She earned a college degree and trained to be an opera singer. She has a bit of a regal air about her even though she's barefoot. But when Rhiannon Giddens sings blues, folk and other styles of American music, she does so with deeply felt authenticity.

Whether it was field hollers, Celtic mouth music or unpublished Bob Dylan lyrics set to her own melodies, Giddens sang it with goosebump-inducing authority Tuesday night at the Pantages Theatre in Minneapolis. There was a certain formality to her body language and a properness to her diction, but the 37-year-old North Carolinian proved that she is a great American vocal treasure, probably the best pure and versatile American voice to come along since Alison Krauss.

After nearly a decade of performances with the old-timey string band Carolina Chocolate Drops at Cedar Cultural Center and the Minnesota Zoo, Giddens had a coming-out party at the Pantages to promote her first solo album, "Tomorrow Is My Turn." The record celebrates songs associated with such historic vocalists as Odetta, Nina Simone and Dolly Parton.

Giddens assembled a set list for her 90-minute performance with a great sense of purpose. Written from a woman's point of view, these were songs of nuanced humanity, telling stories of sadness and strength. She educated with her introductions (about lefthanded blues guitarist Libba Cotten, for example) and entertained with her remarkable voice.

On the country classic "She's Got You," Giddens unleashed her soprano filled with sorrow, dipping down in her lower register with despair, out-Patsying Patsy Cline. She hung on that last line, turning up the tears as she crooned "I've got these little things and she's got you." And Giddens smartly underscored the sadness by having a cello take the parts usually played by a fiddle in this and other country-leaning tunes.

On the folk chestnut "Waterboy," identified with the great black folk singer Odetta, Giddens started a cappella like a field holler, then built it into a lazy country blues as her five musicians joined in and eventually climaxed with an ending that was emphatic with vocals and dramatic with lighting. The performance earned her one of several standing ovations.

Although she wasn't much of a physical performer (except for a little dancing during the R&B stomp "Black Is the Colour"), Giddens had a warm and wise presence. Still, her inexperience as a solo artist became apparent. She exited for a couple of songs to let her band show their considerable skills. However, Hubby Jenkins, her bandmate in the Chocolate Drops, admitted that he was tired and distracted by events in Baltimore. His heart wasn't in his performance of a Lead Belly tune, and suddenly it seemed as if someone had let the air out of Giddens' I-finally-made-it balloon.

Indeed, life can interrupt art. But Giddens returned to the stage and proclaimed, "Music can lift us if we let it."

And that's exactly what she did with a wide range of sounds — from the French vibe of "Tomorrow Is My Turn" and a tongue-twisting Irish mouth music number (I'll spare you the long title) to the Dylan jig "Duncan and Jimmy" and the Sister Rosetta Tharpe tent-revival gospel of "Up Above My Head."

In the end, it felt like an extraordinary jubilee of American music by a great new voice — maybe like seeing the great opera star Marian Anderson let her hair down.