It is not hard to see how the name "Campo Formosa" (Beautiful Field) was applied to this hemispherical area. It has the ability to retain water in soil at all times of the year even in an arid sub-equatorial climate. The "Campo" is surrounded by high hills on the North, South, and East sides, and low hills on the west.
Any rain that falls here has almost no opportunity to escape so it pools in the SE corner.
The rain is scarce (15 inches) and very seasonal ( https://pt.weatherspark.com/y/30913/Clima-característico-em-Campo-Formoso-Brasil-durante-o-ano ).
At the tail of the wet season (April) only small pools of water can be found within the tenements.
There are some signs of sheetwash but there are no bridges outside of towns so those events seem to be minor. Anything that looks like it could be a stream is a collection of pools linked by dry run-off channels.
View Tenements and Sample Locations in 3D :
use Google Earth ( URL ) with the GMN Tenements kml file and Sample Locations kml file below.
View DEM : use SentinelHub ( URL ) with the GMN Tenements json file below. Change the filename suffix to json and drag into the SentinelHub popup "upload area of interest".
The map above shows the tenement boundaries over Radiometric Potassium and the mineral mentioned in the Claim. The very dark areas are interpreted to be K-Granites. By chance some of the sample locations are near these dark areas. Typically, they return a high assay. A geochemist would not be surprised.
We don't know the month when the samples were taken, but the last dry season ended in October last year. You will see that some sampling sites are "downstream" of each other. In the "stream sampling model" all points in a catchment that are downstream of another point are expected to contain mobile components of the upstream points. This works well for some minerals in some catchments.
However the water solubility of Lithium is so high (it forms soluble hydrate molecules) that it leaches out of fine sediments very quickly and is the first to be purged if there is run-off.
In the dry season the area has a very high evaporation rate. The evaporation draws soil salts to the surface potentially causing "soil salinity".
As the evaporation of moisture in soils (including dry stream beds) proceeds all salts begin to move. Not laterally, but vertically.
Only if a dry "stream" happens to cross a Lithium source then the assay will detect that source below the intersection.
At this point the "stream sampling" model breaks down. The inferences that are sought about upstream catchments are no longer available.
BTW: it is always invalid to infer a Assay range to all points in a catchment (refer Figure 3, pg 4 ).
In the Google Earth 3D browser the altitude of the earth’s surface under the cursor is displayed on screen (bottom right corner). When the Sample Locations kml file is loaded the Li assay range of each sample is indicated by the colour and size of the dot at the sampling location. You will see that there are some points with low Li assays that are downstream of points with high Lithium assays.
Comparisons have been made with SLM's Jaguar prospect ( 871427/2006, see insert in the map above ).
SLM walked away from the prospect after having found spod ( see pg 2. SLM ann 17th July 2023 ) even though an extension was available.
Cost and Drilling Performance have been mentioned as hurting the risk/reward at the prospect.
The map above shows that the GMN "Campo" tenements are "near" significantly more K-Granite than at Jaguar.
If goldilocks zones can be measured by contour lengths, and Jaguar was assigned a score of 1, then nearby GNM tenements would has assigned values as follows ( Juremal North : 2.6. Juremal : 2.9. Campo Formosa : 5.6 ). By that measure alone, Spod potential is significantly higher in the GMN tenements .
There is a NE trending chain of linear hills at "Campo Formosa". One is in the GMN tenements ( -10.4966. -40.3897 ). It has all the characteristics of a pegmatite. There other candidates in the tenements and elsewhere within the "Campo" hemisphere. If they are pegmatites, then they are unusual; they are highly eroded, and even rotated 90 degrees CW. It could be that massive intrusions 100km to the west and SW have been responsible for the creation of the hemispherical "campo" and the manipulation of the pegmatites.
Another distinction between Jaguar and Campo Formosa tenements can be seen in the NDCI (a hyper-spectral index).
Less than 2% of the Jaguar area has an NDCI greater than or equal to 0.3; for Campo Formosa this is more than 10% of the area.
It may also indicate (to a Botanist) that Lithium in soils are part of the reason for the name "Campo Formosa".
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GLTALTH and DYOR
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Sample Locations (2024-04-20) kml.txt
Tenement Boundaries (2024-04-20) kml.txt
Tenement Boundaries (2024-04-20) json.txt
(20min delay)