RECONNAISSANCE GRAVITY SURVEY OF AUSTRALIA

Geophysics ◽  
1976 ◽  
Vol 41 (6) ◽  
pp. 1337-1345 ◽  
Author(s):  
A. R. Fraser ◽  
F. J. Moss ◽  
A. Turpie
Keyword(s):  
Bouguer Anomaly ◽  
South Australia ◽  
Mineral Resources ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Aerial Photographs ◽  
Gravity Survey ◽  
State Governments ◽  
Anomaly Map ◽  
Considerable Benefit

The Australian Bureau of Mineral Resources, Geology and Geophysics, completed a 15 year systematic reconnaissance gravity survey of Australia in 1974. Using helicopters, gravity stations were established at 11 km spacing over most of the continent, and at 7 km spacing in South Australia and Tasmania. Station elevations were measured barometrically and station positions were marked on aerial photographs and transferred to 1:250,000 photocenter base maps. Gravity and elevation controls were maintained by ties to specially established control networks. A Bouguer anomaly map of Australia has been compiled from the reconnaissance data, and from information from other gravity surveys by state governments, petroleum exploration companies, and academic institutions which together cover about 15 percent of the total area. The compilation uses a total of about 170,000 gravity observations. The accuracy of Bouguer anomaly values, taking account of errors in the gravity, elevation, and position measurements, is estimated to be better than ± 2.0 mgal. The Bouguer anomaly fields over Australia are divided into nine regional gravity divisions, in each of which the gravity contour pattern has some degree of uniformity, or is such as to imply tectonic affinities between the sources of individual gravity features. The gravity divisions can be correlated with various metamorphic complexes and orogenic provinces, ranging in age from Archaean to Paleozoic, which also form the basements to extensive sedimentary platform covers. The reconnaissance gravity results have been made public as the survey has progressed to assist in regional geologic studies and the search for petroleum and minerals. They have proved to be of considerable benefit in delineating regional structures and in providing leads for more detailed geophysical investigations. Predictions of the structures of sedimentary basins have been made and possible extensions to mineral provinces have been indicated. The results have also been used in deep crustal and upper mantle studies and in geodesy.

PROGRESS OF STUDIES, BASIN STUDY GROUP, BUREAU OF MINERAL RESOURCES

1970 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
K. G. Smith
Keyword(s):  
Cross Sections ◽  
Mineral Resources ◽  
Sedimentary Basins ◽  
Basic Data ◽  
Petroleum Exploration ◽  
Geological Survey ◽  
Study Group ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Contour Maps

The Basins Study Group is part of the Subsurface Section of the Bureau's Petroleum Exploration Branch and was formed in 1962 to collect and review available basic data on the sedimentary basins of Australia and Papua-New Guinea. The Core and Cuttings Laboratory forms the second part of the Subsurface Section, and the Laboratory's technical staff contribute to basin reviews by carrying out analyses of various kinds, and assist in the collection of data principally by providing thin sections of various sedimentary formations.Recent activities of the Basins Study Group include a review of the Sydney Basin, and an increased effort to assemble basic data on all sedimentary basins, with particular emphasis on the Canning and Carnarvon Basins.The review of the Sydney Basin is nearing completion. It was undertaken with the co-operation of the Geological Survey of New South Wales and received generous support from petroleum exploration companies active in the Basin. The review included detailed petrological examination of twelve wells and selected outcrop samples. The results confirmed the previously-held opinions that the reservoir characteristics of Sydney Basin sediments are generally unfavourable. At present there are no indications of untested onshore areas where an improvement in reservoir properties may occur. The Bureau petrologists detected the rare mineral dawsonite in eight wells; the mineral occurred mostly in Permian sediments, both in marine and non-marine rocks, but it was recorded also from Triassic rocks in the Kurrajong Heights No. 1 well. The review of geophysical data from the Sydney Basin was concentrated mainly on seismic work. The magnetic tapes of three surveys were replayed and considerable improvement in records was effected. Record sections of all seismic surveys were reduced photographically to a horizontal scale of 1:50,000 and the reductions were spliced to provide easily-managed cross-sections. The geophysical review is nearing completion and structure contour maps and isochrons are in preparation.The collection of basic data is done for each sedimentary basin as it becomes available, but present emphasis is on assembling data from Western Australian basins: all seismic traverses in the onshore parts of the Canning and Carnarvon Basins have been plotted at 1:250,000 scale, and with the co-operation of the Geological Survey of Western Australia, bibliographies of the Canning, Carnarvon and Perth Basins have been compiled for issue as Open-file Records. Bibliographies of the Papuan and Ipswich-Clarence Basins have also been compiled.

