Cretaceous/Paleogene boundary bathyal paleo-environments in the central North Pacific (DSDP Site 465), the northwestern Atlantic (ODP Site 1049), the Gulf of Mexico and the Tethys; the benthic foraminiferal record

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doi: 10.1016/j.palaeo.2005.03.031
Author(s): Alegret, Laia; Thomas, Ellen
Author Affiliation(s): Primary:
University College London, Department of Earth Sciences, London, United Kingdom
Florida International University, United States
Wesleyan University, United States
Volume Title: Paleobiotic changes in Earth history and their causes
Volume Author(s): Lamolda, Marcos A., editor; Maurrasse, Florentin J. M. R.; Paul, Christopher R. C.
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, 224(1-3), p.53-82; International conference on Bioevents; their stratigraphic records, patterns and causes, Caravaca de la Cruz, Spain, June 3-8, 2003, edited by Marcos A. Lamolda, Florentin J. M. R. Maurrasse and Christopher R. C. Paul. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. Includes appendix. 91 refs.; illus., incl. sects., 2 tables, sketch maps
Summary: Uppermost Maastrichtian benthic foraminiferal assemblages (>63 µm) are diverse, indicating mesotrophic conditions in lower bathyal DSDP Hole 465A (Hess Rise, central North Pacific), in 4 lower bathyal land sections in central-East and Northeastern Mexico, and in the upper to middle bathyal Agost section (Tethys area, Southeastern Spain). They indicate more eutrophic conditions in lower bathyal ODP Hole 1049C (Blake Nose, Northwestern Atlantic). Benthic foraminifers did not suffer significant extinction at the K/Pg boundary, but diversity and heterogeneity of the assemblages and the percentage of infaunal morphogroups decreased drastically in all sections, with the exception of DSDP Hole 465A where the percentage of infaunal taxa increased. These faunal changes probably reflect the effect on the benthic faunas of a widespread decrease in the food supply to the sea floor, as a result of the collapse of primary productivity at the K/Pg boundary. The decrease in food supply apparently affected the benthic faunas least at more eutrophic NW Atlantic ODP Site 1049 and at Pacific DSDP Site 465, which is distal from the impact site of the K/Pg bolide on the Yucatan Peninsula. At these sites the faunas recovered within the Parvulorugoglobigerina eugubina Biozone (∼100 ky), although diversity and heterogeneity remained low through the early Danian, possibly indicating environmental stress. This stress might be related to a high or fluctuating food supply by primary producers that could not easily be used by the benthos, such as various bloom species of dinoflagellates. Benthic assemblages recovered more slowly (∼300 ky) in the Mexican and Spanish sections. Low oxygen conditions after the K/Pg boundary could be inferred from the benthic assemblages at Agost (Southeastern Spain) only. A short episode of hypoxia, however, may be obscured at Pacific DSDP Hole 465A by drilling disturbance, and in the Mexican sections and Hole 1049C by incomplete sections due to downslope transport. Benthic foraminiferal assemblages thus appear to have been affected by the collapse of primary productivity at the K/Pg boundary to a different extent in different regions, and took different lengths of time for their recovery after the boundary. Abstract Copyright (2005) Elsevier, B.V.
Year of Publication: 2005
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Agost Spain; Assemblages; Atlantic Ocean; Bathyal environment; Benthic taxa; Betic Cordillera; Biostratigraphy; Cenozoic; Cretaceous; DSDP Site 465; Deep Sea Drilling Project; Europe; Foraminifera; Gulf of Mexico; IPOD; Iberian Peninsula; Invertebrata; K-T boundary; Leg 171B; Leg 62; Lower Paleocene; Marine environment; Mesozoic; Mexico; Microfossils; North Atlantic; North Pacific; Northwest Atlantic; ODP Site 1049; Ocean Drilling Program; Pacific Ocean; Paleo-oceanography; Paleocene; Paleoecology; Paleoenvironment; Paleogene; Protista; Southeastern Spain; Southern Europe; Spain; Stratigraphic boundary; Tertiary; Tethys; Trophic analysis; Upper Cretaceous
Coordinates: N300832 N300832 W0760644 W0760644
N334914 N334914 E1785508 E1785508
Record ID: 2005062762
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands