Distribution of the caves in the uplifted atoll of Walpole. Consequence onthe process of karstification by meteoric waters

The distribution of voids recorded along the cliffs bordering the karstifie d coral island of Walpole shows that numerous metric aperture joints, enlar ged by dissolution, are present in the thinner part of the island. By contr ast, along the wider parts of the island, karstic voids consist in a few la rge caves. We suggest that those observations may be compared to experiment s of acid injection in a limestone slice that result firstly in numerous sh ort length channels, while the final state of the system consists of only o ne long wormhole, developing at the expense of all others. (C) 2001 Academi e des sciences / Editions scientifiques et medicales Elsevier SAS.