Palaeogeographic evolution of the Triassic succession, central North West Shelf

Triassic petroleum systems on the central North West Shelf – Learnings from the greater Phoenix area seismic mapping and geochemical studies

“…The stratigraphic framework has been updated using new biostratigraphic analyses (Hannaford et al, 2016;. Recent seismic and well interpretations ( Figure 3; Abbott et al, 2019;Nguyen et al, 2019;Orlov et al, this volume) were used to produce paleogeographic maps showing the distribution of gross depositional facies (Abbott et al, this volume) and preserved extent of gross depositional facies at key intervals (TR10.0_SB-TR15.0_SB, TR15.0_SB-TR17.0_SB and TR17.0_SB-Top Triassic; Figures 4b, d and f, respectively) to predict source rock facies distribution and their depositional environments. The correlation of organic geochemical data with biostratigraphy and lithology identified regional intervals with source rock potential.…”

The influence of mantle flow on intracontinental basins: Three examples from Australia

“…Landward edge of Rowley Sub‐basin volcanic coliforms from Abbott et al. (2019b) is marked by the magenta line. Locations of Canning Basin wells that intersect igneous rocks from Reeckmann and Mebberson (1984) are indicated by white circles and Rowley Sub‐basin well intersections in black; the wells are only displayed at times which correspond to the probable age of the intrusions…”

“…The results for case M600 and the spatio-temporal extent of igneous rocks on the north-west shelf of Australia suggest an active mantle upwelling could have affected the area between 250 and 170 Ma (Figure 12). Recent (2014) 3D seismic acquisition in the Rowley Subbasin revealed clinoforms dipping 20°-30° landward, interpreted to represent a 10 km thick lava complex that prograded southeast from the Argo/West Burma landmass (Abbott et al, 2019b;MacNeill et al, 2018). Regional stratigraphy suggests the lava flows could be between 250-240 Myr old (Abbott et al, 2019a;MacNeill et al, 2018), and comparable seismic facies from the northwest Rowley Sub-basin may represent younger volcanism (240-210 Ma) (Abbott et al, 2019b).…”

“…Recent (2014) 3D seismic acquisition in the Rowley Subbasin revealed clinoforms dipping 20°-30° landward, interpreted to represent a 10 km thick lava complex that prograded southeast from the Argo/West Burma landmass (Abbott et al, 2019b;MacNeill et al, 2018). Regional stratigraphy suggests the lava flows could be between 250-240 Myr old (Abbott et al, 2019a;MacNeill et al, 2018), and comparable seismic facies from the northwest Rowley Sub-basin may represent younger volcanism (240-210 Ma) (Abbott et al, 2019b). MacNeill et al (2018) suggest an Early-Middle Triassic mantle plume could have produced the lava complexes; which is consistent with our model, in which a plume occurs within 10 Myr and 650 km of the Rowley Sub-basin lava flows (Figure 12).…”

Geochemical evidence for a new Triassic petroleum system on the western margin of Australia

“…1b), Lower to Middle Triassic rocks were investigated for their hydrocarbon source potential using publicly available Rock-Eval pyrolysis data to identify the most suitable candidates for oil to source correlations. Sediments between TR10.0_SB and TR15.0_SB were deposited in a fluvial-deltaic environment with occasional minor marine influences (Abbott et al 2019;Rollet et al 2019). In the Bedout Sub-basin, sedimentary rocks that have available geochemical data have a mean total organic carbon (TOC) content of 3.1 wt.% and a mean genetic potential S1 þ S2 of 9.4 mg hydrocarbons (HC)/g rock, exhibiting good to excellent hydrocarbon-generating potential.…”