title: Comment on "A vestige of Earth's oldest ophiolite".
abstract: Furnes et al. (Reports, 23 March 2007, p. 1704) reported the identification of an ophiolite sequence within the approximately 3.8-billion-year-old Isua supracrustal belt. However, they did not acknowledge that the belt contains supracrustal rocks and mafic dikes of different ages, nor did they demonstrate that the proposed components of the ophiolite are coeval.
authors.affiliation: Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing 100037, China. nutman@bjshrimp.cn
authors.forename: Allen P
authors.initials: AP
authors.lastname: Nutman
authors.forename: Clark R L
authors.initials: CR
authors.lastname: Friend