Carmen E. Turner, the Metro system's interim chief, was chosen yesterday as the transit authority's general manager, becoming the first black woman to head a major U.S. transit system.

Turner, 53, a former civil rights official in the U.S. Department of Transportation who has been a senior Metro administrator since 1977, was selected in a surprise move by Metro's board of directors.

At a news conference yesterday, she indicated no plans for immediate shifts at the transit agency.

"I haven't been general manager long enough to know," Turner replied when asked whether she would alter any of the policies established by Metro's previous general manager, Richard S. Page. "I think Dick and I share many similar objectives."

Although Turner has been the transit agency's acting general manager for the past month, she had not been considered a candidate for the permanent post. She had not sought the job and board members reportedly were not certain that she would accept it.

"We did not know. She had not peeped a word," said Arlington County Board Vice Chairman John G. Milliken, a Metro board member.

While Turner is the first black woman to head a major American transit system, there have been at least 25 white women and numerous black men in similar posts across the United States in recent years, according to the American Public Transit Association.

Turner's selection ended an apparent deadlock within the transit authority's politically fragmented board of directors, which includes government officials from the District of Columbia, Maryland and Virginia.

According to reliable sources, the District's board members had supported former D.C. City Council Chairman Sterling Tucker for the Metro position.

Maryland and Virginia members had backed two assistant Metro general managers, William A. Boleyn and Theodore G. Weigle.

In an attempt to break the impasse, board members recently began discussing other possible choices for general manager, including Turner.

They reached agreement yesterday after meeting for more than four hours.

Turner was surprised by the decision when she was summoned by the board at about 2:30 p.m., officials said.

"I was quite pleased and proud," Turner said.

Her selection partly reflected agreement among key board members to promote a senior Metro official instead of hiring an outsider.

Milliken said that the board's aim was to ensure a continuation of recent efforts to curb the transit system's soaring multimillion-dollar deficits and to make bus and subway service more reliable.

Turner is regarded as a low-key administrator with a conciliatory approach to management. She is thought likely to be able to deal diplomatically with Metro's frequently contentious policy-setting board.

"She knows the system. She gets along well with people. And she is the first female," said D.C. City Council member Hilda H. M. Mason, who serves on Metro's board.

Page resigned as Metro's general manager May 31 to become president of the Seattle-based Washington Roundtable, a group formed by Washington State businesses to study economic and social problems.

Turner's appointment is scheduled to take effect July 14. Her salary has not yet been set, officials said. She now earns $77,388 a year as an assistant general manager. Page had been paid $77,938.

As Metro's assistant general manager for administration, Turner has played a key role in several sensitive issues, including civil rights and labor relations.

Metro's D.C. board members repeatedly have pressed the transit authority to ensure jobs and construction work for blacks, other minorities and women.

Metro's relations with its employes' labor unions frequently have been strained. Turner has backed a policy of seeking to settle union contracts through negotiations instead of allowing them to be turned over to arbitration panels.

It is unclear whether this strategy will result in financial savings or improved labor relations. The transit authority currently is engaged in protracted bargaining with its employes' largest union, Local 689 of the Amalgamated Transit Union.

Before joining Metro's staff, Turner was deputy director of civil rights in the federal Urban Mass Transportation Administration, a Transportation Department agency that helps finance the Metro system.

In 1976 she was called upon by former Transportation Secretary William T. Coleman Jr. to head his affirmative action program, after Coleman had ousted the department's two top civil rights officers.

At Metro, Turner also has been in charge of computer systems and the purchasing of fuel, spare parts and other equipment and services.

She lives in the District and is a graduate of Dunbar Senior High School.

She holds a bachelor's degree from Howard University and a master's degree in public administration and political behavior from American University.