Some New Tertiary Radiolaria from Antarctic Deep-Sea Sediments

Abstract

Systematic descriptions of fifteen new species and one new subspecies of Tertiary Antarctic Radiolaria are presented in this paper. These Radiolaria, ranging in age from Oligocene to Pleistocene, are constituents of the biosiliceous sediments collected from 16 holes drilled in the ocean floor during Leg 28 of the Glomar Challenger. In addition, several are designated as index fossils in a proposed radiolarian zonation. Some new Tertiary Radiolaria from Antarctic deep-sea sediments INTRODUCTION Systematic descriptions of fifteen new species and one new subspecies of Tertiary Radiolaria are presented in this paper. These Radiolaria are constituents of the southern high-latitude fauna extracted from the sediments recovered by Leg 28 of the Deep Sea Drilling Project. This cruise represents the first of five expeditions by the Glomar Challenger into Antarctic waters. The pre-Pliocene sediments recovered during this leg have not previously been collected by other coring techniques. Therefore some Radiolaria in the drilling cores have been made available for examination for the first time. It is anticipated that subsequent legs of the Glomar Challenger may recover siliceous sediments of similar ages. Consequently, it is desirable to establish the taxonomy of previously undescribed Radiolaria discovered in the recovery from the drill holes of Leg 28 at the earliest possible time. A more detailed treatment of the total radiolarian assemblages observed in these sediments will be presented in the initial reports of the Deep Sea Drilling Project for Leg 28. Sixteen holes at eleven sites were drilled in the Australian sector of the Antarctic during Leg 28 (text-figure 1 and table 1). All of the drilling sites yielded Radiolaria of varying abundance and preservation. Much of the recovery from holes drilled on or adjacent to the Antarctic continental rise (Holes 268, 269 and 269A) and on the Ross Sea shelf (Holes 270, 271, 272 and 273) contained only sparse quantities of Radiolaria because of the masking effects of terrigenous components. Other intervals in these holes were barren of Radiolaria. Moderately well-preserved Radiolaria were found only in restricted stratigraphic levels on the Naturaliste Plateau (Holes 264 and 264A), where calcareous sediments dominate. Holes drilled on the flanks of the Southeast Indian Ridge or in deep basins far from the Antarctic continent (Holes 265, 266, 267, 267A and 267B) generally had substantial amounts of well-preserved Radiolaria. Radiolaria in Leg-28 sediments range in age from Eocene to Pleistocene. Eocene radiolarian-bearing sediments are present at Site 264, the only site drilled north of the Antarctic Polar Front. This radiolarian assemblage is similar to but less diverse than Eocene low-latitude assemblages, yet it is approximately correlatable with the zonation of Riedel and Sanfilippo (1970). None of these Eocene Radiolaria is treated in this paper. Sediments ranging in age from Oligocene to Pleistocene were recovered from sites drilled south of the Antarctic Polar Front (Sites 265 to 274). The radiolarian biostratigraphy established by Hays and Opdyke (1967) has been micropaleontology, vol. 20, no. 4, pp. 480-492, pis. 1-4, october, 1974 480 This content downloaded from 157.55.39.17 on Thu, 01 Sep 2016 06:08:07 UTC All use subject to http://about.jstor.org/terms