Sharon Pratt Dixon's upset victory in the Democratic mayoral primary has exposed growing divisions between economic classes in a city already deeply divided by race, according to a review of voting patterns and interviews with city political analysts.

An analysis of how social and economic factors shaped Tuesday's mayoral voting disclosed that Dixon swept every predominantly white precinct in the city and led among upper middle-class black voters. But she lost -- sometimes badly -- in virtually every low-income neighborhood.

City political figures say this pattern of polarization by economic class presents major challenges to Dixon and some unexpected opportunities for her challenger, Republican Maurice T. Turner Jr., as they begin the general election campaign.

The results also raise questions about whether anyone -- Dixon or Turner, Democrat or Republican, reformer or defender of the status quo -- can assemble a coalition large and stable enough to govern effectively a city so clearly separated by class as well as by race.

"We are divided on a race basis, but also along class lines," said Donna Brazile, campaign manager for Eleanor Holmes Norton, who won the Democratic nomination for D.C. delegate. "Not only is the city divided black and white, but we're divided rich and poor. People see these things through completely different prisms."

The voting patterns mirrored demographic trends reflected in preliminary census data, which indicate that thousands of middle-class blacks moved out of the District during the 1980s.

"We're moving toward a city just made up of the very well-to-do and the very poor," said Dwight S. Cropp, a former aide to Mayor Marion Barry and director of the city's Intergovernmental Relations Office. "The question is, how can you appeal to both groups?"

The computer-assisted study of voting patterns showed Dixon was able to win only seven of 57 precincts in predominantly lower middle-class to poor areas of the city, where she claimed only about one out of every six votes.

But in the city's middle-class and wealthy neighborhoods, she finished first in 55 precincts and lost in 17, most by narrow margins.

And she split the vote with challengers John Ray and Charlene Drew Jarvis in the city's 11 precincts that included a mix of both upper and lower-class neighborhoods.

The analysis showed Dixon claimed at least 60 percent of the vote in 16 precincts, all in predominantly white and wealthy neighborhoods in Northwest Washington or on Capitol Hill. She received her largest share of the vote -- 66 percent -- in Precinct 136, a neighborhood favored by younger professionals near the National Zoo in Northwest Washington.

Just up Connecticut Avenue, voters in Precinct 27 gave 65 percent of their votes to Dixon, while in Precinct 13 in Kalorama, one of the most exclusive neighborhoods in the city, 64 percent of the votes were cast for her.

Dixon also led among voters in the black upper-middle class neighborhoods of the Gold Coast east of Rock Creek Park. She also carried most of the comfortable black neighborhoods in the Brookland area off Rhode Island Avenue in Northeast Washington.

Those big totals contrast dramatically with her showing in the city's less affluent neighborhoods, all predominantly black and most of them in Southeast.

In Ward 8, an area that includes some of the city's poorest and most troubled neighborhoods, Dixon claimed fewer than one out of five votes. In Precinct 131 in Ward 2 near the Washington Navy Yard, home to many elderly voters and public housing residents, Dixon received 17 out of 283 votes cast, or 6 percent.

"There's more at work here than just race," said Jim Zais, a longtime constituent services worker for Barry. "The economic polarization in the city -- I think it is potentially explosive."

"It's sort of beneath the surface," he said. "If we don't pay more attention to increasing self-sufficiency in the poor communities, we're going to become more and more two cities -- one that is dependent, and another that pays for the dependency and resents it."

Zais and others said concerns about Dixon among the city's less affluent voters were fed by Dixon's promise to clean out city hall with "a shovel, not a broom." That reformist message, legitimized by the editorial endorsement of The Washington Post, appealed to the city's upscale residents, black and white.

At the same time, the message may have frightened many of the city's older voters as well as lower middle-class and poor voters, groups that have directly benefited from the expansion of city services during the stormy Marion Barry era and whose members continue to closely identify with the mayor.

One of the heaviest concentrations of older voters in the city is in Precinct 139, which covers the Fort Lincoln community in Northeast. In this precinct, Dixon finished third with 21 percent of the vote, trailing well behind John Ray, who had lined up many of the area's civic leaders behind his candidacy, and Jarvis.

Bob King, president of the Fort Lincoln Civic Association and a Ray supporter, said that Dixon "kind of distanced herself from them. They were scared that she was going to cut senior citizen programs back." He also said that many people in public housing "had problems with Dixon's campaign from Day One . . . . They see her as a corporate person who hasn't paid her dues."

King and others say some voters are even talking about supporting Republican Turner, the former D.C. police chief.

Zais also said Dixon must broaden her appeal. "She never reached out to the elderly, to the public housing community," he said. "If she were smart, she would start doing that. Otherwise Turner may make some inroads in that area."

Dixon dismisses the notion that her campaign disproportionately appealed to the city's more affluent voters and she reminds those who fault her for not reaching out to the city's poor and elderly voters that her campaign lacked money to mount little more than token organizing efforts in most parts of the city.

"I think I got pretty broad-based support," Dixon said. "Clearly it was biracial support. I think a lot of working-class people and middle-class folks who were unhappy about the direction we were going came out and supported me."

Many active in city politics say the general election campaign can be Dixon's chance to reach out and broaden her base. "She's got to reach out -- convince the seniors that she's going to keep the programs intact and expand them," King said. "People are very concerned about what she says about wiping out programs," King said. "She cannot just be the mayor of The Washington Post, white people and middle-class blacks . . . she's got to be the mayor of all the people."

Many knowledgeable political observers said that Dixon, if elected, should look at Barry's first term in office as a model of how to cobble together diverse and often opposing constituencies.

In key ways, many say the coalition that gave Dixon the nomination was similar to the coalition that elected Barry in 1978. But Barry moved swiftly after the election to build bridges with the black middle and lower middle class, the churches, and to make peace with his opponents.

"She's got to do what Marion was able to do," said Robert L. Johnson, campaign manager for Walter E. Fauntroy. "She's got to figure out how to bring the lower-class blacks into the coalition. Marion hugged all the old ladies, played basketball with the guys. I don't know if Sharon can do it. That is the question."

Cropp says that the challenge to Dixon would become even greater if she is elected. "She's going to have a very complex task ahead of her," he said. "She comes in fresh with progressive ideas and a reformist mandate. There will be high expectations. She's going to face pressure to cut back expenditures and increase service levels, all at the same time. But that's a test of leadership."

To examine the social and economic factors that influenced the mayoral primary, each of the city's 140 precincts was matched by computer with the detailed demographic profiles of the neighborhood in which that precinct is located.

This analysis found that virtually all of the precincts fell into one of seven demographic categories developed by the Claritas Corp. These categories included separately identified upscale black and upscale white neighborhood types, as well as separate categories for wealthy and poor urban neighborhoods. The voting patterns in precincts within the same demographic category were then analyzed to see how similar socioeconomic groups voted.

Staff writer Mary Ann French contributed to this report.