DID DECCAN VOLCANISM PRE-DATE THE CRETACEOUS-TERTIARY TRANSITION

Nine basalt samples collected from the bottom to the top of a > 2.5 km thick composite section in the western margin of the Deccan Flood bas alt province, India, yield Ar-40-Ar-39 plateau ages between 67 and 62. 5 Ma relative to an age of 520.4 Ma for the monitor standard MMhb-1. T hese ages are consistent with the stratigraphy and comparable to earli er results [1]. They indicate that the lower approximately 2 km thick reversely magnetised lava sequence erupted within approximately 1 Ma c lose to 67 Ma ago and the eruption interval even for the exposed and s urviving units of the Deccan was not less than 3 Ma. With the Cretaceo us/Tertiary boundary as demarcated by Haiti tektites (65.2 +/- 0.1 Ma) [2] and melt rock glasses from Chicxulub crater dated precisely at 64 .98 +/- 0.10 Ma [3] relative to MMhb-1 (age 520.4 Ma), our results on the thick reversely magnetised lava units imply their eruption before the Cretaceous/Tertiary boundary events by more than the 1.0 Ma.