Papa New Guinea

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Understanding the evolution of basins and fold belts on New Guinea in a tectonic and geodynamic context are keys in unlocking oil and gas resources. Using simulations and modelling, this research project aims to value-add to decades of data collection and exploration and help inform risk analyses and interpretations for industry partners.
This project focuses on Papua New Guinea (PNG), which provides a modern template to study the evolution continental margins involved in a complex collisional setting, as well as very active surface processes. This project aims at understanding how the interplay of global mantle, regional tectonics and surface processes control the transfer of sediments from source to sink, and the thermo-tectonic evolution of oil and gas provinces in PNG.

A series of projects focusing on key aspects of the geodynamics, tectonics and surface processes are detailed below:

 

The sedimentary evolution of the Gulf of Papua

To understand the Late Quaternary evolution of source-to-sink systems in the Gulf of Papua, numerical simulations have been carried out. The simulations include the surface uplift and subsidence history of the Gulf and use present day precipitation rates. The simulation shows sediment delivered to the Gulf of Papua primarily by the Fly, Kikori and Purari Rivers and deposited in the western deep-sea basin, with shorter rivers draining the Papuan Peninsula contributing to sedimentation in the eastern Gulf. Sea level rise over the past 16 Kyr prevents the rivers draining the mainland from depositing directly into the deep-sea, with sediment becoming trapped on the submerged continental shelf.

 

Investigating the geological history of the Muller Range in the Papuan Fold and Thrust Belt

Thermal history models based on these data suggest two major Cenozoic cooling episodes. The youngest, and best constrained, is clearly recorded in the stratigraphic record and relates to Neogene collision at the northern margin of the Australian continent. An older episode of comparable or greater magnitude occurred in the Eocene to Oligocene and may relate to the removal of 1500–3000 m of Late Cretaceous to Eocene section across the Muller Range prior to the widespread deposition of the shelfal Darai Limestone. We suggest that extension along major faults beneath the Muller Range accommodated sedimentation from the Late Cretaceous to the Eocene, consistent with long-lived extensional structures observed in neighbouring regions. In contrast to the Muller Range area, an almost continuous Late Cretaceous to Eocene stratigraphic sequence is preserved in the hinterland <50 km to the northeast. The selective removal of this sequence across the Muller Range suggests it was uplifted in the Eocene to Oligocene, possibly in part facilitated by the inversion of extensional faults in the Muller Range area. We suggest that this inversion was related to the Eocene to Oligocene collision of the expansive Sepik Terrane to the northwest of the PNG margin. The new data and interpretations presented here have significant implications for the evolution of the Papuan Fold and Thrust Belt and for tectonic reconstructions of PNG.

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