REGIONAL GRAVITY SURVEY IN NORTHEASTERN OKLAHOMA AND SOUTHEASTERN KANSAS

Geophysics ◽  
1956 ◽  
Vol 21 (1) ◽  
pp. 88-106 ◽  
Author(s):  
Kenneth L. Cook
Keyword(s):  
Structural Geology ◽  
Bouguer Anomaly ◽  
Gravity Anomalies ◽  
Close Correlation ◽  
Geodetic Survey ◽  
Gravity Survey ◽  
Complex Nature ◽  
Gravity Gradients ◽  
Anomaly Map ◽  
Regional Gravity

In 1948 the U. S. Geological Survey, in cooperation with the U. S. Coast and Geodetic Survey, made a regional gravity survey in northeastern Oklahoma and southeastern Kansas in connection with the studies of the deflection of the vertical. About 550 gravity stations were occupied with spacings of 5 to 10 miles in parts of 54 counties, and a Bouguer anomaly map, contoured at intervals of 5 milligals, was drawn. In southeastern Kansas there is a lack of correlation of regional gravity with known regional structural geology. The observed gravity anomalies are apparently caused principally by variations of density in the Precambrian basement and indicate a basement of complex nature, made up of rocks of contrasting properties, with a regional grain striking predominantly west or west‐northwest. In northeastern Oklahoma the several observed regional gravity anomalies indicate different degrees of correlation of regional gravity with regional structural geology. In the Precambrian highland area in Osage, Pawnee, and Creek Counties, there is a lack of correlation, as the gravity anomaly is probably caused chiefly by density contrasts within the basement complex. The anomaly associated with the Hunton arch is probably caused partly by structural relief of the rocks of pre‐Pennsylvanian age and partly by density contrasts within the basement, and thus indicates some correlation. The steep gravity gradients along the outer flanks of the Ozark uplift indicate good correlation with the subsurface geology. The great anomaly over the Arkansas basin, which indicates a close correlation, is probably caused largely—but perhaps not entirely—by downwarping of the basement and pre‐Pennsylvanian rocks.

ANALYSIS OF GRAVITY DATA NEAR CONTINENTAL MARGINS

1974 ◽  
Vol 14 (1) ◽  
pp. 114
Author(s):  
A. J. Flavelle ◽  
Y. Yoshimura
Keyword(s):  
Continental Margin ◽  
Sea Water ◽  
Gravity Data ◽  
Bouguer Anomaly ◽  
Sedimentary Basins ◽  
Continental Margins ◽  
Upper Crust ◽  
Anomaly Map ◽  
Bouguer Anomaly Map ◽  
Thickness Variations

In general large, thick sedimentary basins are delineated by negative gravity features. The gravity data are usually expressed in the form of Bouguer anomaly contours.Ordinary Bouguer anomaly data fail as a direct indicator of approximate sedimentary thickness in zones on and adjacent to the continental margin. Rapid variations in crustal and ocean thickness cause gravitational variations which are not removed during the computation of Bouguer anomaly values.If crustal thickness variations are known or can be calculated then gravitational corrections can be made which take this factor into account. Similar corrections for variations in sea water attraction can be made. The resultant Bouguer anomaly map, corrected for those variations, will indicate in more definite terms density variations in the material of the upper crust. In particular Bouguer anomaly patterns over continental areas adjacent to the continental slope can be more easily interpreted in terms of sedimentary thickness.

Gravity Survey of King Fahd University of Petroleum and Minerals Dammam Dome, Saudi Arabia

2021 ◽  
Author(s):  
Pantelis Soupios ◽  
Alexandros Stampolidis ◽  
Maurizio Fedi ◽  
SanLinn Kaka ◽  
Khalid Al-Ramadan ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Gravity Data ◽  
Bouguer Anomaly ◽  
3D Models ◽  
Low Noise ◽  
Gravity Survey ◽  
Differential Gps ◽  
Gravity Measurements ◽  
Anomaly Map ◽  
Bouguer Anomaly Map

Abstract The study area is a part of Dammam Dome that is situated at King Fahd University of Petroleum & Minerals (KFUPM) campus, Dhahran, Kingdom of Saudi Arabia. The gravity survey was conducted as a pilot case study to explore part of Dammam Dome in greater detail. Gravity data were collected solely during night hours due to low noise levels. A significant part of the survey was conducted during the summer holiday period, , when there was no student are on campus. A total of 235 gravity measurements were made using a Scintrex CG5 gravitometer, while a Trimble R10+ differential GPS (DGPS) was used to measure the stations’ location and elevation with the highest accuracy. All gravity data were reduced using several algorithms, and their outcomes were cross-compared. The Complete Bouguer anomaly map for the campus was then generated. Several enhancement filters including edged detection and shallow to deeper source separation were applied. Data were inverted, and 2.5D and 3D models were created to image the subsurface conditions. The main purpose of this study is to better understand the subsurface geology, tectonic settings of the Dammam Dome by applying the high-resolution gravity method before carrying out any comprehensive geophysical (seismic) 3D survey.

SOME COMPUTING TECHNIQUES FOR STORAGE, RETRIEVAL AND INTERPRETATION OF GRAVIMETRIC DATA

1975 ◽  
Vol 15 (1) ◽  
pp. 87
Author(s):  
G. Morony
Keyword(s):  
Gravity Data ◽  
Bouguer Anomaly ◽  
South Australia ◽  
Mineral Resources ◽  
Grid Spacing ◽  
Storage And Retrieval ◽  
Gravimetric Data ◽  
Data Files ◽  
Grid Operators ◽  
Australian Department

Gravity coverage of South Australia, with stations on a grid of approximately 7 km, is almost complete. A project aimed at computer-storage, retrieval and utilization of these data has been under-way within the Geophysics Division of the South Australian Department of Mines for two years.The storage and retrieval system has been adapted from one developed for gravity data by the Bureau of Mineral Resources. Two data files have been established using this system. The first contains all data from individual surveys stored as a retrievable block on the file. The second contains all gravity data recorded on each 1:250,000 scale published map sheet within the State.Experimental analysis of digitized gravity data from the Great Artesian Basin in South Australia has been undertaken using standard anomaly-separation techniques. A published set of grid operators has been used as the coefficients for each analysis. These coefficients, which are designed for upward and downward continuation and long and short wavelength filtering of potential fields, have each been applied to the test data with various grid spacings. Computer presentation of results allows quick evaluation and comparison of each operator set. Results obtained are suitable for qualitative examination and in the examples chosen indicate limits of intracratonic basins and some detail within them. The nature of this information depends on the grid spacing and operator used. Large amplitude anomalies which cover a considerable area and are due to basement features become more apparent than on the Bouguer anomaly data. An estimate of depth to major density discontinuities has been obtained.Future aims of the project are: (i) processing of raw data files to prepare and update integrated Bouguer anomaly maps using more accurate density information for the Bouguer correction, and (ii) preparation of processed maps on a statewide basis to aid interpretation of the tectonic and basin framework of the State of South Australia.

