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Report on the Sixth and Seventh Victoria University of Wellington Antarctic Expedition 1962-63: VUWAE 6 & 7

Beacon Series:

Beacon Series:

Over 1800 feet of low dipping Beacon sediment unconformably overlies the basement. At Bastion Hill the contact of basement and Beacon is well exposed. The granite is weathered to a depth of 6-15 feet below the unconformity. At least 60 feet of quartz pebble sandstone is exposed as the basal formation on Bastion Rill.

Ten miles to the south-west at Darwin Mountains, the most basal formation exposed is about 600 feet of well sorted, finely bedded, cross bedded orthoquartzite. Good specimens of Beaconites antarcticus Vialov are common.

The orthoquartzite is overlain by 200 feet of light green siltstone containing scattered weathered pebbles and boulders of granite and metasediments. Some horizons are made up of very finely banded alternating mudstone and siltstone - microscopic analysis of sections of these may reveal grading, indicating them to be varves. A representative collection of pebbles was made for sectioning in order to establish provenance. The formation is similar to Gridnley's tillite in the Beardmore Glacier area.

The tillite is overlain by a 1 inch to 1 foot layer of pebbles and boulders of weathered granite and metasediment similar to those scattered in the tillite below. The layer represents an erosion interval in which concentration of the pebble-boulders from at least 100 feet of the tillite occurred. Immediately above the pebble band a discontinuous carbonaceous band occurs containing poor leaf and stem impressions of Gloesopteris and Gangamopteris. This in turn is overlain by 2000 feet of massive grey sandstone with thin interbedded grit layers.

The highest Beacon examined was 50 feet of light grey finely banded mudstone and siltstone with occasional pebble bands and contraformational breccias.

Samples of Beacon were collected where favourable throughout the section for spore and pollen analysis.