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Cordilleran Vein Type Deposits Examples

Cordilleran Vein Type Deposits Examples

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<strong>Vein</strong>s 11/3/10<br />

Ore deposits<br />

• Most in fractures and shears in Belt rocks<br />

– Minor structures more favorable than major<br />

• Some ore in monzonites, lamprophyres<br />

unmineralized<br />

• Briile rocks more highly mineralized<br />

• Galena, sphalerite, tetrahedrite,<br />

chalcopyrite, pyrrho>te, magne>te,<br />

arsenopyrite<br />

– Minor bornite, chalcocite, s>bnite, Cu-­‐Sb-­‐S<br />

sulfosalts, scheelite, uraninite<br />

Ores (cont)<br />

• Arsenopyrite forms envelopes around ore<br />

• Qtz, siderite, pyrite, (barite) as gangue<br />

– Typical ‘mesothermal’ assemblage<br />

• 10% combined Pb-­‐Zn; 1 oz/tonne Ag<br />

• Ag in tetrahedrite, not galena<br />

20

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