Exploration Permit for Coal (Epc) 1633 Augathella South East 1

EXPLORATION PERMIT FOR COAL (EPC) 1633 AUGATHELLA SOUTH EAST 1

FINAL REPORT FOR THE PERIOD 29 OCTOBER 2010 – 12 FEBRUARY 2015

TENEMENT HOLDER(S): Tambo Coal & Gas Pty Ltd Coalbank Limited

PREPARED BY: Bruce Patrick Coalbank Limited

SUBMITTED BY: COALBANK Limited

EPC1633 Final Report February 2016

CONTENTS

COPYRIGHT STATEMENT ...... 1 1.0 SUMMARY ...... 2 2.0 INTRODUCTION ...... 3 2.1 Tenure ...... 3 2.2 Location and Access ...... 4 2.3 Previous Exploration ...... 7 2.3.1 Exploration History – Coal ...... 7 2.4.2 Exploration History – Petroleum and Stratigraphic Boreholes ...... 10 3.0 GEOLOGY ...... 14 3.1 Regional Geology ...... 14 3.2 Stratigraphy ...... 14 3.3 Structure ...... 15 3.4 Coal Measures ...... 16 3.5 Coal Quality ...... 16 3.6 Geology of EPC 1633 ...... 17 4.0 CURRENT WORK PROGRAMME ...... 18 4.1 Openfile Data Review ...... 18 4.2 Photogeological Interpretation ...... 19 4.3 Exploration Drilling ...... 20 4.4 Data Processing ...... 21 5.0 RESULTS/CONCLUSIONS ...... 23 6.0 REFERENCES ...... 24

Tables Table 1 EPC 1633 Blocks and Sub-blocks at Grant Table 2 EPC 1633 Blocks and Sub-blocks at Surrender

Figures Figure 1 Location of COALBANK Limited’s Eromanga and Surat Basins Coal Project Figure 2 Location of EPC 1633 (Augathella South East 1) Figure 3 Historical exploration in and around the Eromanga and Surat Basins Coal project area

EPC1633 Final Report February 2016

Figure 4 Stratigraphy of the Eromanga and Surat Basins Figure 5 EPC 1633 Historical Boreholes Figure 6 EPC 1633 Drilling Targets Figure 7 Coalbank Eromanga and Surat Basins Photogeological Interpretation

Appendices Appendix 1 Photogeological Report

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ACKNOWLEDGEMENT AND WARRANTY 1. Subject to 2, the mining tenement holder acknowledges that this report, including the material, information and data incorporated in it, has been made under the direction or control of the State of Queensland (the State) within the meaning of section 176 of the Copyright Act 1968 (Cwlth). 2. To the extent that copyright in any material included in this report is not owned by the State, the mining tenement holder warrants that it has the full legal right and authority to grant, and does hereby grant, to the State, subject to any confidentiality obligation undertaken by the State, the right to do (including to authorise any other person to do) any act in the copyright, including to:  use;  reproduce;  publish; or  communicate in electronic form to the public, such material, including any data and information included in the material. 3. Without limiting the scope of 1 and 2 above, the mining tenement holder warrants that all relevant authorizations and consents have been obtained for all acts referred to in 1 and 2 above, to ensure that the doing of any of the acts is not unauthorized within the meaning of section 29(6) of the Copyright Act 1968 (Cwlth).

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1.0 SUMMARY

Exploration Permit for Coal (EPC) 1633 (Augathella South East 1) was granted jointly to Lodestone Energy Limited and Tambo Coal & Gas Pty Ltd on the 29th October 2010 for a term of 5 years. On the 2nd June 2011

Coalbank Limited’s Eromanga and Surat Coal Project tenements provide leverage to a vast area of the Eromanga Basin and western Surat Basin that is almost totally under- explored for coal.

A database of historical geological information for the entire Eromanga and Surat Basins Coal Project area was assembled. To facilitate this, the Company acquired all available water bore data for the area, as well as any GSQ stratigraphic borehole data and open file drilling records. Over 3400 boreholes were thus obtained, dating from 2009 back to the 1890s. The vast majority of the holes were water bores, with the remainder being oil and gas exploration wells, GSQ boreholes and a few coal and oil shale exploration holes.

The database contains 15 historical boreholes located within EPC 1633, of which 3 have records of coal being intersected during drilling (Figure 5).

Over time 110 sub-blocks have been relinquished from EPC 1633 in areas that Coalbank considered of low exploration potential, with 52 sub-blocks retained.

No field based exploration has been carried out during the period of tenure.

In 2014 Coalbank further reviewed the economic potential of the permit and it has been surrendered.

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2.0 INTRODUCTION Coalbank Limited’s Eromanga and Surat Basins Coal Project are early stage exploration project overlying the eastern margin of the Eromanga Basin and western margin of the Surat Basin in southwestern Queensland.

2.1 Tenure Exploration Permit for Coal Number EPC 1633 (Augathella South East 1) was granted jointly to Lodestone Energy Limited and Tambo Coal & Gas Pty Ltd on the 29th October 2010 for a term of 5 years. On the 2nd June 2011 Lodestone Energy Limited changed its name to Coalbank Limited, and Tambo Coal & Gas Pty Ltd is now a 100% owned subsidiary of Coalbank Limited.

The tenement originally consisted of 162 sub-blocks as listed below in Table 1.

1:1M Block Number of Sub- Identification Map Block ID Sub-Block ID Blocks CHARLEVILLE 1692 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1693 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1694 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1766 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1767 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1839 ABCDEFGHJKLMNOPQRSTUVWXYZ 25 CHARLEVILLE 1840 ABCDE 5 CHARLEVILLE 1841 ABCDE JK 7 Total Sub-Blocks 162

Table 1: EPC 1633 Blocks and Sub-blocks at Grant

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The tenement was reduced to 52 sub-blocks through a relinquishment in November 2012. Current sub-blocks are listed in Table 2 below:

1:1M Block Number of Sub- Identification Map Block ID Sub-Block ID Blocks CHARLEVILLE 1694 DE JK OP UZ 8 CHARLEVILLE 1766 E 1 CHARLEVILLE 1767 ABCGHJMNORSTVWXYZ 17 CHARLEVILLE 1839 ABCDEFGHJKLMNO 14 CHARLEVILLE 1840 ABCDE 5 CHARLEVILLE 1841 ABCDE JK 7 Total Sub-Blocks 52

Table 2: EPC 1633 Blocks and Sub-blocks at Surrender

2.2 Location and Access The Eromanga and Surat Basins Coal Project area is located in southwestern Queensland, some 110km northeast of Charleville and 680km west-northwest of Brisbane. The EPC’s making up the project extended over a 400km strike length, from 20km north of Roma to 125km north of Tambo (Figure 1).

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Figure 1: Location of Coalbank Limited’s Eromanga and Surat Basins Coal Project

EPC 1633 is located in the southwestern portion of the Eromanga and Surat Basins Coal Project area, and is situated some 60km southeast of Augathella township and about 100km northeast of Charleville (Figure 2). Qantas Airways has daily scheduled commercial flights between Brisbane and Charleville, and major sealed highways link Charleville to Augathella and Morven, and the Landsborough Highway (A2) links Augathella and Morven. The primary access into EPC 1633 is from the west via the unsealed Clara Creek Road that branches off the Landsborough Highway, or from the south via the Killarney- Morven Road or Winneba Road from Morven. Unsealed minor roads and farm tracks branch off these roads and will be used for exploration activities.

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Figure 2: Location of EPC 1633 (Augathella South East 1)

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2.3 Previous Exploration The Eromanga and Surat Basins Coal Project adjoins EPC’s held by other companies to the north, west and southeast. There are no coal mines or gas production areas within the project area but extensive resources of both commodities have been defined to the southeast and north.

2.3.1 Exploration History – Coal The Eromanga and Surat Basins Coal Project area is largely lacking in any previous coal exploration activity. Much of the region had Restricted Area status (as part of RA 55) and hence was not available for coal exploration. Historical coal tenements in the Project area are mostly confined to the western parts of the Surat Basin, and to the Rolleston- Springsure Shelf region to the north where the Permian Bandanna/Rangal Formation is the target. Those historical coal tenements that covered (more or less) equivalent stratigraphic intervals to the Eromanga and Surat Basins Coal Project are illustrated in Figure 3a & b.

The following is a brief summary of exploration results obtained from relevant historical coal tenements that covered (more or less) equivalent stratigraphic intervals to those of the Eromanga and Surat Basins Coal Project.

EPC 151 ‘Injune’ This prospect, located immediately east and north of Coalbank EPC’s 1623 and 1795 (Figure 3a), was held by a Joint Venture between Brigalow Mines Pty Ltd and Syncline Pty Ltd for 8 years from 1974 to 1982. The JV drilled almost 200 boreholes in an area of known Walloon Coal Measures and was able to define a small coal deposit of some 22 million tonnes in the northwestern portion of the tenement – the Bymount deposit. Coal seams were intersected elsewhere in the lease but were generally thin (<2.5m), banded, dirty and limited in lateral extent.

The tenure was surrendered in 1982 because the Bymount deposit was not large enough to justify its development as a mine, and it was believed that insufficient additional resources existed within the rest of the tenement.

EPC 154 ‘Blackall’ This tenement was held briefly by Brigalow Mines Pty Ltd in 1974-1975 while the company evaluated reports of coal seams intersected by earlier shot hole drilling for a seismic programme in 1962-1963. Thirty-eight open and partly cored boreholes were drilled for seam correlation and coal quality purposes. A number of thin, banded seams were

7 EPC1633 Final Report February 2016 encountered within the Cretaceous aged Winton Formation. However the coals were deemed to be of poor quality, very low rank, with high ash, low volatile and poor specific energy values. Furthermore, the coal seam horizons were believed to be discontinuous laterally and multi-split, so that any resources would be contained in small, discontinuous deposits not conducive to mining. The tenure was relinquished after only 1 year.

EPC 259 ‘Merivale’ From 1979 to 1984, Marathon Petroleum’s EPC 259 ‘Merivale’ covered an area to the north and east of Coalbank EPC’s 1623 and 1624 (Figure 3a). Exploration was conducted over an area of Walloon Coal Measures/Birkhead Formation within the Merivale Syncline. A total of 227 cored and non-cored boreholes were drilled, with most being geophysically logged. Many coal horizons were intersected in the exploration drilling but most were thin and banded, and they characteristically exhibited considerable variations over short lateral distances. Two small inferred coal resources were defined (Munya, and Ninderra resources) within the tenement for an aggregate of 35 million tonnes of in situ coal.

The tenement was relinquished because it contained only limited resources that were situated a long way from any mining or transport infrastructure at that time.

EPC 263 ‘Forest Vale’ The ‘Forest Vale’ area, EPC 263, in the westernmost part of the Surat Basin was held briefly by Mobil Energy Minerals Australia between 1979 and 1981. It coincides with an area immediately to the north of, and adjacent to the Eromanga and Surat Basins Coal Project EPC’s 1623, 1624 and 1777 (Figure 3a).

During its tenure, Mobil carried out significant rotary chip drilling and minor coring, together with geophysical logging of all holes. Some 66 drill holes were completed, most of which intersected coal seams within the Taroom and/or Juandah Coal Measures. The Juandah Coal Measures were generally 30 to 40m thick and contained a good number of thin (up to 2m) coal seams that gave an aggregate coal thickness of 3 to 4m. The Taroom Coal Measures averaged 55m thick but its coal seams were thinner (up to 1m thick) and not as regularly spaced as in the Juandah’s. Despite the obvious presence of coal resources at relatively shallow depths, the tenement was relinquished.

EPC 288 ‘Lucky Downs’ This EPC, covering the northeastern corner of Coalbank EPC 1795 (Figure 3a), was granted to Marathon Petroleum Australia in February 1980 but was relinquished after only 6 months. The Company drilled, and geophysically logged, 24 rotary chip holes up to

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180m deep across the tenement. The exploration target was the Walloon Coal Measures, however only rocks of the Westbourne to Orallo Formations were encountered. Some coal seams up to 1.8m thick were intersected in the drilling but most were less than 0.8m thick. From the results of the exploration, the prospects for finding mineable open cut resources were deemed to be severely limited and the tenure was released.

EPC 314 ‘Redford’ EPC 314, held by CRA Exploration (Pacific Coal Pty Ltd) between 1980 and 1981, is probably the most relevant historical tenement for the Eromanga and Surat Basins Coal Project as it coincides with a significant area of Coalbank EPC’s 1414 and 1776 (Figure 3a). Pacific Coal conducted an initial period of scout mapping and ground-truthing in an effort to target its exploration effort - ultimately drilling 31 rotary holes, including 8 partially cored holes. Seven (7) holes intersected minor coal seams, up to a maximum thickness of 0.7 metres. Although their tenement area was very large, the drilling campaign completed by Pacific Coal covered only a very small percentage of the tenement area.

