LAKE BARLEE PROJECT
LAKE BARLEE PROJECT
The Lake Barlee Project ( Figure 1 ) is situated on the Yilgarn block and lies approximately 65 km southeast of Youanmi and 293 km north of the mining town of Southern Cross.
The project tenements lie predominantly on an intermittent playa salt lake, the second largest in Western Australia. The nearest village to Lake Barlee is Mount Magnet, some 163 km to the northwest (cf. Figure 1 ).
The lake fills with water approximately every ten years. The water may persist for 6 months thereafter. Access to Lake Barlee is via the Evanston-Menzies Road and the Lake Barlee - Youanmi Road. The most conspicuous physiographic element in the area is Lake Barlee, which is part of an endorheic salt lake chain that drains south-easterly through the Raeside Palaeoriver.The tectonic evolution of the highly mineralised Yilgarn Craton exposes upper-crustal, Meso- to Neoarchean volcano-sedimentary sequences (greenstones) associated with 2960–2600 Ma granites and granite gneisses.
Figure 1: Locality of Western Australian Project, showing nearest access roads, tracks, and settlements. The remote tenements predominantly overlie a large playa lake of saline sediments.
Figure 2. Major geological and tectonic domains and structure of the Murchison granite-greenstone terrane. The Lake Barlee Prospect tenements are shown in blue overlying predominantly Cenozoic playa sediments of Lake Barlee. (YSZ = Youanmi Shear Zone, YMSZ = Yuinmery Shear Zone, IDF = Ida Fault).
The craton is divided into several terranes, based on distinctive stratigraphic and magmatic characteristics, geochemistry, and age. In the western half of the craton, the Youanmi Terrane includes the Murchison and Southern Cross domains, showing distinct lithostratigraphic assemblages in greenstone belts, which are juxtaposed by the Youanmi shear zone (Figure 2). The Murchison Domain is flanked by the Narryer and the Southwest terranes, in the northwest and southwest, respectively (cf. Figure 2).
Field and geophysical data indicate that the Murchison Domain, as well as the whole craton, is transected by a network of dominantly east-dipping, listric crustal-scale shear zones, juxtaposing terranes with contrasting stratigraphy. In map view (cf. Figure 2), these shear zones are broadly north-striking and can be followed for hundreds of kilometres along strike, and are flanked by north-striking, generally high-strain greenstone belts.
The Lake Barlee tenements lie entirely in the central part of the Southern Cross Granite–Greenstone Terrane (Figure 3), one of the major geological subdivisions of the Archaean Yilgarn Craton. The Southern Cross Granite–Greenstone Terrane is bound to the west and east by the Murchison and Eastern Goldfields Granite–Greenstone Terranes respectively. It is notable that less than 5% of the Lake Barlee area is occupied or underlain by greenstones, the remainder consisting of granitoid rocks.
Figure 3. Simplified regional geological and tectonic setting of the Lake Barlee area (Riganti, 2002). Lozenge-shape granite-greenstones and N/S trending fault and shear zones attest to E/W compression and shortening (e.g., Zibra, 2020) (YSZ = Youanmi Shear Zone, ESZ = Evanston Shear Zone, YMSZ = Yuinmery Shear Zone).
A greenstone-associated gold target defined under Lake Barlee on E77/2700 during interpretation of magnetic data in 2009 has not been drill tested. Approximately 60,000 kg/Au @ 10.6g/t Au has been mined from Halleys East, located some 15km southwest of the Lake Barlee tenements. Geological mapping indicates no greenstone outcrop on Lake Barlee tenements and only little exploration has been reported in some areas of residual soil over granite proximal to greenstone on tenement E77/2700, or distal from greenstone on tenements E57/1158 and 1168.The Yuimery Shear Zone which defines a highly prospective granite-greenstone boundary (cf. Figure 2, Figure 3) and is one of the principal exploration targets, along with a fault splay off the Youanmi Fault (inset). Both faulted and shear-zone structures seem to have formed as a competency (rheology) contrast between granite-greenstone contacts. These spatial and temporal relationships across highly strained zones hosting compressional folding, traditionally act as mineralising conduits for concentrated hydrothermal fluid flow.
The exposed greenstones at the Lake Barlee area are the northernmost outcrops of the Marda–Diemals greenstone belt (Figure 4), which combines the Marda and Diemals belts of Griffin (1990). Aeromagnetic images, including a drone magnetic interpretation conducted by Taiton, confirm, as per the published geology records, that some greenstones also underlie the southwestern arm of Lake Barlee (Figure 5). The regional stratigraphy of the belt comprises a mafic- and BIF-dominated lower greenstone succession unconformably overlain by an upper greenstone succession that includes the felsic volcanic rocks of the Marda Complex and the clastic sedimentary rocks of the Diemals. Only the lower greenstone succession has been recognized at Lake Barlee. The lower greenstone succession is inferred to have a depositional age of 3 Ga.
Figure 4. Local geology (1:250,000) and major structures around Lake Barlee (dark blue outline). The tenements have been sited along significant discontinuities and lithological contacts, which are prospective for gold mineralisation.
The age of the upper greenstone succession is well constrained at c. 2730 Ma by conventional and SHRIMP U–Pb zircon dating. Granitoid intrusions in the Marda–Diemals region range in age from c. 2730 to c. 2635 Ma. Gold mineralization is typical of zones of alteration marginal to quartz veins. Quartz veins with intersected widths up to 16 m (but mostly up to 3 m) are surrounded by gold-bearing alteration zones consisting of fine-grained, sheared, silicified, and sericitized mafic and ultramafic rocks with grades up to 7.7 g/t Au. Competency contrasts, such as fold hinges in BIFs and shear zones, were also targeted.
