Reply to 'Ar-40/Ar-39 dating of the Rajahmundry Traps, Eastern India and their relationship to the Deccan Traps: Discussion' by A.K. Baksi

We appreciate this opportunity for further discussion\ud of flow and field relations within the Rajahmundry Traps,\ud and their timing relative to Deccan Trap volcanism.\ud Knight et al., 2003a relied on simplified stratigraphic\ud designation and nomenclature for Rajahmundry Trap\ud flows, labeling dUpperT or dLowerT flows relative to the\ud presence of a primary sedimentary interlayer [1]. This\ud designation and its implication of related lava packages\ud may not be strictly valid, as suggested by Baski (this\ud volume), and we present further insight below. Several\ud points of the comment [2] are based on the assumption\ud that a single flow is present for each of the Upper and\ud Lower Rajahmundry Trap units. Both drill hole and field\ud observation, however, suggest otherwise. Multiple flows\ud (as many as 8) of Rajahmundry Trap lavas assigned to\ud both Upper and Lower units are well documented [e.g.,\ud 3–5], often occurring sandwiched between multiple sedimentary horizons above and below the thick (and thus\ud designated as the dmainT) sedimentary interlayer. The\ud assumption of a single flow may hold for the surface\ud exposures of the Upper unit used in the study of [1],\ud where flow boundaries (if present) were not possible to\ud discern. Within Lower unit exposures, however, at least\ud two distinct lava flows were observed and sampled in the\ud field (Fig. 1), and have been reported by multiple authors\ud from [6], to the present. Further geochemical evaluation\ud (discussed here) supports the presence of at least three\ud lava groups. The discussion [2] also presents a re-evaluation of our age data resulting in conclusions identical to those of [1].We stand by our published acceptance and rejection criteria for our data, as well as our quoted errors. Additional graphics relating unpublished geochemical and chronological data [2] are interesting, but\ud cannot be properly evaluated in the absence of the inclusion\ud of the raw data