Gretchen Luepke was born in Tucson, Arizona in 1943 where her parents owned a 20-acre tract in north Tucson. Young Gretchen began at the age of five to wander the ranch and bring home rock specimens, to the bewilderment of her parents and siblings. In time she began to distinguish between rocks and minerals and educated herself about them.

She began exhibiting mineral specimens from her collection at the annual Tucson Gem & Mineral Show as early as 1957. In 1961 she graduated from Catalina High School in Tucson, after which she attended the University of Arizona where she earned her B.S. in 1965 and M.S. in 1967, both in Geology. After receiving her M.S., Gretchen secured a position as a Geologist with The United States Geological Survey in Menlo Park, Califomia where she served for 32 years.

Gretchen's professional expertise lay in the field of sedimentary river and marine sands and heavy minerals. She was the author and/or editor of many different works in that field, including textbooks and USGS reports. After retiring in 1999, she continued with the USGS as an emeritus employee working on various projects. That same year she married her longtime boyfriend, Robert Bynum, whom she met through a Sierra Club singles event.

Gretchen was a long-standing member of Bay Area Mineralogists and served as BAM President from 1979 to 1980. She was an active participant in BAM, assisting in administrative matters until shortly before her passing. Although primarily living in the San Francisco Bay Area, Gretchen maintained her membership in the Tucson Gem & Mineral Society and entered competitive mineral displays on an annual basis at the Tucson Gem & Mineral Show, frequently winning Best in Class awards. Gretchen sought Tucson's first place trophy for many years. Shortly before her death BAM presented her with the trophy pictured here for her efforts there over the years.

Gretchen was an occasional field collector of mineral specimens. She was also a musician (flute), an avid hiker and a supporter of environmental organizations.

Gretchen succumbed to Creutzfeld-Jakov disease in July 2010.

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Published Works

Stability of Heavy Minerals in Sediments (Van Nostrand 1984)

Economic Analysis of Heavy Minerals in Sediments (Van Nostrand 1985)

Heavy-Mineral data from samples collected in Willapa Bay and vicinity, Washington (1982)

Sand-sized heavy-mineral distributions in offshore insular shelf sediments of north-central Puerto Rico (1993)

Titanium analyses of black sands from six beaches, San Francisco and San Mateo Counties, California (1987)

Variations in titanium and chromium concentrations in magnetite separates from beach and offshore sediments, San Francisco and San Mateo counties, California (1994)

Heavy minerals from cores in a deep-sea channel off Cape Mendocino, California (1995)

Sand-sized heavy-mineral distributions in the Rio Cibuco system and adjacent rivers of north-central Puerto Rico (1993)

Areal and textural distribution of particulate gold in sediments from Bluff Beach, Alaska (1981)

Bibliography of the geology of the Oregon-Washington continental shelf and coastal zone, 1899-1978 (1980)

Distribution of economic heavy minerals in sediments of Saco Bay, Maine (1986)

Economic heavy minerals in glaciofluvial sediments in Minnesota (1993)

Economic heavy minerals in sediments from an off-shore area east of Cape Charles, Virginia (1991)

Grain-size, heavy-mineral and geochemical analyses of sediments from the Chuckchi Sea, Alaska (1989)

Occurrence of platinum in a black sand from a beach deposit in San Mateo County, California (1991)