(Table 1) Biostratigraphic zonation and core depth of microtektite occurrences in marine sediment sequences

• Main Authors: Keller, Gerta, DHondt, Steven, Vallier, Tracy L
• Format: Dataset
• Language: English
• Published: PANGAEA 1983
• Subjects: 10-94; 15-149; 17-167; 25-242; 31-292; Caribbean Sea/BASIN; Deep Sea Drilling Project; Depth; bottom/max; sediment/rock; top/min; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Gulf of Mexico/SCARP; Indian Ocean//CHANNEL; Leg10; Leg15; Leg17; Leg25; Leg31; Nannofossil zone; North Pacific/CONT RISE; North Pacific/Philippine Sea/CONT RISE; PC; Piston corer; Planktic foraminifera zone; RC09; RC09-58; Robert Conrad; Sample code/label; Sample code/label 2; Antarctic; Indian; Pacific; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.772149; https://doi.org/10.1594/PANGAEA.772149

Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago); and three are of middle Oligocene age (31 to 32 million years ago). In addition, rare probable microtektites have been found in sediments with ages of about 36.0 to 36.5 million years. The microtektite horizon at 37.5 to 38.0 million years can be correlated with the North American tektite-strewn field, which has a fission track age (minimum) of 34 to 35 million years and a paleomagnetic age of 37.5 to 38.0 million years. There is no evidence for mass faunal extinctions at any of the microtektite horizons. Many of the distinct faunal changes that occurred in the middle Eocene to middle Oligocene can be related to the formation of the Antarctic ice sheet and the associated cooling phenomena and intensification of bottom currents that led to large-scale dissolution of calcium carbonate and erosion, which created areally extensive hiatuses in the deep-sea sediment records. The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time.