More recently, with fellow Staff Member Yingwei Fei, Boyd created the cubic-anvil apparatus. With a pressure range from 5 to 25 GPa, this equipment allows scientists to conduct phase studies with large-volume samples. Although Boyd officially retired in 1996, he continues to be an active researcher at the lab. He is well known for his other petrologic work on the nature and structural history of the crust and mantle. He is one of the world's leading experts on the mantle root of the Kaapvaal craton in southern Africa.
Cratons are the kernels on which continents grow.
They are much older and deeper than the neighboring crust and mantle. The Kaapvaal craton is some 3.5 billion years old. At 200 kilometers deep, it is well below the crust-mantle boundary. To study it, Boyd gathers and analyzes fragments of mantle wall rocks contained in diamond-bearing volcanic breccias called kimberlite that erupted onto the southern African surface millions of years ago. Each fragment of mantle rock contains a chemical signature that tells its depth, age, and chemical history.