Mumford and Sons' 'Babel' logs year's biggest debut

• 'Babel' bypasses Justin Bieber's 'Believe,' which sold 374,000 copies in June
• It's the most debut copies sold since Drake's 'Take Care' last November
• But the biggest weekly sales go to Adele's '21,' which sold 730,000 after the Grammys

Crushing stiff competition from a slew of superstar acts, Mumford and Sons' Babel scores the biggest debut of the year, landing atop the Billboard album chart after selling 600,000 copies.

Babel's start, the heftiest since Drake's Take Care opened with 631,000 last November, vastly outdistanced four other chart arrivals. Green Day's Uno!, the first in a trilogy, sold 139,000 copies to land at No. 2, according to Nielsen SoundScan. No Doubt's Push and Shove, the quartet's first studio album in 11 years, is third with 115,000. Lupe Fiasco's Food and Liquor II: The Great American Rap sold 89,000 to place fifth, behind last week's chart-topping The Truth About Love by Pink. And Deadmau5's >album title goes here< lands at No. 6 with 58,000.

The U.K. indie folk group's sophomore release didn't tally the year's largest weekly take. That honor stays with Adele's record-shattering 21, which sold 730,000 copies the week after she won an armload of Grammys. With scant promotional hoopla, the band's opener surpasses former 2012 leader Justin Bieber, whose Believe sold 374,000 copies in June.

"It blows Bieber out of the water," says Keith Caulfield, Billboard's director of charts. "Mumford isn't a traditional singles act, like Rihanna. It's not about hits. They appeal to consumers who still want the experience of an album. They have a wide appeal, from young folks who see them on tour to older NPR listeners."

Babel was streamed 8 million times by Spotify's U.S.users in the past week, the biggest week for any album this year. One in 10 Spotify listeners heard at least one Babel track.

"This was a hotly anticipated album that shattered this year's record by a factor of three," says Ken Parks, Spotify's chief content officer. "It shows what you can do when you get amazing music and let people listen to it. We're connected to Facebook, and a lot of people were getting into it through social and viral channels. There was a lot of heat around this album."

The band's 2010 debut, Sigh No More, has sold 2.5 million copies and never left the top 200.

"In all that time, you're building up a robust fan base," Caulfield says. "A huge chunk of those people are going to show up to purchase the new album the first week. That just makes sense."

Mumford's profile grew with heavy touring and Grammy exposure. Yet this week's sales bonanza "was bigger than a lot of people expected," considering the lack of a media blitz, Caulfield says.

"They've been conservative in their promotion," he says. "It's not a sexy, glitzy, fireworks rollout. They're not the type of artist that oversaturates the market. It's low key. A lot of people wish they could have the type of success Mumford is having."