Pagoda Tillite

The Pagoda Tillite, which is the oldest formation of the Victoria Group in Table 10.7, was deposited during the Late Carboniferous/Pennian on the eroded surface of the Alexandra Formation. The erosion surface is equivalent to the Maya disconformity in the Beacon rocks of southern Victoria Land. In places where the Alexandra Formation was eroded or was not deposited, the Pagoda Formation was deposited directly on the Kukri erosion surface which was polished and striated by the continental ice sheet. 

The Pagoda Tillite is composed of massive, poorly sorted sandstone containing scattered pebbles and cobbles. It is interbedded with layers of sandstone and shale studied by Lindsay (1968,1969,1970a, b) as well as by Frakes et al. (1971). In addition, Coates (1972, 1985) considered the Pagoda Tillite of the Queen Alexandra Range in the context of glacial deposits elsewhere in the central Transantarctic Mountains. 

The ice-flow direction is indicated by grooved and striated bedrock surfaces at the base of the Pagoda Tillite and by the orientation of the long axes of clasts. Lindsay (1970a) reported an ice-flow direction of 168 24 (southeast) which is in good agreement with the ice-flow direction of 155 reported by Frakes et al. (1968) for the Darwin Tillite in the Darwin Mountains of southern Victoria Land. 

The glacial sediments of the Pagoda Formation were deposited during the retreat of the large continental ice sheet in Gondwana. The tillites formed directly by ablation of basal ice, whereas the sandstones, siltstones, shales, and thin carbonate beds formed in ice-marginal lakes and meltwater streams. Some 

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The Pagoda Tillite in the Cumulus Hills was deposited on the eroded surface of the local basement complex consisting primarily of the Granite Harbor Intrusives (Chapter 6, Table 6.1). The Pagoda Formation is composed of tillite interbedded with sandstone containing microfloras of Early Permian (or Late Carboniferous) age (Askin and Schopf 1982). Tht Mackellar Formation which overlies the Pagoda Tillite consists of black shale and fine grained sandstone. It was succeeded by the sandstones of the Fairchild Formation, followed by the Buckley Coal Measures. 

The six calcite samples from the Pagoda Tillite in Table 11.2 analyzed by Lord et al. (1988) and by Faure and Lord (1990) have an average c PDB - -26.4 0.5%o. Converting this value to the SMOW scale by means of Eq. 11.3 yields ... 

The most plausible interpretation of the result of this calculation is that carbonate concretions in the Pagoda Tillite formed in contact with glacial meltwater of the continental ice sheets that covered a large area of Gondwana during the Permian Period. This... 

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