Springsure Explanatory Notes
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DEPARTMENT OF NATIONAL DEVELOPMENT BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS 1:250000 GEOLOGICAL SERIES-EXPLANATORY NOTES SPRINasURE QUEENSLAND SHEET SG/55-3 INTERNATIONAL INDEX COMPILED BY R. G. MOLLAN AUSTRALIAN GOVERNMENT PUBLISHING SERVICE, CANBERRA 1972 BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS DIRECTOR: N. H. FISHER ASSISTANT DIRECTOR (GEOLOGICAL BRANCH): J. N. CASEY Published for the Minister for National Development, Sir Reginald Swartz, K.B.E., E.D., M.P., by the Australian Government Publishing Service. First printed 1967 Reprinted 1972 Printed by Graphic Services Pty. Ltd., 60 Wyatt Street, Adelaide 5000 Explanatory Notes on the Springsure Geological Sheet Compiled by R. G. Mol/an The Springsure Sheet area is bounded by longitudes 147°E and 148°30'E and latitudes 24 oS and 25 oS; the eastern boundary is 170 miles from the coast near Rockhampton. Springsure, the only town in the area, is 200 miles from Rock• harnpton by road and rail. It is served by a branch railway from Emerald and connected by road to Emerald, Rolleston (Springsure-Duaringa Highway), and Tambo (Central Western Highway). A network of graded roads and station tracks provides good vehicular access in the northern half of the Sheet area, but in the south there are very few tracks. The climate is subtropical. The annual rainfall is extremely variable; the average ranges from 24 inches in the west to 28 inches in the east (Fig. 1).· Most of the rain is cyclonic, and falls in January, February, and March; early summer storms occur from October to December, but the rest of the year is usually dry. The summer is very hot; in the winter, the days are warm but the nights are generally cool to frosty. The vegetation is predominantly of the savannah type with tall grass and an even cover of timber, but it varies in density and type with the soil and underlying rock: the black soil derived from basalt supports grassy downs, and sandstone commonly supports a dense timber cover. Dense brigalow scrub covers parts of the western half of the Sheet area. Cattle raising is the main industry, though several stations run sheep. Wheat and other grain crops are grown in some areas, notably near Springsure, where the land holdings are small. Several large holdings in the western half of the Sheet area are being subdivided and cleared of scrub. The Springsure Sheet area is almost covered by two sets of air-photographs taken by Adastra Airways Pty Ltd, at a scale of about 1 : 85,000. The photo• graphs may be obtained from the Division of National Mapping, Department of National Development. Previous Investigations Geological. These explanatory notes are ba<;ed on combined survevs by the Bureau of Mineral Resources and the Geological Survey of Queensland in 1963 and 1964, the results of which are recorded by Mollan, Dickins, Exon, & Kirkegaard (in press). Before 1930, several geologists made reconnaissance surveys of parts of the Springsure Sheet area. Since 1930 many geologists have mapped the Permian rocks exposed in the Springsure and Serocold Anticlines, and a few have mapped the Devonian-Carboniferous rocks in the Telemon and Nogoa Anticlines. Much of the work was done in the search for oil. * Isohyets shown in Figure 1 are based on data contained in 'Climate' map sheet and booklet, FiW"oy Region, Queensland: Re~'ources Series producecl by the Deoartment of National Development, Resources Information and Dev.lopment Branch, Canberra, 1965. 1 ---------------------------------------------------- -- - - -.-..- Jack (1895), who made the first geological observations in the area, recorded marine fossils at many localities. Richards (1918a) described the volcanic rocks around Springsure. Jensen (1926) made a geological reconnaissance of the Sheet and areas to the east and south, and recognized the Serocold Anticline. Reid (1930) mapped the anticline in detail, and subdivided the Permian rocks into formations; Reves (1936) revised and extended this mapping. The detailed work of Shell (Queensland) Development Pty Ltd is recorded in several unpublished reports: notably Schneeberger (1942), Woolley (1943), and SQD (1952). The first edition qf the Springsure 4-mile Geological Sheet, published by the Bureau of Mineral Resources with explanatory notes by Hill (1957), was based essentially on the work of Shell (Queensland) Development Pty Ltd. Whitehouse (1955) mapped the Mesozoic rocks; Patters on (1955, 1956) mapped the Springsure Anticline in detail; and Webb (1956) reviewed the results of the exploratory wells drilled in the Permian sediments, and incorporated Patterson's stratigraphy. Phillips (1959; and in Hill & Denmead, 1960) mapped the Springsure and Serocold Anticlines; Laing (1961) mapped Reids Dome; and Madden (1960) mapped the Permian rocks on the Springsure Shelf. The Com• pagnie Franco-Africaine de Recherches p6trolieres (Francarep) surveyed much of the Sheet