Vein- or Fissure-Filling Deposits of Native Gold and Silver, or Copper

Multiple Choice

Vein- or fissure-filling deposits of native gold and silver, or copper and zinc sulphides, would be more common in ________.

A) hydrothermally fractured rocks in the contact-metamorphic zone formed above a shallow felsic pluton like the setting at Yellowstone
B) rocks formed deep in a layered magma chamber like the Bird River Sill in Manitoba
C) in faults, impactites, and shattered rock of a meteorite impact zone like Sudbury
D) in limestone dissolution and collapse breccias such as occur at Pine Point, NWT