Tuvatu is a high grade alkaline gold deposit forming a small part of the 7 km diameter Navilawa Caldera on a corridor of high grade alkaline gold systems in Fiji.
The Project lies within the Fiji Gold Trend, which is a northeast trending extensional fault zone across northern Viti Levu and Vanua Levu (the two main Fijian islands). Virtually all significant gold occurrences in Fiji occur along the Fiji Gold Trend in clusters surrounding igneous craters such as the Tavua Caldera hosting the Vatukoula Gold Mine and the Navilawa Caldera hosting Tuvatu.
The main characteristics of these gold deposits/occurrences are:
1. The gold is igneous hydrothermal (250°C) in origin, introduced by the potassic, shoshonitic tertiary intrusives, which represent the feeders and latest phases of the volcanic rocks that dominate northern Fiji. Hydrous mineral phases (biotite and hornblende, particularly) in the intrusives develop whenever the hydrothermal mineralization systems have developed.
2. Gold is generally vein-controlled and can be restricted to narrow bonanza-grade lodes within weakly altered host rocks. Primary gold is fine-grained and can be in the following forms:
- Gold-silver tellurides
- Electrum
- Native gold
- Gold-bearing pyrite
3. Common minerals associated with mineralization are:
- Quartz
- Carbonates
- Adularia - K-feldspars
- Pyrite
- Roscoelite (green vanadium-titanium micas)
- Smec ........