DEPLETION HALOES IN FRESH ROCKS SURROUNDING THE COBAR OREBODIES, NSW, AUSTRALIA - IMPLICATIONS FOR EXPLORATION AND ORE GENESIS

Whether or not the model is accepted, the extensive but cryptic depletion haloes are a valid exploration target in mildly metamorphosed turbidite sequences and slate belts and could lead to hitherto undiscovered blind orebodies or even to a new mining field. This study has shown that actual haloes can be very different in both character and extent from those that might be expected about this style of mineralization. It is essential for an orientation survey to include as broad a spectrum of elements as practicable. Sampling must extend very far from known ore to obtain reliable background data. Cryptic haloes, by their nature, have to be tested to be perceived.