In its final report, Pacific Coal states “…It was thought that some thickening of the coal horizons in the Birkhead Formation might occur to the northwest, away from the Nebine Ridge. However, the constraint imposed by the southern boundary of the Central Queensland Coal Reserve Area 55D prevented application for potentially more prospective ground in the region of the Chesterton Syncline and other synclinal axes to the northwest.” (Hewitt, 1981).

EPC 937 EPC 937 is located in the southeastern corner of the Coalbank EPC area immediately adjacent to EPC 1795 (Figure 3b). It was granted to Santos QNT Pty Ltd in May 2005 for an initial 3 year period and then renewed in May 2008 for a further 3 years. The Company has relinquished a significant portion of the original grant area in two separate tranches. Open file reports exist for these relinquishment transactions but no new exploration work was carried out in either of the relinquished areas prior to their release. And the geological content of the EPC area cannot be determined from the available reports.

EPC 1149 ‘Blackall’ This is a current exploration permit held by East Energy Resources Limited, located in the west-southwest of the Tambo Project area and in part immediately adjacent to Coalbank’s EPC 1993 (Figure 3b). It is more or less coincident with EPC 154 described above. No openfile information from East Energy’s exploration is yet available but information on the

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Company’s website indicates that the tenement contains significant coal resources within the Winton Formation.

EPC 1155 ‘Jericho South’ This tenement is currently held by Waratah Coal as part of the Company’s Galilee Coal Project. It bounds Coalbank’s EPC 1697 to the north and east (Figure 3b). No information pertaining to the lease is publically available.

EPC 1167 ‘Roma North’ This current tenement is held by Metrocoal Limited and it abuts part of the eastern boundary of Coalbank’s EPC 1795 (Figure 3b). It was granted in December 2007 for a 3 year period.

While it contains the Clifford and Norwood coal deposits (Juandah Coal Measures) in the far eastern portion of the EPC, no data pertaining to the potential of the western portion of the EPC adjacent to EPC 1795 is publically available.

EPC 1190, EPC 1191, EPC 1192, EPC 1203 These four tenements form a contiguous exploration area held by Argos (Qld) Pty Ltd immediately adjacent to the Coalbank EPC’s 1623, 1624, 1777, 1789, 1795 and 1800 (Figure 3b). The leases were granted variously between January and April 2008, and there are as yet no open file company reports available on which to assess exploration results, potential, or the geology of the area.

The tenements in part coincide with the known location of the Hendon Park and Cornwall inferred coal resource areas, which lie close to the western boundary of EPC 1192 and adjacent to the neighbouring Tambo tenement, EPC 1623.

EPC 1816 This newly granted tenement was assigned to New Coal Energy Pty Ltd in December 2009 for 5 year period. It adjoins the southern boundary of Coalbank’s EPC 1795 (Figure 3b). No information is yet publically available for the tenement.

2.4.2 Exploration History – Petroleum and Stratigraphic Boreholes While the Eromanga and Surat Basins Coal Project EPC’s have only a limited coal exploration history, the number of petroleum tenure records for the area is more significant. The drilling of petroleum exploration wells has occurred across the Coalbank study area from the late 1920’s up to 2004. These usually penetrate deep into the rock

10 EPC1633 Final Report February 2016 section and have significant datasets. Open file records for 31 such wells are available for the Tambo Coal Project area (Figure 3b). Wells with information relevant to Coalbank’s coal exploration include:-  Allendale 1,  Bindango 1,  Brynderwin 1,  Donnybrook 1,  Dulbydilla 1,  Eldorado 1,  Esor 1 and Esor 2,  Heather Downs 1,  Mooga 3,  Mungallala 1 and 2,  Nive River 1,  Swaylands 1,  Valetta 1,  Wollomai 1.

However, not all of the petroleum exploration data have proved to be suitable for coal exploration purposes. For example, seismic recordings often do not show the shallow portions of the sequences, which is precisely the zone that most coal exploration companies are interested in. To be usable, those seismic lines that actually recorded the shallow depths will need to be reprocessed.

Boreholes drilled for stratigraphic purposes by Government agencies (GSQ and BMR) are another good source of exploration data. These were fully-cored holes (from surface), and provide high quality, reliable and accurate descriptions of the sections penetrated, and were often also geophysically logged. Some 23 such boreholes are located within the Eromanga and Surat Basins Coal Project area (Figure 3b) and the following have been used to date:-  BMR Augathella 3 and 7,  GSQ DRD 25 and 26,  GSQ Mitchell 1 and 2  BMR Roma 7 and 7A,  GSQ Tambo 2.

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There is evidence in these holes that coal is present, spread over a relatively wide stratigraphic interval, from at least the Hooray Sandstone (re-picked by Coalbank to be within the Birkhead Formation) at the top of the sequence, to the Evergreen Formation.

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Figure 3a & b: Historical exploration in and around the Eromanga and Surat Basins Coal Project area

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3.0 GEOLOGY 3.1 Regional Geology The Eromanga and Surat Basins Coal Project is located within the southeastern Eromanga Basin and western Surat Basin. Both the Eromanga and Surat Basins are components of the Great Artesian Basin which is a Jurassic-Cretaceous intra-cratonic basin that covers 1.7 million km2 of Eastern Australia. Whilst the Surat and Eromanga basins are separated by the Nebine Ridge, a structural basement high trending north- south and aligned approximately through Morven and Injune, both contain age-equivalent and lithologically very similar rock sequences.

The stratigraphy of each basin was defined during the 1960s by the Bureau of Mineral Resources (now Geoscience Australia) using separate geological teams to map the Eromanga and Surat Basins at 1:250,000 scale. The boundary between the areas of responsibility of two teams seems to coincide with the boundary between the Surat Basin and the Eromanga Basin. Consequently different stratigraphic units have been distinguished for each basin and the gap between these two data sets was arbitrarily divided. The published stratigraphy has generally continued to be used by oil and gas explorers in the Eromanga Basin and by coal and CSG explorers in the Surat Basin. Whilst extensive exploration for shallow coal resources in the Walloon Coal Measures has enhanced the understanding of the stratigraphy in the Surat Basin, the Jurassic sediments of the Eromanga Basin have been largely ignored for their coal potential.

3.2 Stratigraphy The regional geology of the Surat Basin has been described in detail by Exon (1976, 1980) Jones & Patrick (1981) and Goscombe & Coxhead (1995). The Eromanga and Surat Basins contain sediments of fluvial and fluvial-lacustrine origin deposited during the late Triassic to the early Cretaceous, followed by fluvial sedimentation in the early-middle Cretaceous. A number of sedimentation cycles have been recognised in both basins which are considered to be tectonic-eustatic cycles, related to varying tectonic activity in the active volcanic arc which existed to the eastern margin of these intra-cratonic basins. The thickest sedimentation occurred in the slowly subsiding Taroom Trough with up to 2,500m of sedimentary rocks deposited.

The Jurassic and Cretaceous stratigraphy of the Eromanga and Surat Basins is shown in Figure 4. The Early Jurassic was dominated by deposition of fluvial sands and silts forming the Precipice and Hutton Sandstones with the intermediate Evergreen Formation. This was followed in the Middle Jurassic by the generally finer grained sediments from a lower

14 EPC1633 Final Report February 2016 fluviatile-deltaic environment of the Injune Creek Group. In the Late Jurassic to Early Cretaceous a more fluviatile environment was again established. Since the Late Jurassic, the Surat and Eromanga Basins have been stable with a marine transgression in the Early Cretaceous which withdrew in the Late Cretaceous. Weathering of the land surface during the Tertiary created a deep weathering profile which was largely stripped from the northern areas of these basins by subsequent erosion.

Figure 4: Stratigraphy of the Eromanga and Surat Basins

3.3 Structure The Surat Basin is bounded to the east by the Kumbarilla Ridge, to the southeast by the New England Fold Belt, to the southwest by the Central West Folded Belt, and to the north by the Permo-Triassic Bowen Basin. The basin is centred on the north-south trending axis of the Mimosa Syncline. The subcrop of the Surat Basin extends in a generally east- southeast to west-northwest line from east of Chinchilla to west of Mitchell where it converges with the more northerly trending Eromanga Basin. The boundary of the two basins is considered to be the north-south trending Nebine Ridge. The strata of the Surat Basin dip gently to the southwest and south whilst the Eromanga strata have a more southwesterly direction. Major faulting within the basin predominantly mirrors basinal

15 EPC1633 Final Report February 2016 boundary faults of the underlying Bowen Basin. There is substantial folding across the basin, which is due to compaction and draping, as well as some rejuvenation of older pre- Jurassic structures and faults. The north-south trending Burunga – Leichhardt Fault zone interrupts the eastern limb of the basin.

3.4 Coal Measures Across the Surat Basin there have been several coal seam groups identified and correlated within the Walloon Coal Measures. The Juandah Coal Measures generally contains five groups of coal seams. In descending stratigraphic order these are the Kogan, Macalister (Upper and Lower), Wambo, Iona and Argyle seam groups. Within the Taroom Coal Measures three groups are recognised, being the Auburn, Bulwer, and Condamine.

Whilst coal seam groups can be identified over many kilometres it is not generally possible to easily correlate individual seams over significant distances. These seams are highly variable in thickness and are known to thin and split over hundreds of meters. Similarly, these seams and plies can rapidly coalesce and form relatively thick coal intervals with minimal clastic partings. Between depocentres, the seams may still exist but are thin and separated by various thicknesses of lithic sediments.

Individual seams are typically less than 2m thick but in some places there are 30 or more individual coal seams. In the eastern Surat Basin the Walloon Coal Measures is 300 to 350m thick and contains 20 to 30m of net coal. Traditionally, the overall Walloon’s thickness and the amount of net coal present are thought to thin towards the west, becoming 150 to 200m thick, with 10 to 15m of net coal, on the Roma Shelf.

Coal has also been recorded in the Westbourne, Orallo and Bungil Formations, as well as at the top of the Hooray Sandstone and in the Winton Formation. Of these, the most significant are probably in the early Cretaceous Winton Formation of the Eromanga Basin where lenticular coal seams, up to 5m thick, occurring within a broader (24m) package of coal, carbonaceous shale, siltstone and minor sandstone, have been reported at shallow depths.

3.5 Coal Quality All of the known coal resources in the Surat Basin are low rank sub-bituminous to bituminous and are of thermal quality. They are generally of moderate ash, high volatile, moderate energy but provide excellent combustion and burn-out characteristics with minimal slagging and fouling problems, and low levels of trace elements and atmospheric

16 EPC1633 Final Report February 2016 pollutants. They are also perhydrous and are potentially suited to gasification or liquefaction to produce liquid fuels. Coals of the Walloon Coal Measures also contain (up to 30%) more organically-bound hydrogen than most other thermal coals which results in lower combustion emissions of carbon dioxide (kg per MWh sent-out).

The coal resources in the Eromanga Basin are low rank, high ash, low volatile and poor specific energy. Both Surat and Eromanga coals show improved quality characteristics after washing.

3.6 Geology of EPC 1633 EPC 1633 is situated just to the west of the Nebine Ridge so, by definition, is located within the Eromanga Basin. The area is relatively benign structurally except for an un- named, northeast trending anticline that crosses the centre of the EPC and has a very strong influence on the regional strike of bedding. To the north of this structure, bedding appears to be generally trending north-south but changes to a more northwest-southeast trend south of the anticline.

Previous mapping (Exon, 1968; Exon, 1971; Galloway et al, 1970) suggests that the sandstone-dominated rock units outcropping within the EPC belong to the Doncaster Member, Hooray Sandstone and Westbourne Formation portion of the sequence. In addition, significant areas of the EPC are blanketed by Quaternary (sands, gravels, clays and soils) and Tertiary (clayey sandstones, sandy mudstones, siltstones and conglomerates) alluvial sediments. Coalbank’s modifications to this stratigraphy from the new photogeological interpretations are yet to be tested in the field.

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4.0 CURRENT WORK PROGRAMME In the period since the application for EPC 1633 was first lodged in October 2008, Coalbank has been engaged in a number of different exploration activities relating to the EPC and these are summarised below.

4.1 Openfile Data Review Coalbank’s initial effort was directed towards building up a database of historical geological information for the entire Eromanga and Surat Basins Coal Project area. To facilitate this, the Company acquired all available water bore data for the area, as well as any GSQ stratigraphic borehole data and open file drilling records. Almost 3800 boreholes have thus been obtained, dating from 2009 back to the 1890’s. The vast majority of the holes are water bores, with the remainder being oil and gas exploration wells, GSQ boreholes and a few coal and oil shale exploration holes.

