Olduvai Gorge, the site in Tanzania where Louis and Mary Leakey made many of the fossil discoveries that established East Africa as an important region in human evolution, will soon be under the scientific control of the Leakeys' arch rival, American paleoanthropologist Donald C. Johanson.

Louis Leakey died in 1972 and his wife Mary, who continued work at Olduvai, retired in 1982. Since then, no work has been done at the site.

Earlier this year, the Tanzanian government invited Johanson, who heads the Institute of Human Origins in Berkeley, Calif., to resume explorations there. Johanson and his colleagues will start next June.

Olduvai is a small canyon in northern Tanzania that cuts through layers of ancient sediments dating as far back as 1.75 million years. Scores of fossil bones of human ancestors and hundreds of their stone tools have been found in nearly all levels of the gorge. The oldest are those of Australopithecus and Homo habilis, an early member of the human genus.

Johanson is best known for his discovery in Ethiopia of an earlier form of Australopithecus that he dubbed Lucy. Specimens of this species offer the earliest positive evidence of walking on two legs. In recent years, Johanson has been unable to continue explorations in Ethiopia because of a government ban on field research.

As part of a 10-year agreement with Tanzania, Johanson's institute will also train Tanzanians in anthropology and archeology and develop research facilities for storage and study of the finds. Most of the fossils from Olduvai are housed in Kenya at the National Museum run by the Leakeys' son, Richard.

The American research team will include Johanson, Robert Drake and William Kimbel of the institute, Gerald Eck of the University of Washington and Tim White of the University of California at Berkeley.

Archeological research, dealing with stone tools rather than fossil bones, will be directed by Fidelis Masao, director of the National Museums of Tanzania.

Johanson said part of the funding for the new explorations will come from a $500,000 gift to the institute from Gordon Getty, a board member. The gift is a challenge grant requiring the institute to raise an additional $1.5 million.