Early to early-middle Paleocene diatom zonation

Gordon, A. L., and Molmelli, E. 1975. LI.S.N.S. Eltanin southern ocean oceanographic atlas. Palisades, N.Y.: Lamont-Doherty Geological Observatory. Hays, J. D., Imbrie, J., and Shackleton, N. J. 1976. Variations in the Earth's orbit: Pacemaker of the ice ages. Science, 194, 1121-1132. Heezen, B. C., Tharp, M., and Bentley, C. R. 1972. Morphology of the Earth in the Antarctic and subantarctic (Folio 16). Antarctic map folio series. New York: American Geographical Society. Kellogg, T. B. 1980. Paleocimatology and paleo-oceanography of the Norwegian and Greenland Seas, glacial-interglacial contrasts. Boreas, 9, 115-137.

Rodman, M. 1977. Hydrology of the southeast Indian-antarctic ocean. Unpublished doctoral dissertation, Columbia University. Schnitker, D. 1979. The deep waters of the western North Atlantic during the past 24,000 years, and the re-initiation of the western boundary undercurrent. Marine Micropaleontology, 4, 265-280. Streeter, S. S., and Shackleton, N. J. 1979. Paleocirculation of the deep North Atlantic: 150,000 year record of benthic foraminifera and oxygen-18. Science, 203, 168-171. Sverdrup, H. V., Johnson, M. W., and Fleming, R. H. 1942. The oceans-Their physics, chemistry and general biology. Englewood Cliffs, N.J.: Prentice-Hall.

Early to early-middle Paleocene diatom zonation

Combos (1977) established three tentative late Paleocene diatom zones from the southwestern Atlantic. This article reports on an early to early-middle Paleocene diatom zonation based on submarine deposits of site 208 and nearly completes a Paleocene diatom zonation. Site 208 of leg 21 of the DSDP was located on the northern part of the Lord Howe Rise at 26°06.61'S 161°13.27'E at a water depth of 1,545 meters (figure 1). Of the 255.4 meters of cored sediments recovered from this site, 21 meters (cores 29 through 31) were referred to as early (Danian) to middle Paleocene age on the basis of calcareous nannofossils (Martini 1971). Generally, the Paleocene sediments consist of gray, siliceous fossilbearing and nannofossil-bearing radiolarite or diatomite. Disconformities occur above and below this section between the middle-middle Eocene/early-middle Paleocene and the Mesozoic and Cenozoic (Burns et al. 1973). From a moderately well-preserved diatom assemblage recovered from this Paleocene section, diatom microflora of over 40 species distributed in 16 genera were recognized (dePrado 1981). We propose four new diatom zones for the early to early-middle Paleocene sections. They are (in ascending order): the Hemiaulus caracteristicus s.l. partial range zone; the Notiostyrax tasmanos partial range zone; the Riedelia ? cylindrica partial range zone; and the Stephanopyxis conici local range zone (figures 2 and 3). This work was supported in part by National Science Foundation grant DPP 79-11304 (to H. Y. Ling).

CONNIE A. DEPRADO and HsIN Yi LING Department of Geology Northern Illinois University DeKaIb, Illinois 60115

Knowledge of Paleocene diatoms is still in its infancy, primarily because Paleocene deposits bearing siliceous microfossils are extremely rare, both on land and under the sea. With the exception of Combos' (1977) report of late Paleocene diatoms from hole 327A of leg 36 of the Deep Sea Drilling Project (DSDP), which is by far the most comprehensive and readily accessible reference to date, information regarding Paleocene diatom biostratigraphy is limited and inconclusive and comes almost solely from the land outcrop sections.

25°S 0208 NEW GUINVA

b

I

_"___;,

91

CORAL SEA NIW 'b• CALEDONIAN

References 31°S

I

208 I -I

AUSTRALIA

1000 KILOMETERS

0206 AT THE IQUATOS

207 'IlL_

NEW TASMAN ISEA ZEALAND

Figure 1. Location map for site 208 of leg 21 of the Deep Sea Drilling Project. Contour Interval of bathymetric insert, 300 fathoms (after Mammerlckx et al 1971).