Given the wide range of data sources, the borehole information was of varying quality, complexity and reliability, so it had to be converted where possible into a standardised (digital) format for evaluation. All borehole collar elevations were adjusted to a single datum using the Shuttle Radar Topography Mission (SRTM) digital elevation model data with an accuracy of +/-10m. Any recorded lithological information was converted from English language descriptions into geological codes using a standardised dictionary tool. Coal seams were labelled where possible to enable evaluation of the depth, thickness and extent of any potential resources. Coal horizons were double-checked for accuracy against wireline logs in those few boreholes that had been geophysically logged. Stratigraphic units were identified and labelled with both the historically defined units and Coalbank‘s re- interpreted nomenclature. These re-interpreted unit names were a combination of conversions from original Eromanga Basin formation nomenclature to the equivalent Surat Basin nomenclature, plus the reassignment of formations to fit in with Coalbank’s new stratigraphic model.

The resulting database was then interrogated to highlight all intervals that mentioned coal seams or coaly material. Boreholes with coal horizons within the Taroom and Juandah Coal Measures were of most interest and these were assessed to determine the total thickness of coal in the borehole and the depth of occurrence. A prioritised list of potential drilling targets across the full Eromanga and Surat Basins Coal Project area was developed via this process.

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The database contains 15 historical boreholes located within EPC 1633, of which 3 have records of coal being intersected during drilling (Figure 5). One of these holes, waterbore RN116119 was selected as the primary target for Coalbank’s initial exploration drilling programme within EPC1633 (Figure 6).

Figure 5: EPC 1633 historical boreholes

4.2 Photogeological Interpretation In October 2009, Coalbank commissioned consultants Colin Nash and Associates Pty Ltd to conduct a 1:100,000 scale photogeological study over an area of 11,700km2 in the Tambo-Augathella area. The objective of the study was to investigate the local stratigraphy and structure of the Eromanga/Surat Basins with a view to providing drilling targets for Coalbank’s gas exploration lease. The outstanding results obtained from the initial phase of work led Coalbank to commission Colin Nash and Associates to carry out three further extensions to the study, one to the north (February 2010), one to the south (December 2009-January 2010), and one to the southeast (April 2010) until all portions of the Eromanga and Surat Basins Coal Project area were covered. In total, an area of some 45,000km2 has been analysed.

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The study was carried out using stereoscopic, 2.5m resolution, natural colour LANDSAT/SPOTMAPS satellite imagery, processed with SRTM DEM topographic data to produce hardcopy 1:100,000 scale pseudo-stereo images for interpretation. A total of 27 stereopairs were produced, each consisting of a normal Vertical image with coordinate grid and a Left Stereo image for stereo viewing. Photogeological interpretation of the 1:100,000 scale hardcopy stereopairs was carried out by viewing the Vertical and Left-Stereo images under a mirror stereoscope, with reference to available geological maps in ArcView GIS. Interpreted geological data were annotated in ink onto clear drafting film overlay sheets. The interpretation sheets were printed on stable matt film, and hand-coloured to show relevant lithology and structure. The hand-coloured maps were colour scanned, geo- referenced and digitally mosaiced to produce a GIS compatible final image.

The final interpretation provides excellent definition of the poorly-exposed Mesozoic strata in the whole Eromanga and Surat Basins Coal Project study area and has clearly identified discernable stratigraphic units continuing from the Surat Basin into the Eromanga Basin. The work has highlighted some significant errors in the published geology for the region and challenges the previous understanding of the structural controls to sedimentation in the area. The interpretation includes a major facies change across the Claraville lineament (a north-south trending structure between Roma and Mitchell) marked by a substantial sandstone dominated package to the west, and some significant unconformities. This transitional upper Surat Basin sequence displays strong lateral changes in thickness and continuity, and is interpreted to thin to the west over the Nebine Antiform. Available borehole data suggests that coal measures do exist within this package and potentially represent an upper Juandah Coal Measure sequence. This interpretation supports Coalbank‘s contention that the coal bearing strata in the study area may be the lateral equivalent of the Walloon Coal Measures and may be thicker than previously understood.

A copy of the final report is included herein as Appendix 1.

4.3 Exploration Drilling In mid November 2009 Coalbank mobilised a drilling company to carry out an initial exploration drilling programme within the granted EPC’s of the Eromanga and Surat Basins Coal Project.

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The focus of exploration was to be around waterbore RN116119 in the centre of the EPC. A potential drilling grid of 1km by 1km spaced drill sites around the central target waterbore had been proposed for this area.

Figure 6: EPC 1633 planned drilling targets

4.4 Data Processing Coalbank continued to expand its database of technical information, and refine its stratigraphic interpretations of the Eromanga and Surat Basins Coal Project area. Additional historical drilling records, plus new boreholes drilled to date by Coalbank have been uploaded to the Company’s digital borehole database. The database now includes almost 3500 boreholes, comprised mainly of water bores but with some petroleum and gas exploration wells, Government stratigraphic bores and coal exploration boreholes.

To further assist with developing exploration drilling targets, the borehole database has been utilised to construct a series of regional scale, stratigraphic cross-sections that transect the Eromanga and Surat Basins Coal Project area. These have been used to graphically illustrate the extents of potential coal-bearing horizons, and to understand the Company’s reviewed Eromanga-Surat Basin stratigraphic interpretations.

21 EPC1633 Final Report February 2016

A total of 110 sub-blocks have been relinquished from EPC 1633 in areas that Coalbank considered to be of low potential. The selected sub-blocks were located within the EPC where Coalbank’s regional model (Figure 7) suggests that if any coal-bearing sequences are present, they are at such depths below ground surface to be uneconomic for mining using currently available technologies.

Figure 7: Coalbank Eromanga and Surat Basins Photogeological Interpretation

22 EPC1633 Final Report February 2016

5.0 RESULTS/CONCLUSIONS Coalbank Limited’s Eromanga and Surat Basins Coal Project tenements provide leverage to a vast area of the Eromanga Basin and western Surat Basin that is almost totally under- explored for coal. A review of the established stratigraphy of this area by COALBANK has led to its proposition that there has been a mismatch of the stratigraphy west of Roma and across the Nebine Ridge, and that the Eromanga Basin in the Tambo area is actually a western extension of the Surat Basin. Coalbank has questioned the relationship between the mapped stratigraphic units and suggests that the Injune Creek Group may be thicker in the Eromanga Basin than previously understood. That is, the unit previously mapped as the Westbourne Formation west of Roma contains coal seams and may be a lateral equivalent of the Juandah Coal Measures, and that the Birkhead Formation represents the lower Taroom Coal Measures

A database of historical geological information for the entire Eromanga and Surat Basins Coal Project area was assembled. To facilitate this, the Company acquired all available water bore data for the area, as well as any GSQ stratigraphic borehole data and open file drilling records. Over 3400 boreholes were thus obtained, dating from 2009 back to the 1890’s. The vast majority of the holes were water bores, with the remainder being oil and gas exploration wells, GSQ boreholes and a few coal and oil shale exploration holes.

The database contains 15 historical boreholes located within EPC 1633, of which 3 have records of coal being intersected during drilling. One of these holes, waterbore RN116119 was selected as the primary target for Coalbank’s initial exploration drilling programme within EPC1633.

During the period of tenure, Coalbank conducted a review of the prospectivity of the EPC to re-prioritise identified drilling targets, and to highlight those sub-blocks suitable for relinquishment at the end of the tenure year as per the lease conditions.

110 sub-blocks were relinquished from EPC 1633 in areas that Coalbank considered to be of low exploration potential.

No field based exploration has been carried out.

In 2014 Coalbank further reviewed the economic potential of the permit and it has been surrendered.

23 EPC1633 Final Report February 2016

6.0 REFERENCES

Exon, N.F., 1968. Eddystone, Queensland 1:250,000 Geological Sheet. Bureau of Mineral Resources, Australia. Explanatory Notes, SG 55/7.

Exon, N.F., 1971. Mitchell, Queensland 1:250,000 Geological Sheet. Bureau of Mineral Resources, Australia. Explanatory Notes, SG 55/11.

Exon, N.F., 1976: Geology of the Surat Basin in Queensland. Canberra: Australian Government Publication Service.

Exon, N.F., 1980: The stratigraphy of the Surat Basin, with special reference to coal deposits. Coal Geology, 1 (3), 57-69.

Galloway, M.C., Exon, N.F., and Feeken, E.H.J., 1970. Augathella, Queensland 1:250,000 Geological Sheet. Bureau of Mineral Resources, Australia. Explanatory Notes, SG 55/6.

Goscombe, P.W., and Coxhead, B.A., 1995: Clarence-Moreton, Surat, Eromanga, Nambour, and Mulgildie Basins. In Ward, C.R., et al (Editors): Geology of Australian Coal Basins. Geological Society of Australia Coal Geology Group Special Publication, 1, 489- 511.

Hewitt, G. R., 1981. A-P 314C, Redford, Final Geological Report. Unpublished Company Report (CR9351).

Jones, G.D., and Patrick, R.B., 1981: Stratigraphy and coal exploration geology of the northeastern Surat Basin. Geological Society of Australia. Coal Geology Group. Journal 1(4) p153-163.

*********

24 EPC1633 Final Report February 2016

APPENDIX 1

PHOTOGEOLOGICAL REPORT

PHOTOGEOLOGICAL INTERPRETATION OF STEREOSCOPIC SPOTMAPS/SRTM IMAGERY, TAMBO PROJECT AREA, QUEENSLAND

(a) Report on Study of Northern Tambo Area (b) Final Report on Entire Study Area

For: Lodestone Energy Ltd

February, 2010

Undertaken by:

Colin Nash and Associates Pty Ltd (A.B.N. 30 080 088 277) PO Box 519, Mt Gravatt Plaza Qld 4122, Australia

The information contained in this report is derived from a qualitative interpretation of imaged satellite image data and integration of supportive geological map data. The interpretation is largely subjective, and relies principally upon the recognition of patterns within the data to reach conclusions regarding geological structure and other information depicted on the accompanying maps. While every effort has been made to carry out the interpretation as diligently as possible, no responsibility can be accepted for commercial decisions arising from the interpretations and conclusions expressed in this report and accompanying maps

d:\reports\196.doc Job No: 10/003

28 TABLE OF CONTENTS

1. INTRODUCTION

2. METHOD

2.1 Pan-sharpened Landsat 7 ETM+ /SRTM Stereoscopic Imagery 2.2 Available Geological Data and Geologic Setting 2.3 Photogeological Interpretation

3. RESULTS OF STUDY: (a) Northern Tambo Area

3.1 Stratigraphy 3.2 Structure 3.3 Geomorphology

4. RESULTS OF STUDY: (b) Entire Study Area

4.1 Stratigraphy 4.2 Structure 4.3 Geomorphology

5. CONCLUSIONS

6. REFERENCES CITED

APPENDIX: STRATIGRAPHIC CORRELATION, SURAT BASIN

LIST OF FIGURES

Figure 1. Location of study area

Figure 2. BMR mapping, Alicker Anticline area

Figure 3. BMR mapping, Forest Vale Anticline area

Figure 4. SPOTMAPS/LANDSAT and SRTM images: Holmleigh area

Figure 5. Summary geology: North Tambo area

Figure 6. SPOTMAPS/LANDSAT images: photogeological markers

Figure 7. Interpretation of areas N of Mitchell

Figure 8. SPOTMAPS/LANDSAT images; Roma-Mitchell area

Figure 9. Major structures and regional gravity image

Figure 10. Structural summary map

Figure 11. Units J2, J2s, J3, J4

Figure 12. Units JK0, JK1, JK2, JK3

Figure 13. Units Klmk, Kln, Kli, Kld, Klc

Figure 14. SRTM/DEM topographic image, southeastern study area

29 Executive Summary

This report contains (i) results of a photogeological study over an area located between Tambo and Jericho in central Queensland, and (ii) a summary of the results of three studies, covering a larger region extending from Jericho in the northwest to Roma in the southeast (the total study area covers 45,000 km2).

Three-dimensional, high-resolution satellite imagery has provided a unique new map of the numerous topographically distinctive sandstone marker beds within the Jurassic Surat Basin

The resulting photogeological maps reveal major inconsistencies in existing Government small-scale reconnaissance geological maps compiled in the late 1960‟s. Based on the present study, a revised stratigraphic nomenclature has been developed (table), which largely resolves these inconsistencies. An informal system of stratigraphic nomenclature has been adopted pending confirmation of stratigraphy by drilling.

