Chert-hosted manganese deposits in the Wahrah Formation: a depositional model

Abstract

The non-metamorphic, stratiform manganese deposits in the Wahrah Formation (Al Hammah Range, 125 km south of Muscat) are of upper Berriasian to Hauterivian age. Sedimentological and geochemical features prove that the host rock of the manganese deposits exclusively consisting of red cherts are of biogenic, non-hydrothermal origin, deposited in a distal part of the Hawasina Basin. A depositional (geochemical) environment comparable to that of a siliceous ooze facies is highly likely. Geochemical differences and similarities of nodular and layered ore types are attributed to later minor element redistributions. -from Authors