124

Burns, R. E., Andrews, J. E., van der Lingen, G. J., Churkin, M., Galehouse, J . S., Packham, G. H., Davis, T. A., Kennett, J. P., Dumitrica, P., Edwards, A. R., and von Herzen, R. P. 1973. Site 208. In R. E. Burns et al., Initial reports of the Deep Sea Drilling Project, Vol. 21. Washington, D.C.: U.S. Government Printing Office. dePrado, C. A. 1981. High-latitude Paleocene diatoms of the southern oceans. Unpublished masters thesis, Northern Illinois University. Combos, A. M., Jr. 1977. Paleogene and Neogene diatoms from the Falkland Plateau and Malvinas Outer Basin. In P. F. Barker et al., Initial reports of the Deep Sea Drilling Project, Vol. 36. Washington, D.C.: U.S. Government Printing Office. Mammerickx, J., Chase, T. E., Smith, W. L., and Taylor, I. L. 1971. Bat hymetry of the South Pacific. Charts 11-12. LaJolla, Calif.: Scripps Institution of Oceanography. Martini, E. 1971. Standard Tertiary and Quaternary calcareous nannoplankton zonation. In A. Farinacci (Ed.), Proceedings of the II Plankton Conference, Rome. Rome: Edizioni Tecnoscienza.

ANTARCTIC JOURNAL



SITE 208

TAXA

CALCAREOUS

0.

0

c DIATOM NANNOFOSSIL

00

,

Z -

Z w 0 Q) — . 0-

d—

0

ZONES

0.

AGE

ZONES

.

V .: v su Q.

() 2 .

0

In

9.

0

In - 0 so 0 E E

E

. E

4)CL 0 0 0 so 0

-

°'

0. C) Q) a) ... 0)

I Cs) --

4 72 —74

NO ZONE

29 5 70 -72

Fasciculithus

Sr ephanopyxis conic' LRZ rympaniformis

____I !

6 70-72 1 70-72

I I

Riedelia ? cylincirica

I I

2 80-82

MIDDLE PALEOCENE

• I

• •

PRZ Prinsius

3 72-74

30 - 4 80-82

mart ni, Notiostyrax tasmanos

5 70-72

• •

6 70-72 2 70 — 72 31 3 102 - 104

RARE COMMON

PALEOCENE

PRZ

•

EARLY

Hem,au/us caracteristicus s i.

ABUNDANT

PRZ

Chiasmolithus danicus_

Figure 2. Early (Danlan) to early-middle Paleocene diatom zones proposed In the present study showing ranges of key and selected species and correlation with the calcareous nannofossil zones of Martini (1971). Rare = less than 2 percent; Common = 2 to 10 percent; Abundant = greater than 10 percent of the total diatom assemblage.

CALCAREOUS NANNO FOSSIL ZONES FA SC IC UL ITH US YMPANIFORMIS

PRINSIUS MARTINII

F POCH Last occurrence of Stephanopyxis conicj ii. sp.

D D P L F A L E 0 E C A R E L N Y E

Stephanopyxis conici

LRZ

Initial occurrence of Stephanopyxis conici

n.sp.

Riedelia ? cy/indrica

PRZ Initial occurrence of Riedelia 7 cylindrica

n. sp.

Notiostyrax tasmanos

PRZ Initial occurrence of Notiostyrax tasmanos

n.sp.

Hernia u/us caracteristicus s.I.

C HIASMOLITHUS DANICUS

PRZ

Initial occurrence of Hemiaulus caracteristicus s.l.

Figure 3. Definitions of the early (Danian) to early-middle Paleocene diatom zones from the southwestern Pacific. PRZ = partial range zone; LRZ = local range zone. (Calcareous nannofossil zones are after Martini 1971.)

1981 REVIEW

125