The joint Getty Conservation Institute (GCI)—Government of Tanzania project to preserve the hominid footprint trail at Laetoli took place in four phases from 1992-1998. The goals established in an agreement signed by the GCI and the Government of Tanzania in 1994 were: to implement a conservation program for the hominid trackway at Site G, which included reburial of the trackway for the long term; to develop a monitoring and maintenance program for the long-term preservation of the site; and to create a museum exhibition in Tanzania for public education and to raise public awareness about the importance of the Laetoli site.


Background


Discovery, excavation, reburial, and tree growth 1978–1992
Mary Leakey and her team discovered the 3.6 million-year-old fossil hominid trackway at Laetoli in northwest Tanzania in 1977 and began excavating in 1978. Excavation continued in 1979 revealing more prints. The combined excavations yielded a trackway 27m long. After the trackway was photographed, molded and cast, and documented photographically and photogrammetrically, it was reburied for its protection under a mantle of soil capped with lava boulders.

After the reburial of the trackway in 1979, and absent maintenance or monitoring, the site gradually began to re-vegetate. The loose reburial fill and the lava boulder capping provided an environment conducive to germination and growth of acacia trees which had reached a height of over 2m by 1985 raising concerns about damage to the footprints.

In 1992 the Tanzanian government invited the GCI to assess the feasibility of undertaking a conservation project. To this end, the Tanzanian Department of Antiquities (DoA) opened a 3 x 3m trench on the southern portion of the trackway. The brief assessment revealed a fragile and weathered tuff surface, penetrated and disrupted by acacia tree roots.


Overview of the Conservation Project


Formal assessment
In 1993 the Getty Conservation Institute entered into a formal collaborative agreement with the Tanzanian government to jointly undertake the conservation of the trackway. In July 1993 a full condition assessment and field testing was conducted in order to plan a conservation program for the site. A test site was established to test herbicides for killing acacia trees and for evaluating geotextiles as a root deterrent under reburial conditions. Off-site tests were also carried out on exposed tuff surfaces to determine the most appropriate materials for consolidating fragile tuff and to assess the feasibility of taking a new mold of the trackway.

The condition assessment confirmed the fragile nature of the tuff and led to the unanimous decision, endorsed by the Consultative Committee, that reburial was the most appropriate long-term conservation strategy for preserving the trackway. The testing also indicated that taking a new mold of the trackway surface might endanger the footprints.

Re-excavation, conservation, documentation, site stabilization, and reburial
The 1994 season at Laetoli focused on mapping and stabilizing the site and gullies and constructing berms to reduce erosion from rain water, and killing the trees growing on and adjacent to the trackway in preparation for re-excavation and conservation in 1995.

The first major conservation campaign in 1995 involved re-excavation, conservation, documentation, scientific study, and reburial of the southern 10m of the trackway where the best-preserved footprints were found in 1979. Excavation revealed 29 hominid footprints and numerous hipparion, lagomorph and carnivore prints. Thirty-eight acacia trees were found growing within the 10 x 4.5m trench. Four of the hominid prints were damaged by root growth.

The second conservation campaign took place in 1996, when the remaining 20 meters of the middle and northern trackway was excavated, conserved, documented and reburied according to the methodology established for the 1995 season. Excavation of this section revealed 23 hominid footprints with discernible morphology, 18 hipparion prints, and over 145 lagomorph prints. Thirty-six acacia trees that had grown since 1978 were inventoried within the excavated trenches. The hominid prints in the northern trackway were not as well preserved as those in the south due to natural weathering and erosion of the volcanic tuff prior to their original excavation in 1978. Two prints at the northern end of the trackway were lost to erosion of the shallow 1978 reburial mound by surface run-off.

Conservation of the excavated trackway began with detailed condition recording of footprints and included treatment or removal of all roots and tree stumps. Additional berms and stabilization measures were undertaken in 1996-97 to divert run-off away from the trackway and protect the reburial mound from erosion.

Silicone rubber molds and polyester casts were made of existing 1978-79 casts beginning in 1994 and continued in 1996 with patination of a cast of the southern part of the trackway for use in the Dar es Salaam Museum and making of an archival epoxy cast. Photography and photogrammetry was undertaken of the hominid prints.

Under separate permit from the Department of Antiquities, a three-member team consisting of one geologist and two anatomists conducted a re-study of the taphonomy, morphology and gait of the prints in 1995 and 1996.

To involve the local Maasai community in the protection of the site, numerous meetings were held with Maasai elders from nearby villages beginning in 1994. This initiative led to a ceremony attended by the local communities in which the trackway was blessed by the traditional religious leader, the Oloiboni, to enhance its value to the Maasai. Two local Maasai guards were permanently posted to the site by the DoA.

Exhibits for the Olduvai Museum:
Design, production and installation of a new exhibit for the Olduvai Museum took place in 1997-1998 with the official opening of the museum in October 1998. The museum's three rooms offer an orientation to the region and displays on Olduvai Gorge and Laetoli. The Olduvai exhibit was a renewed version with some updates of the original exhibition done by the Leakeys. The Laetoli exhibition was entirely new and included a cast of the trackway and numerous didactic panels that tell the story of its conservation. All text was in Swahili and English.

For an overview of the project in photographs, see the visual summary

For details of all activities see Related Materials