DEPARTMENT OF MINES AND ENERGY

Uncovering the greater

McArthur Basin,

Northern Territory Tania Dhu

Manager Geophysics and Remote Sensing,

Northern Territory Geological Survey

www.minerals.nt.gov.au

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• Large, highly prospective, Palaeo-

Mesoproterozoic sedimentary basin

• Hosts the McArthur River Pb-Zn-Ag mine, within

the HYC Pyritic Shale Member of the Barney

Creek Formation in the Batten Fault Zone

• The ca 1640 Ma Barney Creek Formation is a

significant unconventional hydrocarbon prospect

• Oil and gas shows in Lamont Pass-3, Cow

Lagoon-1 and Glyde-1 ST1 (Armour Energy Ltd)

within the Batten Fault Zone

• Contains the Roper iron field within the 1500-

1400 Ma Roper Group

• Still relatively underexplored, especially away

from the exposed stratigraphy of the Batten Fault

Zone

• Extensive new work being undertaken by

industry including seismic and drilling

Why focus on the McArthur Basin?

Roper iron field McArthur

River Mine

Batten Fault Zone

Cow Lagoon 1

Lamont Pass-3

Glyde-1 ST1

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• Stratigraphic correlations between the McArthur

Basin, Birrindudu Basin and Tomkinson

Province have been recognised – Stratigraphic correlations recognised based on

lithostratigraphy, age of tuffaceous units and similar

provenance from U-Pb dating of detritral zircons

producing maximum deposition ages

– Interpretation of newly acquired seismic data supports

undercover continuity between these basins

• The interpreted extent of these regions has

been informally referred to as the greater

McArthur Basin (black line) extends across

almost half the Northern Territory however

further work is required to: – Understand the true extent of the McArthur Basin,

Birrindudu Basin and Tomkinson Province and identify

any links between them

– Establish stratigraphic correlations

– Understand the 3D architecture and structural evolution

of the Basin

The greater McArthur Basin

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• Southern McArthur Basin Gravity

Survey (funded through the

Creating Opportunities for

Resource Exploration – CORE

initiative) – 4,618 stations at 4 x 4 km spacing

– Falcon Oil & Gas Australia Ltd and

Santos Limited collaborated to infill

areas of interest to 2 x 2 km spacing,

1,657 stations

• Dunmarra magnetic and

radiometric survey scheduled to

commence in June

• Proposed Northern McArthur

Basin Gravity Survey dependent

on initiative funding

Current Work - Geophysics

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• Unconventional hydrocarbon potential and

metallogenic assessment of shales – Petroleum sampling program for source rock analysis,

palynology, geochemistry and formation evaluation

– Metallogenic sampling program for precious and base

metals, including geochemical characterisation for

evidence of metal mobilisation

– Unconventional hydrocarbon assessment using the

USGS methodology

• Stratigraphic correlation within the greater

McArthur Basin – Systematic characterisation of outcropping and drillcore

stratigraphy (sedimentology, petrography,

biostratigraphy, depositional environment)

– Compilation of baseline geochemistry, stable isotope and

geochronological datasets

• Correlation of drillcore stratigraphy using the

HyLoggerTM – Applying the HyLogger to identify discrepancies between

logged stratigraphy and mineralogy

Current Work - Geology

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• Understanding the structural evolution of the

greater McArthur Basin (PGN Geosciences) – Interpreting geophysical data to assist in understanding

basin architecture and evolution through time

– Identifying potential growth faults and depocentres

• 3D model of the McArthur Basin – View heterogeneous geophysical and geological data in

a single environment to allow a consistent interpretation

that addresses all data

– Using the model to identify discrepancies in the data and

areas where more data is required, addressing these

issues than creating new model realisations

Current Work – 3D Basin Architecture

www.nt.gov.au DEPARTMENT OF MINES AND ENERGY

• NTGS is undertaking a range of projects aimed at

improving our understanding of the extent and

prospectivity of the greater McArthur Basin

• Current efforts in the basin are producing new data that

is feeding into this work

• In many instances NTGS has been able to work closely

with industry with sharing of both closed file data and

interpretation

• The challenge remains producing products in a timely

manner that build the regional framework but respect

data confidentiality

Summary