Geoscientists use radar to locate lost graves (1/19/2008)

Acquiring GPR data at Wyatt Chapel Cemetery

Participants in a summer course for educators used ground-penetrating radar (GPR) to locate a pair of lost graves at an abandoned cemetery outside Houston. The site might become a historical monument.

Nineteen in-service K-12 teachers from urban Houston school districts where the majority of students are members of historically underrepresented minority groups enrolled in the class -- ESCI 515: Geophysical Field Work for Educators.

Alison Henning, lecturer in the Department of Earth Science, taught the course. Dale Sawyer, professor of Earth science, and graduate student Priyank Jaiswal also took part in the endeavor.

Henning said some faculty members at Prairie View A&M University (PVAMU), aware of a previous Rice project in the summer of 2006 that investigated the Evergreen Negro Cemetery in Houston, suggested they focus attention on a site near the campus about 50 miles northwest of Houston. The PVAMU faculty members are hoping to turn the site, which is believed to have originated as a slave burial ground in the 1850s, into a historical monument to the early settlers of Prairie View.

Joined by PVAMU students and faculty, Henning and her crew began their work last July. Over two weeks, the group acquired and interpreted 59 GPR profiles in Wyatt Chapel Cemetery and surrounding areas to determine the local stratigraphy and try to locate unmarked graves.

"The soil at Prairie View is ideally suited for GPR investigations, and we obtained some spectacular results," Henning said. The stratigraphy in the area consists of three to six feet of reddish-brown, medium-grained sand overlying a light gray, highly compacted clay, she explained. The sand-clay boundary appears as a strong reflector on the GPR profiles.

"The class identified numerous subsurface anomalies that might have indicated unmarked burials," Henning said. Archeologists from Texas A&M later joined the project in the field and excavated two of the anomalies. The first consisted of a pair of bright hyperbolae on the GPR, suggesting two edges of a metal object. This excavation resulted in the discovery of a metal plank thought to be a burial cover. The second anomaly consisted of a break in the horizon representing the top of the clay layer, and subsequent excavation revealed a grave shaft.

ESCI 515 is aimed at educators who are currently teaching science without a science degree. Participants in the Wyatt Chapel Cemetery project included elementary, middle and high school teachers. This summer experience is followed by a content-intensive academic year course in physical geology.

"GPR is an excellent tool for archeological and cultural investigations," Henning said, "because it is nondestructive (no digging or trenching required). It also provides the opportunity for service learning. As a geoscientist, I find it very gratifying to use geophysics for community service."

Note: This story has been adapted from a news release issued by Rice University

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