Deputy Secretary of State William P. Clark fired George H. Aldrich, head of the U.S. delegation to the Law of the Sea Conference, along with several senior members yesterday; virtually on the eve of the conference's resumption Monday at the United Nations.

Clark named James Malone as new U.S. chief negotiator. Malone has been designated, but not yet confirmed, as assistant secretary of state for oceans, international environmental and scientific affairs.

Clark, who heads an interagency group of a dozen government departments and agencies concerned with the Law of the Sea Conference, called for a delay in final agreement on a treaty. The forthcoming 10th session of the conference was expected to complete a treaty text and have a final version ready for signature by more than 150 nations in Geneva this summer.

At a Senate Foreign Relations subcommittee hearing Thursday, George Taft, director of the State Department's office of law of the sea negotiations, said the administration would not accept the tentative provisions of the treaty dealing with deep sea-bed mining.

But he told senators that the United States hopes that the mining section could be redrafted without disturbing agreements reached in other areas -- such as freedom of navigation and research, and guarantees for environmental protection.

Taft, who has served on the delegation for five years, was dismissed along with Aldrich. Alan James, a retired career diplomat who was serving under contract as chief of staff for the U.S. delegation, was also removed. Of delegates from outside the State Department, John Swing, vice president of the Council on Foreign Relations, also was known to have been replaced.

Elliot L. Richardson, who headed the delegation for three years until his resignation last October and who remained as chairman of an advisory group, was believed to be staying on in his advisory capacity. Richardson appeared at the Senate hearing Thursday, however, to urge that the U.S. delegates be permitted to go ahead with completion of the treaty.