Figure 5. Showing detail of southern tenements with projected granite-greenstone contacts and principal shear zones. These contacts are almost wholly buried beneath depositional units of the Lake Barlee playa-lake system and are targets of the proposed exploration programs (after Riganti, 2002).
Exploration on and around the Lake Barlee tenements has focussed on orogenic gold within greenstone sequences as well as calcrete-hosted uranium and salt lake potash deposits in playa lakes. Beacon Minerals explored parts of E77/2700 and an extensive trend to the southwest between 2007 and 2014 for orogenic gold systems; work culminated in extracting high grade ore from a small pit (60kt @ 10.6g/t Au) at Halleys East located 10-15km southwest of the Lake Barlee tenements. Between 2009 and 2013 Goldpride Pty Ltd and Jervois Mining conducted cursory exploration over Lake Barlee for uranium and potash deposits. Parkway Minerals undertook substantial exploration for potash in 2017 and 2018, which included reprocessing of historic airborne geophysical data, passive seismic surveys, auger sampling and drilling east of the Lake Barlee tenements. Historic exploration is summarised in the table below.
In April 2022, Taiton Resources sought Mitre Geophysics’ opinion regarding the interpretation of orogenic gold-style targets in its Lake Barlee tenements, in the Yilgarn goldfields WA. Taiton supplied a regional 40 m merged aeromagnetic dataset from the WA State Department of Mines, Industry Regulation & Safety, and UAV magnetic data acquired by AirGeoX Pty Ltd for Taiton’s subsidiary Lake Barlee Gold Pty Ltd, in December 2021-March 2022. The data was almost entirely sampled from the inshore of the lake itself.
The three surveyed areas are shown in Figure 6.
Figure 6. Geophysical survey conducted by a UAV in tenements E57/1168 and E77/2700. The flight areas are indicated in green polygons and areas of interest highlighted within these (gneisses – dark brown, migmatitic granites – red, BIF and cherts – dark green).
Three patches of drone magnetic data across a regional RTP TMI, have identified an intense linear anomaly that most likely sourced by chemical ironstone or jaspilite from the high strain Archean metavolcanic package (AMV). Taiton is of the opinion that this AMV package is similar in mode, occurrence and age to Taiton’s preferred analogue, the 2.6 M Oz Big Bell deposit in the Cue region (cf. Figure 7). From their study, Taiton concluded that a comparison between the RTP and analytical signal suggests that part of the host sequence is remanent, due to the presence, in the Big Bell analogy, to monoclinic pyrrhotite and mafic units comprising the potential ore host rocks (cf. Figure 7). Gold mineralisation is associated with distinct magnetic highs within a weakly magnetic felsic volcanic host. A high magnetic susceptibility is due to abundant disseminated pyrrhotite at the Big Bell and may be the case with the Lake Barlee UAV magnetic targets.
Figure 7. Left - an Archaean-age low TMI para-gneiss domain to the west of the linear structure (Anb), accompanied with a high TMI signature domain migmatites and granites to the east (Agx), separate an interpreted meta-volcanic package at their common contact (AMV). Right - the Big Bell deposit at Cue to the north of the tenements. It is suggested that the Lake Barlee lithologies and structures beneath the Lake are analogous.
No substantive exploration for gold has been reported in some areas of residual soil over granite proximal to greenstone on tenement E77/2700 or distal from greenstone on tenements E57/1158 and E57/1168. However, a target for gold mineralisation, comprising demagnetisation of north-south striking magnetic greenstone (likely BIF) at the intersection with NE-striking structures, was defined onshore of the lake at its southern end on E77/2700 (cf. Figure 5). The target has not been drilled. Additional targets were defined immediately south of the Lake Barlee tenements, these prospective trends are likely to continue along strike under cover onto the tenements (cf. Figure 5, Figure 6). The interpretation of the continuation of the subsurface geology and structure under the playa lake system has been conjectured by Taiton, due to the continued magnetic expression of this geology under the lake’s playa sedimentary cover (cf. Figure 6).
Figure 8. Planned RC drilling program of identified high-interest magnetic anomalies beneath Lake Barlee. The anomalies outline a narrow, linear zone of metavolcanics (AMV), which is thought to be an analogue of the Big Bell deposit in the Cue region to the north.
The following exploration targets have been planned by the Company (Figure 8) on the outcome of the AirGeoX Pty Ltd UAV magnetic data.
The Company anticipates that the targets generated by this methodology are of sufficient resolution to conduct a first-phase reconnaissance drilling operation. All planned collar positions have been sited on solid ground, away from the soft-sediment playa lake fill (Figure 9). Any alteration or mineralised zones intersected during this reconnaissance phase drilling will be characterised to provide vectors as to the size and distribution of mineralisation and guide a second round of definition drilling.
It is anticipated that the first target (Target A) will comprise thirteen (13) RC drill holes. Target B comprises a drill fence of five (5) RC drill holes (cf. Figure 9).
Figure 9. Lake Barlee proposed drilling program. Overlain is a TMI_RTP_2VD_ 6.25m image over a Google Earth base map. Drill collars indicated for Target A and Target B.