Integrating exploration dataset in GIS using index overlay inference modeling in Ferdows-Khousf zone

The South Khorasan area is located in the southern portion of the Khorasan province approximately around Ferdows town in the north, Birjand city in the center and Nehbandan town in the south. This study area consists of fourteen (14) 1:100,000 scale sheets located in the Lut Block totaling approximately 30,674 square kilometers.
Maps showing spatial variation of epithermal gold and copper porphyry potential in the South Khorasan zone have been generated by combining digital data from a variety of sources.
A regional scale GIS contains an enormous amount of data from a wide variety of sources including geologic, geochemical, geophysical, and other exploration data sets. The evidences are divided into five categories, consisting of, the formation of ore deposits as requiring the right geology (Host), ground preparation (Structure), metals source and/or heat engine (Source) and most important some form of Ore Forming Process (OFP).
The fundamental goal of such a system is to identify areas of potential mineralization through spatial analysis and other modeling functions. For the first phase of modeling we have used simple overlay approaches. This is done because we need to get a good understanding as to the quality of the data and the significance of the assumed models in the exploration area. The Index Overlay method is the closest approach to what is typically done in a manual compilation. It provides the user the greatest control as to the influence of each data set in the modeling process.
As expected, the 1st versions of the gold and porphyry copper models generated a lot of targets. This included a number of targets which after the first fieldwork clearly did not warrant evaluation. Therefore, the 2nd version of the models was generated after stints of fieldwork which incorporated the field-based observation. This resulted to only 94 targets, effectively reducing the number of targets by 75%. The some new deposit discovery at this area made during June 2004 is in a favorable zone as predicted by this model.