The Journal of Foraminiferal Research; April 2008; v. 38; no. 2;
p. 162-182; DOI: 10.2113/gsjfr.38.2.162
© 2008 Cushman Foundation for Foraminiferal Research
CHRONOSTRATIGRAPHIC FRAMEWORK FOR UPPER CAMPANIAN-MAASTRICHTIAN SEDIMENTS ON THE BLAKE NOSE (SUBTROPICAL NORTH ATLANTIC)
Brian T. Huber1,4,
Kenneth G. MacLeod2 and
Nataliya A. Tur3
1 Department of Paleobiology, MRC-121, Smithsonian Museum of Natural History, Washington, DC 20013-7012
2 Department of Geological Sciences, University of Missouri-Columbia, Columbia, MO 65211
3 All-Russian Geological Institute (VSEGEI), Sredny pr., 74, St.-Petersburg, 199106 Russia
4 Correspondence author. E-mail: huberb{at}si.edu
A new chronostratigraphic framework is presented for upper Campanian-Maastrichtian pelagic sediments cored at DSDP/ODP Sites 390A/1049, 1050, and 1052, which were drilled across a 1300-m depth transect on the Blake Nose (subtropical western Atlantic Ocean). The planktonic foraminiferal zonation is based on standard global biozones for this interval, but rare and sporadic occurrence of two zonal biomarkers, Gansserina gansseri and Globotruncana aegyptiaca, precludes reliable identification of the nominate zones for those species. The Pseudoguembelina palpebra Partial-range Zone is defined as a means of subdividing this upper Campanian biostratigraphic interval. Planktonic foraminiferal, calcareous nannofossil and paleomagnetic datums are integrated to construct reliable age-depth curves for each of the Blake Nose drill sites. These age models are largely confirmed by Sr-isotopic data and suggest significant unconformities at various positions within the sections. Compilation of stable isotope datasets for this time interval from the Blake Nose sites reveals no significant shifts in
18O and
13C at the time of the inoceramid bivalve extinction (now dated as 68.5–68.7 Ma in the Blake Nose sections) and no correlation with proposed Campanian-Maastrichtian glacial intervals. However, benthic warming associated with Deccan volcanism during the late Maastrichtian is supported.
Copyright © 2009 by Cushman Foundation for Foraminiferal Research