GSV Report 124 - Buffalo 1:100 000 map area geological report

Category: Geological Survey Reports	Product Code: MP-R-29729
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Abstract The Buffalo 1:100 000 map area lies in the northeastern highlands of Victoria about 200 km northeast of Melbourne. The four geological maps covering this area have been published at 1:50 000 scale and are referred to as MYRTLEFORD, BRIGHT, DANDONGADALE and BUFFALO in this report, with the entire area collectively referred to as BUFFALO. The aim of the maps and report is to document the geological history, structure, stratigraphy and economic potential of the rocks of the region. The mapping was aided by airborne magnetic and radiometric surveys flown at a height of 80 m with a 200-m line spacing. Mapping was conducted between January and May 2000 with follow-up field work in January, April and October 2001.

The region is mountainous with a relief of up to 500 m in the east and south, and more than 1000 m around the Mount Buffalo massif. Relief is low to moderate in the northwest and north of the map area where much of the land is cleared for grazing. The highest points in BUFFALO are on the Mount Buffalo massif with several "peaks" in excess of 1400 m; the Horn is the highest (1723 m). Other high points are Mount Porepunkah (1185 m) in the northeast and Black Range (1195 m) and Mount Emu (1082 m) in the west. Main ridges in the south have ridgetops with numerous points above 1300 m; these are branch spurs of the Main Dividing Range that lies just to the south of BUFFALO. Much of the area is thickly forested, mostly by natural forest but with the lower ridges in the northern half covered by extensive pine plantations. The lower hill country in the northwest and the subdued Happy Valley is mostly cleared for grazing, and the fertile alluvial flats along the Ovens, Buffalo and Buckland rivers support a mixture of grazing, viticulture, tobacco and hop farming. Mining of both alluvial and reef gold was historically important in BUFFALO but is currently restricted to minor retreatment of tailings. Past mining left its mark on the landscape, particularly as changed levels, pits and banks in the sluiced and dredged alluvium along the valleys of the Ovens and Buckland rivers and Morses Creek. Sand and gravel for construction are currently obtained from a few pits in river alluvium and hard rock for roadmaking from Palaeozoic sedimentary rock and hornfels.

Access varies considerably, with the northern half of the area covered by a network of all-weather roads and tracks. The pine plantations have dense networks of logging roads, although in some places these have become inaccessible through disuse. The southern half is accessible by all-weather roads along Buckland River and Buffalo River and to the foot of Mount Typo. Major ridges and many spurs have four wheel drive tracks, mostly of good quality. Least accessible are the upper reaches of the Dandongadale River and Yarrarabula Creek, areas of geological importance because of their structural complexity.

The new 1:50 000 maps are based on 1:25 000 topographic maps published by VICMAP (Survey and Mapping Victoria) in the 1980s. Road and track information on these maps is, with rare exceptions, very accurate. Where appropriate, tracks have been changed to show their present position. While Global Positioning System information has been used throughout the duration of the project, the Selective Availability function that was operative during most of the project meant that GPS positions were commonly hundreds of metres off the true positions. In the latter stages of field work, with Selective Availability discontinued, the accuracy of satellite position information made it possible to map at a much finer scale, with an accurate, often to within a few metres, position obtained in a few minutes, even in moderately forested terrain. Without such information it would have been impossible to achieve the detail in mapping the Upper Devonian rocks.

All grid references are stated as AMG easting and northing, using the AGD66 datum.

Bibliographic reference VandenBerg, A.H.M., Willman, C.E., Morand, V.J., McHaffie, I.W., Simons, B.A., Quinn, C. and Westcott, A., 2004. Buffalo 1:100 000 map area geological report. Geological Survey of Victoria Report 124, GeoScience Victoria.