Nov 5 2014
Cornerstone Capital Resources Inc. announces that it is initiating an exploration program on its Miocene project located in Northern Chile through its Chilean subsidiary Minera Cornerstone Chile Limitada (MCCL).
HIGHLIGHTS:
- Regional compilation work completed.
- Review and integration of data from previous surveys and from surrounding properties.
- Definition of large, highly prospective areas for porphyry and epithermal style of mineralization to be systematically explored in the next several months.
References to figures related to the version of this release on the Company's website (www.cornerstoneresources.com) or visible in PDF format by clicking the link below:
http://www.cornerstoneresources.com/i/pdf/NR14-25Figures.pdf.
"We are very pleased to restart exploration on the Miocene project", stated Cornerstone's President & CEO, Brooke Macdonald. "Generative work done by our geologists is very encouraging and discoveries made next door and on strike with our exploration targets by our neighbor Mirasol Resources demonstrate that this underexplored and exciting part of northern Chile has high potential to host a new mineralized district and large deposits".
Miocene Property
The Miocene project granted concessions cover an area of 152.1 km2 (15,210 hectares) across two contiguous concession blocks in northern Chile. The project spans the boundary between the Antofagasta region (Region II) and the Atacama region (Region III), although it lies mostly within the Atacama region, approximately 250 km southeast of the port city of Antofagasta.
The project area lies at elevations ranging from 3720m on the eastern margin of the concessions to 4845m near the western margin of the concessions on the flank of the Chaco volcano. The terrain is largely denuded of vegetation, typical of high elevation in the Atacama desert.
Regional Geology
The Miocene volcanic belt in Chile and Argentina extends from around 24°S to 47°S. In northern Chile the Miocene belt lies along the eastern (inland) side of the Eocene-Oligocene belt. However, the metallogenically productive section of this belt extends from around 25°S to 35°S (Figure 1).
The Miocene volcanic rocks near the northern end of the Miocene belt, between latitudes 26°S and 28°S, comprise the Maricunga belt, a linear belt of volcanic rocks, and a metallogenic unit, that is defined by at least 14 zones of gold and silver mineralization in this latitude interval. This belt is well studied and provides good background to the more extensively covered Miocene sequences further north in the area of Cornerstone's Miocene project.
The area to the north of the Maricunga Belt is increasingly covered by Late Miocene to Pliocene volcanic sequences and surficial gravel deposits derived from these younger volcanic sequences. Exploration north of the Maricunga belt, between latitudes 25°S to 26°S, has been less intense and less effective due to this Late Miocene and younger cover.
Furthermore, the structural framework in the region supports the prospectivity of this northern extension to the Miocene Belt, as it is transected by NW-SE trending crustal lineaments (Figure 2 and 3). Particularly prospective regions are where these NW-SE trending lineaments intersect the Domeyko Fault Zone, e.g. Oligocene - Chuquicamata, Escondida, El Salvador, Potrerillos; Miocene - Cerro Casale, Pascua Lama, Veladero. The Miocene Project lies at a similar structural setting, where the NW-SE trending Culampaja Fault intersects the Domeyko Fault Zone.
Project Geology
The area is underlain by a series of andesitic lava flows and tuffaceous units at the base of the local stratigraphic column (24-20My) and aligned in a NNW direction possibly indicating the general direction of structures controlling the position of volcanic vents (Figure 4).
Around 18-16 My, flows and tuffs of dacitic composition were deposited to the southeast at about the same time than the ignimbrites of the Rio Frio Formation. Towards the end of the period, andesitic to rhyolitic volcanic and pyroclatics units were deposited at Cerro Chaco and Cerro Blanco.
The volcanic activity followed during the period 13 My to 11 My with the deposition of ash and lapilli tuffs part of the Plato Superior Formation in the Llano Blanco valley and Salar Agua Amarga areas and andesitic lava flows at Cerro de Azufre.
Quaternary age gravels derived from these volcanic units occupy lower ground as a thin veneer over large areas and some depressions. These non-consolidated units have been divided into 3 units to better characterize the soil geochemical anomalies: containing hydrothermally altered clasts, containing colloform silica clasts and, containing unaltered clasts.
The older sequences (24-16Ma) are broadly confined to a subtle structural depression (~6 km wide) that trends northwest-southeast, while the younger sequences (16-11 Ma) tend to occur on the northeast and southwest side of this depression. Most of the mapped alteration is confined to this structural depression where it appears to primarily affect the oldest andesite sequence.
Previous Exploration Conducted by MCCL
Initial exploration activity conducted by MCCL involved acquisition and processing of Landsat and ASTER (Advanced Spaceborne Thermal Emission and Reflectance Radiometer) satellite imagery data defining a series of anomalies across a broad region of the Miocene Project, some of which lie beyond the current outline of the Miocene property.
MCCL undertook reconnaissance geological mapping across the entire Project area. The mapping revealed a detailed volcanic stratigraphy within the region and also identified the distribution of hydrothermally altered bedrock in areas where it was exposed, or not covered by surficial gravel (Figures 4 and 5).
MCCL covered the entire concession area with a relatively open soil sampling grid of 1 km spaced lines, with sample spacing along the lines alternating between 250m and 500m spacing and collected scattered rock-chip sampling over and beyond the concession area. Soil samples were analyzed utilizing a combination of analytical techniques (partial and total digestion) designed to detect deep and/or buried mineralization.
Exploration data generated by MCCL and other exploration companies working in the same district was compiled and integrated within a regional database including airborne magnetic data. Metallotects and several large (several km) and highly prospective areas were defined on strike with mineralized prospects recently discovered on neighboring ground. A follow up exploration program has been designed to evaluate anomalous zones defined by previous surveys and new targets defined by compilation work.