Unit Informal Unit Name (this Equivalent Units on BMR Alternative correlation study) 1:250,000 Geological Maps (Lodestone Energy)

JK3 Speckly upper sandstone Hooray Sst, Bungil Fm JK2 Scarp-forming sandstone Hooray Sst, Bungil Fm Springbok Sandstone? JK1 Lower transitional sandstone Hooray Sst: Southlands, Orallo Fms Springbok Sandstone? JK0 Basal transitional unit Gubberamunda, Southlands Fms J4 Pink marker unit Westbourne Fm Juandah CM? J3 Regional sandstone marker Springbok/Adori Sst Tangalooma Sandstone? J2/J2s Unit overlying Hutton Sst Birkhead Fm Taroom CM?

The revised stratigraphic scheme recognises for the first time a transitional upper Surat Basin- Eromanga Basin sandstone-dominated package (units JK0-JK3). The package pinches out completely to the northwest of Tambo to the north of the present study area, and some of the units appear to terminate against a major N-S structure (Claravale lineament) in the east. Oil well drilling suggests the presence of coal within this package near Morven

The JK0-JK3 package displays strong lateral changes in thickness and continuity. In particular, the units appear to thin over major antiformal structures, suggesting that the latter were formed by inversion of pre-existing fault-bounded horst and graben blocks. Since the upper units (JK2 and JK3) appear to terminate along the Claravale lineament in the vicinity of Roma, they are unlikely to be widely developed in portions of the Surat Basin east of Roma, which have been tested by drilling, except in localised downwarps. Such structural controls and settings may have been active during development of the Upper Juandah Coal Measures.

In the west of the study area, there is a strong association between mapped NNE-SSW antiformal structures and linear gravity highs, suggesting that Late Jurassic structures formed in response to continued vertical faulting in the basement, which presumably also provided a structural control of sedimentation, possibly in the form of NNE-SSW grabens and half- grabens.

The Nebine Ridge appears to be a major, 50 km wide, NNE-SSW-trending gravity high associated with a shallower basement block. All the mapped Jurassic boundaries are shifted basinwards (i.e. towards the southwest) across the structure, suggesting that it was an emergent, horst-like feature during sedimentation .

The mapped structures tend to be concentrated in the Middle-Late Jurassic portion of the stratigraphic sequence (units J2-JK3), and appear to die out upwards into the overlying, probably post-tectonic Early Cretaceous Eromanga Basin sequence, as well as downwards into the massive, competent, Early Jurassic Hutton Sandstone which underlies unit J2.

30 Some of the major structural lineaments, however, do appear to continue upwards into, and to affect the overlying Eromanga Basin sequence. In the east, two Early Cretaceous sequences that are well developed around Roma (Mooga and Bungil Fms) terminate abruptly against the major N-S Claravale lineament, which also marks the eastern extent of the upper JK0-JK3 package, and was therefore a tectonically-active Late Jurassic-Early Cretaceous structural features. Stratigraphic variations in the Late Jurassic and Early Cretaceous also appear to be related to the NNE-SSW oriented Birkhead structural zone to the northwest of the present study area.

31 1. INTRODUCTION

This report initially describes the results of a 1:100,000 scale photogeological study over the Northern Tambo area, carried out on behalf of Lodestone Energy Ltd during February, 2010. The location of the study area, which covers 11,700 km2 in central Queensland, is shown in Fig. 1.

The second part of the report is a summary of work over all three study areas carried out for Lodestone Energy between October, 2009 and February, 2010. The combined studies cover an area of 45,000 km2; their locations are shown in Fig. 1. The previous studies have been reported as the Tambo- Augathella area and the South-Eastern area (Nash, 2009; 2010).

The objective of the studies has been to investigate the local stratigraphy and structure of the Eromanga/Surat Basins with a view to providing data for Lodestone‟s ongoing coal and CSG exploration in the region. In particular, Lodestone have challenged conventional stratigraphic assignments of the prospective Middle Jurassic-Early Cretaceous coal-prone sequences in the region, which were based upon reconnaissance-style 1:250,000 scale mapping by the Australian Bureau of Mineral Resources (now Geoscience Australia) during the late 1960‟s. The studies were carried out using 3-D stereoscopic images prepared by GeoImage Pty Ltd from 2.5 m resolution natural colour SPOTMAPS satellite imagery, processed with SRTM (Shuttle Radar) DEM topographic data to produce hardcopy 1:100,000 scale pseudo-stereo images for interpretation.

For the North Tambo area, a total of six stereopairs were produced, each consisting of a normal Vertical image with coordinate grid and a Left Stereo image for stereo viewing. GeoImage also produced a set of digital Landsat 7 ETM+ images for spectral work. All images are in GDA94/MGA55 projection.

Photogeological interpretation of the 1:100,000 scale hardcopy stereopairs was carried out by viewing the Vertical and Left-Stereo images under a mirror stereoscope, with reference to available geological maps in ArcView GIS. Interpreted geological data were annotated in ink on to a double-clear drafting film overlay sheets. The interpretation sheets were printed on stable matt film, and hand- coloured to show relevant lithology and structure. The hand-coloured maps were colour scanned, geo- referenced and digitally mosaiced as an .ecw compressed image.

Deliverables to Lodestone Energy from the Northern Tambo component of the study are as follows:

1. 6 x 1:100,000 scale hardcopy SPOTMAPS/SRTM stereo image pairs 2. 6 x 1:100,000 scale hand-drawn coloured interpretation maps 3. 1 x DVD with Landsat digital data 4. 2 x DVD‟s with SPOTMAPS digital data 5. 1 x CD ROM with scanned interpretation map and report .doc file 6. Bound copy of report (this document)

Figure 1. Location and 1:100,000 scale sheet layout of North Tambo study area (red lines and numerals), locations of previous study areas (blue outlines), and coverage by 1:250,000 scale BMR geological maps (broken green lines).

33 2. METHOD

2.1 SPOTMAPS/SRTM Stereoscopic and Landsat 7 Imagery

Hardcopy SPOTMAPS/SRTM stereoscopic images at 1:100,000 scale were prepared for the study by GeoImage Pty Ltd, Brisbane. SPOTMAPS data is seamless, large-region coverage of high-resolution (2.5 m) in natural colour (3 visible bands), which is used for Google Earth and other regional GIS applications. Coverage of digital SPOTMAPS data was acquired by Geolmage Pty Ltd on behalf of Lodestone Energy over all their tenement areas.

In the present study, the SPOTMAPS natural colour data was merged with mosaiced LANDSAT 7 image data acquired in winter 2002. The LANDSAT data were colour matched to the SPOTMAPS data using a process developed by GeoImage. This stretch increases the colour contrast within a moving box and improves the overall contrast in the image by reducing brightness in saturated areas and by brightening dark areas. Stereoscopy was introduced from Shuttle Radar (SRTM) Digital Elevation Model (DEM) data.

6 x hardcopy stereopairs were prepared for the North Tambo study (see Fig. 1 for locations), each pair consisting of a normal Vertical image with coordinate grid and a Left-Stereo image in which the pixels have been shifted to provide a „pseudo-stereo‟ effect. The images are natural colour band combinations in GDA94/MGA55 projection. GeoImage have provided digital SPOTMAPS/LANDSAT image data and a set of topographic images derived from the SRTM/DEM data on a set of four DVD‟s which accompany this report.

2.2 Available Geological Data

1960’s and 1970’s BMR Mapping

Accessible geologic data over the study area which were available for the present study were restricted to portions of the 1:250,000 scale EDDYSTONE (Exon, 1968), TAMBO (Exon, 1970), AUGATHELLA (Galloway, 1970), SPRINGSURE (Mollan, 1967), CHARLEVILLE (Senior, 1971), MITCHELL (Exon, 1971a), TAROOM (Forbes, 1968), JERICHO (Senior, 1973) and ROMA (Exon, 1971b) Geological Sheets, compiled by the Australian Bureau of Mineral Resources, Geology and Geophysics during the 1960‟s and early 1970‟s. These studies are summarised in the BMR Bulletin covering the Surat Basin in Queensland (Exon, 1976), which is accompanied by a 1:1,000,000 scale overview geological map covering the study region.

Coal deposits are known in the Jurassic Walloon Gp of the Surat Basin, and in the equivalent Injune Creek Gp as far west as the town of Injune (Maranoa Colliery). Test drilling of the prospective Injune Creek Gp by the Queensland Dept of Mines (Swarbrick, 1973) established the stratigraphy of the unit, and revealed that the entire sequence thins out westwards over a broad antiformal structure, variously referred to as the „Maranoa Anticline‟ or the „Nebine Ridge‟ (Appendix 1), becoming the Birkhead Fm in the Eromanga Basin to the west. As discussed in the following sub-section, subsequent coal and coal seam gas exploration drilling resulted in a re-definiton of Surat Basin stratigraphy, firstly by Jones and Patrick (1981) and more recently by Hamilton (2007). This work highlighted deficiencies in the existing BMR stratigraphic correlation of Jurassic units extending westwards into the Eromanga Basin.

Examples of major inconsistencies in published mapping at two localities within the present study area are discussed below. The most severe example is the Alicker Anticline area, which covers the northern join between the MITCHELL and ROMA sheets (see Fig. 2). It will be noted that in the north, the Springbok/Adori Sst (unit Js) is mapped to the east as „undifferentiated Injune Gp‟ (unit Ji), and that further south, the Gubberamunda Sst, Orallo Fm, Mooga Sst, and Kingull Mbr of Bungil Fm (units Jug, Juo, Klm and Klk) are all mapped further east as the „Southlands Fm‟ (JKs). It should also be noted with regard to Fig. 2 that no major E-W inconsistencies occur in the highest stratigraphic units (Doncaster Mbr and Coreena Mbr of Wallumbilla Fm, Kld and Klc), which can be followed without interruption westwards into the Augathella-Tambo area previously mapped.

Figure 2. Examples of inconsistencies in published BMR 1:250,000 geological sheets (MITCHELL AND ROMA) in the Alicker Anticline area. Red bar symbol highlights abrupt terminations of mapped geological units. Jmb – Taroom CM; Ji – undifferentiated Injune Ck Gp; Js – Springbok/Adori Sst; Juw – Westbourne Fm; Jug – Gubberamunda Sst; Juo – Orallo Fm; JKs – Southlands Fm; Klm – Mooga Sst; Klk – Kingull Mbr; Kln – Nullawurt Sst Mbr; Kli – Minmi Mbr; Kld – Doncaster Mbr; Klc – Coreena Mbr.

35 A second region of major mapping inconsistency occurs in the Forest Vale Anticline area on the MITCHELL sheet (Fig. 3). Here the Southlands Fm in the east (JKs) appears to interfinger with and terminate in the Hooray Sandstone in the west (JKh). The Gubberamunda Sst (Jug) also terminates against the Hooray Sst in the west (KKh). Finally, in the south of the area covered by Fig. 3, the members of the inferred Early Cretaceous Bungil Fm (Klk, Kln, Kli) appear to terminate abruptly against the Southlands Fm (Jks) and Hooray Sst (Jkh), which seems unlikely.

Closer inspection of SPOTMAPS and SRTM/DEM topographic images in the valley of the Maranoa River near „Holmleigh‟ reveals the nature of this problem. It is clear from the SPOTMAPS image (Fig. 4(a)) that the horizontal sandstone beds mapped as Hooray Sandstone to the west of the river have an identical appearance to those mapped as younger „Bungil Fm‟ to the east of the river, and that the two units occur at the same elevation (Fig. 4(b)). Since it is inconceivable that either of the two units could pinch out over a distance of < 2,000 m, and it is extremely unlikely that the Bungil Fm overlies the Hooray Sst, it must be concluded that they are the same unit.

It may therefore be concluded from the foregoing discussion that major problems exist in the published mapping and interpreted stratigraphy over the Nebine Ridge/Maranoa Anticline. This comment applies to statigraphic units between the top of the Early Jurassic Huttin Sandstone and the base of the Early Cretaceous Wallumbilla Fm.

Results of Coal Exploration in the 1970’s

Coal exploration drilling within the Surat Basin began in earnest in the early 1970‟s, targeting reported caol intersections in waterbores. Thiess Bros Pty Ltd were a pioneer in this activity, often in partnership with MIM Holdings Ltd, under the Brigalow JV. Their work enabled the true Surat Basin stratigraphy to be revealed, as summarised in Jones and Patrick (1981).

