GIS - The different layers of information that can be combined in any way are :

1. Geochronological Synthesis GIS of the Arabian Shield and Peninsula Nehlig P., Asfirane F., Braux Ch., Genna A., Guerrot C., Eberlé J.M., Lasserre J.L., Nicol N., Salpeteur I., Shanti M., Thiéblemont D. and the Arabian Shield Project Participants (*) BRGM, B.P. 6009, 45060 Orléans Cedex 2 (France), (*)DMMR P.O. Box 345, Jeddah 21191 (Saudi Arabia) GIS ARABIA is a homogeneous information system of the Arabian Shield and Peninsula, based on original synthesis, reevaluations and compilations. Conceived as a tool for both the mining sector as an aid to minerals exploration and development and the academic sector. Over 4000 mineral deposits can be displayed and analysed in conjunction with the geological and major geographical features. Geological Setting - Before the opening of the Red Sea, 30-25 Ma ago, the Arabian Shield (650,000 km2) formed part of a larger geological ensemble, the Arabian-Nubian Shield, which covers several countries, mainly Egypt, Eritrea, Ethiopia, Saudi Arabia, Somalia, Sudan and Yemen. The Arabian-Nubian Shield consists primarily of Neoproterozoic juvenile crust and represents an area of suturing between East and West Gondwana before the Paleozoic. It formed through the accretion of numerous, mainly inter-oceanic, island arcs along ophiolite-lined suture zones and gneissic fault zones between 900 Ma and 550 Ma when the Mozambique ocean closed. GIS - The different layers of information that can be combined in any way are : A geographic base of the Peninsula A digital elevation model of the Peninsula An aeromagnetic synthesis of the Shield A 1:1,000,000 scale geological synthesis of the Shield A 1:2,000,000 scale geological synthesis of the Peninsula Geological Map coverage of the Peninsula A 1:1,000,000 scale structural map of the Shield A 1:1,000,000 scale surficial formation map of the Shield A 1:1,000,000 scale metamorphic map of the Shield A geochemical database of the Shield A seismic database of recent earthquakes Spot and Landsat images A reevaluation of all geochronological analyses A metallogenic synthesis and reevaluation of more than 4000 mineral occurrences A reevaluation of geological, geochemical and geophysical exploration data. Aeromagnetic Synthesis Geological evolution Surficial Formations Mineralized Occurrences Geochemical Exploration Geology

2. Adakites HP Partial melting of basic rocks Fractional crystallization of arc magma " " " ¸ ¸ ¸ " B $ ¸ % C % C B $ " ´ " " ¸ ¸ J & " x M " ¸ | ± " " " B $ ¸ ¸ " " B $ " ¸ ¸ B $ ² " x " B $ " ¸ } ² ¸ " " ¸ ¸ $ $ % $ y y " $ ¸ x y $ $ B $ % " y ¸ y y B $ x " ¸ O % " ´ " ¸ B $ $ % P & y B $ x " % ¸ A u o c c u r r e n c e s % % x ( F B $ x x % x | " ¸ x " ² E ' ³ " E B $ " ¸ " " ¸ ´ B $ x } ¶ " $ D & y % " E / H F ? ¸ x R ( " $ ´ B $ P & x B $ y } B $ " B $ ² " B $ ¸ " ² B $ " " ¸ ( F ¸ " ¸ E ? B $ ¶ " 8 " H F " D & ¸ $ % I y x % x x } I / P ? E ' B $ E ' " ¸ ( R I / S Z " ¸ E ' E ' % " x ¸ " " ¸ ¸ C % I ? P & ' ( F Q " ¸ B $ " ¸ " ¸ % % G " x x " ¸ J & P x % } x % x E ' " ¸ $ P & R ( P / E ? y " ¸ x } " " ¸ ¸ " ¸ % C " " ¸ K ' ¸ " ¸ % P ? x E ' " ¸ G " L ( " " % ¸ ¸ R / V S x E ' " % ¸ x " ¸ S Z " ¸ " ¸ " ¸ " ¸ ± " S Z / E ? % O S Z / H F ? " ¸ ( R B $ ' Q S Z / I " ¸ " ¸ $ M " y % S Z / I / H F % x % x % x " % ¸ " x ¸ ' x " Q ¸ % x | S Z / I ? x L ( E ' " ¸ " ¸ " ¸ H $ " ¸ " ¸ S Z / P " " ¸ ¸ J & J & " C % " ¸ ¸ ( L " ¸ " ¸ " ¸ E ' " " ¸ ² S Z / P ? " ¸ % " ¸ x B $ L ( " ³ " ¸ S Z / U M " I % " ¸ ¸ S Z / V S ? P & " ¸ " " ¸ ´ " S Z ? E ' ¸ % " ¸ x " ¸ " H $ ¸ E ' " ' ¸ Q V S B $ " ¸ B $ K ' V S / E G " V S / E ? 8 " V S / S D " ¸ A u O c c u r e n c e s d e n s i t y I % l o w " ¸ m e d i u m h i g h v e r y h i g h Reappraisal of the mineral potential of the Arabian Shield A multicriteria cross-analysis of geologic and metallogenic data Present state of mineral explorationin the Arabian Shield : 2 mines in exploitation, several mining projects at a feasibility or investment stage and numerous promising occurrences at the evaluation stage....but the mineral exploration remains still insufficient...  the regional exploration is not complete (often focused only on old workings areas) and its distribution is heterogeneous, some large areas were explored with methods no longer considered as the most effective, newly developed metallogenic concepts were not considered at the time of the regional exploration, the possibility of hidden deposits under thin allochtonous cover was little or not at all testedthe mass of available data has been growing exponentially Geography Geology Prospective maps Prospective maps Geochemistry Geophysics Integration Integration Selection of Selection of Geochronology targets targets in GIS in GIS Surficialformations Paleosurfaces Exploration Exploration methodology methodology Metallogeny Exploration • Mineralizations  Some of the mineralizations were emplaced at least in part during the oceanic-basin stages; this includes the Cr-Ti-Fe-Ni-Cu associated with ophiolites and some of the volcanic massive-sulfide (“VMS”) and Cu, Ni-Mo orebodies.  Other types of mineralizations are related to the volcanic activity in island arcs, such as VMS deposits in submarine environments, epithermal orebodies in subaerial environments, and porphyry stocks in the plutonic roots of arcs.  Further types are the result of remobilization of pre-existing mineralization, particularly gold of the mesothermal type that is related to arc-accretion and Panafrican cratonization.  Tin-tungsten mineralization in places is associated with syn- to post-cratonization peraluminous intrusive plutons.  Pb-Zn mineralization is related to carbonate-platform or paleo-channel environments in Cenozoic sandstone around the Red Sea.  Some mineralization is associated with (paleo)-placers (gold) or weathered rocks related to lateritic paleosurfaces (bauxite). Geochemical favorability Exploration reevaluation Exploration reevaluation Metallogenical evaluation Au-occurences Au-Potential vs Exploration Au-density Proterozoic outcropps Au-density Faults Au-density Concessions CONCLUSION -The geology (in a broad sense) and mineral deposits of the Arabian Shield have been worked in very different ways during the past decades. The resulting information is very heterogeneous and has only rarely been synthesised. In particular, synthesis documents for mining exploration purpose are very scarce, and often only available in the form of paper maps and not in a more modern version, namely Geographical Information System (GIS) and attached databases. A first stage in the achievement of this program involved a geological and metallogenical synthesis (under Arcview™) at the scale of the Arabo-Nubian Shield (1:1 000 000). Following this preliminary stage, we focused on the Arabian Shield and reevaluated and compiled under Arcview™ and Mapinfo™ software several layers of information : geography, geology, structures, geochemistry, aeromagnetics, geochronology, paleosurfaces, surficial formations…and linked to a mineralised occurrence data base containing not only known information on the occurrences but also a new reappraisal of the metallogenic data as well as a quantitative evaluation of the regional- and local-scale geological, geophysical and geochemical exploration work that has been conducted on the different occurrences.Cross-analysis of these different layers of information with Synarc™, a software tool developed by BRGM and ESRI, allows to produce synthetic documents and thematic maps which can be used for the selection of new exploration targets and adapted methodologies.