Sequence stratigraphy and sea-level change across the Cretaceous-Tertiary boundary on the New Jersey passive margin

In the New Jersey coastal plain the Cretaceous-Tertiary (K-T) boundary is within an unconformity-bounded Navesink depositional sequence (ca. 69.1-64.5 Ma). At the Bass River, New Jersey, borehole, a 2.2 m.y. hiatus separates the Navesink sequence from underlying Campanian sequences, and an ∼1.5 m.y. hiatus separates Danian zone P1a from zone P1c and younger sequences. A 6-cm-thick spherule layer that contains shocked minerals and an iridium anomaly marks the K-T boundary at this site. Benthic foraminiferal biofacies and biostratigraphy indicate that sedimentation was continuous across the K-T boundary. During deposition of the Navesink sequence, relative sea level fell from 100-150 m above present sea level in the lower part of the sequence (transgressive systems tract) to ∼50 m (highstand systems tract) at the K-T boundary. Three significant events are inferred from the Navesink depositional record: (1) an ∼5°C warming of sea-surface temperatures perhaps related to the main outpouring of the Deccan Traps in India that began ∼500 k.y. and ended ∼22 k.y. before the K-T boundary; (2) the K-T event caused by an asteroid impact at Chicxulub, Mexico; and (3) a tsunami event immediately following the ballistic fallout of tektites from the Chicxulub ejecta vapor cloud, possibly triggered by massive slumping on the Atlantic slope. There is no relationship between these events and sea-level change during deposition of the Navesink sequence.