Subdivision of the Injune Creek Gp to the east of Injune and Roma had been suggested by Swarbrick (1973). Accordingly, Jones and Patrick in (1981) published a revised stratigraphic subdivision of the Injune Creek Gp, in which the Walloon Coal Measures were subdivided into three units comprising the Walloon Subgp (Table 1) :-

Group Sub-Group Formation

Gubberamunda Sst

Injune Creek Gp Westbourne Fm Injune Creek Gp Springbok Sst Injune Creek Gp Walloon Subgp Juandah CM Injune Creek Gp Walloon Subgp Tangalooma Sst Injune Creek Gp Walloon Subgp Taroom CM Injune Creek Gp Eurombah Fm

Hutton Sst

Table 1. Stratigraphy of northeastern Surat Basin (Jones and Patrick, 1981).

Results of Coal Seam Gas Exploration, 1990’s and 2000’s

From the late 1990‟s, interest in Surat Basin stratigraphy has re-emerged as a result of coal seam gas exploration of the Walloon Coal Measures. The early work by Jones and Patrick has recently been ratified by the Geological Survey of Queensland (Hamilton, 2007), whose stratigraphic correlation diagram is included in Appendix I.

To date, however, attempts to extend the modern correlation of the Walloon Coal Measures toward the west has been blocked by the inability to correlate the currently accepted stratigraphic breakdown of Jurassic units in areas of confused stratigraphy shown on published maps to the west of Roma.

Figure 3. Further examples of inconsistencies in published BMR 1:250,000 MITCHELL geological sheet in the Forest Vale Anticline area. Red bar symbol highlights abrupt terminations of mapped geological units. Js – Springbok/Adori Sst; Juw – Westbourne Fm; Jug – Gubberamunda Sst; JKs – Southlands Fm; Klk/Kli – Kingull Mbr; Nullawurt Sst Mbr, Minmi Mbr; Kld – Doncaster Mbr, Tmb – Tertiary basalt cover. Images over southern part of area are shown in Fig. 4.

Figure 4(a). A closer view of the major discrepancy in BMR mapping shown in Fig. 3.. SPOTMAPS/LANDSAT natural colour image of the Holmleigh area (map sheet 13), showing identical appearance of flat-lying sandstone beds, mapped on BMR Mitchell 1:250,000 scale Geological Sheet as Late Jurassic-Early Cretaceous Hooray Sandstone (Jkh) in the west, and as Early Cretaceous „Bungil Fm‟ (Klx-Kln-Kli) in the east. (b). Colour SRTM/DEM topographic image shows the units occur at identical elevations.

38 Results of Lodestone Energy Assessment of Waterbores

Because of the very low number of oil wells and QSQ boreholes within the projected outcrop area of the Walloon CM to the west of Roma, Lodestone compiled a large database of waterbores, from which numerous cross-sections were drawn. From these data, Lodestone deduced that two populations of coaly intersections existed, one corresponding to the Birkhead Fm as shown on published maps, and another higher in the sequence, variously corresponding to units shown as Hooray Sandstone, Westbourne Fm etc on published maps.

Using the stratigraphic schema of Hamilton (2007), Lodestone nominated the Birkhead Fm as being only equivalent to the lowermost part of the Walloon, i.e. the Taroom CM. It is Lodestone‟s contention that the sandstone units immediately above the Birkhead Fm may be mis-represented on existing maps, and may in fact be hitherto-unrecognised equivalents of units such as the Tangalooma Sandstone.

Therefore photogeological evidence is being sought to demonstrate possible anomalies in existing maps, leading to a possible re-interpretation of published stratigraphy and the possible extension of Hamilton‟s (2007) Jurassic stratigraphy into the Eromanga Basin. If evident, these concepts are to be tested by subsequent drilling.

2.3 Photogeological Interpretation

Previous Studies

A photogeological interpretation, based on 1:80,000 scale B&W airphotos, was carried out in the late 1970‟s over the area extending to the east of Injune by consultants Loxton Hunting and Associates on behalf of Brigalow Mines Pty Ltd (Jones and Patrick, 1981). It was noted from this study that although outcrop of the Injune Creek Gp is very poor (90% of outcrop is lime-cemented sandstone), and that the base and top of the 800 m thick unit could only be identified from overlying Gubberamunda and underlying Hutton Sandstone units. The following photogeological observations were made at the time:-

Springbok Sandstone: resistant, pale-toned ridges Juandah CM: soft, pale-toned unit with „break-away topography; rare outcrop Tangalooma Sst: Similar resistant hills to Springbok Sst; dark-toned Taroom CM: Soft, mottled unit with „break-away‟ topography

In the context of the present study, it is interesting to note the comment made by Loxton Huntings, that “…..within the Injune Creek Gp, only two boundaries are consistently and confidently identifiable over most of their strike length. These are the lower boundaries of the Springbok Sandstone and the „Upper Sandstone Mbr‟ of the Walloon CM” (which may be the Tangalooma Sst??).

Current Study

Interpretation of the 6 x 1:100,000 scale Landsat/SRTM satellite images was performed under a mirror stereoscope, on to double-clear film overlays attached to the Vertical 1:100,000 scale images of the stereopairs. The Left-hand Stereo images were cut into strips approximately 10 cm wide, and placed on top of the Vertical images under the stereoscope to form a 3-D image. Interpretation was carried out following the methods suggested by Nash (1998), using permanent drawing ink on a transparent overlay attached to the Vertical image, which was backlit using a light table.

The 6 x 1: 100,000 scale interpretation overlays were printed on to semi-matt stable film and were hand-coloured to highlight significant geological units. The sheets were then colour scanned as .tiff images, which was in turn geo-rectified and mosaiced into GDA94/MGA55 projection as an .ecw compressed file.

39 3. RESULTS OF STUDY: (a) Northern Tambo Area

3.1 Stratigraphy

The main results of the Northern Tambo study are shown on the accompanying 1:100,000 scale interpretation maps. It has been possible to identify some important additions and modifications to the main litho-stratigraphic units shown on the published 1:250,000 scale geological maps, as summarized in Table 2 below.

Because of the inconsistent nature of the stratigraphic nomenclature on the published BMR mapping (see section 2.2 above), and because of the suggested changes in stratigraphic nomenclature proposed by Lodestone Energy, in the present study we have used an informal system of naming units which occur between the Hutton Sandstone at the base and the Doncaster Mbr at the top (no controversy attaches to the lateral continuity of either of these units). Likely correlations of the units identifed are discussed in Section 5.

Symbol Unit Name Appearance on Images and Inferred Inferred Age (units J0-JK3 informal) Lithology

Q Modern alluvium Active alluvial material in drainages Quaternary

Qt Fluviatile channel deposits Light-toned terraces of coarse fluviatile Quaternary material in modern drainages Qs Outwash fans and colluvium Light-toned, gently sloping areas of Quaternary colluvial material TQs Fluviatile sheets Gently-sloping, consolidated fluviatile Cenozoic sheets, partially silicified sil Silcrete Light-toned scarps around TQs plateaus: Cenozoic resistant silcrete? Ts High-level older sandstone Small scarp-bounded plateaus at high Cenozoic cappings elevations. Partially silicified?

deep weathering, uplift and erosion

Kw Winton Fm Smooth, monotonous „black soil plain‟ Early-Late Cretaceous topography; labile sandstone, siltstone, mudstone, minor coal Klm Mackunda Fm Strongly outcropping unit forming Early-Late Cretaceous promient sandstone hills, plateaus Kla Allaru Mudstone Forms smooth, low-lying areas with little Early Cretaceous structure, mudstone; siltstone Klc Coreena Mbr Resistant, layered unit with prominent Early Cretaceous (Wallumbilla Fm) light-toned sandstone beds (Albian) Kld Doncaster Mbr Weakly outcropping dark bluish areas: Early Cretaceous (Wallumbilla Fm) mudstone, siltstone with black soils (Aptian)

unconformity?

JK3 Speckly upper sandstone Forms characteristic light-toned, speckly Jurassic-Cretaceous? (informal) outcrop areas: mainly sandstone JK2 Scarp-forming sandstone Strongly outcropping, cliff-forming unit: Jurassic-Cretaceous? (informal) massive sandstone or conglomerate? JK1 Lower transitional Flat-lying, thin sandstone with low scarp at Jurassic-Cretaceous? sandstone (informal) base

transgression?

J4 Pink marker unit (informal) Low, smooth topography (siltstone?), Middle-Late Jurassic characteristic yellow colour J3 Regional sandstone marker Prominent, vegetated outcrops; cuestas and Middle-Late Jurassic (informal) scarps; impure sandstones?

40 J2 Basal unit overlying Hutton Weakly outcropping strata (soft Middle-Late Jurassic Sandstone sandstones, shales, carbonaceous units), Jlh Hutton Sandstone Extensive, flat-lying, weakly bedded Early Jurassic sandstone areas, strongly vegetated Jlb Boxvale Sst Mbr Rugged, dissected terrain; quartzose Early Jurassic sandstone Jlp Precipice Sandstone Scarp-forming unit: massive quartzose Early Jurassic sandstone Trm Moolyamber Fm Poorly-exposed, low-lying unit: siltstone, Middle-Late Triassic mudstone, labile sandstone Tre Clematis Sandstone Prominent dip cuestas formed by thick- Middle-Late Triassic bedded quartzose sandstone Trld Dunda Beds Moderate to prominent outcrops, massive Early Triassic sandstone, siltstone, mudstone

Table 2. Litho-stratigraphic units identified from stereoscopic SPOTMAPS/SRTM images in Northern Tambo area

Triassic Stratigraphy of the Galilee Basin (map units Trld, Tre, Trm)

The Northern Tambo area contains units which are ascribed to the Permo-Triassic Galilee Basin (Senior, 1973), forming a range of hills extending south-southeast from Jericho. The lowermost Triassic unit (Dunda Beds, map unit Trld) and the overlying Clematis Sandstone (map unit Tre) are well-exposed, sandstone-dominated sequences that form prominent dip cuestas. The uppermost Moolyamber Fm (map unit Trm) is poorly-exposed and forms a regional plain.

Jurassic Surat Basin Stratigraphy (map units Jlp, Jle, Jlh, J1, J2, J3, J4)

The oldest Jurassic units exposed in the north of the study area, begin with the Early Jurassic Precipice Sandstone (map unit Jlp), which is a very prominent scarp-forming quartzose sandstone unit, followed by the Evergreen Fm (map unit Jle), composed of labile sandstone, carbonaceous shale and coal, and a thick, monotonous sequence of quartzose and sub-labile sandstones (Hutton Sandstone, map unit Jlh). The Units Jlp, Jle and Jlh are characteristed by eucalypt vegetation, which has generally not been cleared for grazing due to poor soils.

The areas shown on BMR maps as the Middle Jurassic Birkhead Fm (map unit J2) reportedly consist of labile sandstone, carbonaceous siltstone and coal. They form relative topographic lows, and have been extensively cleared.

In the North Tambo area, map unit J3 forms homogenous, scarp-bounded cuesta landforms, and has therefore been informally named the „regional sandstone marker‟. The unit is more topographically pronounced than further south, and is extensively covered in bush owing to poor soils. Comparison with BMR maps suggests that unit J3 correlates spatially with the Adori Sandstone, composed of cross- bedded labile sandstone (pebbly in part) with siltstone intercalations.

Unit J3 is overlain by a distinctive yellow coloured unit (map unit J4) that forms a belt of low country between topogrphically prominent sandstone units J3 and JK1/JK2. This unit corresponds to the Westbourne Fm on BMR maps, and appears to pinch out at the edge of the mapped area.

Late Jurassic-Early Cretaceous Transitional Stratigraphy (map units JK1, JK2, JK3)

Our interpretation suggests that the Late Jurassic to Early Cretaceous sedimentary package shown on published maps as the „Hooray Sandstone‟comprises a (a) a lower sandstone unit (map unit JK1), which is generally flat-lying, thin sandstone beds with a low scarp at base, followed by (b) a strongly outcropping, scarp-forming sub-unit (map unit JK2), which may be composed locally of conglomerates, and (c) an upper, less resistant sub-unit (map unit JK3) composed of clayey, quartzose

41 and sub-labile sandstone which has a distinctive whitish or yellowish „speckled‟ appearance on the images due to sandy soils. Unit JK2 is well-bedded, and forms mesas and dip cuestas.

Early Cretaceous Stratigraphy (map units Kld, Klc, Kla, Klm, Kw)

The Early Cretaceous Doncaster Mbr of the Wallumbilla Fm (map unit Kla) may rest disconformably upon unit JK3 The Doncaster Mbr is composed of mudstone and siltstone, and forms recessive topography with little evidence of bedding. Exon (1970) mentions a sandy basal facies of the Doncaster Mbr across the Birkhead antiform, which runs NNE-SSW through Tambo. This sequence, however is most probably part of the underlying Hooray Sandstone.

The overlying Coreena Mbr of the Wallumbilla Fm (map unit Klc) has a distinctive banded appearance on images, owing to thin interbedded sandstones. The unit is quite resistant compared to the underlying Doncaster Mbr and the overlying Allaru Mudstone, and forms local drainage divides.

