Otway Basin Top Basement Two Way Time Structure Map using sun shading. Sun angle 80, azimuth 35 and vertical exaggeration 10. Pixel colours indicate red shallow (0ms), purple deep (4813ms) This structure map highlights the Late Jurassic - Early Cretaceous structure of the Otway Basin. The grid is based on mapping done by Minerals and Petroleum Victoria, Primary Industries and Resources South Australia, Origin Energy and Cooper (1995b). The main feature to note in this image is the variation in the orientation of the Late Jurassic - Early Cretaceous troughs and highs along the length of the basin. At the western and eastern ends of the basin, the troughs and highs are oriented both NE-SW and E-W (Robe Trough, St. Clair Trough, Rivoli Trough, Lake Eliza High, Beachport High, Elingamite Trough, Gellibrand Trough, Ombersely Trough, Nerita Deep, Snail Terrace). Those in the centre are oriented NW-SE (Penola Trough, Tantanoola Trough, Kalangadoo High, Hatherleigh High, Tahara Trough, Branxholme High, Ardonachie Trough, Lake Condah High). This variation in the orientation of the Late Jurassic - Early Cretaceous troughs and highs has resulted in considerable debate over the extension direction during this period. Some worker believe it was oriented NW-SE (Willcox & Stagg, 1990; Willcox et al., 1992; O'Brien et al., 1994), whereas others believe it was NNW-SSE (Cooper, 1995a,b; Cooper & Hill, 1997), N-S (Boeuf & Doust,1975; Ellenor, 1976; Hill et al., 1994a) or NNESSW (Etheridge et al., 1985, 1987; Smith, 1988). This image was extracted from Petroleum Atlas of Victoria Figure C21 (November 2001) The entire report may be downloaded ( at no cost ) from https://gsv.vic.gov.au/searchAssistant/document.php?q=parent_id:43977

This image shows the natural geothermal heat flow as measured by precision temperature logging and thermal conductivity analysis in approximately 100 groundwater bores across the State. Measurements in mW/m2 with middle (green) value of 65 in colour spectrum set from expected global average heat flow for Late Proterozoic to Early Palaeozoic crust.

Gippsland Basin Top Latrobe Structure Map using sun shading. Sun angle 80, azimuth 35 and vertical exaggeration 10. Pixel colours indicate white shallow (-450m) purple deep (3559m) The top- Latrobe Group structure map has been compiled from numerous open file reports held by the Department of Primary Industries and from grid files generated by the Basin Studies Group for previous acreage release reports under the VIMP program. At this stage, the map does not show the faulting at top-Latrobe level, however many of the fault trends are clearly evident in the offshore morphology. The horizon is picked on a prominent unconformity surface marking the boundary between the marine and non-marine siliciclastics of the top- Latrobe Group and the calcareous sediments of the overlying Seaspray Group. The largest gas fields are associated with significant NW-SE Miocene inversion anticlinal trends that dominate the northern and western margins of the basin. A regional NNE-SSW high trend across the Central Deep hosts the Kingfish and Halibut-Fortescue-Cobia oil fields. The influence of this older trend is most apparent in the Central Deep and parallels the Cape Everard Fault System defining the eastern margin of the Central Deep"

Otway Basin Top Sherbrook Two Way Time Structure Map using sun shading. Sun angle 80, azimuth 35 and vertical exaggeration 10. Pixel colours indicate red shallow (0ms), purple deep (4813ms) The top of the Sherbrook Group has also been extensively mapped in the Otway Basin, both onshore and offshore, as the event coincides with the breakup of Australia and Antarctica. This image is based on mapping done by Minerals and Petroleum Victoria, Primary Industries and Resources South Australia, and Oil Company of Australia. Several structural features are visible in this image including the Portland Trough and Bridgewater High. The Portland Trough shows up as an elongate NW-trending depression approximately 120 km long and 25 km wide centred on the peninsula SW of Portland. About two-thirds of the trough is located onshore; the other third offshore. The Bridgewater High is located offshore to the SW of the Portland Trough and shows up as a broad, Seplunging anticline about 25 km wide. The distribution of faulting at the Top Sherbrook Group level is quite interesting as most of it is located to the south of the Tartwaup - Mussel Hingeline in the Voluta Trough. In this image, the Tartwaup - Mussel Hingeline is not as well defined compared to the Top Eumeralla TWT structure map, but its arcuate trace is still visible. North of it, there is very little faulting at the Top Sherbrook level when compared to the south, where the faults have a strong NW-SE orientation and are characterised by relatively small, down-to-the-south, throws. The faulting decreases in intensity towards the SE, and virtually dies out SE of the Portland Trough and Bridgewater High. Another interesting feature which shows up on the Top Sherbrook Group grid are a series of SW-plunging folds visible offshore SW of the Otway Ranges. These folds are also visible in the Top Eumeralla and Top Wangerrip TWT structure images and extend onshore into the Colac Sub-basin and Otway Ranges. The Port Campbell Embayment is also clearly evident in this image as a semi-circular depression facing southwest. The Shipwreck rough has no expression at this level. This image is extracted from Petroleum Atlas of Victoria Figure C23 (November 2001) The entire report may be downloaded ( at no cost ) from https://gsv.vic.gov.au/searchAssistant/document.php?q=parent_id:43977

Otway Basin Top Crayfish Two Way Time Structure Map using sun shading. Sun angle 80, azimuth 35 and vertical exaggeration 10. Pixel colours indicate red shallow (114ms), purple deep (3628ms) This structure map is a composite grid based on mapping done by Minerals and Petroleum Victoria, Primary Industries and Resources South Australia, Origin Energy and Cooper (1995b). The main features to note in this image are: 1) the southwesterly regional dip of the Top Crayfish Subgroup surface in the western and central parts of the basin relative to the eastern part where it dips towards the south, and 2) the absence of Crayfish Subgroup sediments on some of the basement highs in the western and central parts of the basin (e.g. Beachport, Hatherleigh, Kalangadoo, Lake Condah, Branxholme). This image is extracted from Petroleum Atlas of Victoria Figure C22 (November 2001) The entire report may be downloaded ( at no cost ) from https://gsv.vic.gov.au/searchAssistant/document.php?q=parent_id:43977

This image shows the depth at which temperatures of 150°C can be expected, and was created using temperature data from GeoScience Victoria’s VIMP Report 85 (Driscoll, 2006). Only temperature data from wells deeper than 1000 m was used to construct the image.

Otway Basin Top Eumeralla Two Way Time Structure Map using sun shading. Sun angle 80, azimuth 35 and vertical exaggeration 10. Pixel colours indicate red shallow (0ms), purple deep (4813ms) This image is a TWT structure map for the top of the Eumeralla Formation (Top Otway Group) based on extensive regional mapping done by Minerals and Petroleum Victoria, Primary Industries and Resources South Australia, Origin Energy and Cooper (1995b). The main features to note in this image are: 1) the regional dip of the top of the Eumeralla Formation in the western and central parts of the basin; 2) the large depression to the southwest of the Tartwaup-Mussel Hingeline; 3) the intensity of faulting at the top Eumeralla level; and 4) the N-S oriented trough (Shipwreck Trough) to the southwest of the Otway Ranges. Several structural features are visible in this image. These include the Crayfish, Mumbannar, Mussel and Prawn platforms; the Shipwreck and Voluta troughs, the Bridgewater Arch, and the Port Campbell Embayment. The faulting visible at the Top Eumeralla Formation level is largely a response of the Late Cretaceous rift event. Most of the faulting associated with this event is located to the south of the Tartwaup-Mussel Hingeline in the Voluta Trough. The faults are largely oriented NW-SE with down-to-the-south throws. The Tartwaup- Mussel Hingeline shows up particularly well in this image as a series of enechelon, down-to-the-south faults, with individual throws of up to 2 seconds TWT. The fault system is concave to the southwest. The northern end of the Shipwreck Trough starts to splay to the NW and NE, and spreads out onshore where it has a semi-circular, bowl-shaped appearance open to the south. This image is extracted from Petroleum Atlas of Victoria Figure C23 (November 2001) The entire report may be downloaded ( at no cost ) from https://gsv.vic.gov.au/searchAssistant/document.php?q=parent_id:43977