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Victoria University Antarctic Research Expedition Science and Logistics Reports 1968-69: VUWAE 13

Geological Results

Geological Results

During the last decade investigations of Beacon Group rocks have been undertaken alone the entire length of Victoria Land. Naturally enough, the more accessible areas have received a great deal of attention, the more inaccessible have been barely scratched. The Beacon Group exposures in the type area west of McMurdo Sound have witnessed hundreds of investigators. Since 1907, when Ferrar's initial account of these rocks appeared, there have been more than forty papers published on the Beacon sediments of this area alone. The rocks of this area are now quite well known although many stratigraphic and nomenclatural problems remain. The basic stratigraphy is now known through most of Victoria Land and it is now possible to compare, contrast and correlate Beacon Group sediments over great distances. Nevertheless, outstanding differences between areas have emerged.

Important differences in the stratigraphy of the Beardmore and Taylor Glacier areas have been highlighted in recent syntheses. Most of these occur in pre-Permian sediments. For example, tillites were reported north and south of the Beardmore Glacier region but were apparently absent in the Taylor Glacier region; Devonian fish faunas were present just south of the Taylor Glacier area but had not been seen in the Beardmore Glacier region. Later, it became apparent that the stratigraphy of the Beardmore area could be traced as far north as the Darwin Glacier area, i.e. only 150 miles south of the classic Taylor Glacier area. Why then did the tillite of the Darwin Glacier page 15 not continue north to the Taylor area? Clearly, the answer to these and many other problems lay in the intervening area, i.e. the ranges bordering the Skelton Névé. As mentioned earlier, this area had been investigated by Gunn and Warren for about a week in 1953, but much remained to be done. With this in mind it was decided that VUWAE should investigate the critical Boomerang Range area during the 1968/69 season with the aim of
1.providing a more detailed stratigraphy for the lower Beacon Group sediments, i.e. the Devonian, Carboniferous and Permian.
2.improve if at all possible the most promising paleontological collections of fish made by barren in the Boomerang Range.

Despite the great number of Investigators who have visited the Wright-Taylor area, many critical problems had been overlooked or greatly simplified, and much work regained to be done. Therefore, the second phase of this year's geological programme included a re-evaluation of the Beacon Group in the type area. Having done this we were then in a better position to discuss stratigraphic problems between the Boomerang Range in the south and the Olympus Range in the north.

I do not intend to provide detailed results and discussion here. Results may be briefly summarised as follows:
1.Detailed sections, measured with Jacob staff, were prepared at
  • Boomerang Range (3 sections)
  • Warren Range (northern part of)
  • Mt Metschel nunatak
  • Portal Mountain
  • Table Mountain
  • Knobhead (three sections)
  • Aztec Mountain
  • Maya Mountain
  • Kennar Valley (two sections)
  • Mt Planing (two sections)
  • Mt Boreas
  • Mt Electra
  • Mt Aeolus
  • Mt Baldur
  • Mt Thor (two sections)
  • Mt Odin
page 16
2.Devonian fish collections were made at the following localities:
  • Boomerang Range
  • Warren Range (northern part)
  • Portal Mountain
  • Ht Metschel nunatak
  • Aztec Mountain
  • Kennar Valley
  • Mt Fleming

Fish material consists of fin-spines, plates, skull plates, jaws, teeth, etc. These occur in red and green Aztec Siltstone, usually confined to narrow horizons out reworked and disseminated in to higher levels. Concentrated fossil pavements are common at some localities.
3.Permian plant collections were noted and/or made at
  • Warren Range
  • Aztec Mountain
  • Maya Mountain
  • Mt Fleming
4.Devonian lycopod collections were made at lit Fleming.
5.? [sic]Carboniferous tillite was observed at many localities within the Boomerang Range and at barren Range, Mt Metschel nunatak, Aztec Mountain, Maya Mountain, Kennar Valley and Mt Fleming.
6.A distinct regional disconformity separates the top of the tillite (or where this is absent the top of the Aztec Siltstone) from the overlying Permian coal measures. This was traced from north to south over a distance of about seventy miles.
7.Special attention was paid to the lithostratigraphy of Devonian sediments, including a critical re-examination of the Odin Arkose, Boreas Subgreywacke, Beacon Heights Orthoquartzite, and Aztec Siltstone of Webb (1963), the New Mountain Sandstone of Hamilton and Hayes (1963) and McElroy (in press), the Pyramid Sandstone of Hamilton and Hayes (1963), the Terra Cotta Windy Gully member of Seller, Angino and Turner (1961) and the Altar Mountain Formation of McElroy (in press). Most of these formations have their page 17 stratotypes in the Taylor Glacier region: many are synonymous. It is hoped that as a result of this summer's work a more rational nomenclature can be evolved for the lower Beacon Group.
8.Large collections of rock specimens have been made for petrographic analysis. Rock types include arkoses, orthoquartzites, siltstones, claystones, etc.
9.Existing geological maps have been corrected and new data added.