Resource Dictionary

Precambrian Shield

Precambrian refers to the geologic time scale prior to the Cambrian period, which began 500 million years ago. Precambrian period includes the Archean and Proterozoic eras. Lode deposits tend to be the dominant gold deposits of the Precambrian shields of Canada, Australia, South America and Africa – and include veins and shear zones that host gold, pyrite, quartz and carbonates Typical of Precambrian deposits are greenstone belts, which are country rock made up of metamorphosed volcanic and sedimentary rocks. Greenstone belts are found most frequently in Precambrian rock, but can occur throughout geologic time.The oldest, most stable regions of the earth’s crust, the largest of which is the Canadian Shield.