He pioneered exploration within the Dauphiné Alps in the French Alps, in 1862 making the first crossings of the col des Ecrins, the col du Sélé and the col du Glacier Blanc in the Massif des Écrins with the guides Michel Croz, Peter Perren and Bartolommeo Peyrotte. He also made an attempt, with the same party, on the highest mountain in the range, the unclimbed Barre des Ecrins. In Tuckett's own words: