Eritrea Geology

Figure 1: The Upper Proterozoic Arabian-Nubian Shield (ANS) and major gold deposits

Chalice's exploration tenure lies within the south-western part of the Late Proterozoic Arabian–Nubian Shield, an emerging gold and base metal province that hosts the ~13 million ounce Sukari gold deposit in Egypt, the ~2 million ounce Ariab/Hassaï gold and base metal deposit in Sudan and the ~1 million ounce Bisha gold and base metal deposit in Eritrea (Figure 1).

In Eritrea, the Arabian-Nubian basement has been divided into five domains on the basis of distinct stratigraphic and structural characteristics (Figure 2). These include:

• the Barka domain to the far west (predominantly amphibolite-grade metasedimentary and mafic gneisses);
• the Hagar domain to the north (principally mafic metavolcanic rocks, including ophiolite-like assemblages), the Nakfa domain, the largest of the four (granite-greenstone belts and syn- to post-tectonic granitoid rocks); and
• the Augarao domain to the east (granitoid and metasedimentary rocks).
• The Adobha Abi domain, a folded clastic and carbonate sediment dominated assemblage, separates the Hagar and Nakfa domains in a series of lenticular basins.

Figure 2:  Regional Geology of northern Eritrea showing gold and VHMS occurrences

In northwestern Eritrea major west-over east thrust faults define many of the domain boundaries. The gold deposits in the region are often spatially associated with these thrusts or related second and third order splays which appear to represent regional fluid pathways typical of gold-bearing cratons worldwide.

The volcanic sequences of the Nakfa domain comprise a significant bi-modal felsic component consistent with evolved volcanic- and back-arc terrains. This is a common setting for Volcanic-hosted Massive Sulphide (VHMS) deposits worldwide. The Bisha polymetallic deposit and the cluster of similar prospects nearby (Harena, Hambok) share characteristics typical of VHMS deposits. In addition, because of the arid environment, many of these deposits have been subjected to near-surface oxidation and supergene enrichment so that gold and copper are relatively enriched at shallow depths, making them favourable targets for exploration from an economic standpoint.

Competent Person Statement
The information contained on this website that relates to Exploration Results is based on information compiled by Dr Doug Jones, a full-time employee and Director of Chalice Gold Mines Limited, who is a Member of the Australasian Institute of Mining and Metallurgy and is a Chartered Professional Geologist. Dr Jones has sufficient experience in the field of activity being reported to qualify as a Competent Person as defined in the 2004 edition of the Australasian Code for Reporting of Exploration Results, Minerals Resources and Ore Reserves (the JORC Code) and is a "Qualified Person" under National Instrument 43-101 - 'Standards of Disclosure for Mineral Projects‘. Dr Jones consents to the release of information in the form and context in which it appears here.