Calexico is not a rock band, and it’s gratifying that the Tucson, Ariz. collective is finally ready to acknowledge it. Since 1996, Joey Burns and John Convertino, the core members, along with a crack team of studio musicians, produced four increasingly great albums, peaking with 2003’s “Feast of Wire,” which drew from American folk, Mexican mariachi and tejano, cool jazz, Ennio Morricone-style film scores, surf, Jamaican dub and a wide variety of Latin American and Caribbean styles, as well as their own classical training. I realize that the above description makes the group sound like a bunch of infuriating musical tourists, but their respect for their sources along with their intense drive to innovate made their music beautiful, evocative and above all, original. Their records captured the atmosphere of their (and also my) Southwestern home.

Then in 2006, after recording an EP with Iron and Wine in 2005, they released “Garden Ruin,” a relatively conventional alt-country album with a few Southwestern flourishes and (gasp!) no instrumental pieces. Those two records, especially “In the Reins” (the collaborative EP), were excellent, but it was a little disappointing to hear Calexico dulling rather than refining their idiosyncrasies.

Well, worry no more, dear Calexico fans. The band announces its return to its old eclectic sound within the first few seconds of their sixth full-length “Carried to Dust.” On the leading track, “Victor Jarra’s Hands,” Burn’s vaguely Hispanic acoustic guitar intertwines with Convertino’s understated, unpredictable snare hits before electric guitars and bass drift into the mix, joined by a chorus of olés and swelling mariachi horns. It’s an inspiring return to form that the album extends. The old influences are back, as are the instrumentals. They also introduce some new tricks. “Two Silver Trees” prominently features guizeng, a kind of Chinese zither, while “Contention City” uses toy piano, Wurlitzer and post-rock inspired atmospheric electronics.

It’s all even less conventional than it sounds. Calexico’s arrangements are intricate, but each part is almost Spoon-like in its minimalism. Appropriately for a desert band, the sound is full of open space; it’s never fussy. Each song might contain wildly divergent elements — surf guitar, “Birth of the Cool”-inspired drums, accordion — but they lock together perfectly. Trumpeter Jacob Valenzuela stands out in particular. He has cultivated a remarkable mariachi-influenced jazz sound. While too may Latin-inspired trumpeters rely on exhausting demonstrations of tin-eared technical ability, Valenzuela understates the swells and stabs of mariachi horns, sounding coolly reserved like a norteño Chet Baker.

It’s tempting to compare “Carried to Dust” to “Feast of Wire.” They are far and away Calexico’s best, and they both feature the band’s mariachi-meets-everything aesthetic, but they are also markedly different in sound and tone. The songs on “Feast” veered wildly from style to style, while the sound of “Dust” is a more unified synthesis. There’s plenty of variety on the new record, but not the frenzied experimentation of the old one. “Carried to Dust” also features a few of the more American country-inflected songs typical of “Garden Ruin,” though they don’t dominate the mix. It also features a guest appearance by new buddy Sam Beam of Iron and Wine. The themes of the two records are miles apart. “Feast of Wire” was full of social-realist dramas about life in contemporary Arizona, dealing with the immigrant experience, the drug war, and the mounting anomie in suburban sprawls. “Carried to Dust” focuses on lonely figures moving through ruined unfamiliar landscapes.

Evidently, this is a concept album about a striking Hollywood writer finding a mysterious map and traveling out into the desert. The lyrics are impressionistic in the extreme, so you probably won’t notice the plot if you aren’t looking, but the themes of restless exploration and dislocation are pervasive. “Bend in the Road” is a perfect song for paranoid late-night driving, while “Man Made Lake” evokes the existential creepiness of the enormous, oft-abandoned engineering projects which dot the Southwestern deserts. “Inspiración”, an en español track written and sung by Valenzuela, sounds like an old Mexican pop gem wafting through the static out of a busted radio. “Contention City” is a perfect companion piece for its namesake, the real-world ghost town where the character end ups; there’s so little sound on that it’s like a specter of a song, yet it manages to be moving in its emptiness.

“Carried to Dust” is not a revolution for Calexico, but it shouldn’t be. It’s a refinement, and the songwriting on this record is probably the best of their career. The world (and more importantly, Tucson expatriates like me) needs that core Calexico sound. “Carried to Dust” does an admirable job capturing the essence of a place. It’s an impressive achievement — nostalgia in a bottle for we lucky Arizona natives, and the cheapest available vacation for y’all.