A largely convergent setting is proposed for crustal, tectonic and basin evolution of the intracratonic regions of north‐central Australia between 1800 and 1575 Ma. The new geodynamic model contrasts with previous proposals of widespread extension during the Leichhardt, Calvert and Isa intervals. Local transtensional to extensional structures exist, but these are best explained by a combination of flexural, thermal and dynamic processes related to an active southern margin. The development of thick accumulations of sediments (superbasins) is linked geodynamically to interpreted active margin processes (subduction and magmatic arcs) in central Australia. A synthesis of geochemical data from the 1870–1575 Ma igneous units from the Arnhem, McArthur and Mt Isa regions of north‐central Australia confirms the intracratonic setting of these units and suggests that a long‐lived thermal anomaly was responsible for the generation of both mafic and felsic magmas. The geochemical characteristics suggest the igneous units are derived from the lithospheric mantle and are not typical rift‐ or plume‐related melts. A review of the U–Pb SHRIMP ages for the entire region demonstrates the minimum distribution of correlative igneous rocks was widespread. Exotic populations in the 207Pb/206Pb isotopic data provide insights into the nature and evolution of the crust throughout north‐central Australia. Archaean inheritance is found to be nearly ubiquitous. The data support the temporal subdivision of north‐central Australia into the Leichhardt (1800–1750 Ma), Calvert (1750–1690 Ma) and Isa (1690–1575 Ma) intervals which are marked by superbasins and concomitant episodes of igneous activity. A highly heterogeneous pre‐superbasin crust is interpreted from regional, newly processed geophysical data. The cratonic portion of north‐central Australia is interpreted to consist of three broad northwest‐trending belts or elements that are further distinguished into western, central and eastern geophysically distinct provinces. A map of the superbasin distribution is derived and integrated with structural and stratigraphic data to assess the evolution of the basins and the crust through time. The superbasin successions of north‐central Australia are synchronous and widespread, although not necessarily interconnected. The tectonic model incorporates dynamic tilting of the craton during episodes of subduction and transmission of compressive intraplate stresses through the craton during intervening episodes of orogeny. These processes resulted in flexure, strike‐slip deformation and a complex thermal structure. These mechanisms account for the subsidence and basin evolution that results in widespread ramp and strike‐slip basins. The model also accounts for the thermal history recorded by magmatic events. The proposed geodynamical model provides a unifying crustal evolution scenario for central and northern Australia for approximately 225 million years of the Proterozoic.

The Northern Lawn Hill Platform (NLHP) comprises an area of approximately 16,000 km2 in north-central Australia. Thick packages of Proterozoic strata outcrop in the region, although large areas are also covered by younger strata. The packages contain basin sediments and igneous rocks that span ∼400 m.y. We present a regional synthesis of approximately 150 m.y. of the tectonostratigraphic history of the area which hosts several world-class base metals deposits. The interpretation is based primarily on a sequence stratigraphic and structural interpretation of seismic data, a common approach in the petroleum resource sector, but rare in analyses of mineral resources. Models of subsurface geology and a basement template are provided using observed geopotential data that are iteratively calibrated with other data. Geochronological, palaeomagnetic, geochemical and sequence stratigraphic investigations on outcrop and drill core also are integrated into the history. The seismic data allow separated outcrop belts to be confidently correlated for the first time. Geochronological data control the basin history delineated by this interpretation. Palaeomagnetic data allow the results presented here to be extrapolated regionally and globally. Although considered to be deposited on entirely intracontinental lithosphere, the basin phases record significant fluctuations in the volume and geometry of accommodation space for sedimentation. Multiple pulses of deformation are recorded by changing depositional geometries. We propose a history of re-activation of a basement template and speculate on geodynamical mechanisms for accommodation space fluctuations and geometric variability. The detailed understanding of the basin evolution of the NLHP gained by integrated basin analysis provides a powerful tool for predictive fluid flow models as an aid to resource exploration. It should also provide a useful analogy in understanding tectonic processes and basin evolution of other similar aged intracontinental basins.

An accurate estimate of the depth to the crystalline basement in sedimentary basins is of great importance for mining and oil exploration.

The method of summary representation developed by G. N. Polozhii is a quasi‐analytical method for solving self‐adjoint, finite‐difference boundary value problems expressed on regular meshes. In principle, the method should allow considerable savings in computing time as well as improved accuracy when compared to commonly used finite‐difference schemes. We have used summary representation as the basis for a new hybrid scheme to solve the two‐dimensional Helmholtz equation for electromagnetic modeling. The theory behind this hybrid scheme is presented. Preliminary results for the two‐dimensional problem show that substantial computing time and storage savings can be made.