The main part of the Allaru Mudstone (map unit Kla) is composed of mudstone and siltstone, and forms low topography with little photogeological information. In the west of the Tambo-Augathella study area, evidence was seen for distinctive, light-toned upper sub-unit in the Allaru Mudstone (map unit (Kla2), not shown on published maps.

The Allaru Mudstone is followed by a resistant sandstone unit (Mackunda Fm, map unit Klm), which forms hilly areas, plateaus and dip cuestas. The Mackunda Fm forms dipslopes in the extreme west of the study area, and is composed of labile sandstone, siltstone and mudstone. The uppermost Eromanga Basin sequence, exposed in the extreme west of the North Tambo area, is the Early-Late Cretaceous Winton Fm (map unit Kw), which forms smooth, monotonous „black soil plain‟ topography and is composed of labile sandstone, siltstone, mudstone and minor coal.

Superficial Deposits (map units Ts, sil, TQs, Qs, Qt, Q)

Small, steep-sided plateaus (map unit Ts) form the highest topographic prominences in the southern part of the study area. Most are developed upon the resistant J3 and JK2 sandstone units. In the north of the area, the resistant Ts sandstones form the base of a N-plunging basin (Jordan Creek basin) that extends NNW to Jericho.

Within the Jordan Creek basin, the basal Ts sandstones are overlain by extensive low plateaus formed by younger extensive sheets of gently-sloping consolidated fluviatile material (map unit TQs), which represent a second episode of Cenozoic erosion and deposition. Some or most of the material in the younger sheets may have been derived form the earlier (unit Ts) fluviatile deposits.

The TQs fluviatile deposits are largely developed upon the basal Doncaster Mbr of the Eromanga Basin sequence, which formed recessive topography. The TQs plateaus are locally surrounded by a steep, light-toned scarps (map unit sil), which are thought to be composed of silcrete.

3.2 Structure

Fig. 5 is a summary geological map of the North Tambo area based on results of the present study. The diagram shows the presence of three major, sub-parallel, NNE-SSW trending antiformal structures, which correspond to the Enniskillen, Birkdale and Truno Anticlines shown on published BMR maps. The Enniskillen Anticline appears to mainly affect Jurassic strata, and dies out in the basal Kld unit of the Eromanga Basin. Dip observations suggest the presence of a hitherto-unrecognised domal structure (Wyanga antiform) within the Doncaster Mbr.

Figure 5. Summary geologic map of North Tambo area. BA – Birkhead Anticline; EA – Enniskillen Anticline; WA – Wyanga antiform; Truno Anticline

43 4. RESULTS OF STUDY: (b) Entire Area

4.1 Stratigraphy

The main results of the study are shown on the accompanying 1:100,000 scale interpretation maps. It has been possible to identify some important additions and modifications to the main litho-stratigraphic units shown on the published 1:250,000 scale geological maps, as summarized in Table 3 below.

Symbol Unit Name Appearance on Images and Inferred Inferred Age (units J0-JK3 informal) Lithology

Q Modern alluvium Active alluvial material in drainages Quaternary

Qt Fluviatile channel deposits Light-toned terraces of coarse fluviatile Quaternary material in modern drainages Qs Outwash fans and colluvium Light-toned, gently sloping areas of Quaternary colluvial material Tmb Basalt flows Flat-topped, resistant mesas; pale grey Miocene colour on images Tbi Basalt plugs Prominent small dark-toned peaks: basaltic Miocene plugs Tt Tabor Gabbro Prominent annular gently dipping body: Miocene gabbro sill TQs Fluviatile sheets Gently-sloping, consolidated fluviatile Cenozoic sheets, partially silicified sil Silcrete Light-toned scarps around TQs plateaus: Cenozoic resistant silcrete? Ts High-level older sandstone Small scarp-bounded plateaus at high Cenozoic cappings elevations. Partially silicified?

deep weathering, uplift and erosion

Kw Winton Fm Smooth, monotonous „black soil plain‟ Early-Late Cretaceous topography; labile sandstone, siltstone, mudstone, minor coal Klm Mackunda Fm Strongly outcropping unit forming Early-Late Cretaceous prominent sandstone hills, plateaus Kla2 Upper Allaru Mudstone? More resistant than Kla, with pale Early Cretaceous interbeds; possibly sandstone-rich? Kla Allaru Mudstone Forms smooth, low-lying areas with little Early Cretaceous structure, mudstone; siltstone Klc Coreena Mbr Resistant, layered unit with prominent Early Cretaceous (Wallumbilla Fm) light-toned sandstone beds (Albian) Kld(w) Altered Doncaster Mbr? Whitish, low outcrops, possibly altered or unknown deeply weathered Klw? Kld Doncaster Mbr Weakly outcropping dark bluish areas: Early Cretaceous (Wallumbilla Fm) mudstone, siltstone with black soils (Aptian)

Kli Minmi Mbr Reddish, flat-lying, unit, low bounding Early Cretaceous (Bungil Fm) scarp; mainly sandstone Kln Nullawurt Sst Mbr Greyish, flat-lying low outcrops: mainly Early Cretaceous (Bungil Fm) sandstone Klm-k Mooga Sst, Kungil Mbr Reddish-brown, flat-lying, units, low Early Cretaceous bounding scarps: mainly sandstone

unconformity?

transgression?

J4 Pink marker unit (informal) Low, smooth topography (siltstone?), Middle-Late Jurassic characteristic pink-yellow bed at base J3 Regional sandstone marker Low to prominent, non-bedded, vegetated Middle-Late Jurassic (informal) outcrops; local basal scarp; impure sandstones? Probably unconformable on J2 J2 Basal units overlying Weakly outcropping strata (soft Middle-Late Jurassic Hutton Sandstone (Injune sandstones, shales, carbonaceous units), J2s Gp in east, Birkhead Fm in with irregular locally more resistant rest of area) sandstone-rich units (J2s) Jlh Hutton Sandstone Extensive, flat-lying, weakly bedded Early Jurassic sandstone areas, strongly vegetated Jlw Westgrove Ironstone Mbr Thin, softer unit between Jlb, Jlh; oolitic Early Jurassic ironstone, siltstone Jlb Boxvale Sst Mbr Rugged, dissected terrain; quartzose Early Jurassic sandstone Jlp Precipice Sandstone Scarp-forming unit: massive quartzose Early Jurassic sandstone Trm Moolyamber Fm Poorly-exposed, low-lying unit: siltstone, Middle-Late Triassic mudstone, labile sandstone Tre Clematis Sandstone Prominent dip cuestas formed by thick- Middle-Late Triassic bedded quartzose sandstone Trld Dunda Beds Moderate to prominent outcrops, massive Early Triassic sandstone, siltstone, mudstone

Table 3. Litho-stratigraphic units identified from stereoscopic SPOTMAPS /SRTM images over entire study area between Jericho (north) and Roma (southeast)

Triassic Stratigraphy of the Galilee Basin (map units Trld, Tre, Trm)

The northernmost part of the Tambo project area contains units which are ascribed to the Permo- Triassic Galilee Basin (Senior, 1973). The lowermost Triassic unit (Dunda Beds, map unit Trld) and the overlying Clematis Sandstone (map unit Tre) are well-exposed, sandstone-dominated sequences that form prominent dip cuestas. The uppermost Moolyamber Fm (map unit Trm) is poorly-exposed and forms a regional plain.

Jurassic Surat Basin Stratigraphy (map units Jlp, Jle, Jlb, Jlw, Jlh, J1, J2, J3, J4)

The oldest Jurassic stratigraphic unit exposed in the far north of the study area, which rests upon the Triassic Moolyamber Fm, is shown on BMR maps as the Early Jurassic Precipice Sandstone (map unit Jlp). This is a very prominent scarp-forming quartzose sandstone unit, followed by the equally prominent Evergreen Fm (map unit Jle), composed of labile sandstone, carbonaceous shale and coal, and its component Westgrove Ironstone and Boxvale Sandstone members (map units Jlw and Jlb). These units are exposed in the core of a regional antiform, named the „Maranoa Anticline‟ on published BMR maps, which corresponds to the „Nebine Ridge‟ of Swarbrick (1973).

45 The Evergreen Fm is overlain by a thick, monotonous sequence of quartzose and sub-labile sandstones (Hutton Sandstone, map unit Jlh), which form large regions of very low dip occupying the „Maranoa Anticline‟. The principal photogeological characteristic of the Hutton Sandstone is the presence of eucalypt vegetation, which has not been cleared due to poor soils. This contrasts strongly with the overlying Birkhead Fm/Injune Creek Gp, which has been extensively cleared for grazing.

The areas shown on BMR maps as the Middle Jurassic Birkhead Fm in the west and Injune Creek Gp in the east, reportedly consist of labile sandstone, carbonaceous siltstone and coal. They form relative topographic lows, and has been extensively cleared. (Work by Lodestone Energy suggests that the Birkhead Fm may be equivalent only to the Taroom Coal Measures within the Walloon Coal Measures of the Injune Creek Gp). Our study does not provide stratigraphic differentiation within the area shown on published maps as „Birkhead Fm‟, nor is there continuity between this sequence and the lower Injune Creek Gp in the east. Our interpretation suggests the possible presence of two lithologic associations of uncertain stratigraphic correlation, which we have informally mapped as units J2 and J2s. Unit J2s forms low ridges in which occasional bedding dipslopes are visible, and is thought to be mainly sandstone. Unit J2 forms low-lying, whitish areas which may be composed of softer, impure sandstones, shales and carbonaceous sediments. The whitish colour may be due to the preponderance of calcareous cemented outcrops note by Jones and Patrick (1987).

Because of the lack of continuity between these rocks and the area around Injune in the east, we have not attempted to assign stratigraphic names to the latter area, although there is some evidence for more- and less-resistant units.

Map unit J3 forms fairly homogenous, massive, but generally low-lying outcrops (Fig. 6(a)), in which weak bedding traces can be seen on the stereo images. In the west, the base of the unit is marked by a a distinct scarp, and is extensively covered in bush owing to poor soils. Further east, the unit has been cleared but a scarp forming a local drainage divide is located at the base. Comparison with BMR maps suggests that unit J3 correlates spatially with the Adori/Springbok Sandstone, composed of cross- bedded labile sandstone (pebbly in part) with siltstone intercalations. To the northwest of the present study area, unit J3 forms a very prominent set of scarps and dip cuestas and has therefore been informally named the „regional sandstone marker‟

The correlation chart prepared by Hamilton (2007) suggests an unconformity at the base of the Springbok Sandstone (see Appendix I), suggesting perhaps that the sandstone represents a high-energy transgressive cycle following the deposition of the Walloon coal measures. Possible evidence for such an unconformity is present in an area located 65 km north of Mitchell (Fig. 7), where our interpretation suggests that the basal contact of unit J3 appears to cut obliquely across the E-W trending beds of underlying units J2/J2s. Assuming that unit J3 is the same as the Springbok Sandstone, then it would be assumed that it rests unconformably (at least locally) upon the Birkhead Fm, although evidence for the unconformity is not strong in the rest of the study area.

Map unit J4 forms low-lying areas between the slightly more resistant J4 and JK1 sandstone beds, where it forms a smooth, low, dark-toned plain on satellite images. A thin pink/yellow bed at the base of the unit (Fig, 6(a)) is a valuable photogeological marker, and may be due to a thin carbonate or tuffaceous bed. According to the BMR mapping, this is the Westbourne Fm, mainly composed of mudstone and siltstone.

Late Jurassic-Early Cretaceous Transitional Stratigraphy (map units JK0, JK1, JK2, JK3)

The „typical‟ Jurassic Surat Basin sequence which terminates in unit J4 (Westbourne Fm?) is followed by a transgressive(?) clastic-dominated, sandstone-rich sequence that includes our map units JK0, JK1, JK2 and JK3. These units appear to be transitional between the Late Jurassic Surat Basin and the overlying Early Cretaceous, argillite-dominated, Eromanga Basin.

Our interpretation suggests that the Late Jurassic to Early Cretaceous sedimentary package, which spans the interval between the „typical‟ Jurassic Surat Basin sequence and the overlying Eromanga Basin sequence, comprises a (a) a lower sandstone unit (map unit JK1), which is generally flat-lying, thin sandstone beds with a low scarp at base, followed by (b) a strongly outcropping, scarp-forming

Figure 6. Important photogeological markers visible on SPOTMAPS/LANDSAT images. (a). Distinctive, thin, pink/yellow marker bed occurring locally at the base of unit J4, which is composed of siltstones/mudstones and forms smooth, low outcrops, and is overlain by pale-toned sandstones of transitional unit JK1. Unit JK2 is a prominent scarp-forming sandstone or conglomerate bed, (possibly unconformable), which can be traced throughout much of the study area. (b). Clearly defined contact west of „Maranoa Anticline‟ between white sandy soils on upper sandstone of transitional unit JK3 and overlying black soils on Doncaster Mbr mudstones (Kld).

