Francis R. (Joe) Boyd, 77, a geologist whose research contributed to the understanding of the formation of the earth, died of sepsis on Tuesday, Jan. 13, in Washington, D.C. He lived in Chevy Chase, Md., but had enjoyed summers on Martha's Vineyard since the 1960s and owned a summer residence in West Tisbury for the last 30 years. Many of his happiest days were spent at the cabin on the Tisbury Great Pond. He loved exploring the ancients ways in the woods around the pond, sailing his Sunfish or canoeing on the pond. He found the peace of his Vineyard cabin a perfect setting for writing his scientific papers. Many mornings were begun with a refreshing swim in the pond waters.

Joe (as he was known to family and friends) Boyd was born on Jan. 30, 1926 in Boston, to Sarah Lyles Boyd and Francis R. Boyd, a prominent Boston attorney. He attended the Milton Academy in Milton, and was graduated in 1943. He continued his education at Harvard University, receiving a B.A. in geology in 1949. While at Harvard, Joe worked summers during World War II as a welder in the Charlestown Navy Yard. He was awarded an M.S. from Stanford University in 1950, an M.S. from Harvard University in 1951 and a Ph.D. in geology from Harvard University in 1958.

Dr. Boyd was a member of the National Academy of Sciences, a fellow of the Geological Society of America, a fellow of the American Geophysical Union, a past president of the Geochemical Society and a past president of the Geological Society of Washington. He was a longtime member of the Cosmos Club of Washington.

Late in 2003, the Mineralogical Society of America named him recipient of the 2004 Roebling Medal, awarded for his lifetime contributions to the understanding of the geologic development of the earth.

Mr. Boyd spent his entire career doing research at the Geophysical Laboratory of the Carnegie Institution in Washington, D.C. His earliest research involved study of the origin of volcanic rocks in Yellowstone National Park. There, he discovered that the volcanic eruptions that formed Yellowstone Plateau produced rocks of an unusual type, called welded tuff.

His Yellowstone research received popular attention in the early 1990s with production of an IMAX film, Yellowstone. The script for the film was reviewed and authorized by Mr. Boyd and the film was shown at the National Air and Space Museum of the Smithsonian Institution and at the West Yellowstone Feature Park.

In the 1960s, he developed with John England a piston-cylinder device to simulate in the laboratory the pressure exerted on minerals deep within the earth. The device provided scientists with a tool to determine the composition of minerals and rocks formed deep within the earth. Known as the Boyd-England device, it was used to create a synthetic diamond.

He was a leading expert on the 3.5-billion-year-old Kaapvaal craton in southern Africa. Cratons are the oldest and most stable rocks of the continental crust. The research he conducted in southern Africa has led to further studies in Siberia and elsewhere around the world. He was the principal author or co-author of more than 75 scientific papers. He retired in 1996 but continued active research until shortly before his death.

Joe Boyd was an avid outdoorsman, committed conservationist and a vigorous supporter of Vineyard conservation groups, including the Sheriff's Meadow Foundation, Felix Neck Wildlife Sanctuary, the Vineyard Conservation Society and The Trustees of Reservations. He loved hiking with his family over these beautiful properties, particularly Sepiessa Point and Cedar Tree Neck. He was a keen observer and delighted in sharing stories of his travels around the world.

He enjoyed bird watching in the many different environments all over the Island, and kept nesting boxes on his property, which led to studies of various nests, often built upon one another. One of his hobbies was carpentry. He loved making furniture for his cabin from salvaged driftwood. With his wife, Margo Kingston, he had a great time playing croquet as a member of the Edgartown Croquet Association. Although he enjoyed sampling the fare at Vineyard restaurants, he achieved culinary renown among family and friends with his grilled stuffed lobster, stuffed quahaugs and the many barbecues featuring fresh caught fish from Menemsha village shops.

In the 50th reunion book for Harvard College, he wrote: "I don't know what I deserve, but what I have had has mainly been a very good life."

He is survived by his wife of 24 years, Margo J. Kingston, also a geologist, of Chevy Chase; a daughter, Hadley Boyd, of Washington, DC; and a son, Duncan Boyd, of Kittery Point, Me.; stepdaughters Suzanne LaPiana of Washington, DC; and Siobhan LaPiana of Cleveland Heights, Ohio; and a stepson, Vincent LaPiana of Arlington, Virginia; two grandchildren and four step-grandchildren; and a sister, Harriet B. Sedgwick of Scarsdale, NY. His marriage to Barbara Boyd ended in divorce.