RECENT EXPLORATION DEVELOPMENTS IN THE NGALIA BASIN, NORTHERN TERRITORY

1983 ◽  
Vol 23 (1) ◽  
pp. 182
Author(s):  
D. D. Benbow ◽  
J. Davidson ◽  
J. Mulready
Keyword(s):  
Source Rock ◽  
Gas Flow ◽  
Mineral Resources ◽  
Petroleum Exploration ◽  
Seismic Survey ◽  
Gravity Survey ◽  
Geochemical Data ◽  
Surface Mapping ◽  
Northern Margin ◽  
Geophysical Surveys

Petroleum exploration of the Ngalia Basin commenced with the Pacific-American Oil Company's seismic and gravity survey in 1964, followed by geological and geophysical surveys by the Bureau of Mineral Resources (BMR) between 1967 and 1978, and then Magellan's Ngalia seismic and gravity survey in 1971.After a ten year break, exploration resumed with the drilling of the Davis-1 well by a consortium of Australian companies which farmed-in to Magellan's Ngalia Basin Permit (OP165). The well was drilled on the flank of a large east-west trending anticlinal dome outlined by surface mapping and limited seismic coverage, and located near the northern margin of the basin. The section penetrated in the well consists of 1134 m of Carboniferous-Devonian sediments unconformably overlying 479 m of probable Cambro-Ordovician marine sediments, which in turn unconformably overlie approximately 246 m of marine ?Adelaidean sediments, including a basal sequence of dark grey marine shale. Source rock analysis indicates that this latter section may provide a significant source rock potential for the basin. A small gas flow was observed during the course of the well, which was air-drilled to a total depth of 1899 m, bottoming in metamorphics which are tentatively correlated with the Pre-Cambrian Patmungala Beds (?Arunta Block). The current exploration effort is now aimed at:more deeply buried structures in the Naburula Fault Trough, in the western half of the basin, andsub-surface extensions of the Walbiri-Bloodwood Fold Zone, in the eastern half.In both cases a more extensive section of marine Cambro-Ordovician age rocks is anticipated, and the limited geochemical data available suggest that these sediments should lie within the oil window.The Newhaven-Mt Allan Seismic Survey, consisting of 344 km of 12-fold vibroseis coverage was shot in these areas in November-December, 1981, in an attempt to define prospects and leads for evaluation by additional drilling over the next three years. The structures mapped to date include reverse faulted blocks with salt-involvement in the Newhaven area to the west, and "sled-runner" thrusts with a plane of décollement in salt in the Mt Allan area to the east.

EXPLORATION AND ITS RESPONSE TO DIVERGENT INFLUENCES

1975 ◽  
Vol 15 (1) ◽  
pp. 153
Author(s):  
W. G. H. Maxwell
Keyword(s):  
Technological Factor ◽  
South Australia ◽  
Sedimentary Basins ◽  
Social Background ◽  
Petroleum Exploration ◽  
Social Trends ◽  
Oil Boom ◽  
Third Phase ◽  
Political Events ◽  
Fluctuating Course

Petroleum exploration in Australia has evolved through three distinct phases and is now entering a fourth. It began with the wild, speculative flurries that culminated in drilling on the Coorong, South Australia in 1892, it was revived by the accidental discovery of gas near Roma at the turn of the century leading to the oil boom from 1926 to 1933, and it reached its peak in 1962-72 in the third phase, after which exploration activity has gone into decline. Examination of the economic, political and social background to the industry reveals that, on the national scene, political events rather than economic and social trends have had greater impact on the fluctuating course of its development. International influences also appear, in many instances, to be of greater significance than domestic factors. Much time and effort have been devoted by industry, government and academics to the analysis of economic, political and social influences on Australia's petroleum exploration but it is quite obvious that the basic determinant Is still the oft-forgotten geologic-technological factor. The condition of the domestic industry depends primarily on the potential of Australia's sedimentary basins and the quality of the technology used to explore them. In the long term, all other influences are temporary in their impact and subordinate in their ultimate effect.

scholarly journals Penentuan Anomali Gayaberat Regional dan Residual Menggunakan Filter Gaussian Daerah Mamuju Sulawesi Barat

EKSPLORIUM ◽  
2017 ◽  
Vol 38 (2) ◽  
pp. 89
Author(s):  
Adhika Junara Karunianto ◽  
Dwi Haryanto ◽  
Fajar Hikmatullah ◽  
Agus Laesanpura
Keyword(s):  
Bouguer Anomaly ◽  
Mineral Resources ◽  
Gravity Anomalies ◽  
Research Area ◽  
Wave Number ◽  
Eurasian Plate ◽  
Gaussian Filtering ◽  
Residual Gravity ◽  
Filtering Technique ◽  
Anomaly Map

AbstrakMetode gayaberat merupakan metode geofisika yang sudah sering digunakan dalam prospeksi sumberdaya mineral. Parameter objek pencarian berdasarkan variasi pengukuran percepatan gayaberat di permukaan yang diakibatkan oleh variasi perubahan geologi bawah permukaan. Lokasi penelitian di daerah Mamuju Provinsi Sulawesi Barat yang secara tektonik merupakan wilayah geologi kompleks berada pada pertemuan tiga lempeng besar yaitu Pasifik, Indo-Australia, dan Eurasia serta Lempeng Filipina yang berukuran lebih kecil. Selain itu Mamuju merupakan wilayah dengan laju dosis radioaktivitas tinggi sehingga berpotensi memiliki sumberdaya mineral radioaktif. Tujuan dari penelitian adalah mendapatkan anomali gayaberat dengan cara melakukan pemisahan dan interpretasi secara kualitatif anomali gayaberat regional dan residual. Nilai Anomali Bouguer Lengkap (ABL) daerah penelitian yang didapat dari hasil pengukuran adalah 46,0 – 115,7 mgal. Berdasarkan peta ABL tersebut proses pemisahan anomali gayaberat regional dan residual dilakukan dengan menggunakan teknik Gaussian Filtering. Teknik filtering ini bekerja berdasarkan analisis spektrum perubahan amplitudo gayaberat secara spasial yang hasilnya berupa bilangan gelombang dengan cutoff sebesar 1,1736 x 10-3/ m dan panjang gelombang sebesar 5373,45 m. Anomali gayaberat regional dan residual berturut-turut memiliki rentang nilai 51,8 sampai 102 mGal dan -10,4 sampai 14,8 mGal. Kedalaman wilayah spektrum masing-masing anomali tersebut dapat dihitung berdasarkan panjang gelombangnya yaitu anomali regional sebesar 970,97 m dan anomali residual sebesar 100,21 m. Terdapat lima zona berdasarkan peta anomali residualnya yaitu zona A, B, C, D, dan E. Anomali gayaberat positif paling besar terdapat pada zona A dan B yang diperkirakan dipengaruhi oleh keberadaan lava Adang dengan arah penyebaran relatif utara – selatan. AbstractGravity method is a geophysical method that has been frequently used in prospecting mineral resources. The parameter of searched object is based on variations of gravity acceleration measurements on the surface due to variations in sub-surface geological changes. Research area is located in Mamuju Area of West Sulawesi Province where tectonically a complex geological region, which is at a meeting of three large plates, the Pacific plate, the Indo-Australian plate and the Eurasian plate and the smaller Philippine plate. In addition, Mamuju is an area with a high radioactivity dose rate that has potency to radioactive minerals resources. The purpose of the research is to obtain gravity anomalies by using qualitative separation and interpretation of regional and residual gravity anomalies. Complete Bouguer Anomaly (CBA) value of the research area obtained from the measurements was 46.0 – 115.7 mGal. Based on the CBA map, the separation process of regional gravity anomalies and residual using Gaussian filtering technique conducted. This filtering technique works based on spectral analysis of gravity amplitude changes in spatial where the result is a cutoff wave number of 1.1736 x 10-3/meter and a wavelength of 5373.45 m. The regional and residual gravity anomalies range from 51.8 to 102 mGal and -10.4 to 14.8 mGal respectively. The depth of influence of each anomaly is calculated based on their spectral wavelengths, resulting 970.97 m and 100.21 m for regional and residual anomalies respectively. There are five zones based on the residual anomaly map, which are zones A, B, C, D and E. The heaviest positive gravity anomaly is found in zone A and B, which is predicted to be influenced by Adang lava with relative north – south distribution.