Figure 7. Photogeological interpretation of SPOTMAPS image over area located 65 km north of Mitchell. Jlh – Hutton Sandstone; J2/J2s – Birkdale Fm; J3 – soft sandstone unit; J3 – pink marker unit; JK0-JK2 – transitional clastic units. All beds dip gently to the S.

48 sub-unit (map unit JK2), which may be composed locally of conglomerates, and (c) an upper, less resistant sub-unit (map unit JK3) composed of clayey, quartzose and sub-labile sandstone which has a distinctive whitish or yellowish „speckled‟ appearance on the images due to sandy soils. Unit JK2 is well-bedded, and forms mesas and dip cuestas.

To the west of the „Maranoa Anticline‟, unit JK3 is always overlain by the Early Cretaceous Doncaster Mbr of the Eromanga Basin sequence (Fig. 6(b)), however to the east of the anticline a number of additional Cretaceous units are present (see below). Significantly, units JK2 and JK3 of the transitional sedimentary package are not present to the east of Roma. These units may represent an additional Late Jurassic accumulation, formed in a localised structural depression located to the west of Roma, in which coals are reported in petroleum wells drilled near Morven.

Published BMR maps show the „Gubberamunda Sst‟ overlying the Westbourne Fm in the Alicker Anticline area, and pinching out to the west in the Forest Vale Anticline area (Figs. 2 and 3). Our mapping suggests that a separate, poorly-outcropping sandstone may be best developed in the Forest Vale Synform region and to the east of the Alicker Antiform, where a local clastic unit, (shown as our map unit JK0), occurs beneath more prominent sandstones of units JK1 and JK2. Elsewhere, however, areas shown on BMR maps as Gubberamunda Sst appears to be part of unit JK1.

Early Cretaceous Eromanga Basin Stratigraphy West of Maranoa Anticline (map units Kld, Klc, Kla, Kla2, Klm, Kw))

It was suggested in the previous study (Nash, 2009), that the early Cretaceous Doncaster Mbr of the Wallumbilla Fm (map unit Kld) may rest unconformably upon unit JK3 in the Tambo area, since some of the antiformal flexures affecting the latter unit do not appear to continue into the former. This appears to apply to the present study area as well. The Doncaster Mbr is composed of mudstone and siltstone, and forms recessive topography with little evidence of bedding. In the western part of the present study area, the Doncaster Mbr forms characteristic low-lying, non-bedded grey-blue outcrops (due to black soils?), which are quite distinctive on Landsat and which contrast strongly with the underlying whitish, sandy, well-vegetated soils of the underlying JK3 unit (Fig. 5(b)). The unit is also characterized by extensive development of Tertiary weathering profiles and silcrete bluffs, described in a succeeding sub-section.

Between Mitchell and Roma, the Doncaster Mbr is overlain by the distinctive Coreena Mbr of the Wallumbilla Fm (map unit Klc), which has a distinctive appearance on imagery due to interbedded thin sandstone beds. Within the Doncaster Mbr, an anomalous N-S trending zone 35 km long and up to 14 km wide of pale-toned outcrop has been mapped (map unit Kldw). The cause of this colour and texture are not known; some form of regional alteration or deep weathering may be involved. The zone is located along a major inferred structural lineament (see Section 3.2).

West of Tambo, the Coreena Mbr is overlain by the Allaru Mudstone (map unit Kla). The main part of the Allaru Mudstone is composed of mudstone and siltstone, and forms low topography with little photogeological information. In the west of the Tambo-Augathella study area, evidence was seen for distinctive, light-toned upper sub-unit in the Allaru Mudstone (map unit (Kla2), not shown on published maps.

The Allaru Mudstone is followed by a resistant sandstone unit (Mackunda Fm, map unit Klm), which forms hiily areas, plateaus and dip cuestas. The Mackunda Fm dipslopes in the extreme west of the study area, and is composed of labile sandstone, siltstone and mudstone. The uppermost Eromanga Basin sequence, exposed in the extreme west of the North Tambo area, is the Early-Late Cretaceous Winton Fm (map unit Kw), which forms smooth, monotonous „black soil plain‟ topography and is composed of labile sandstone, siltstone, mudstone and minor coal.

Early Cretaceous Eromanga Basin Stratigraphy East of Maranoa Anticline (map units Klm-k, Kln, Kli)

A number of Early Cretaceous units are shown on published maps to the east of the „Maranoa Anticline‟ (Fig. 8(a)). These units, which can be defined quite easily on the Landsat data, occur

Figure 8(a)). SPOTMAPS/LANDSAT image of area 38 km northwest of Roma, showing distinctive reddish units of basal Early Cretaceous sequence, resting upon white sandy soils developed on transitional unit JK3 (locally mapped by BMR as Orallo Fm, Juo). Klm – Mooga Sst; Klk – Kingull Mbr of Bungil Fm; Kln – Nullawaurt Sst Mbe of Bungil Fm. (b). Image of area 10 km south of Mungallala, showing Tertiary silcrete scarps (sil) on Doncaster Mbr siltstones, capped by fluviatile deposits (TQs).

50 between the uppermost transitional unit JK3 and the widespread Doncaster Mbr (unit Kld). According to the published 1:250,000 scale MITCHELL geological sheet, the following units are locally present in the region between Roma and Mitchell:-

Bungil Fm Kli Minmi Mbr Mainly sandstone Kln Nullawurt Sst Mbr Sandstone, siltstone, mudstone Klx Claravale Sst Mbr Coarse quartzose sandstone Klk Kingull Mbr Sandstone, carbonaceous siltstone Mooga Sandstone Klm Quartzose sandstone, mudstone

Although very thin and apparently of similar lithology, most of these units can be mapped on the SPOTMAPS/LANDSAT images in the area between Roma and Mitchell (Fig. 8(a)). The Early Cretaceous sequence has a distinctive reddish appearance, which contrasts strongly with the underlying uppermost transitional unit (JK3), which is locally shown on published maps as the Late Jurassic Orallo Fm.

The individual Early Cretaceous units have variable erosional resistance. Because they are very similar in appearance (Fig. 8(a)), we have included he lowermost Mooga Sst and the overlying Kingull Mbr of the Bungil Fm as a single unit on our interpretation maps (map unit Klmk). The next unit up is the Nullawurt Mbr (our map unit Kln), which forms smooth, dark, gently-dipping surfaces. The next highest unit identified is the Minmi Mbr (map unit Kli), which has a distinctive texture due to its sandstone content. The Mooga/Bungil Fms are probably overlain disconformably by the Doncaster Mbr.

Superficial Deposits (map units Ts, sil, TQs, Qs, Qt, Q)

Small, steep-sided plateaus (map unit Ts) form the very highest topographic prominences in the study area. Many are developed upon the resistant map unit JK2. According to the descriptions accompanying the Eddystone 1:250,000 Sheet (Exon, 1968), these plateaus are „lateritised‟ (siliceous duricrust?). The plateaus are probably remnants of a generally flat-lying consolidated fluviatile sheet that was deposited across an eroded surface cut on the gently-inclined Jurassic strata during the Late Cretaceous or Cenozoic.

Much more widespread are plateaus composed of gently-sloping consolidated fluviatile material (map unit TQs), which represent a second episode of Cenozoic erosion and deposition. Some or most of the material in the younger sheets may have been derived form the earlier (unit Ts) fluviatile deposits. In the region south of the Warrego Hwy between Morven and Mungallalla, the TQs plateaus rest upon extensive areas of light-toned scarps (map unit sil), which are composed of silcrete material formed during supergene weathering (see Fig. 8(b)).

4.2 Structure and Stratigraphic Controls

In the following discussion we define the Surat and Eromanga Basins as stratigraphic, not geographic sedimentary packages, separated by a transitional package. The stratigraphic units within these packages are summarised in the following table.

Eromanga Basin Late Cretaceous transgression Mapped units Kld, Klc, Klm-k, associated with sea-level rise Kln, Kli, Kla, Kla2, Klm, Kw Surat-Eromanga Transition Jurassic-Cretaceous clastic Mapped units JK0, JK1, JK2, units, with rapid lateral facies JK3 variation Surat Basin Early-Late Jurassic, regionally Mapped units Jle, Jlb, Jlw, Jlh, extensive units J2, J3, J4

51 A summary map of major structures interpreted from SPOTMAPS imagery is shown in Fig. 9, superimposed upon a colour gravity image of the study region. The latter is a useful backdrop, as it shows the probable location of the NNE-SSW trending lineasr Nebine Ridge basement structure as a gravity high, along with a number of other basement features of possible significance.

Fig. 9 shows the locations of some of the major mapped faults and anticlines in the study area, as well as the locations of three inferred lineament zones of unknown significance. „WNL‟ and „ENL‟ are gravity lineaments bounding the inferred NNE-SSW trending Nebine Ridge basement high structure seen in the gravity data. The Claravale lineament („CL‟) does not have an obvious gravity expression, however our mapping has shown that major Late Jurassic and Early Cretaceous stratigraphic pinchouts of units occur along this lineament, suggesting structural activity at this time.

In the west, it is noteworthy that all four of the major mapped NNE-SSW to NE-SW oriented antiforms are associated with linear gravity highs, and include the Enniskillen Anticline (EA), Birkdale Anticline (BA), Truno Anticline TA) and Cunno Anticline(CA). This suggests that the Late Jurassic structures formed in response to continued vertical faulting in the basement, which presumably also provided a structural control of sedimentation (NNE-SSW grabens and half-grabens?)

The Nebine Ridge appears to be a major, 50 km wide, NNE-SSW-trending basement horst block. All the mapped Jurassic boundaries are shifted basinwards (i.e. towards the southwest) across the structure. The Maranoa Anticline (MA) is sub-parallel to the Nebine Ridge, and is possibly associated with a weak gravity high within the broader definition of the Nebine Ridge structure. The location of the Forest Vale Anticline (FVA) does not appear to have a correlation with the gravity data.

Fig. 10 is a summary structural diagram of the study area. The figure emphasises the importance of the NNE-SSW structural trend, i.e. parallel to the Nebine Ridge over most of the study area, however the area east of the Nebine Ridge seems to have different structuural orientations.

The figure also reveals the fact that a considerable majority of the mapped structures occur within the package of sedimentary rocks between the Early Jurassic Hutton Sandstone in the north and the Early Cretaceous Eromanga Basin sequence in the south. Neither of these packages appear to be particularly affected by the interpreted structures. This may be due to the (a) the structural rigidity and competence of the basal Hutton Sandstone unit, and (b) to the possibility that the structures may largely predate the Early Cretaceous Eromanga Basin deposition. It should be noted, however, that the important Birkhead antiform to the northwest of the present study area shows evidence of continued activity in the overlying Early Cretaceous units.

Figures 11-13 are a series of „time-slice‟ diagrams showing the relationships between the mapped structures and the various stratigraphic units. Fig. 10 shows the mapped extent of the J2, J2s, J3 and J4 units in the main part of the study area, along with the area mapped as shown as „Injune Creek Gp‟ around Injune township in the northeast. The Injune area has a generally similar photogeological aspect to that of units J2/J2s further west, however as there is no direct linkage between the areas on imagery, a stratigraphic continuation cannot be assumed.

Jurassic Injune Creek Gp and units J2, J2s, J3, J4

Fig. 11 shows that units J2, J3 and J4 maintain a reasonably consistent thickness (allowing for dip changes) throughout the study area. Although unit J3 can be seen to thin out in the extreme NW of its mapped extent (north of Tambo). Unit J3 also appears to thin across some of the larger antiforms, but this may be due to dip changes. The distribution of inferred sandstone-rich sub-units (unit J2s) appears to be somewhat haphazard and shows no clear structural control.

Transitional Units JK0, JK1, JK2 and JK3

Fig. 12 shows the mapped extent of transitional units JK0, JK1, JK2 and JK3. The transgressive sandstone units JK0 and JK1 appear to display quite marked changes in thickness. Unit JK0 in particular appears to pinch out completely to the west of the Forest Vale Antiform. These rapid

Figure 9. Photogeologically-interpreted boundaries, faults and selected anticlinal axes superimposed upon a colour gravity image of the study area and surroundings. Yellow/red colours are gravity highs, implying shallower high-density basement rocks, while blue colours are gravity lows, possibly implying thickened sequence of low-density sedimentary rocks. Positions of the inferred West and East Nebine lineaments (WNL and ENL) are suggested by the gravity data. The inferred Claraville lineament (CL) coincides with major facies changes in the Late Jurassic-Early Cretaceous stratigraphy.

