Shackleton Glacier Area

The basement rocks adjacent to the Shackleton Glacier in Table 5.6 consist of interbedded quartzites, volcanic rocks, and marbles that have been subdivided into several formations described by Wade (1974), Stump (1985), and by Wade and Cathey (1986)  

Henson marble Taylor formation (jreenlee fonnation 

The Taylor Formation was shown to be of Early to Middle Cambrian age by Yochelson and Stump (1977) and by Encamacion et al. (1999). 

Ordovician Intrusive Contact Granite Harbor Intrusives 

The sediment was deposited near-shore in shallow water of a basin that was slowly subsiding. The sediment was derived from an area of low relief as weathering products of granitic rocks. The rocks of the Greenlee Formation dip south at 45° to nearly 90° and may form the limb of a major fold, the axis of which presumably trends east-west. Wade and Cathey (1986) estimated that the thickness of the Greenlee Formation exceeds 13 km provided that the exposure along the Shackleton Glacier is a continuous sequence without repetitions. 

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All investigators agree that the rocks of the Byrd Group were deposited during the Cambrian Period because the Shackleton Limestone as well as the Taylor Formation (in the Shackleton Glacier area) contain fossils of Cambrian age (Laird and Waterhouse 1962 Hill 1964a, b Palmer and Gatehouse 1972 Yochelson and Stump 1977 Debrenne and Kruse 1986). 

Fig. 5.17 The plutons of Hope Granite that intruded the metasedimentary basement rocks of the Shackleton-Glacier area are collectively referred to as the Queen Maud batholith. The modal concentrations of Quartz (Q), alkali feldspar (A), and plagioclase (P) are used to classify a representative collection of the Hope Granite from this area (see also Fig. 3.21, Appendix 3.6.1). The distribution of data points indicates that the Hope Granite consists of granite (field 3), granodiorite (field 4), and quartz diorite (field 5) (Data by Wade and Cathey (1986) and classification of plutonic igneous rocks by Streckeisen (1967))...

Queen Maud Mountains in the Duncan Mountains which will serve as a transition from the geology of the Shackleton Glacier area to the metasedimentary and metavolcanic basement rocks that occur west of the Scott Glacier. 

The Fairweather Formation is younger than the Duncan Formation and was originally described by McCjregor (1965b) as a crushed quartz-sandstone. Stump et al. (1976) classified it as a massive, silicic, porphyritic volcanic rock including nonporphyritic varieties and volcanic breccias. In addition, the Fairweather Formation contains thin beds of marble and chert. Wade and Cathey (1986) considered that the lithologic composition of the Fairweather Formation resembles the Taylor Formation in the Shackleton Glacier area and therefore correlated the two formations as indicated in Table 6.1. 

The Section Peak Formation was deposited on the margins of Rennick basin after that basin was filled by sediment of the Takrouna Formation. The rocks of the Section Peak Formation resemble sedimentary rocks that occur at the top of the Lashly Formation in the Allan Hills (Table 10.2). Collinson et al. (1986) suggested that the Section Peak and Lashly formations are similar to the Late Triassic Falla Formation in the Beardmore and Shackleton glacier areas. 

The Fremouw Formation is widely distributed in the central Transantarctic Mountains and occurs in the Queen Alexandra and Queen Ehzabeth ranges as well in the Dominion and Supporters ranges at the head of the Beardmore Glacier (McGregor 1965a, b). In addition, Collinson and Elliot (1984) mapped the Fremouw Formation in the Shackleton Glacier area of the Queen Maud Mountains. Barrett et al. (1986) estimated that the total thickness of the Fremouw Formation lies between 670 and 800 m. 

