The Cretaceous-Tertiary boundary transition in the Antarctic Ocean and its global implications

Author(s): Keller, Gerta
Author Affiliation(s): Primary:
Princeton University, Department of Geological and Geophysical Sciences, Princeton, NJ, United States
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 21(1-3), p.1-45. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. 65 refs.; illus. incl. 2 tables, sketch map
Summary: Three Antarctic Ocean K/T boundary sequences from ODP Site 738C on the Kerguelen Plateau, ODP Site, 752B on Broken Ridge and ODP Site 690C on Maud Rise, Weddell Sea, have been analyzed for stratigraphic completeness and faunal turnover based on quantitative planktic foraminiferal studies. Results show that Site 738C, which has a laminated clay layer spanning the K/T boundary, is biostratigraphically complete with the earliest Tertiary Zones P0 and P1a present, but with short intrazonal hiatuses. Site 752B may be biostratigraphically complete and Site 690C has a hiatus at the K/T boundary with Zones P0 and P1a missing. Latest Cretaceous to earliest Tertiary planktic foraminiferal faunas from the Antarctic Ocean are cosmopolitan and similar to coeval faunas dominating in low, middle and northern high latitudes, although a few endemic species are present. This allows application of the current low and middle latitude zonation to Antarctic K/T boundary sequences. The most abundant endemic species is Chiloguembelina waiparaensis, which was believed to have evolved in the early Tertiary, but which apparently evolved as early as Chron 30N at Site 738C. Since this species is only rare in sediments of Site 690C in the Weddell Sea, this suggests that a watermass oceanographic barrier may have existed between the Indian and Atlantic Antarctic Oceans. The cosmopolitan nature of the dominant fauna began during the last 200,000 to 300,000 years of the Cretaceous and continued at least 300,000 years into the Tertiary. This indicates a long-term environmental crisis that led to gradual elimination of specialized forms and takeover by generalists tolerant of wide ranging temperature, oxygen, salinity and nutrient conditions. A few thousand years before the K/T boundary these generalists gradually declined in abundance and species became generally dwarfed due to increased environmental stress. There is no evidence of a sudden mass killing of the Cretaceous fauna associated with a bolide impact at the K/T boundary. Instead, the already declining Cretaceous taxa gradually disappear in the early Danian and the opportunistic survivor taxa (Ch.waiparaensis and Guembelitria cretacea) increase in relative abundance coincident with the evolution of the first new Tertiary species.
Year of Publication: 1993
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Antarctic Ocean; Biologic evolution; Biostratigraphy; Broken Ridge; Cenozoic; Cretaceous; Faunal studies; Foraminifera; Indian Ocean; Invertebrata; K-T boundary; Kerguelen Plateau; Leg 113; Leg 119; Leg 121; Lower Paleocene; Mesozoic; Microfossils; ODP Site 690; ODP Site 738; ODP Site 752; Ocean Drilling Program; Paleocene; Paleoenvironment; Paleogene; Planktonic taxa; Protista; Southern Ocean; Stratigraphic boundary; Tertiary; Upper Cretaceous; Weddell Sea
Coordinates: S305329 S305328 E0933440 E0933439
S624233 S624232 E0824715 E0824714
S650938 S650937 E0011218 E0011218
Record ID: 1993010301
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands