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Victoria University Antarctic Research Expedition Science and Logistics Reports 1979-80: VUWAE 24

Report on diatoms from MSSTS 1 (HTB)

page 27

Report on diatoms from MSSTS 1 (HTB)

Two hundred and thirty samples (approx. 5 cc) were taken from the MSSTS core at Scott Base for fossil diatom analysis. These were treated with Hydrogen Peroxide in the U.S. Thiel Earth Laboratory at McMurdo and smear slides were made using Naphrax as a mounting media.

Fossil diatom fragments occur in at least 60% of the samples. Preservation is poor and identification difficult. No samples have been found which can provide an easy key to the stratigraphy such as occurred in DVDP 10 and DVDP 11. There is so much evidence of reworked Middle Miocene material that this author provisionally interprets the core interval from 35.43 m to 222.43 m as sediments scoured from ancient Miocene fjords during the uplift Of the Transantarctic Mountains.

So far, no Pliocene or Pleistocene diatoms have been found in the 38.43 −222.54 m interval. This suggests a Miocene age for the material even if it has been reworked. Fossil diatoms themselves indicate a Middle Miocene age with close affinities to the RISP J9 cores. No subdivision of this large interval has yet been found except there are some intervals barren of fossil material (148.63 - 167.17 m and 186.09 - 213.70 m).

The upper section 9.71 m - 21.70 m is different. Even though the majority of diatom fragments are similar to those in the lower core, non-marine diatoms occur. The analysis of DVDP 10 & 11 indicates that this flora is a Pleistocene to Early Pliocene flora which lived in terrestrial lakes, or in freshwater lakes wedged between ice shelves and the land, or in freshwater pools on ice shelf surfaces. As yet no definite date can be assigned to this upper section other than to indicate a Pleistocene - Pliocene age.

In August-September a fuller report will be available on the diatom stratigraphy of the MSSTS core. There are some intervals which may provide some control if the diatom fration can be concentrated by heavy liquid techniques.