Basin analyses – data integration
High level basin analyses must consider the information gained from all public open file data available online and the use of the most recent company data as required to interpret and solve local anomalies . The following discussion looks at the publicly available data to undertake an analysis of Queensland’s basins. Each data set tells us something about the underlying rocks, but a results from interpretation of a single data set is not always directly applicable to the results of interpretation of another. A linking flow chart of the information from each data set to a final interpretation may allow a more comprehensive understanding for each basin. The sequence of using data sets is always from a regional concept (1:250 000 to 1:100 000 scale) to the detailed exploration project (<1:10,000 scale), and it is important to understand the geology at all scales using the appropriate technique for each scaling parameter.
The location of major mineral and energy resources of the state is given on a state-wide basis by the Department of Natural Resources and Mines (qld-resources-map (1))
The Late Palaeozoic to Mesozoic basins of Queensland have been extensively drilled particularly for energy resources (coal, oil and gas), but much of the mapping dates back to the 1960s and 1970s. Linking the outcropping geology to the subsurface information delivers a holistic three dimensional view of these basins.
Much of Queensland has been flown by airborne geophysics and this data set has not been used extensively to update the detailed geology of these basins. To maximise the potential of these basins it is important that all this data is used to update the interpretation of these economic basins.
This requires integration of available data sets and the solving of anomalies in interpretation locally and regionally. The variation in the type of data and the scale of the information poses a range of issues in data integration. Concepts of geology have been modified from the early mapping of the basin areas with updates to knowledge from sequence stratigraphy, chronstratigraphy and lithostratigraphy.
To generate a comprehensive interpretation of these basins requires an integrated approach by government and industry data to deliver a three dimensional basin concept to maximise knowledge of energy resources within basins and potential mineral resources at the margins of these basins.
Large Publicly available data sets that can be integrated with your project
A major coverage publicly available source of data is the geophysical data coverage of Queensland. A major significant coverage of data is Geophysical Data coverage.
Major subsets of this data are the 2D and 3D seismic lines mainly completed by exploration companies, deep crustal seismic, magnetotellurics, gravity and regional airborne geophysics completed by the state and commonwealth governments, and drill hole data completed by exploration companies and the state and commonwealth governments. These coverages are depicted below. Data was extracted from the DNRM website in March 2018.
Seismic data coverage (March, 2018)
The seismic data coverage is mainly concentrated in the southwest corner and the southern central part of the state associated with oil and gas in the Cooper and Surat Basins. Combinations of drilling, geological mapping and seismic data could be integrated to solve local interpretation anomalies. The 2D and 3D seismic is applicable for the subsurface data and linking to detailed drill hole interpretation of the stratigraphy.
Deep Crustal Seismic and Magnetotelluric surveys (March 2018)
At the margins of mineralised provinces in north Queensland deep crustal seismic reflection surveys have been completed. These surveys use the structural and petrophysical properties of rock bodies to create a depth profile of the geology. The acquired data (in conjunction with rock properties and geophysical data) is enabling a much better understanding of the geology and mineral potential of northern Queensland. It allows the imaging of deep regions of basinal areas and can pick older basinal straigraphy and structural disconformities at a significant depth.
Magnetotellurics (MT) was used along the same lines as the deep crustal seismic surveys. These currents are influenced by rock properties such as type, porosity, permeability and temperature. MT is an electromagnetic technique that measures naturally occurring electric (telluric) currents induced by variations in Earth’s magnetic field. These techniques were implemented to image the conductivity of Earth’s crust to similar depths as attained by the deep crustal surveys.
The extent of the magentotellurics surveys is given below.
Airborne Geophysical Data Coverage (March, 2018)
The airborne geophysical data coverage is extensive with only the south-east corner, the northern tropical coast and an area in the central part of the state with no coverage. the south-east has flight restrictions around the major Brisbane and Cooloongatta airports and the northern coast World Heritage tropical rain forest areas are unlikely to be covered by data. Integration of the radiometrics and magnetic data captured by this technique can improve the interpretation of stratigraphic contacts between basin units and show the magnetic (airborne magnetics) and non-magnetic (radiometics) fault features and the features of buried magnetic stratigraphy and igneous rock bodies (magnetics). This technique is particularly useful to update geological mapping interpretation derived solely from the use of aerial photographic interpretation over sedimentary basins from scales of 1:250 000 to 1:100 000.
Gravity Data over Queensland (March, 2018)
Gravity data detects variation in the density of rock bodies and is appropriate technique to assist in the location of mineral deposits that have a higher density than the surrounding rock bodies.
GSQ has completed regional gravity surveys with a station spacing that is equal to or less than 4km. The collected data was incorporated into the National Gravity Database.
Drilling Database Queensland (March 2018)
DNRM has major drilling data over the state derived from departmental and exploration drilling for water, stratigraphic interpretation and energy exploration and this can be downloaded from databases available online. Departmental custodians of this data that keep the information current in line with legislative controls of data delivery and public availability. To solve local issue requires access to other and more current company exploratory drilling. The use of drilling data with extensive seismic data can generate a 3D picture of large basin areas and identify the likely presence of fluids in these basins. This can be accompanied by local knowledge on specific products.
For any additional information on your projects and details of experience contact me.