Most of the basement of Yemen consists of early Precambrian continental high-grade terranes and Neoproterozoic low-grade island arcs that were accreted together to form an arc-continent collage during the Pan-African orogeny (Windley et al., 1996; Whitehouse et al., 1998; Whitehouse et al., in press). The suture zones between the arc and gneiss terranes are major crustal- scale tectonic boundaries. The terranes are situated east of the Nabitah suture and of the collage of low-grade, mainly island arc terranes of the Arabian Shield, but they have been reworked by a Neoproterozoic event associated with island arc accretion. Further east in Yemen are mostly unconformable, very weakly deformed and very low-grade or unmetamorphosed sediments. Thus Yemen provides key information on the broad zone of Neoproterozoic reworking associated with the collisional boundary between western and eastern Gondwana.