The new Turner Contemporary gallery is visible as soon as you leave Margate's train station: two glassy buildings whose slanting roofs cut against the sky. From a distance, the gallery - designed by the architect David Chipperfield - looks like it's falling into the sea. Inside are pools of natural light, bare concrete floors, new work by the artists Conrad Shawcross, Russell Crotty, Ellen Harvey and a hustle of photographers waiting for Tracey Emin.

Emin is the gallery's natural ambassador, a child of the town and an advocate for its regeneration after years of neglect. Overwhelmed by the occasion, she wipes away tears as the photographers angle their cameras at her face. "Are you crying in a good way?" one asks. "I'm crying in a brilliant way," she replies.

At present, there is only one painting by J M W Turner in the gallery, of a volcano, Eruption of the Soufriere Mountains in the Island of St Vincent, 30th April 1812. Turner composed the work from his imagination, informed by news reports: sparks of fire flash across black and reddened clouds. The gallery's promise is that it will always have at least one Turner picture on display. And within the first year, it will host a major touring exhibition of his work.

Turner was a regular visitor to Margate and the surrounding areas, staying at a guest house on the site of the new gallery. The skies of Thanet, he once said, "are the loveliest in all Europe". In the past 20 years, Margate has struggled to attract such praise. Holidaymakers stopped coming in the 1970s and 1980s, businesses closed and buildings fell into disrepair - including Dreamland, a once-famous amusement park.

The Turner gallery is already helping to revive Margate; there are arty cafés and chic boutiques awaiting a fresh influx of visitors. Dreamland will be revamped and reopened. The town even has a new slogan - "Margate: the original seaside" - drawing on its history as one of Britain's earliest resorts (and the first to have donkey rides on the beach, as one resident proudly tells me). Turner wouldn't recognise Margate now: many of the old buildings were destroyed in the Second World War. But perhaps he would appreciate its latest form, a fine work of reinvention.