Jardine River Orford Bay Queensland
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DEPARTMENT OF NATIONAL RESOURCES BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS DEPARTMENT OF MINES, STATE OF QUEENSLAND GEOLOGICAL SURVEY OF QUEENSLAND 1:250 000 GEOLOGICAL SERIES-EXPLANATORY NOTES .. JARDINE RIVER ORFORD BAY QUEENSLAND SHEETS SC/54-15 AND SC/54-16 INTERNATIONAL INDEX COMPILED BY B. S. POWELL & 1. SMART AUSTRALIAN GOVERNMENT PUBLISHING SERVICE CANBERRA 1977 DEPARTMENT OF NATIONAL RESOURCES .MINISTER: THE RT HoN. J. D. ANTHONY, M.P. SECRETARY: J. SCULLY BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS DIRECTOR: L. C. NOAKES ASSISTANT DIRECTOR, GEOLOGICAL BRANCH: J. N. CASEY DEPARTMENT OF MINES, STATE OF QUEENSLAND MINISTER: THE HoN. R. E. C.o\MM, M.LA. UNDER-SECRETARY: J. T. WOODS GEOLOGICAL SURVEY OF QUEENSLAND CHIEF GovERNMENT GEOLOGIST: R. J. ALLEN ISBN 0 642 02845 I Published for the Bureau of Mineral Resources, Geology and Geophysics by the Australian Government Publishing Service _ MANUSCRIPT RECEIVED: MAY 1975. ISSUED: JULY 1977 Printed by Graphic Services Pty Ltd, 516-518 Grand Junction Road, Northfield, S.A. 5085 Explanatory Notes on the Jardine River and Orford Bay Geological Sheets Compiled by B. S. Powell and J. Smart The Jardine River and Orford Bay 1 :250 000 Sheet areas are bounded by latitudes 11 ·oo•s and 12·oo•s and longitudes 141 ·oo'E and 144.00'E. The total land area of both Sheet areas is about 9600 km 2 • Geologically, nearly all of the area lies within the Mesozoic Carpentaria and Cainozoic Karumba Basins, with a small area of the Palaeozoic of the Coen Jnlier in the southeast corner. There are no towns, main roads, or railways in the area and only two pastoral stations have been established, both in the Orford Bay Sheet area. Land access is poor, with a track along the Coen-Bamaga telephone line, and a few tracks east wards from it. Heathlands homestead is served by a regular air service from Cairns. The area is covered by aerial photographs at 1 :50 000 nominal scale taken in 1958 and 1965, and at 1:80 000 nominal scale taken in 1971. Planimetric maps. at 1:250 000 scale are available from the Division of National Mapping, Canberra. A small area in the southeast of Orford Bay Sheet area was geologically mapped by a combined Bureau of Mineral Resources (BMR) and Geological Survey of Queensland (GSQ) field party in 1967 and a preliminary map at 1:250 000 scale issued in 1968. The remainder of the Sheet area and J ardine River Sheet area were mapped in 1972 and 1973 by another combined BMR and GSQ field party, resulting in further 1 :250 000 preliminary maps being issued in 1974. These notes are based mainly on the work of the latter party. PREVIOUS JNVESTIGA TJONS The first geological observations in the Sheet areas were made by ship-borne explorers such as Jukes (1847), Stokes (1846), and Rattray (1869), who noted crystalline rocks near Cape Grenville and the adjacent islands. Kennedy's ill-fated expedition was the first to travel through the area overland, but few geological observations were made (MacGillivray, 1852). Jack (1881) reported on the rocks found during an expedition which crossed the area in 1880. In 1902, C. F. V. 1ackson visited the west coast of Cape York Peninsula and recorded laterite at Vrilya Point and in the Weipa area (J ackson, 1902). Jack ( 1922) gave a comprehnsive history of early geological investigations and mining in Cape York Peninsula. Whitehouse ( 194 7) noted the existence of bauxite in the area. The area is included in Sheet 7 of the Atlas of Australian Soils (Isbell, Webb, & Murtha, 1968). More general reports of the area have been given by Jensen (1923), Richards & Hedley (1925), Bryan & Jones (1946), David (1950), Hill (1956), Hill & 3 Denmead (1960), and Jcnsen (1964). Welded tuff from Clerke Island near Cape Grenville (Orford Bay Sheet area was described by Jones & Jones (1956); Patter son (1957) examined beach sands along the east coast. In 1964 geologists of Australian Aquitaine Petroleum examined the Mesozoic rocks of the Carpentaria Basin in the Orford Bay Sheet area (Australian Aquitaine Petroleum Pty Ltd, 1965, 1967); concurrent seismic and gravity surveys were confined to the adjacent Cape Weymouth and Weipa Sheet areas, but associated aeromagnetic coverage included all Sheet areas north of latitude 14 o south (Adastra Hunting Geophysics Pty Ltd, 1964; Compagnie Generale de Geophysique, 1965). Other aeromagnetic and seismic surveys in the offshore part of Orford Bay Sheet area were conducted by Gulf Interstate Overseas Ltd ( 1962, 1965) and Tenneco Australia Inc. (1967, 1968); and in the Gulf of Carpentaria by Marathon Petro leum (Aust.) Ltd (1965). In 1963-4 the U.S. Navy carried out reconnaissance gravity and magnetic surveys of the Gulf of Carpentaria, which included the off shore part of the Jardine River Sheet area (U.S. Naval Oceanographic Office, 1967). A regional helicopter