO. B12, PAGES 17,713-17,720, DECEMBER 10, 1989
Limits on the Age of theDeccanTrapsof India From Paleomagnetic
and Plate Reconstruction Data and Their Uncertainties
GARY D. ACTON AND RICHARD G. GORDON
Departmentof GeologicalSciences,NorthwesternUniversity,Evanston,Illinois
Revisedlimitsontheageof theDeccanTrapsof Indiaareprovidedby recentimprove-
mentsto reconstructionsof India relativeto surroundingplatessinceLate Cretaceoustime,
realisticestimatesof theuncertaintiesin theplatereconstructions,andrecentpaleomagnetic
datafromtheDeccansTrapsandfromNorthAmerica.We estimatetheageof theDeccan
TrapsbyrotatingitspaleomagneticpoleintotheNorthAmericanreferenceframe.Different
assumedagesfortheDeccanTrapsresultinverydifferentpositionsforitspaleomagneticpole
relativetoNorthAmerica.ComparingthesepositionswiththeNorthAmericanapparentpolar
wanderpathandaccountingforuncertaintiesinboththepaleomagneticpolesandintherecon-
structions,weplacelimitsontheageoftheDeccanTrapsof62-72Ma,significantlyyounger
thanfoundin severalpriorstudies.The62-72Ma limitsareconsistentwithagesobtained
independentlyfromradiometricdatingandpaleontologyandareconsistentwiththehypothesis
thattheDeccanTrapswereextrudedrapidlyduringreversedpolaritychron29r,whichcon-
rainstheCretaceous-Tertiaryboundary.
INTRODUCTION
The Cretaceous-Tertiary(K-T) boundarymarksa catas-
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