The
Upper Miocene tonalite stock is a north–south oriented oval, 4.5 by 2.4 km in size, which has undergone
hydrothermal alteration. The stock
intruded into
andesitic host rocks.
Glaciation during the
Pleistocene carved the
U-shaped Los Pelambres valley. The head of the valley has the highest concentration of
ore in a
roche moutonnee. A core of potassium silicate alteration contains the economic copper-molybdenum
mineralization.
Sulfide minerals include
chalcopyrite,
bornite,
pyrite and
molybdenite. ==See also==