Sedimentological and petrophysical characterisation of the Birrindudu Basin, Northern Territory

Abstract

The Birrindudu Basin is located in the north-western Northern Territory and comprises sedimentary successions of Palaeoproterozoic to Mesoproterozoic age. To date, there has not been a consistent sedimentological and stratigraphic framework developed to investigate the evolution of the Birrindudu Basin and its sedimentary fill, nor has there been a thorough assessment of its sediment-hosted mineral potential. This is due in part to the remote and isolated location of this frontier basin and the paucity of subsurface geoscientific data available.

A collaborative study commissioned by the Northern Territory Geological Survey (NTGS) under its Resourcing the Territory program and being undertaken by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) seeks to address these gaps in our knowledge. This Record represents the findings of Module 1 of this study; namely the systematic characterisation of the sedimentary facies and petrophysical signature of the Birrindudu Basin succession. Establishing a sequence stratigraphic framework of the Birrindudu Basin and conducting a detailed assessment of its sediment-hosted mineral potential will form the crux of future Module 2 of this study.

Petrophysical data acquisition (handheld gamma, sonic velocity and pXRF) and detailed sedimentary logging and facies analysis were undertaken on core from six diamond drillholes from across the Birrindudu Basin: WLMB001B, LBD2, ANT003, Hidden Valley S2, Manbulloo S1, and NTGS 82/68. The appendices contain the following data for each drillhole:

DataSummary.pdf

FaciesAssociations_Codes.xlsx

FaciesAssociations_Depths.xlsx

GammaRay.xlsx

GammaRay.las

Lithofacies_Depths.xlsx

PwaveVelocity.xlsx

PwaveVelocity.las

SedimentaryLog.pdf

This Record details 32 distinct sedimentary lithofacies that have been grouped into nine discrete sedimentary facies associations, in addition to a downhole synthesis of petrophysical data across the six drillholes. Furthermore, this Record also illustrates preliminary interpretations of the palaeogeographic evolution of the Birrindudu Basin. Investigations of intrabasinal stratigraphic correlations and the sequence stratigraphic framework of the Birrindudu Basin, in addition to discussion regarding its sediment-hosted mineral potential, will be detailed in Module 2.This Record details 32 distinct sedimentary lithofacies that have been grouped into nine discrete sedimentary facies associations, in addition to a downhole synthesis of petrophysical data across the six drillholes. Furthermore, this Record also illustrates preliminary interpretations of the palaeogeographic evolution of the Birrindudu Basin. Investigations of intrabasinal stratigraphic correlations and the sequence stratigraphic framework of the Birrindudu Basin, in addition to discussion regarding its sediment-hosted mineral potential, will be detailed in Module 2.