Abstract: The William G. Pierce Collection: The Heart of Heart Mountain

STEELE, DEBORAH D.

William G. Pierce was a USGS geologist with a long record of outstanding scientific achievements. After his death in 1994, his family donated his papers, correspondence files and over 2,000 annotated slides to Buffalo Bill Historical Center's Natural History Collection, allowing researchers to review his meticulous work.

Pierce started at USGS in 1929. He contributed to America's war effort in 1943 as the primary author of Oil and Gas Fields of the United States. He co-authored the 1947 Structure Contour Map of the Bighorn Basin, which was invaluable for hydrocarbon exploration. In the late 1950s he evaluated salt deposits for radioactive waste disposal potential. He received the Department of the Interior's Distinguished Service Award in 1965. His Wyoming field notebooks cover 1935 through 1988.

Pierce is probably best known for his work on Heart Mountain, in northwest Wyoming. At Heart Mountain, Paleozoic carbonates rest on Eocene sandstones and shales. Beginning in 1935, Pierce covered thousands of miles to map the extent of the Heart Mountain Fault, determine its origin and decipher its history. Pierce's work documents that a massive block of Ordovician Bighorn and Mississippian Madison broke loose about 45 million years ago. The block was 2000 feet thick and covered 500 square miles. Portions of it traveled over 30 miles on a very low angle surface. Postulated mechanisms for triggering this event, from earthquakes to gravity spreading, have inspired debate for decades. Pierce's correspondence with geologists worldwide records the scientific dialog inspired by his field evidence.

AAPG Search and Discovery Article #90946©1997 AAPG Rocky Mountain Section Meeting, Denver, Colorado