Gold Mountain (ASX: GMN) has defined extensive multi-element anomalism pointing to iron oxide copper-gold (IOCG) and lithium potential in two areas covered by an initial 231 stream sediment samples from its Iguatu Project in Brazil.
The company says it has identified clusters of broad halo-style iron and sodium anomalies and copper-gold-mercury anomalies generally associated with the more strongly-mineralised parts of Australia’s renowned Olympic Dam IOCG deposit.
Gold Mountain’s Iguatu and Iguatu North tenements enclose a total area of 1322 square kilometres. Management says its data reviews confirm that extensive structures – typically associated with the massive Olympic Dam breccia-style IOCG deposits – can be identified in its Iguatu ground.
The company initially undertook regional-scale geochemical stream sediment sampling to determine the potential for the ground to host IOCG and/or lithium mineralisation. It followed the geochemical work with a review of regional magnetic data to identify magnetic anomalies that tie in with geochemical anomalism – especially that which might be related to elevated iron concentrations.
The company considered a post-tectonic Olympic Dam-type IOCG-style of mineralisation in its initial model at Iguatu, employing zonation patterns drawn from that project’s surface samples as interpretative guides. The baseline work outlines strong indications that the company is on the mark.
Three IOCG-style anomalies have been identified within the company’s Iguatu ground. Two big anomalies measure about 7km by 4km, while a smaller zone measures about 3km by 1.5km.
All three anomalies feature elevated iron signatures in association with other varying characteristics of IOCG multi-element geochemistry. Copper was identified to peak values of 74.7 parts per million, in sharp contrast with the local background maximum of less than 28ppm.
At Iguatu North, a broad zone of IOCG-favouring anomalism has been interpreted from the available data that measures about 6km north-south and between 1.5km and 2.6km east-west, centred around a key IOCG copper-gold-mercury signature with peripheral iron anomalism.
This is a fantastic first step, proving GMN ground is fertile and has the potential to host a world class IOCG deposit similar to Olympic Dam.
Gold Mountain managing director David Evans
In addition to its IOCG focus, Gold Mountain has also kept its eye open for potential lithium hosts as the region is known to be laced with high-LCT (lithium-caesium-tantalum)-type pegmatites, which could represent evolved lithium-rich hosts. And indeed, the company’s geochemistry does reveal anomalous lithium that correlates strongly with rubidium, beryllium, caesium, niobium, thallium and tin.
Also, peak values for lithium in the stream sediments attain 105ppm, which in most geochemical environments would be considered a high-order stream anomaly.
The lithium and multi-element association strongly indicates the likely presence of LCT-type pegmatites – a conclusion further supported by the existence of local artisanal gem-quality tourmaline workings that are even referred to in Geological Survey of Brazil records.
Gold Mountain has defined 16 LCT anomalies at Iguatu. At Iguatu North, five high-value LCT responses and one medium and two lower-order anomalies have been defined, covering a significant area of the tenement.
Pegmatites have also been mapped by the Geological Survey of Brazil in several of the company’s tenements and some appear to be associated with its geochemical anomalism. Further work will entail follow-up sampling and mapping of two IOCG anomalies from results received to date, coupled with a new campaign of infill sampling between anomalous areas, many of which were defined from broadly-spaced reconnaissance level sample spacing.
Mapping and soil sampling is also proposed for confirmed LCT-type pegmatites in a bid to close-in on potential drill targets.
Many samples are also still awaiting laboratory assay results and will be subject to progressive interpretation and addition to the database as they come to hand and keep adding to the evolving picture. Offering the vision of a second Olympic Dam-style deposit is all that this project needs to keep it on the “watch this space” list.
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