Compiling biostratigraphic and borehole stratigraphic correlation data in the Amadeus, Georgina, Officer, South Nicholson and southern McArthur basins- Compilation of existing data and knowledge in a common stratigraphic framework  

Authors / CoAuthors

Rollet, N. | Hannaford, C. | Norton, C. | Kelman, A. | Bishop, C.

Abstract

<div>This report and associated data package provide a compilation of biostratigraphic summaries, borehole logs, and stratigraphic correlations for key boreholes across the Amadeus, Officer and Georgina basins in the Paleozoic‒Neoproterozoic Centralian Superbasin and in the underlying older Mesoproterozoic South Nicholson and southern McArthur basins, laying the groundwork for further studies. This study is part of Geoscience Australia’s National Groundwater Systems project in the Exploring for the Future (EFTF) program.</div><div>This work compiles publicly available borehole data to enhance regional stratigraphic understanding. Future studies should incorporate outcrop constraints, geophysical data, and additional geological dating, alongside collaboration with experts to validate sequence chronostratigraphic correlations. The stratigraphic framework aligns geological units with timeframes, enabling consistent interbasinal correlation to group aquifers and aquitards and sedimentary mapping across lithologies and time periods. This alignment supports the integration of hydrostratigraphic classifications, potentially revealing a more accurate model of water flow connectivity over geological time units. The compilation standardises borehole log interpretation and integrates geological and hydrogeological data, contributing to national databases, exploration guidance, improving groundwater understanding, and resource impact assessments for decision-making across various groundwater, energy and minerals disciplines.</div><div>The study builds on previous EFTF program work (e.g., Bradshaw et al., 2021; Khider et al., 2021; Carson et al., 2023; Anderson et al., 2023) and legacy studies across Australia, addressing challenges in understanding groundwater systems due to limited subsurface geology knowledge and fragmented data across jurisdictions. A nationally coordinated approach is essential, with well logs playing a key role in interpreting subsurface geology. The mapping process involves interpolating between surface outcrops and subsurface strata using borehole data, integrated with geophysical interpretations. The goal is to create a consistent 3D geological framework across time-equivalent basins and jurisdictions, enabling consistent groundwater system assessments and water flow path analysis at regional and national scales.</div><div>Although not intended to be a major re-interpretation of existing data, this stratigraphy review updates stratigraphic picks where necessary to ensure a consistent interpretation across the study area. This framework is based on the 13 Centralian Supersequences defined in Bradshaw et al. (2021). Using this framework, a revised stratigraphic chart is proposed in this study to align geological units across the Officer, Amadeus, and Georgina basins with the geological time scale (Gradstein et al., 2020), incorporating significant events, such as major glaciations, orogens and other tectonic movements. </div><div>This report aims to summarise the main biostratigraphic groups used, where they have been found, and provide a detailed list of the reports available. Existing biostratigraphic data from 142 boreholes in the Georgina, Amadeus, and Officer basins and underlying older southern McArthur and South Nicholson basins, were compiled to improve regional correlations, addressing data gaps identified in previous studies. Due to time constraints, only the five fossil groups found most in borehole data are included, such as trilobites, palynology, conodonts, stromatolites and small shelly fossils. However, outcrop data provides a much larger dataset and set of fossil groups and will need to be incorporated for future studies. Outcrop biostratigraphic data was excluded here, as the focus of this study was collating borehole data. Efforts were made to refine and update formation picks, ensuring consistency in correlations across larger areas. The correlation of geological units and their assignment to the corresponding 13 Centralian Supersequences in 272 key boreholes provide a foundational stratigraphic framework. Challenges include limited biostratigraphic data, diverse dating methods, and complex structural histories in the studied basins. Problems and inconsistencies in the input data or current interpretations are highlighted to suggest where further studies or investigations may be useful. Borehole correlation transects have been established across each of the basins (20 in total), displaying age data points along with formation picks and supersequence divisions. While these simple 2D transects may not capture the structural complexity of specific areas, they provide a broad overview of the interrelationships between different units across each basin.</div><div>The datasets compiled and used in this study are in Appendix A (Biostratigraphic data) and Appendix B (Borehole stratigraphic data).</div>

Product Type

document

eCat Id

149317

Contact for the resource

Digital Object Identifier

https://dx.doi.org/10.26186/149317

Keywords

( Project )

• National Groundwater Systems

• biostratigraphic data

• borehole stratigraphic correlation

• formation picks

• borehole log

• Centralian Superbasin

theme.ANZRC Fields of Research.rdf

• Stratigraphy (incl. biostratigraphysequence stratigraphy and basin analysis)

( Project )

• EFTF - Exploring for the Future

• Published_External

Publication Date

2024-10-10T22:10:52

Creation Date

2024-03-10T01:00:00

Security Constraints

Australian Government Security Classification System    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Use - license otherRestrictions

Status

completed

Purpose

Compilation of biostratigraphic data, existing formation picks, and correlating borehole log characteristics from diverse jurisdictions to bring outdated information up to date and to establish a unified stratigraphic framework within the Centralian Superbasin as a basis to consistently map hydrogeological surfaces across time-equivalent sedimentary basins in this region.

Maintenance Information

asNeeded

Topic Category

geoscientificInformation

Series Information

GA Record 2024/49

Lineage

<div>This study was undertaken under the Exploring For the Future National Groundwater Systems project.</div>

Parent Information

Extents

[-26.00, -11.00, 129.00, 138.00]

Reference System

Spatial Resolution

Service Information

Associations

Downloads and Links

Download the Record (pdf) [13.9 MB]  

Download Appendix A – Biostratigraphic data (zip) [128 KB]  

Download Appendix B – Borehole stratigraphic data (zip) [387.1 MB]  

Source Information