PARIS/DAKAR, May 2 (Reuters) - Total (TOTF.PA) has signed an agreement to explore for oil and gas off Senegal's Atlantic coast, boosting the prospect of major oil developments in the West African country.

Under the deal Total will explore in the deepwater Rufisque Offshore Profond Block where it will be the operator with a 90 percent stake and Senegal's state-run oil company Petrosen will hold the remaining 10 percent.

The two parties also agreed to cooperate on exploration in "ultra-deep" offshore waters, with the potential for Total to become an operator there too.

The financial terms of the deal were not disclosed.

Senegal is on the verge of an oil and gas boom, as newly discovered oil and gas fields are expected to begin production within the next decade. Companies including British-based Cairn Energy (CNE.L) and Dallas-based Kosmos Energy (KOS.N) have reported a string of successful finds that could transform Senegal's agricultural economy.

"These agreements are part of the group's strategy to carry out exploration activities in new deepwater basins in Africa," Total's chief executive Patrick Pouyanne said in a statement.

Total's investment marks a new direction in Senegal where it currently owns 174 service stations but has no actual production, and fits with its goal of making cheaper investments with the hope of greater returns.