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Location Map - IRN Projects - Northern Chile
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PBA & PS - Geology - CSAMT Anomaly Trends
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PBA & PS - As in Colluvial & Soil & Float - CSAMT Anomaly Trends
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PBA & PS - Sb in Colluvial & Soil & Float - CSAMT Anomaly Trends
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PBA & PS - Au in Float & As in Colluvial & Soil - CSAMT Anomaly Trends
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PBA & PS - Ag in Float & As in Colluvial & Soil - CSAMT Anomaly Trends
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PBA & PS - CSAMT Resistivity at - 50m - CSAMT Anomaly Trends
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PBA & PS - CSAMT Resistivity at - 100m - CSAMT Anomaly Trends
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PBA & PS - RTP Magnetics (Grey) - CSAMT Anomaly Trends
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PBA & PS - RTP Magnetics (Colour) - CSAMT Anomaly Trends
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PBA & PS - Principal Geochemical & Geophysical Anomalies - Priority Ranking
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PBA & PS - Aster Image - False Colour
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The Pampa Sur project covers approximately 11,300 hectares and more than 15km of continuous strike length of the prospective Dominador Fault Zone (DFZ). The project is located approximately 40km south-southwest of Yamana's Peñon and Fortuna deposits (+7 million oz gold and +200 million oz silver), and immediately south of Iron Creek's Pampa Buenos Aires project that is being explored in joint venture with Andina Minerals. The DFZ lies within the Palaeocene-Eocene volcanic belt of northern Chile that hosts some of the most important precious metals and copper deposits in the country.
Iron Creek is exploring the Pampa Sur property for epithermal gold and silver mineralization of El Peñon / Fortuna and Guanaco types, and also for possible porphyry copper mineralization.
Geological Setting of Pampa Sur
The property is largely covered by post-mineral gravels with sparse outcropping Palaeocene-age volcanic rocks towards the southwest of the property area. The property is cut by strands of the DFZ, which defines the structural grain of the project area.
The Palaeocene to Early Eocene Volcanic Belt of northern Chile underlies much of the Atacama Desert in the Antofagasta and Atacama regions of northern Chile. The belt extends north-south for about 600km and is bounded to the west by the Coastal Cordillera and to the east by the Domeyko Cordillera. The geology of the belt is dominated by Late Cretaceous to Early Tertiary calc-alkaline to sub-alkaline bimodal volcanic rocks that range from basaltic andesite to rhyolite, and by sub-volcanic porphyritic intrusions and granitoid stocks.
The portion of the belt between Sierra Gorda in the north and Sierra Overa in the south, which includes Pampa Sur, is characterized by exposures of felsic volcanic rocks, and is host to several precious metal epithermal deposits including the El Peñon and Fortuna gold-silver deposits, as well as other significant precious metal deposits at San Cristobal, Faride, El Soldado, Cachinal de la Sierra, El Guanaco, Amancaya and Sierra Overa.
Work Completed To Date
Geological and float mapping and sampling were carried out in conjunction with colluvial and soil pH & ICP geochemical survey programs in three phases. The first sampling phase, between October 2007 and May 2008, consisted of approximately 76 line kilometers along 200m spaced east-west lines, with samples every 25 meters (3,900 samples). At the end of the second quarter of 2009, Iron Creek resumed geochemical surveying at Pampa Sur, focused on the eastern half of the Property. The second sampling phase consisted of approximately 40 line kilometers along 1km spaced east-west lines with sampling every 25m (1,715 samples). A third phase of sampling was designed to infill geochemical anomalies with shorter 200m spaced east-west lines, totalling 1,560 samples.
In early 2008 Argali Geofisica Chile E.I.R.L. conducted ground magnetic surveys on a portion of the Pampa Sur property with a line spacing of 50m and readings acquired as a continuous profile on E-W lines. A total of 920 line kilometers of data were acquired.
During May and June of 2011, approximately 26 line kilometers of Controlled Source Audio-Frequency Magnetic-Telluric (CSAMT) surveying were completed along three east-west oriented survey lines. Additionally, several samples of quartz-vein float material lying on the surface of the gravel-covered pampas were collected in several locations.
Results to Date
Results from the colluvial and soil geochemical programs are extremely encouraging. As can be seen from the accompanying maps on Iron Creek's website, largely coincident arsenic, antimony and partially coincident silver geochemical anomalies occur to the east of the DFZ along an approximately 7km long by 1-2km wide zone that trends north-northwest. This is a significant As-Sb-Ag anomaly with the three metals that are commonly associated with low-sulphidation precious metals veins of the El Peñon type -- the main target type sought on the property. The zone is open to the north-northwest (onto Iron Creek and Andina Minerals' Pampa Buenos Aires property) and to the south-southeast, and is coincident with several occurrences of quartz-vein float at surface.
A second, smaller, but very intense coincident arsenic, antimony and silver anomaly occurs to the west of the DFZ. This anomaly trends approximately north -- south and is about 2.5km long by 0.5km wide, although arsenic anomalies continue more than 2km further to the south. It is broadly coincident with a number of quartz float occurrences.
Other smaller anomalies of one or more of these three key indicator metals occur within the property, and may prove to be significant.
Additionally, a large surface colluvial low pH anomaly has been detected in the NW corner of the property coincident with a surface colluvial molybdenum anomaly. The pH anomaly suggests that oxidizing sulphides related to mineralization in the underlying bedrock may be present below the colluvial cover. However, the exact significance of these coincident anomalies remains to be determined. Other, narrow pH anomalies likely represent underlying mineralized structures or veins in the bedrock.
The quartz-vein float material sampled in several locations occurs along linear trends coincident with some of the principal colluvial and soil geochemical anomalies, and CSAMT anomalies. The assay results show that many samples are anomalous in gold, silver, arsenic and antimony. Arsenic and antimony are common pathfinder elements for low sulphidation quartz veins.
The CSAMT survey was designed to: 1) follow-up extensive surface colluvial and soil geochemical anomalies on the property; and 2) to help define the normally resistive features that may host epithermal quartz veins beneath the extensive post-mineral gravel cover.
The CSAMT survey has defined a series of relatively high resistivity anomalies, some of which are continuous between profiles despite the wide line spacing. Critically, some of the best CSAMT high resistivity anomalies coincide with strong surface colluvial and soil geochemical anomalies, suggesting that they may reflect silicified zones or structural features related to potentially mineralised veins at depth.
The principal geophysical anomalies were determined from both the CSAMT modelled profiles, and from a series of modelled depth slices of resistivity at -50m, -100m, -200m and -300m depths. These principal geophysical anomalies were integrated and compared with the known geochemical anomalies, historic airborne and ground magnetics data, and with mapped geology and areas of hydrothermal alteration.
The combination of the geochemical and geophysical results is extremely encouraging. Major anomalous trends occur in both data sets, and many of the principal anomalies are wholly or partially coincident. The occurrence of metal-bearing epithermal quartz-vein float material coincident with some of the principal geochemical and geophysical anomalies may indicate the presence of mineralised epithermal quartz veins in the bedrock beneath the gravel cover.
Qualified Person:
Demetrius Pohl, P.Geo., is the Company's Qualified Person as defined by National Instrument 43-101, and is responsible for the accuracy of the technical information in this project summary. Dr. Pohl has verified that it is an accurate summary of the results from the Pampa Buenos Aires exploration programme.
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