Larvotto Resources (ASX:LRV) reports it has defined a ‘broad’ lithium geochemical anomaly at its Merivale prospect at the Eyre Project, located in Western Australia.
The Merivale anomaly was generated from Larvotto’s geochemical soil program undertaken earlier this year, which was designed to test the prospective rock units that extend south from Liontown’s Buldania deposit, located just to the north.
These rock units has also been identified by an AngloGod Australia regional auger geochemical program, undertaken between 2009 and 2013, as containing anomalous lithium results.
The main anomaly is currently defined over an area of 4km long and 1m wide with a maximum lithium value of 126ppm Li, which is 5 times background levels. The anomaly trend extends a further 2km north and 1km south.
A central higher value core which appears aligned with a cross cutting structure is over 1km long.
Multiple readings were taken from each sample and where evident, the feslic (lighter coloured) fragments were preferentially analysed to determine if lithium mineralisation was present within the fragments.
Geological mapping undertaken during the company’s survey highlighted the presence of small pegmatite outcrops and broader areas of pegmatite float within the surface soil horizon, the float material deemed to have been locally transported.
The area is predominantly covered by transported soils and this was expected to result in lower order and broader geochemical anomalies due to potential contamination.
For this reason, the preferred method of analysis was to use the latest pLIBS (Laser-induced Breakdown Spectroscopy) technology to augment standard analytical techniques.
The pLIBS, is a pulse laser which samples a 50micron window of the finely sieved sample, allowing selective analysis to determine if any pegmatite within the sample was lithium mineralised.
Samples were collected by hand on 40m to 8m spacing along lines 280m apart. A 2kg soil sample was collected from within 10cm of the surface once surface debris was removed. The sample was sieved to 1mm and a 300g sample was collected for analysis. The sample was then analysed using a SciApps pLIBS instrument.
Larvotto reports that the method successfully identified a cohesive, large, low order lithium anomaly with a higher tenor core.
The anomaly coincides with ultramafic and granite gneiss rocks that geophysics clearly identified extending north into the nearby Liontown Buldania deposit.
Larvotto Managing Director, Ron Heeks said the results from the company’s lithium geochemistry program carried out earlier this year highlight the presence of a significant lithium soil geochemical anomaly associated with minor outcrop and broad areas of pegmatite float.
“Although the weathering of the surface rocks is potentially deeper than those to the north, the sampling technique has provided greater definition of the target area, as we had hoped”
“Although the weathering of the surface rocks is potentially deeper than those to the north, the sampling technique has provided greater definition of the target area, as we had hoped.
The anomaly now requires follow-up drilling to delineate pegmatite horizons and test for significant lithium mineralisation.
We look forward to keeping the market updated as we progress this very exciting program.”
The lithium anomaly is generally associated with the lower magnetic areas, and cross cutting late stage east-west orientated rocks also dissect the prospect.
The lithium anomaly sits predominantly in the felsic volcanic rocks east of the more mafic volcanics and ultramafics.
Several of the magnetic highs represent ultramafic units that have not been mapped in the government’s geology mapping due to the veneer of transported soils, and this also suggests considerably more complex geology than indicated.
Pegmatite outcrop and float mapping undertaken by Larvotto during the geochemical survey have been overlaid over the surface mapping.
Government geological mapping agrees with field observations that highlight the soil horizons are predominantly transported and would be expected to result in a generally ‘broader’, lower tenor anomaly.
Given this, there is still ‘excellent’ correlation between lithium anomalies, airborne magnetics and known mineralised areas to the north.
It is expected that drilling will be required to accurately delineate the pegmatite units due to the effect of covering soils, but the target area has been greatly reduced by the geochemical survey.
The next step for Larvotto is to commence drilling to define the lateral and depth extents of the pegmatite units and test the grade of lithium mineralisation.
Broad lines of RAB and reverse circulation (RC) drilling will be used initially to refine target areas.
Larvotto Resources is actively exploring its portfolio of projects including the ‘large’ Mt Isa copper, gold and cobalt project adjacent to the Mt Isa townsite in Queensland, a gold project at Ohakuri in New Zealand’s North Island, and the Eyre multi-metals and lithium project located 30km east of Norseman in Western Australia.
Larvotto’s board is a mix of experienced explorers and corporate advisors.
Images: Larvotto Resources Limited