Aeromagnetic regional survey of onshore Australia

Geophysics ◽  
1988 ◽  
Vol 53 (2) ◽  
pp. 254-265
Author(s):  
D. H. Tucker ◽  
I. G. Hone ◽  
D. Downie ◽  
A. Luyendyk ◽  
K. Horsfall ◽  
...  
Keyword(s):  
Data Base ◽  
Mineral Resources ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Quality Data ◽  
Magnetic Data ◽  
Regional Survey ◽  
Wide Range ◽  
Line Spacing ◽  
Airborne Magnetic

The Australian Bureau of Mineral Resources (BMR) is responsible for the National Airborne Magnetic Database. This data base consists of results from approximately 3 500 000 line‐km of regional survey flying carried out over 35 years, recording total magnetic intensity. The magnetic data base is one of the most important geophysical data bases for Australia and is used extensively by the minerals and petroleum exploration industries. First‐pass coverage of onshore Australia is aimed for completion in 1992. This coverage contains data from surveys with a wide range of specifications, resulting in a wide range of data quality; some of the areas covered by poorer quality data may be reflown later. For the most part, the intention has been to acquire data at a continuous ground clearance of 150 m and with a line spacing of 1500 m. However, over some sedimentary basins, the line spacing is in excess of 3200 m. New color and grey‐scale (image processed type) digital magnetic maps (pixel maps) are in preparation; these will supersede the 1976 digital magnetic map of Australia, which was gridded on a 1.2 minute mesh (2000 m) mostly by digitizing contours on maps. The new map, produced from flight‐line data, will have a grid size of 0.25 minutes. Initially, a series of maps will be produced with each one covering a block of 4 degrees latitude by 6 degrees longitude, coinciding with standard 1 : 1 000 000 map sheets. An example included for the Adelaide 1 : 1 000 000 map sheet in Southern Australia shows a dramatic increase in the number of anomalies over those that were evident in earlier contour presentations.

Mapping geology beneath volcanics using magnetic data

2018 ◽  
Vol 58 (2) ◽  
pp. 821
Author(s):  
Irena Kivior ◽  
Stephen Markham ◽  
Leslie Mellon ◽  
David Boyd
Keyword(s):  
South Australia ◽  
Sedimentary Basins ◽  
Seismic Signal ◽  
Petroleum Exploration ◽  
Seismic Survey ◽  
Source Distribution ◽  
Magnetic Data ◽  
Large Area ◽  
Magnetic Susceptibilities ◽  
Passive Seismic

Volcanic layers within sedimentary basins cause significant problems for petroleum exploration because the attenuation of the seismic signal masks the underlying geology. A test study was conducted for the South Australia Government to map the thickness of volcanics and sub-volcanic geology over a large area in the Gawler Range Volcanics province. The area is covered by good quality magnetic data. The thickness of volcanics and basement configuration was unknown as there has only been a limited amount of drilling. The Automatic Curve Matching (ACM) method was applied to located magnetic data and detected magnetic sources within different rock units, providing their depth, location, geometry and magnetic susceptibility. The magnetic susceptibilities detected by ACM allowed the differentiation of the volcanics and the underlying basement. The base of volcanics and the depth to the top of basement was mapped along 75 km NS profiles, that were spaced 1 km apart over a distance of 220 km. The volcanic and basement magnetic susceptibilities and the magnetic source distribution pattern were used as key determinants to interpret the depth to the two interfaces. The results for each interface were gridded, and images of the base of volcanics and depth to basement were generated. The mapped volcanics thickness was validated by comparison with the results from drilling, with the volcanics thickness matching very well. After project completion, a passive seismic survey was conducted in part of the test area, indicating a base of volcanics of ~4 km, which further confirmed the results.

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