More than 100,000 blacks in the metropolitan Washington area got jobs in the Maryland and Virginia suburbs between 1970 and 1977, according to a major economic study released yesterday.

But during that same period, 30,000 jobs held by blacks in the District of Columbia disappeared, while the rest of the city's job market remained stagnant.

The 100,000 new jobs that went to blacks represented about two-fifths of all new employment in the metropolitan area in the 1970-77 period, and far exceeded the proportion of blacks in the total population. Blacks make up 27.7 percent of the metropolitan population, but only 9.9 percent of the suburban population.

The report, by Brimmer & Co., economic consultants, was issued at a time of high unemployment, chiefly in the city.

The jobless rate last year was 9.7 percent in the District, but only 3.3 percent in the suburbs. The overall city figure masked a 44.4 percent rate of unemployment among young people in the District, mostly blacks.

The Brimmer report was commissioned by a special committee formed by the Metropolitan Washington Board of Trade to oppose a proposed increase in the D.C. minimum wage to $3.25 an hour, with annual increases beyond that in future years. A City Council committee opened hearings into the proposal yesterday.

In addition to supporting the business group's case, the Brimmer report assembled data of a type never before available, adding up to an economic profile of the metropolitan area.

Andrew Brimmer, president of the firm and a former member of the Federal Reserve Board, said the report shows the District "has not been sharing as fully as many people think in the substantial growth" of the region.

In the 1970-77 period, his report said, "employment opportunities in the city have been shrinking faster than the number of people seeking work," leaving the city with more than its share of the region's unemployment.

Figures from the Commerce Department cited in the report also show that "there has been a steady erosion in the proportion of total income earned from working in the city that is actually received by District residents."

In 1970, District residents earned 44.6 percent of all the wages and salaries paid to people who worked in the city. By 1977, that figure had dropped to 39 percent - meaning that 61 percent of all the dollars earned in the city were being carried to the suburbs.

The dollars earned by suburbanites is a volatile political issue. District officials have asked Congress to pass a law letting the city tax these earnings. Suburban congressmen and officials vehemently oppose the idea.

Only in one form of income did the report find that District residents showed greater gains from 1970 to 1977 than suburbanites: unemployment compensation and public welfare benefits.

The report found that blacks earn, on the average, considerably less than other workers, both in the city and suburbs, and that they made bigger gains in the 1970-76 period than other workers.

The report reflects an irony. While the number of jobs held by black youths in the city was declining, "this group had the most substantial wage increases over the period."

Brimmer contended that such increases can put young people at a serious disadvantage in competing for jobs by overpricing limited skills - a point made by numerous employers who testified at yesterday's council hearing.

In tracking the number of jobs held by blacks and the decline of those jobs in the city, the Brimmer report cited these figures:

In 1970, 242,000 blacks held jobs in the city, and 49,000 held them in the shrank. By 1977, city jobs for blacks shrank to 212,000, a loss of 30,000, while the suburban jobs held by blacks grew to 149,000, a gain of 100,000.

Brimmer did not attempt to trace what happened to the jobs lost in the city. Some in service industries apparently just disappeared, while others apparently were moved to the suburbs as companies changed their business locations.

Brimmer noted that the regional public transportation system is geared to getting workers from the suburbs to jobs in the city and that the road system now centers on the Capital Beltway that carries traffic around the city.

One argument for an expanded Metrorail system has been that it would carry city residents swiftly to jobs in the suburbs. Several witnesses at yesterday's hearing noted that Metrorail service makes it easier for suburbanites, many of them with better education and job qualifications than city youth, to compete for better-paying jobs as the minimum wage rates are raised.

Brimmer and Robert Linowes, president of the Board of Trade, were among witnesses who testified at the hearing, conducted by the council's employment and economic development committee.

The committee is considering a bill by Hilda Mason (Statehood-At Large) that would raise the minimum wage in the city to $3.25 from its present range between $2.65 and $3 and tie future increases to wages paid workers in manufacturing industries in the city.

Most of yesterday's testimony came from restaurant owners and managers, who contended the pay increase would drive business out of the city.

William Rauschelbach, president of the Restaurant Association of Metropolitan Washington and general manager of the Golden Ox Restaurant, said the rising cost of doing business in the city is eroding profits.

Last week, at a meeting of his company's board of directors in Kansas City, Rauschelbach said he received some stark others: "The first month I lose money, I am to lock my doors - there is no incentive for us."

Opposition to the higher minimum wage also was presented by witnesses representing the area's universities, parking industry and gasoline service station operators. All contended that the higher pay would reduce employment of teen-agers.

Robert Petersen, president of the Greater Washington central Labor Council, AFL-CIO, supported the wage increase. "The minimum wage should not be a poverty wage," he said.

Another hearing on the bill is scheduled at 7:30 p.m. June 14 at Terrell School, Wheeler Road and Savannah Street SE.