The Circum-Pacific Plutonism project was organized in 1970 and 1971 under the International Geological Correlations Program (IGCP), which is sponsored jointly by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) and the International Union of Geological Sciences (IUGS). The purpose of the Circum-Pacific Plutonism project is to increase understanding of the role the great circum-Pacific batholiths played in the evolution of the Pacific Basin; this understanding is promoted through mutual exchange of data, ideas, and hypotheses and through examination of representative batholiths around the Pacific. Participation in the project is open to all geologists actively engaged in study of plutonic rocks around the margins of the Pacific. The project actually got underway in 1972 with meetings at Santa Cruz, California, and a field trip into the Sierra Nevada batholith. A South American field trip was part of the second phase of the project program; it consisted of three days of meetings in Santiago, Chile, followed by six days of field excursions in Chile and Argentina and another six days in Peru.