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Brazos River, Texas, Stable Isotope Record

The Brazos River, Texas, K-T stratigraphic section (after Keller et al., 1993) shows negative excursions of the d13C and d18O isotopic records at the beginning at the K-T boundary and persisting for the duration of the main Deccan Traps eruptions. According to (Basu et al., 1993, and pers. comm.), about 90 percent of the Deccan Traps lava pile erupted during a 100,000 to 200,000 year interval beginning at the K-T boundary 65 million years ago. The top of Zone P1a is dated at about 230,000 years after the K-T boundary.

The d13C isotopic record shows a major carbon cycle perturbation coinciding with the duration of the Deccan Traps volcanism. The d18O record, a paleotemperature measuring technique, shows warming coinciding with both the Deccan Traps volcanism and the carbon cycle perturbation.

Copyright © 1995 Dewey M. McLean