Sea-level change across the Cretaceous-Tertiary boundary, a chimera?

Author(s): Olsson, Richard K.; Miller, Kenneth G.; Browning, James V.; Wright, James D.; Cramer, Benjamin S.
Author Affiliation(s): Primary:
Rutgers-State University of New Jersey, Department of Geological Sciences, Piscataway, NJ, United States
Volume Title: Geological Society of America, 2001 annual meeting
Source: Abstracts with Programs - Geological Society of America, 33(6), p.99; Geological Society of America, 2001 annual meeting, Boston, MA, Nov. 1-10, 2001. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Major regression of sea-level has been inferred at Cretaceous-Tertiary (K-T) boundary sections in the Gulf Coastal Plain where some workers place a sequence boundary. However, the discovery of the K-T asteroid impact at Chicxulub, Mexico and continuous cored material from New Jersey yield new insights that requires reinterpretation of sea-level across the boundary. The devastating effect of a high-energy impact (earthquakes, tsunami, ejecta) caused features of deposition (ejecta deposits, tsunamites) and erosion (surface of erosion, slumps) at the K-T boundary in the Gulf Coast. This has made it difficult to determine whether the impact also coincided with a significant change in sea-level. The record in New Jersey is clearer where the K-T boundary lies in the Bass River borehole within an unconformity-bounded, depositional sequence (age ca. 69.1 to 64.5 Ma). A 2.2 m.y. hiatus separates this sequence from underlying Campanian sequences while a ca. 1.5 m.y. hiatus separates Danian Zone P1a from Zone P1c and younger sequences. A 6-cm-thick spherule layer, marks the K-T at this site. Benthic foraminifera indicate that during deposition of the K-T sequence relative sea-level fell from 100-150 m above present sea-level in the lower part of the sequence (transgressive systems tract) to ca. 50 m (highstand systems tract) at the K-T. Three significant events are inferred from the K-T depositional record at Bass River: 1) a ∼5°C warming of sea-surface temperatures perhaps began about 500 k.y. and ended about 22 k.y. before the K-T; this warming may be related to the main outpouring of the Deccan Traps in India, 2) the K-T event was clearly caused by an asteroid impact at Chicxulub, and, 3) a tsunami event influenced the NJ margin, possibly triggered by massive slumping on the Atlantic slope. There was no significant change, if any, in sea-level across the K-T.
Year of Publication: 2001
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Asia; Bass River; Benthic taxa; Burlington County New Jersey; Cenozoic; Chicxulub Crater; Climate change; Cretaceous; Danian; Deccan Traps; Foraminifera; Gulf Coastal Plain; Impacts; India; Indian Peninsula; Invertebrata; K-T boundary; Leg 174AX; Lithostratigraphy; Lower Paleocene; Mass movements; Mesozoic; Microfossils; New Jersey; Ocean Drilling Program; Paleocene; Paleoclimatology; Paleogene; Protista; Regression; Sea-level changes; Sea-surface temperature; Sequence stratigraphy; Slumping; Spherules; Stratigraphic boundary; Tertiary; Tsunamis; Unconformities; United States; Upper Cretaceous
Coordinates: N393700 N393700 W0742600 W0742600
Record ID: 2004013224
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