The '60s seem as if they happened just yesterday. And now, the '70s too are almost past tense.

True, the '70s have left a certain residual waste which will probably linger on like so much static cling: They added words like "interface," "Ayatollah" and "boogie" to our lexicon. Places like Iran, Studio 54 and the Club Med had their fashionable moments. And, of course, there were mega-celebs like Maggie T, "just call me Jimmy" Carter and Joe Who? who enthralled millions.

But one thing's sure: the '70s turned out to be very good for the '60s. On the surface, the '70s represented a backlash to the '60s, the neo-conservativism answering the old lefty liberalism. But that, in truth, is too simple an explanation. While we did indeed become more conservative, this was in perfect accord with the new mood of all those hotshot '60s radicals who, in the '70s, having discovered their mid-30s, were slouching their way toward middle age. Call the '70s, then, "the '60s: Part II."

If you wish confirmation of this, all you need do is listen to recent albums by certain key '60s people and notice how earnestly mainstream they sound. From Joan Baez, you might still expect a hint of her egdy '60s social consciousness. But expect what you will, her newest album, HONEST LULLABY (Portrait), could just as easily have been recorded by Olivia Newton-John or the Norman Luboff Choir. It's an album by a pop singer, nothing more or less, but it's a good album with solid songs - particularly the title track - and the Baez voice is still resonantly powerful after all these years. Of course, those who've been keeping up with her career shouldn't be too surprised; she has, after all, played Las Vegas and, just recently, she denounced the Vietnam government.

Joni Mitchell is a different matter altogether. While Baez has always been comfortable working to crowds, Mitchell has preferred to work in seclusion; if Baez is a muralist, Mitchell is a miniaturist, working with delicate shadings of colors, using only the most supple brush strokes. Mitchell's tribute to - and collaboration with - the late, great jazz bassist, Charles Mingus, represents the culmination of her career so far. And yet, it is her most delicate work.

MINGUS (Asylum Records) features the bassist's music, Mitchell's lyrics and, most importantly, her adaptations of his music. Mingus had a towering ego; many of the musicians who worked with him were either in awe of his rages or terrified of them. But not Mitchell. Her ego is certainly a match for his, and despite the fact that the music on this album is his, the entire album is very much her work, nevertheless.

The sheen of her voice, the great unexpected leaps the melody lines force her to sing and her use of an untuned guitar stamp every work with her own personality. Sometimes, as in "Goodbye Pork Pie Hat," her personality seems to be at odds with his; elsewhere, especially on "The Wolf That Lives In Lindsey," the meeting of these two totally different souls is in perfect harmony.

The maturing of Joni Mitchell has been totally different from that of Joan Baez. While the latter was headed straight for the mainstream, the former has taken even more of a refuge in art - hers and others'. Yet, their response to the '70s is alike in one way: both knew they could not repeat what they'd done in the '60s, that they'd be too vulnerable.

Neil Young's solution to surviving the '70s has been much more direct - he just turned up the volume on his guitar amps, hunkered down and started playing loud, loud music. As he sings in "My my, hey, hey," from his new album RUST NEVER SLEEPS (Warner Bros.), "it's better to burn out than to fade away."

But Young saw the '70s coming early on. In the first few years of the decade, he had recorded some of his most popular music and was out-selling the biggest in the field. He was also, he realized, trapping himself inside his own popularity, catering more and more to his audience and, as a consequence, cutting corners with his music. So, he retired, letting the years drift by as he sat on his farm outside San Francisco.

RUST NEVER SLEEPS represents his re-entry into the fray, but this time around, he has taken on a new persona. He knows he's older than most of his audience; he knows he's regarded as a '60s figure; so, he's taken the only role open to him - that of the teacher, retelling the '60s to a '70s audience.

Actually, when I think of it, the last 10 years really didn't go by all that quickly, they were just masquerading as other years: After 1969, we had a 1928 (THE GREAT GATSBY). Then, there was some 1958 (punk and GREASE). And, finally, just as the decade is coming to a close, we have Neil Young and - but of course - it is 1969 all over again. Whoopee!