Petrology, geochemistry, and origin of the Red Mountain ultramafic body near Seldovia, Alaska

Ophiolites and other mafic-ultramafic complexes in Alaska

“…The mafic-ultrarnafic complexes, which are distributed along the Border Ranges fault between Tonsina and Kodiak were generally thought to be remnants of oceanic crust that formed the basement of the subduction complexes of the Chugach terrane (Beyer, 1980;Toth, 1981). However, recent investigations (Winkler and others, 1981;Pessel and others, 1981;Burns and others, 1983;Burns, 1985) suggest that they have arc affinities and are more closely associated with the Peninsular terrane.…”

“…Several ultramafic bodies have long been known near Seldovia at the southern tip of the Kenai Peninsula (Guild, 1942;Toth, 1981). Red Mountain--the largest of these bodies--is a roughly oval area of layered dunite and clinopyroxenite (wehrlite) about 7 km in length.…”

“…I), between the Border Ranges fault and a prominent thrust fault that forms the eastern limit of the Seldovia Bay complex (Cowan and Bass, 1978;Magoon and others, 1976). Toth (1981) suggests that the Red Mountain body formed at an oceanic spreading center as part of an ophiolite sequence in a Late Cretaceous episode of subduction. More recently Burns (1983Burns ( , 1985 argued that the Red Mountain body formed in an island arc as a cumulate counterpart of volcanic rocks.…”