Figures and Tables
Figure 1. Positions of the continents during end-Permian time. Red dots denote where extraterrestrial fullerenes have been reported. In addition, other suggested impact tracers have been found in Permian-Triassic boundary layers at Graphite Peak, Antarctica, Meishan, China and Sasayama, Japan including meteoritic debris (8), Fe-Ni-Si grains (5,8), shocked quartz (4), impact spherules (6). Recently, large shocked quartz grains (S-1) were found in the Fraser Park, Australia and Graphite Peak Antarctica, Permian-Triassic boundary layer (yellow dot). (Permian map modified from Scotese Paleomap Project website: www.scotese.com).

Figure 2. Base map of the offshore northwestern Canning basin region showing major tectonic elements (i.e. plateaus, basins, platforms, etc.), the Bedout High with the Lagrange-1 and Bedout-1 exploration wells located on top of the high (red dots) and two AGSO regional seismic reflection lines (see Figures. 3, 10, S-16) and the JNOC (JN87-12) seismic line (Figure. 3) that cross over the high (base map modified from 17).

Figure 3. Interpreted section of the multichannel seismic line JN87-12 showing correlated ties to Bedout-1 and Lagrange-1 gamma (left) and sonic (right) well logs (modified from Smith, 1999, 15; location of line in Figure. 2.). Color stratigraphic horizons represent chronostratigraphic picks (CT-1, early Jurassic, red; SQ-2, middle Triassic, blue; Unit VIII, late Permian, purple). Triassic sedimentary rocks overlying Upper Permian (Unit VIII) are thin, however, all of the units were identified in the Bedout-1 and Lagrange-1 core and cuttings (S-2).

Figure 4. Selected intact 5 cm (wide) core from Bedout-1 at 3035 to 3037 m (9960 to 9965 feet; top three photos). These cores display variable sized, angular and subrounded glassy (impact-melted) fragments set in a matrix that is mostly chloritized and carbonate filled. The smaller glassy fragments examined in thin section throughout the core (Figureures S-8-S-14) displayed the same mineralogy and texture as the larger impact-melted glassy fragments seen in hand specimen. The lower photo is the Yucatan-6 impact melt breccia that has similar characteristics to Bedout-1, particularly in hand specimen (Yucatan-6 core photo modified from www.icdp-online.de/sites/chicxulub/ICDP-Chix/Figureures).

Figure 5. (left) A typical core sample from the Bedout impact melt breccia at 3052 m (9986 ft.) displays a distribution of poorly sorted angular and sub-angular clasts in a dark glassy matrix (scale of picture is 6.5 mm - long dimension). Under higher magnification (right, inset), the yellowish clast appears to be a partially melted carbonate clast with fossil ooids characteristic of a marine continental (carbonate reef) margin environment.

Figure 6. (Top) Photomicrograph in plane polarized light of Bedout-1 3044 m (9986 ft.) showing a large plagioclase lath (yellow brown color indicative of alteration) that has been shock melted. Another lath at upper left has also been shock melted (slide width 550 mm). The shock melted plagioclase glass is in the process of alteration (green). The matrix is composed of opaque Fe-Ti oxides (black) and albite (clear). The lower picture is the same view under crossed nicols. All of the plagioclase laths are now extinct (black) at all orientations indicating conversion to maskelynite, shock melted glass that suggests an impact. Note that the two maskelynite laths are at slightly different orientations yet both are completely extinct.

Figure 7(A). Photomicrograph of shock melted fragments of spherulitic glass from Bedout 3044 m (9986 ft.) set in a matrix of dark glass. Similar spherulitic alteration of glass has been identified in other terrestrial craters (e.g. Chicxulub, Sudbury). Width of slide is 1.0 mm.

(B). Back Scattered Electron Image of another spherulitic glass fragment from Bedout 3044 m (9986 ft.). Table 1, Analysis #22. Similar textures have been observed in BSE images of the Chicxulub suevite. Scale bar is 50 mm.

(C). Back Scattered Electron Image of high silica glass from Bedout 3044 m (9986 ft). The large grain of nearly pure silica (analyses #22 and #24) in the center of the image is set in a matrix of plagioclase, altered glass and Fe-Ti oxides. Note the dark and light areas of the BSE image that correspond to different levels of impurities in the silica glass. Ordinary volcanic processes cannot produce glass of >85% silica. Scale bar is 50 mm.

Figure 8. Shock melted plagioclase grains set in a matrix of albite, Fe-Ti Oxides and glass that is altering to chlorite 3044 m (9986 ft.). The rim of the large grain in the upper right is crystalline plagioclase (visible in X-nicols in Figureure inset) with a composition of An50 (analysis 3 in Table S-1). The core of this grain is isotropic glass with a similar composition of An50 plagioclase (analysis 4). Single plagioclase lath (left of center) contains andesine plagioclase (An50) (right side of grain, point 6), diaplectic glass in the center and pure albite (point 7) on the left.

Figure 9. Ar/Ar step-heating ages for the Lagrange-1 a plagioclase separate at 3255 m (10,679 ft.) from the top of the Bedout High indicate an age of 250.1 ± 4.5 Ma.

Figure 10. Reinterpreted 1994 AGSO multichannel seismic line s120-01. This interpretation shows the central uplift of the inferred Bedout impact structure deforming end-Permian (dark blue line) and older sequences (Pre-Permian, orange dashed line and Top Precambrian basement, red dashed line), overprinted by younger faults associated with late-Triassic to mid-Jurassic rifting. The "pre-Permian strata", are inferred only from seismic character (15), yet appear to show uplift with the basement. These reflectors are carried from wells in the adjacent onshore Canning basin.

Figure 11. (left) Blow-up of isostatic residual gravity model over Bedout as compared with (right) Bouguer gravity over Chicxulub (modeled after 12) at approximately the same scale. Diameters of the central uplift (~40-60 km) and transient crater (~100 km, dashed circle) inferred from the gravity model for Bedout are similar in size to these same features inferred for the Chicxulub impact structure. Gravity signature at Bedout is significantly reduced and more subdued than Chicxulub owing to its greater depth of burial (Bedout gravity model by Andrew Lockwood, GSWA, Perth Australia).

Figure 12. Shocked quartz in the K/T (yellow circles) and P/Tr (red crosses) boundaries. Shown is the distribution of the maximum grain size of shocked quartz with distance from the two proposed source craters (Chicxulub for K/T and Bedout for P/Tr). Solid line is a power regression through the K/T data (42).