Catua


The Catua property is a copper prospect in Jujuy Province, northwestern Argentina. This project comprises a single claim of approximately 900 hectares, 100% owned by Aldebaran. The Catua property is located 6 kilometres from the Chilean border and 220 kilometres northwest of the city of Salta (Figure 1). Access is by all weather road.

Geology and Mineralization

The Catua property contains extensive areas of consolidated and unconsolidated sedimentary rocks. The basement rocks consist of a continental red bed sequence that is poorly exposed in the west and south sectors of the property. These rocks are overlain by gravels, which are in turn overlain by partially lithified, fine-grained white-colored sediments. The top of this sedimentary sequence is made up of unconsolidated gravels, which occur mainly to the east of the Catua property, and that are dominated by dark, siliceous, pebble to boulder-sized lithic fragments. The sedimentary unit that hosts the exotic copper mineralization is a poorly exposed, stratigraphic sedimentary breccia, possibly a poorly consolidated colluvial deposit. The unit is of unknown thickness and lateral extent at depth. The matrix, 10 to 70% of the sediment volume, contains sub-rounded quartz crystals, locally cemented by calcium carbonate. Fragments are mostly angular and range in size from 1 to 40 centimetres. The composition of the clasts is mainly rhyolite; although minor dacite and andesite volcanic rock fragments also occur. Mineralization consists of widespread copper wad, malachite, azurite, and chrysocolla within the matrix of this poorly exposed sedimentary breccia.

Two surface exposures of mineralization that are separated by 1 km have been identified to date; a northern area (Catua Norte) measuring 800 by 300 m and a southern area (Catua Sur) measuring 300 by 80 m. Both bodies are nearly flat lying and are elongated along a trend of approximately 310º. In 2001, Mansfield took a total of 58 rock samples of variably indurated sedimentary breccia which returned copper values up to 18.25%, with anomalous lead, zinc and cobalt values. Mansfield's geologists have interpreted the occurrence as a carbonatite breccia pipe with copper mineralization. A total of seven old “winky” drill-hole collars were identified in the field in the vicinity of the Catua Norte copper occurrence; however, no core, logs, assay data, or other information regarding the age of the holes have been located. Discussions with local residents indicate the drilling occurred approximately 40 years ago when a previous property holder also extracted a small volume of material from a series of shallow pits and trenches on the property.

Exploration History

During years 2004-2006 Antares (predecessor of Regulus) had a JV agreement with Mansfield to conduct exploration in Catua. The main activities in that period at the project site were:

  1. Reconnaissance, geological mapping, geochemical sampling, and prospecting,
  2. 54 line kilometre Induced Polarization/Resistivity geophysical survey at 100 m and 300 m dipoles.
  3. Line kilometre gravimetry survey, with the aim to identify the depth of the basement.
  4. 1378.65 meters in 8 drill holes with both, RC and DDH methods.

The geological reconnaissance program consisted of identifying and mapping the main geological units present in Catua property onto a Quick Bird image at a 1:10.000 scale. The purpose of this mapping was to enhance our understanding of the geological setting of the known copper mineralization, look for possible extensions, and to establish possible genetic models and potential for the copper mineralization.

The aim of the Induced Polarization/Resistivity geophysical survey was to try to locate the source of exotic copper that occurs near the centre of the surveyed area. Resistivity measurements for both configurations were low while chargeability measurements were low to at best moderate. The 100m dipole survey was designed to test for a source or ‘feeder’ below the occurrence. While results show a weak anomaly slightly offset from the copper, there is no clear evidence for a ‘feeder’ zone or structure below the occurrence. 3D inversion of the data indicates that the known copper occurrences are at least spatially related to zones of lower chargeability within an implied chargeable ‘ridge’. The 300m dipole survey was designed to try to locate potential distal sources for the copper. While no clear target areas were defined, several areas were identified with elevated chargeability at depth that could represent unoxidized sulphides and a potential source for the known exotic copper oxide mineralization.

Gravity data were collected along two lines approximately 5 km long. The aim was to identify the depth of the basement, which is outcropping to the eastern boundary of the tenement. According to the obtained results, some possibilities have been interpreted: Different interpretations, assuming different ground density values, show the possibility of a concealed intrusive below the gravels or ignimbrites in a graven structure of the basement. Other models are less consistent, but the drill holes did not confirm the models.

Drilling done by Antares (predecessor of Regulus) consisted in 8 drill holes for a total of 1378.65 meters with both, RC and DDH methods (Figure 2). Drill holes did not find additional mineralization, or areas with alteration of interest.

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