Abstract
Abstract: The powerful tools of Geographic Information System (GIS) and remote sensing (RS) have significantly contributed to the modem geological mapping and mineral exploration by enhancing, interpretation and integration of various geological datasets. Integration of remote sensing and airborne magnetic data with other geological data sets are the most promising and cost-effective method to add new structural and lithological aspects to the map of the geology in a diverse geological province as in the area of current research. This is due to the fact that all the geosciences information together with pre-processed remotely sensed data can be used as evidence to delineate possible areas for further study and more investigation (Chang -Jo & Fabbri 1993). The study area is a belt of Upper Devonian sedimentary fom1atio n including iron ore bearing layers, which extend over about 160km, in ENE-WSW direction, on the northern border of the Murzuq Basin. The study area is located in the western central part of Libya within the bounder's 27° South and 28° North Latitude and 12° to 16° East-longitude covering an area of nearly 40,000km2• Th.is study examines the integration of aeromagnetic data with remote sensing to discover any probable extensions of iron ore deposits and any associated minerals in the area of study. The study involves analysis of magnetic data to delineate geological, structures, faults and to extract important information about the locations of buried magnetic bearing rocks. Spatial data integration and analysis for the study area and predicting mineral potential were carried out on the available digital remote sensing data (Landsat ETM+). While searching for mineral potential areas, accurate and up-to-date geological maps are essential as it represents the most basic information for directing exp lo ration activities. To this end, the existing geological map of the study area, which was published by Industrial Research Centre (IRC) in 1984, is too old to extract up-to-date information for mineral exploration. The main objective is to integrate these datasets to update the geological map and produce mineral potential map of the study area. In this research, the various datasets (aeromagnetic data, geological, remote sensing) were processed, integrated, and modeled using GIS techniques. The primary field study was conducted in the potential areas of the iron ore deposits. Few samples were collected from the area and subjected to XRF, XRD analyses. The produced Total Magnetic Intensity (TMI) map shows prominent NW-SE and N-NW trends. The Reduction to the Magnetic Pole (RTP) map is characterized by a dominant WNW-ESE trend in the study area. Total horizontal derivative of the pseudo gravity map generally reflects fault or compositional changes which can be seen to describe structural trends. The central part of the study area can be divided into five zones where the eastern and northern zones show many short anomalies of NW-SE orientation and the southern zone shows E-W orientation, in the northern zone of the central part shows WNW-ESE orientation trends. Strong magnetic anomaly detected in the south of Idri Town can be interpreted as lenses of magnetite or magnetite-rich sandstone within the sedimentary rock sequence. The selective principal component analysis, band ratio, techniques allowed the discrimination of altered areas and the detection of iron and iron oxide bearing minerals. The most imp011ant finding in this study is discovering new potential areas covering about 1000km2 of mineral deposits in the southeast and north-western parts of the area. These results increased the assumption of extending the iron ore belt under the sand dunes in the west and east parts of study area. The mineralogical analysis indicates that the iron ore type is goethite and hematite with percentage between 8 to 46 % Fe2O3 associated with very important minerals such as pyrochlore (Na, Ca, U). Finally, new potential map mineral deposit was produced and classified into four zones which are low, moderate, high, and very high potential zone.