New Zealand Journal of Marine and Freshwater Research abstracts

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FORAMINIFERAL EVIDENCE FOR A PRE-MIDDLE EOCENE AGE OF THE CHATHAM RISE, NEW ZEALAND

James P. Kennett

Department of Geology, Florida State University, Tallahassee, Florida

Richard E. Casey

San Fernando State College, Northridge, California

Abstract Several sediment samples collected from the crest and slope of the Chatham Rise, and from the Chatham Islands, to the east of New Zealand, contain Globigerina linaperta-Globorotalia increbescens foraminiferal faunas of upper Middle and middle Upper Eocene age. The foraminiferal faunas from the Chatham Islands, which include Recluvigerina, Latibolivina, Dyocibicides, Discorbinella, Patellina, and Wadella, indicate shallow-water palaeodepths, probably equivalent to the outer shelf (50-150 m). A faunal assemblage from near the crest of the rise is likewise indicative of shallow water, although distinct differences in the benthonic foraminiferal ifauna suggest slightly deeper-water biofacies than the Eocene of the Chatham Islands. Tn contrast, a fauna of similar age from 1,100 m on the southern slope of the Chatham Rise contains a much deeper-water benthonic foraminiferal assemblage including Osangularia, Vulvulina, Stilostomella, hispidocostate Uvigerina, and smooth-shelled Bulimina, indicative of lower middle bathyal depths (1,500-2,500 m). The nature and distribution of the assemblages, together with previous work by Norris (1964) and Cullen (1965), indicates that the Chatham Rise has been a significant structure since at least the Middle Eocene, with some uplift occurring since then.

N.Z. .11 mar. Freshwat. Res. 3: 20-28.
12 July 1968

PDF file of entire paper: medium quality (542K); (scanned from paper original: notes about this process)

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