In the Eastern Desert we discovered eight tufa deposits from south to north: Wadi Umm Samuki, Wadi Gemal, Wadi Umm Kabo, Wadi Nakkari, Ain Saltout, Wadi Gasus, Wadi Attala, and Wadi Abu Had. We discovered three tufas in southeast Sinai from south to north: Wadi Kid, Wadi Madsus and Wadi Watier (Fig. 1). The geologic and geomorphic settings and the main lithologic characteristics of the tufas are summarized in Table 3. In both areas the tufas rest unconformably on Precambrian basic igneous rocks (e.g. basalt, diabase, or gabbro). Bedrock Refametinib either metavolcanics/metagabbro with a Rb–Sr whole-rock isochron age of 712 ± 24Ma, or Dokhan Volcanics 614–550 Ma old (Stern et al., 1991). Tufas in the south are largely associated with metavolcanics, as at Wadis Kid, Madsus and Umm Kabo, where the bedrock is metabasalt (Fig. 2A), or with metagabbros, as at Umm Samuki and Ain Saltoute (Fig. 2B). Three tufas rest on Dokhan Volcanic rocks, the Abu Had and Gasus tufas on basalts, and the Attala tufa on diabase. The Nakkari tufa is unusual in that it was deposited on Pleistocene alluvium and so is not in direct contact with Precambrian bedrock. The Abu Had and Umm Samuki tufas appear to be of lacustrine origin while the others formed at waterfalls or cascades (Table 3).
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