A Tsunami Deposit at the Cretaceous-Tertiary Boundary in Texas
Abstract
At sites near the Brazos River, Texas, an iridium anomaly and the paleontologic Cretaceous-Tertiary boundary directly overlie a sandstone bed in which coarse-grained sandstone with large clasts of mudstone and reworked carbonate nodules grades upward to wave ripple-laminated, very fine grained sandstone. This bed is the only sandstone bed in a sequence of uppermost Cretaceous to lowermost Paleocene mudstone that records about 1 million years of quiet water deposition in midshelf to outer shelf depths. Conditions for depositing such a sandstone layer at these depths are most consistent with the occurrence of a tsunami about 50 to 100 meters high. The most likely source for such a tsunami at the Cretaceous-Tertiary boundary is a bolide-water impact.
- Publication:
-
Science
- Pub Date:
- July 1988
- DOI:
- 10.1126/science.241.4865.567
- Bibcode:
- 1988Sci...241..567B
- Keywords:
-
- Geochronology;
- Hypervelocity Impact;
- Meteorite Craters;
- Tsunami Waves;
- Carbonates;
- Iridium;
- Paleontology;
- Sandstones;
- Texas;
- Geophysics