WEATHERING AND HEAVY MINERALS

Weathering destroys ome heavy minerals at the source so they are not represented in the resulting sediments. Stable minerals are concentrated by weathering and their proportion in the resulting sediments i greatly increased. Exact information on the variety of garnet, hornblende or other members of variable groups should be given whenever possible, because all varieties of these minerals do not offer the same resistance to weathering. Discrepancies in statements regarding the stability of these minerals during weathering will disappear when more exact data on the composition of the mineral va-riety are available