Time calibration of Triassic/Jurassic microfloral turnover, eastern North America Reply
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چکیده
Evidence from sedimentation rates and stratigraphic ranges of palynomorph species indicate that van Veen is incorrect in inferring a condensed section at the Triassic/Jurassic (TR / J ) boundary in the Newark Supergroup. Van Veen bases his argument entirely on the ranges of palynomorph species in western Europe, but correlation of the European sections is equivocal, and the range data employed by van Veen can also be used to argue against a hiatus in the Late Triassic of the Newark Supergroup. Ranges of Late Triassic species compiled by Brugman (1983) for western Europe (Fig. 1) contradict van Veen 's s tatement that vesicate pollen (e.g. Vallasporites ignacii Leschik, 1955, Enzonalasporites vigens Leschik, 1955, and Patinasporites densus Leschik, 1955) disappear at or below the base of the Rhaetian. Enzonalasporites vigens and Patinasporites densus are present until the latest Rhaetian, albeit in decreased abundances. In addition, comparison of the European and North American ranges of the Late Triassic index species Granuloperculatipollis rudis Venkatachala and G6czfin, 1964 and Ovalipollis pseudoalatus (Thiergart) Schuurman, 1976 indicate that the Newark basin sections are best placed within the Rhaet ian stage. Regarding the absence of European Rhaet ian index species (e.g. Ricciisporites tuberculatus and
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Time calibration of ~riassic/~urassic ~icro~ora~ turnover, eastern North America
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