gravity survey across both Sheet areas was carried out for BMR in 1966 (Shirley & Zadoroznyj, 1974). Meyers (1969) provided a general account of the Carpentaria Basin. Pinchin ( 1973) reviewed most of the geophysical work done to date. Since the late 1950s there has been considerable exploration for bauxite in Cape York Peninsula, including some over the lateritized areas in the J ardine River and Orford Bay Sheet areas. Most of the areas of economic bauxite are held under mining leases and information remains confidential, but there are reports on some areas on open file at the Queensland Mines Department. Clappison ( 1972) des cribed a reconnaissance survey of the eastern side of Orford Bay Sheet area for bauxite and beach sands, and of the northern part of the J ardine River and Orford Bay Sheet areas for bauxite. Gunn ( 1972) reported on drilling for bauxite offshore in the J ardine River and Weipa Sheet areas. Studies of the bauxite within the Sheet areas are described in an unpublished report by Miller (1957), but numerous studies have been carried out in areas to the south (McAndrew & Edwards, 1956; Edwards, 1957, 1958; Baker, 1958, 1961; Evans, 1959, 1965; Loughnan & Bayliss, 1961; Grubb, 1971; MacGeehan, 1972; Plumb & Gostin, 1973). Systematic regional mapping of Cape York Peninsula by combined BMR-GSQ field parties began in 1966, and by 1968 the pre-Mesozoic rocks of the Peninsula Ridge (Coen Inlier) and Cape York/Oriomo Ridge had been mapped (Trail, Willmott, Palfreyman, Spark, & Whitaker, 1969; Willmott, Palfreyman, Trail, & Whitaker, 1969, 1973). The small area of pre-Mesozoic rocks in the Orford Bay Sheet area was mapped in 1967. In 1972 and 1973 another BMR-GSQ field party mapped the Mesozoic and Cainozoic rocks of the Jardine River and Orford Bay Sheet areas. Field work in 1973 included shallow stratigraphic drilling and auger drilling both in these Sheet areas and areas to the south (Gibson, Powell, & Smart, 1974; Smart, Powell, & Gibson, 1974). Doutch (1973) discussed the petroleum potential of the Carpen taria Basin. The geology of adjacent Sheet areas is reported by Willmott & Powell (in press a, b) and Smart (in press). 4 PHYSIOGRAPHY The 7 physiographic units of the area are shown in Figure 1 and described below. The McHenry Uplands, an elevated area of dissected Mesozoic sandstone surrounded by the Bamaga-Shelburne Lowlands, are similar to the Richardson Uplands of Doutch et al. (1973). The McHenry Uplands are bounded to the south west and southeast by steep escarpments; the top of the southeast scarp is the Great Dividing Range. The northern margin is less sharp and merges gradually with the Lowlands. The maximum height measured by helicopter gravity survey was 146 m near Sailor Creek, though there is a considerable variation in elevation over the area. The Uplands are well drained, with a high density of streams, many of which are fed by permanent springs. Most of the drainage has a dendritic pattern, and the streams are markedly incised, owing to a late Pleistocene drop in sea level. A possible nick point is present near the headwaters of a small creek just north of Hunter Hill in the Orford Bay Sheet area; but most waterfalls examined in the field could be the result of resistant rocks. The highly irregular courses of smaller streams within broader valleys is attri- .. buted to joint control, though meandering induced by low stream gradients is apparent in larger rivers such as the McHenry and Jardine. The valleys of these two larger rivers have been infilled by alluvium when base level was higher during a raised Pleistocene sea level; they now appear to be actively eroding their valley fill. Headward erosion of streams has led to the formation of several shallow drainage basins separated by scarps or, more commonly, low gentle watersheds. Most streams are at present depositing little of their load onshore. The present surface of the Uplands has formed by removal of the Tertiary laterite capping the ancestral Weipa Plateau. The deep weathering profile of the Plateau is now represented by highly ferruginized cappings on a few sandstone mesas within the Uplands. Subsequently the erosion surface below the Plateau remnants was affected by an episode of ferruginization in the Pliocene (Tpf). West of the Bamaga telephone line, the oldest laterite surface (T&Qa) merges with this ferruginized, dissected surface and the boundary is difficult to distinguish as there is no marked topographic break or change in air-photo pattern. This suggests that the period of laterite weathering which ferruginized the Helby Beds also affected the remnants of the Tertiary laterite surface on the east and west coasts. The Bamaga-Shelburne Lowlands is low undulating sandstone country that surrounds the McHenry Uplands; it is bounded by the coastal Dunefields in the east, the Mer1una Plain in the south, the Weipa Plateau in the west, and the Jardine Swamps in the north (Fig.