area in 1962. Cundill, Meyers, and Associates made a subsurface study of wells in the Denison Trough related to a survey of the Permian sequence in Reids Dome. Power (1966) has made a similar study of the Permian sequence in the Denison Trough. Palaeontological. The rich invertebrate faunas found in parts of the Permian sequence have attracted much interest. Fletcher (1945a, b) and Dickins (1961) have described the pelecypods; Campbell (1953, 1959, 1960, 1961, 1965) has described the fauna from the Ingelara Formation and the spiriferoids and tere• bratuloids; Maxwell (1954) has described the Strophalosias; Hill (1957, and in unpublished reports of Shell (Queensland) Development Pty Ltd and other com• panies) has identified the marine invertebrate faunas from Permian and pre• Permian rocks; Dear (1962, and in other unpublished reports) has identified fossils from oil wells. Some invertebrate fossils are illustrated in Hill & Woods (1964). Runnegar (1967, in press) & Wass (1967, in press) are currently describing Permian pelecypods and bryozoans. Dickins (App. 1 in Mollan et al., in press) has made a comprehensive list of the marine shelly fossils. Four faunal subdivisions, Faunas I, 11, Ill, and IV, have been rec:ognized by Dickins (1964, and in press) in the marine Permian. Fauna 1I and probably Fauna I are found in the Tiverton Subgroup, Fauna III in the Gebbie Subgroup, and Fauna IV in the Blenheim Subgroup. The three Subgroups of the Back Creek Group (See Table 2) were originally named Units A, B, and C (Dickins, Malone, & Jensen, 1964). The age of the marine sedimen• tation is considered in detail by Dickins (in press). Evans (1964a, b, 1965, and two reports in prep.) has studied the palynology of the Palaeozoic and Mesozoic sediments. White (App. 2 in Monan, Exon, & Kirkegaard, in press; and 1964) has identified and described the plant fossils from the area. Geophysical. The results of a gravity survey of a large part of the Bowen Basin by Starkey & Warren (1959) have been reviewed by Robertson (1961). The results of this survey and of the survey by United Geophysical Corporation (1964) are shown in Figure 3. 2 An airborne magnetometer survey of the area was carried out in 1962 by the Bureau of Mineral Resources (1964). A reflection and seismic survey was carried out in the eastern part of the area by Geophysical Services International (1962), as part of a larger survey for Mines Administration Pty Ltd, mainly in the Baralaba Sheet area. Exploratory Drilling for Oil and Gas. Seven wells have been drilled to the east and south of the Sheet area. AFO Arcturus No. 1 and AFO Inderi No. 1 have produced significant quantities of gas; no oil has been produced. TOPOGRAPHY The elevation of the area ranges from about 700 feet above sea level in the north-east corner to 3340 feet in the Black Alley Range in the south-east. Much of the eastern part of the Great Dividing Range is over 3000 feet above sea level. Five physiographic units have been recognized (Fig. 1). SCALE o 5 10 15MiI•• I I I I REFERENCE TO TOPOGRAPHIC UNITS (He19hts above sea level in brackets) /3500ft:!) Iow';._. __ [JJ]] Dissected fob/elands ~ floooUndulafinl- 2000COUtIIry,ft} (700-IOOO") ~r=====1 floooPlateaux,- 2500m.sas,If)ond buff •• DRt1Ilinfl -• ond· scarps _._~- Main dlvid.$ mo /1000Prominent- 3000ridges,If) cues/as, ..-26-..... Isohy"',in. F1a. 1: Physiography and Isohyets of the Springsure Sheet area 3 The dissected tablelands, known as the Buckland Tableland, form the most prominent topographic feature. They are dissected by broad alleys, bounded by steep scree-covered slopes. The plateaux, mesas, and buttes are characterized by white cliffs of sandstone and acid volcanic rocks (near Springsure); the mesas are separated by sandy flats in the west, and heavy-textured dark soil vales in the north-east. Streams have cut sinuous gorges in the sandstone plateaux in the west. The prominent ridges, cuestas, and scarps form three regions which are dissected by transverse watercourses. The undulating country is characterized by small ridges and scarps which break the topographic monotony of these regions; the streams have fairly mature profiles. The rolling downs have a heavy-textured dark soil which supports a thick grass cover and few trees; the streams meander across small flood plains. The drainage system and main divides are shown in Figure 1. The Great Dividing Range separates the drainage systems that flow north into the Fitzroy River system from those that flow south into the Darling River system. The main streams flowing north are the Nogoa and Claude Rivers, and Vandyke, Cona, Meteor, Consuelo, and Carnarvon Creeks, which are perennial, except during prolonged dry spells. The water in Carnarvon, Consuelo, and Meteor Creeks is notably clear and soft. To the south of the range, the upper reaches of the Warrego and Maranoa Rivers lie within the Sheet area. STRA TIGRAPHY The stratigraphy is illustrated in Figure 2 and is summarized in Tables 1, 2, 3, and 4.