The United States and Britain announced yesterday that they will resume "intensive consultations" with all parties to the Rhodesian dispute in hopes of achieving transfer to black majority rule next year.

Joint announcements in Washington and London said Secretary of State Cyrus Vance and Britain's Foreign Secretary David Owen agreed in London last week to send a special Anglo-American mission to Africa in a fresh effort to solve the Rhodesian crisis.

A State Department spokesman emphasized that Britain had the leading role in the new Anglo-American initiative.

In identical statements, the two governments restated "that determination to work for the independence of Rhodesia" under black majority rule in 1978.

"They have been encouraged by their contacts so far to believe that detailed consultations about an independence constitution and the necessary transitional arrangements could be a satisfactory way to achieve this.

"They have, therefore, agreed that Britain and the United States should now enter into a phase of intensive consultations with the parties."

To carry out that mission, the statements said, Vance and Owen agreed to establish "a consultative group to make contact with the parties which will visit the area as necessary, including Salisbury," Rhodesia's capital.

In London, Owen said the group, headed by a senior Foreign Office official, will leave for Africa next week. He said Vance will neame a senior U.S. official to work with the British group.

Reaction to the annoucement in Salisbury was mixed.

Deupty Prime Minister David Smith, was optimistic.

"There is light at the end of the tunnel" he said. "It may be dim yet, but it is there."

Another official said, "There is nothing new in this, nothing we did not expect."

Earlier yesterday, U.S. diplomatic sources in London outlined a new Anglo-American plan for a Rhodesian settlement that calls for a transition to black majority rule by late next year.

They said the plan had the full support of the U.S. government, which was prepared to provide guarantees to back up the transition proposals.

The London sources said the Owen plan concentrates on drawing up a constitution for Rhodesian only after independence has been achieved in late 1978, rather than making a constitional conference part of the transition process.

Last year's Geneva conference on Rhodesia broke down when the parties could not agree on transition details contained in a plan formulated by Secretary of State Henry Kissinger.

The sources said the new plan would differ from Kissinger's blueprint in several respects, including:

Establishment of some form of British "presence" in Rhodesia during the transition.

Establishment of a Rhodesian government along the lines of the British parliamentary system, rather than separate, balancing executive and legislative branches.

Holding of elections on the one-man, one-vote principle, under international auspices, before independence. The white minority government would resign before the elections.