TheFaUaFormation of the Beardmore and Shackleton glacier areas is time-equivalent to the Lashly Formation of southern Victoria Land because both formations contain leaves of Dicroidium. However, the tuff beds at the top of the Falla Formation occur only in the Beardmore Glacier area (Barrett et al. 1986). The presence of Dicroidium odontopteroides indicates a Middle to Late Triassic age for the Falla Formation (Townrow 1967). The fossil plants in the Beacon rocks of the Beardmore area were described by Taylor and Smoot (1985a, b), Stubblefield and Taylor (1985), and Pigg and Taylor (1985). 

The Triassic rocks of the Fremouw and Falla formations consist of interbedded sandstone and mudstone some of which are carbonaceous. The volcaniclastic rocks of the Prehble Formation top the sequence and are overlain by lava flows of the Kirkpatrick Basalt of Jurassic age. The Beacon rocks in the Shackleton Glacier area were intruded by voluminous sills of the Ferrar Dolerite. 

The Falla Formation is composed of sandstone, shale, and tufifaceous beds as defined by Barrett et al. (1986) in the Queen Alexandra Range. In the Shackleton Glacier area only the lower part of the formation is present composed primarily of quartz sandstones which... 

The Early Triassic Fremouw Eormation has yielded fossil bones of a wide variety of land-based amphibians and reptiles that inhabited the forests on the coastal plain of East Antarctica. The collecting sites in the Beardmore and Shackleton glacier areas of the central Transantarctic Mountains include Graphite Peak, Coalsack Bluff, the Cumulus Hills, and the Gordon Valley. The most famous Triassic reptile is Lystrosaurus which was a plump little animal about 90 cm long that seems to have been well adapted to digging burrows in the soil. 

Fig. 5.1 The central Transantarctic Mountains include the area between the Nimrod and Beardmore Glaciers. The Byrd Glacier in the north and the Shackleton Glacier in the south are off this map. The basement rocks of this area crop out along the coast and are overlain by sandstones of the Beacon Supergroup farther inland. The only exceptions are the Miller and Geologist Ranges at the head of the Nimrod Glacier (Fig. 5.2) where the Nimrod Group is exposed (Adapted from Gunner 1976...

Fig. 5.16 The Gerasimou Glacier, Epidote Peak, Mt. Greenlee, and Taylor Nunatak in the central part of the Shackleton Glacier are the principal landmarks that identify the type section of the Greenlee and Taylor formations and of the Henson Marble which constitute the Byrd Group of this area. Excerpt of the topographic map entitled Shackleton Glacier, Antarctica, SVl-10/1 S 8400-W-16500/1 x 5 published by the US Geological Survey, Washington, DC...

Burgess CJ, Lammerink W (1979) Geology of the Shackleton Limestone (Cambrian) in the By rd Glacier area. New Zealand Antarctic Record 2(1) 12-16... 

Hill D (1964b) Archaeocyatha from the Shackleton Limestone of the Ross System, Nimrod Glacier area, Antarctica. Roy Soc New Zealand Trans, Geol 2 137-146 lUGS (2002) International stratigraphic chart. Commission on the Geologic Map of the World, UNESCO, United Nations, New York... 

Rowell AJ, Rees MN (1989) Early Paleozoic history of the upper Beardmore Glacier area ImpUcations for a major Antarctic structural boundary within the Transantarctic Mountains. Antarctic Sci 1 249-260 Rowell AJ, Rees MN (1991) Setting and significance of the Shackleton Limestone, central Transantarctic Mountains. In Thomson MRA, Crame JA, Thomson JW (eds) Geological evolution of Antarctica. Cambridge University Press, Cambridge, pp 171-175... 

Barrett PJ (1965) Geology of the area between the Axel Heiberg and Shackleton glaciers, Queen Maud Range, Antarctica. Part 2 Beacon Group. New Zealand J Geol Geophys 8 344-363... 

Two calcites from the Triassic Fremouw Formation have identical 8 C values of -17.9%o and contain a major proportion of biogenic carbon. Apparently, vegetation was abundant and supported amphibians and reptiles whose bones were found in the sandstones of the Fremouw Formation in the area of the Beardmore and Shackleton glaciers. 

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