The Cordillera del Condor – the eastern foothills to the Andes in southeastern Ecuador – hosts a well-endowed mineral belt that contains 26 million ounces (“Moz”) of gold and almost 40 billion pounds (“Blbs”) of copper in NI43-101 resources held by various companies (Figure 1). The Lost Cities – Cutucu Project (“Project”) lies along-trend of that mineral belt and so our exploration is focused on finding the same types of deposits that occur in the Cordillera del Condor (Figure 2).
Major Gold Deposits: Cordillera del Condor
Major Copper Deposits: Cordillera del Condor
Figure 1. NI 43-101 resources of the larger gold and copper deposits in the Cordillera del Condor in southeastern Ecuador.
Many of the mineral deposits in the Cordillera del Condor are related to a 200km-long granitic body, the Zamora Batholith, which is the probable source of magma and metal for the associated porphyry copper and copper-gold deposits, and related epithermal gold-silver and gold skarn deposits. Aurania’s new aeromagnetic data suggest that a similar granitic batholith lies beneath the central part the Project area. If this interpretation is correct, this Cutucu Batholith may have provided a similar source as the Zamora Batholith for porphyry, epithermal and skarn mineralization in the Project area.
Figure 2. Map showing the geological continuity between the Cordilleras del Condor and Cutucu in southeastern Ecuador. The location of major gold and copper deposits in the Cordillera del Condor are shown, along with the outline of the concessions (in red) that constitute the Lost Cities – Cutucu Project.
Figure 3. Stratigraphy of the Cordilleras del Condor and Cutucu in southeastern showing the stratigraphy with which the principal deposits or deposit-types are associated in the Cordillera del Condor. The blue- and purple- coloured parts of this stratigraphic column correspond with the purple-coloured rock sequences shown in Figure 2.
Stream sediment geochemistry in the Latorre target has identified two areas, both approximately 3km2 in size, located about 3km apart, of high concentrations of pathfinder elements (Figure L1).
Figure L1. Summary of stream sediment sample results from the Latorre Target coloured by value from pink (highest values) to cooler colours and finally black for the lowest values.
Latorre West Target
Characteristics of Target
The Latorre West target is defined by high concentrations of naturally-occurring arsenic, antimony, molybdenum and silver in silt from streams in an area approximately 3km2 in extent. Locally-derived boulders of chalcedonic silica have been found in streams within the target area. Some boulders consist of chalcedonic silica fragments that are believed to be from a phreatic breccia. Textures in the chalcedonic silica textures from the target area are shown in the adjacent photos.
Latorre East Target
Characteristics of Target
High concentrations of zinc and selenium occur in addition to the arsenic, antimony, silver and molybdenum in silt in streams within an area of approximately 3.6km2. Sphalerite, a zinc sulphide mineral, has been found in outcrops of black, carbon-rich shale within the target area. Sphalerite occurs with pyrite and minor galena, in fine bands within the shale, along with bright yellow secondary minerals of cadmium.
The exploration target concept at Latorre East is not yet clear.
- Outcrops of shale in the target area have been sampled and assay results are awaited.
- More detailed geological mapping is now underway, along with more detailed stream sediment and rock chip sampling.
Characteristics of Target
The Awacha target was defined from the geophysics data collected in the extensive survey that was completed by Aurania in Q4, 2017. The target area consists of ten magnetic centres 0.5km – 2km in diameter, aligned in two northeast trending zones 5km-8km long (Figure A1). The northeast-orientated trends in the magnetic data are disrupted by many northwest-trending features that are interpreted as faults. The centres of discrete magnetism are partially bordered by magnetic lows that may be caused by structurally-controlled alteration in which magnetite may have been replaced by non-magnetic clay minerals. Two of the magnetic peaks evident in the magnetic data were independently identified as possible granitic centres – possible porphyries – in satellite imagery.
Figure A1. Airborne magnetic data from the Awacha Target area of the Lost Cities – Cutucu Project. Three interpreted intrusive centres identified in satellite imagery are shown in yellow circles.
The size and intensity contrast of the magnetic centres that make up the Awacha target are similar those of known porphyry gold-copper and copper deposits in the adjacent Cordillera del Condor, that lies along geological trend.
Many of the mineral deposits in the Cordillera del Condor are related to a 200km-long granitic body, the Zamora Batholith, which is the probable source of magma and metal for the associated porphyry copper and copper-gold deposits, and related epithermal gold-silver and gold skarn deposits. The new aeromagnetic data suggest that a similar granitic batholith lies beneath the central part the Project area. If this interpretation is correct, this Cutucu Batholith may have provided a similar source as the Zamora Batholith for porphyry, epithermal and skarn mineralization in the Project area.
- Stream sediment results from part of the Awacha target are awaited;
- Depending on those results, further infill stream sediment sampling may be warranted in conjunction with geological and alteration mapping.