Summary
Extensive alluvial fans bounding the western edge of the Sharqiya (or Wahiba) Sands are characterized by complex palaeochannel systems now forming a series of superimposed gravel ridges. The oldest, most extensive fan system is crossed by numerous sinuous, superimposed palaeochannel courses comprising highly weathered, chert-rich gravels cemented by clear crystalline calcite. Many of these old fan sediments have been chemically altered to depths of over 200 m to form a pink dolomitic clayey deposit here termed barzamanite. The formation of this calcrete-like deposit was probably associated with rising water tables during long-term fan growth. The younger, more limited fan deposit, by contrast, comprises thin, coarse-grained, broad spreads and terrace veneers of weakly cemented ophiolitic gravels. The fans have been subject to entrenchment and deflation, resulting in extensive land-surface lowering and the exhumation of buried palaeochannels. Although no dates are yet available, the older channel systems are likely to date from more humid phases during the Pliocene-Early Pleistocene, whereas the younger, terraced deposits, and the period of subsequent channel exhumation, may date from semi-arid periods of lower sea level during the Pleistocene.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.