ART text and interview by XERXES COOK all artwork by ROBERT SMITHSON copyright holt / smithson foundation and adagp, paris, 2021 the robert smithson exhibition opened in london the same week scientists announced that the global mass of man-made materials — concrete, metal, asphalt, plastic, etc. — outweighs all living biomass on earth. what would the legendary land-art artist have thought of that? we talked to lisa le feuvre, director of the holt / smithson foundation in santa fe, new mexico, to learn about the artist’s enduring interest in islands. “Imagine yourself in Central Park one million years ago,” Robert Smithson said. We were in Manhattan, the concrete jungle of an island he and his wife, fellow artist Nancy Holt, called home. “You would be standing on a vast ice sheet, a 4,000-mile glacial wall, as much as 2,000-feet thick. Alone on the vast glacier, you would not sense its slow crushing,…