Antiformal structures, shown by broken white lines, include: EA – Enniskillen Anticline; BA – Birkhead Anticline; TA – Truno Anticline; CA – Cunno Anticline; MA – Maranoa Anticline and FVA – Forest Vale Anticline. Towns shown are: Je – Jericho; Bl – Blackall; Ta – Tambo; Mv – Morven; Mt – Mitchell; Ro – Roma; In - Injune

Figure 10. Summary structural map of Tambo project area. EA – Enniskillen Anticline; TA – Truno Anticline; CA – Cunno Anticline; WNL – West Nebine lineament; MA – Maranoa Antiform; ENL – East Nebine lineament; Forest Vale Antiform; CL – Claravale lineament. Town names are shown in Fig. 9.

Figure 11. Extent of mapped units J2, J2s, J3 and J4, and area underlain by undifferentiated „lower Injune Creek Gp‟ in the east. See Figs. 9 and 10 for explanation of structural symbols and town names.

Figure 12. Extent of mapped units JK0, JK1, JK2 and JK3. See Figs. 9 and 10 for explanation of structural symbols and town names.

56 changes must suggest syn-sedimentary vertical movements on relevant N-S structures, particularly in the vicinity of the East Nebine lineament. Unit JK1 also appears to undergo pronounced thickness changes east of the Maranoa Anticline.

The data presented in Figs. 11 and 12 suggest fairly consistent rates of subsidence and sedimentation of the region during the Middle to Late Jurassic (i.e. map units J2, J3 and J4). By contrast, vertical motions on N-S faults became much more important in the Late Jurassic-Early Cretaceous transition period, when predominantly clastic deposits appear to have been deposited with local thickening of units in favourable structural locations.

Unit JK2 is of particular importance as a photogeological marker on account of its strong resistance to erosion and positive outcrop. As the figure shows, unit JK2 undergoes major local changes in thickness, pinching out altogether across the Forest Vale Antiform and thickening considerably in the adjacent synformal basins. The unit, along with overlying unit JK3 is absent altogether east of the Claravale lineament.

In the north of the study area, units JK1, JK2 and JK3 all appear to thin rapidly and to almost disappear locally in the region north of Tambo.

Unit JK3 lies just below the Early Cretaceous Doncaster Mbr, and has been incorrectly mapped by the BMR as the latter in the region around Tambo (see previous study). The unit shows reasonably consistent thickness as far east as the Claravale lineament, where it vanished abruptly (possibly overstepped by the Early Cretaceous?).

Early Cretaceous Units Klmk, Kln, Kli, Kld, Klc, Kla, Kla2, Klm, Kw

The southern and western parts of the study area (Fig. 13) are covered by Early Cretaceous strata which are probably unconformable on the underlying Late Jurassic-Cretaceous transition sequence. The figure shows that between Mitchell and Roma, the three mapped units comprising the Early Cretaceous Mooga and Bungil Fms (map units Klmk, Kln, Kli) only occur to the east of the East Nebine lineament, implying subsidence in the Roma area prior to the much more widespread deposition of argillite and sandstone beds of the Doncaster and Coreena Mbrs of the Wallandilla Fm.

An observation of possible significance is the coincidence of the N-S trending zone of „possibly altered Doncaster Mbr‟ rocks (map unit Kldw) with the inferred southward extension of the East Nebine lineament zone. While the nature of this „alteration‟ (which produces a soft, whitish tone in the otherwise homogenous shales) is totally unknown, it is possibly significant that the linear N-S zone coincides spatially with an inferred deep crustal lineament, which may have acted as a conduit for fluid flow into the overlying Mesozoic sediments.

4.3 Geomorphology

A good overview of the geomorphology of the southeastern part of the study area is provided by a colour ramp Shuttle Radar (SRTM/DEM) topographic image (see Fig. 14). The image shows the deep dissection associated with the Maranoa River drainage basin in the centre of the study area, as well the generally low-lying areas occupied by the Cretaceous Doncaster Mbr in the south and west, suggesting that the Nebine Ridge was an emergent feature at the time of deposition. Note the topographically prominent aspect of marker unit JK2 between the WNL and ENL lineaments, suggesting possible late uplift of the Nebine Ridge and subsidence on its flanks.

The source of the very prominent, plateau-forming, Miocene basalt flow in the east follows the inferred trace of the Claravale lineament. This localised basalt extrusion may well have been controlled by the Claravale structure.

Figure 13. Extent of mapped units Klmk, Kln, Kli, Kld, Klc, Kla, Kla2, Klm and Kw. See Figs. 9 and 10 for explanation of structural symbols and town names.

Figure 14. Colour SRTM/DEM topographic image of southeastern part of study area., with superimposed stratigraphic upper and lower boundaries of unit JK2 (white lines) and structures from previous section (see Fig. 10 for key). Topographically prominent N-S feature on „CL‟ lineament is resistant Tertiary basalt flow.

59 5. CONCLUSIONS

A 1:100,000 scale photogeological study was carried out on behalf of Lodestone Energy Ltd over an area of some 45,000 km2 in central Queensland, located in the region between Jericho in the north and Roma in the southeast. The objective of the study has been to map stratigraphy and structure of the Eromanga/Surat Basins sequences for ongoing coal and CSG exploration in the region.

Method

The study was carried out using stereoscopic, 2.5 m resolution, natural colour LANDSAT/SPOTMAPS satellite imagery, processed with SRTM (Shuttle Radar) DEM topographic data to produce hardcopy 1:100,000 scale pseudo-stereo images for interpretation. A total of 27 stereopairs were produced, each consisting of a normal Vertical image with coordinate grid and a Left Stereo image for stereo viewing. All images are in GDA94/MGA55 projection.

Results

The LANDSAT/SPOTMAPS/SRTM images provide excellent definition of the poorly-exposed Mesozoic strata in the study area. The work has highlighted numerous instances where the reliability of the BMR mapping has been brought into question. Furthermore, new evidence for basement control of sedimentation during the Jurassic-Cretaceous has been brought to light, which is supported by regional gravity data. This has implications for the lateral continuity of the Jurassic Surat basin style stratigraphic units within the study area. Mapped unconformities will need to be resolved by drilling across the structutral domains.

Successful stratigraphic differentiation and structural mapping is possible because the sequence contains several resistant, sandstone-rich units, some of which form positive erosional features and diagnostic „dip flatiron‟ landforms. Most are recognisable through lack of bush clearing due to poor soils, and have a typical whitish, speckly appearance. The sandstone units identified in this way include the Early Jurassic Hutton Sandstone, and a variety of Middle-Late Jurassic sandstone units which equate in part to the Adori /Springbok Sandstone, Hooray Sandstone, Gubberamunda Fm, Southlands Fm, and Orallo Fm as depicted on existing BMR geological maps.

The correlation of these sandstone units remains speculative; existing maps do not correctly show the spatial extent of these units or the intervening more argillaceous units, nor the facies changes within these units. A „data gap‟ to the west of Injune means that we cannot project the well-established stratigraphic subdivisions (Walloon CM, Tangalooma Sst, Juandah CM) into the present study area. Furthermore, the SPOTMAPS images used are not really equal to the task of mapping the very low units within the Injune Creek Fm, and it is suggested that consideration be given to 1960‟s vintage 80% stereo overlap 1:80,000 scale aerial photos, which seem to have been successfully used by earlier consulants.

Based on the information available, we have established a revised, informal stratigraphic framework for the Middle-Late Jurassic units in the area which occur between the Hutton Sst and the Doncaster Mbr, as summarised in the following table. Suggested correlations based on subsurface data proposed by Lodestone Energy are also included.

60 Unit Informal Unit Name Equivalent Units on BMR Correlation suggested by (this study) Maps Lodestone Energy

Kld Doncaster Mbr Doncaster Mbr

JK3 Speckly upper sandstone Hooray Sst, Minmi Mbr of Bungil (informal) Fm JK2 Scarp-forming sandstone Hooray Sst, Claravale Mbr of Springbok Sandstone? (informal) Bungil Fm JK1 Lower sandstone Hooray Sst, Southlands Fm, Orallo Springbok Sandstone? (informal) Fm JK0 Basal transitional unit Gubberamunda Fm, Southlands Fm (informal) J4 Pink marker unit Westbourne Fm Juandah CM? (informal) J3 Soft sandstone unit Springbok/Adori Sst Tangalooma Sandstone? (informal) J2 Unit overlying Hutton Sst Birkhead Fm Taroom CM? J2s (sub-unit J2s is inferred to be sandstone-rich)

Jlh Hutton Sandstone Hutton Sandstone Hutton Sandstone

The J2 unit immediately overlying the Hutton Sandstone is spatially coincident with the Birkhead Fm shown on published maps, and may continue to the east as the lower part of the coal-prospective Injune Ck Gp, in which exploration activity has identified several members. While there is some evidence of more- and less-resistant units within the J2 unit, which may correlate with these members, no definite stratigraphy can be established due to the „data gap‟ mentioned above and the restrictions imposed by the SPOTMAPS imagery. The sub-units identified in J2 may be facies changes.

Mapped antiformal structures affecting the Middle and Late Jurassic stratigraphy in the western part of the study area are strongly related to NNE-SSW or NE-SW oriented linear gravity highs. These include the Enniskillen, Birkdale, Truno and Cunno antiforms, suggesting that the Late Jurassic structures formed in response to continued vertical faulting in the basement, which presumably also provided a structural control of sedimentation (NNE-SSW grabens and half-grabens?)

The Claravale lineament is marked by a prominent N-S Miocene basalt flow, and coincides with profound changes in the Late Jurassic and Early Cretaceous sedimentation patterns. In particular, the Late Jurassic transitional units JK2 and JK3, which include a very prominent sandstone marker, end abruptly aagainst the Claravale structure, and are not seen to the east of the lineament. Conversely, the entire Early Cretaceous Mooga and Bungil Fms, which are well represented around Roma, also terminate abruptly against the structure and are not seen to the west.

The inferred trace of the Claravale lineament is also parallel to a regional N-S synformal structure (Claravale Synform), which may represent a Middle-Late Jurassic faulted depression. The controversial boundary between the prospective lower Injune Creek Gp to the east and the Birkhead Fm to the west is also located in the vicinity of this lineament, however lies outside the present study area.

61 5. REFERENCES CITED

Exon, N.F., 1968. Eddystone, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/7

Exon, N.F., 1970. Tambo, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/2

Exon, N.F., 1971a. Mitchell, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/11

Exon, N.F., 1971b. Roma, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/12

Exon, N.F., 1976. Geology of the Surat Basin in Queensland. Aust. Bur. Mineral Resour. Geol. Geophys., Bull., 166.

Forbes, V.R., 1968. Taroom, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/8

Galloway, M.C., 1970. Augathella, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/6

Hamilton, S., 2007. Regional correlation within the Walloon Subgroup, eastern Surat Basin. In: Changing the Face of Queensland. Proc. 2007 PESA Queensland/Northern Territory Symposium, Brisbane.

Jones, G.D. and Patrick, R.B., 1981. Stratigraphy and coal exploration geology of the northeastern Surat Basin. Geol. Soc. Aust., Coal Geology Group Jour., 1(4), 153-163.

Mollan, R.G., 1967. Springsure, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/3

Nash, C.R., 1998. Geological Image Interpretation (2nd Ed). Adelaide, Aust. Mineral Foundation, Course Notes, 202/98.

Nash, C.R., 2009. Photogeological interpretation of stereoscopic SPOTMAPS/SRTM imagery, Tambo-Augathella area, Queensland. Colin Nash & Assoc. Pty. Ltd., unpubl. rept. for Lodestone Energy Ltd.

Pinchin, J., and Anfiloff, V., 1986. The Canaway Fault and its effect on the Eromanga Basin. Geol. Soc. Aust., Spec. Publ., 12, 163-175.

Senior, D., 1971. Charleville, Queensland 1:250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SG 55/10

Senior, D., Jericho, Queensland :250,000 Geological Sheet. Aust. Bur. Mineral Resour. Geol. Geophys., Explan. Notes, SF 55/14

Swarbrick, C.F.J., 1973. Stratigraphy and economic potential of the Injune Creek Gp in the Surat Basin. Geol. Surv. Qld., Rept., 79.

62 APPENDIX I: STRATIGRAPHIC CORRELATION OF NORTHERN SURAT AND EROMANGA BASINS

(1) Swarbrick (1973) Stratigraphy of Injune Creek Gp

(2) Hamilton 2007 (ref?)

Swarbrick (1973)

Hamilton (2007)