Morella Corporation Limited (ASX: 1MC) has identified a number of drill targets in results from geophysical exploration activities completed at the Fish Lake Valley Lithium Project in Nevada, USA.
Over the past four months, Morella has completed a passive seismic survey (PSS) and a magnetotelluric (MT) survey over select areas of the Project.
Both PSS and MT data capture, analysis and interpretation has been completed for the southern area of the Project which has identified key, prospective drilling targets.
The identification of drilling targets is currently constrained to the southern area where the integration of PSS and MT surveys has been completed and modelled.
Magnetotelluric Survey
Following the preliminary geophysical exploration results, Morella defined and undertook an MT survey along two survey transects across the southern portion of the Project, the purpose of which was to identify potential sub-surface conductive brine accumulations.
MT survey lines were located across sub-basin structures interpreted from regional gravity survey data and PSS data.
US-based Zonge Engineering carried out the MT survey data acquisition at Fish Lake Valley during March 2022.
Data was acquired using X-component electric field dipoles at 200m station spacing, with Y-component electric field dipoles acquired every 400m.
Magnetic field sensor stations were deployed at four stations spaced between 800m and 1,600m along the survey lines.
Perth-based Resource Potentials completed 2D resistivity inversion modelling of the MT survey data using CGG Geotools, which utilises the RLM-2D inversion modelling code. The resistivity range of the 2D MT resistivity model is between approximately 1.2 Ohmm, which may be caused by very saline groundwater or brine, to approximately 100 Ohmm, which may be caused by less-saline groundwater or changes in geological layers.
The 2D MT resistivity model cross section for MT survey line L4190150N indicates a very strong conductivity anomaly located approximately 850m below ground level beneath station 14600, as well as a shallower conductivity anomaly located approximately 235 m below ground level beneath station 13800.
The 2D MT resistivity model cross section for MT survey line L4191150N (Figure 3) indicates three strong conductivity anomalies, including two deep anomalies located approximately 900m to 1,050m below ground level and one shallower conductivity anomaly approximately 150m below ground level.
Review of available historical deep drilling data for a select hole located within the Project area has been used to support analysis and interpretation.
“VRS-1” is a deep 2,628m vertical, historical petroleum exploration well, which was drilled in 1970, the downhole resistivity measurements from VRS-1 show good correlation to the deep conductive zone modelled from the MT survey data, with very low resistivity values of between approximately 0.8 Ohmm and 1.4 Ohmm measured from approximately 500 m to 900 m downhole depth.
Drilling Targets and Forward Work Programme
The deep and broad conductive anomaly zone modelled for both of the MT survey lines may be related to conductive brine accumulations hosted in Late Miocene tuff sediments as well as underlying Silver Peak Formation sediments.
The high-conductivity response may be a function of both brine quality (increasing salinity will correlate with increasing conductivity) and lithology (fine grained sediments such as clay maybe associated with increased conductivity).
Therefore, initial exploration drilling will aim to:
- Confirm the lithology in high-conductivity horizons and underlying and overlying geological units (to allow preliminary assessment of the hydrogeological setting).
- Allow the collection of brine samples from the target horizon (for assays of lithium concentration).
- Provide data against which future geophysical surveys can be calibrated.
In support of the above exploration efforts, Morella has identified three initial drill targets FLVSP001, FLVSP002 and FLVSP003.
These targets are constrained to the southern portion of the Project area at this time. Additional drill targets may be identified once Morella is able to review and consider the outcomes of the ongoing geophysical exploration being conducted in the northern area of the Project.
With clear targets and drill programmr concept confirmed, Morella’s immediate focus will be to commence market solicitation and permitting to support a drill program expected to be conducted in the second half of 2022.
For further information please visit: https://www.morellacorp.com/
