Palma: A Nonmetamorphic Stratabound Massive Zn-Ba Occurrence in the Eastern Casma Group of Central Peru

Massive Zn-Ba deposits are found in the Mesozoic coastal belt of central Peru (Steinmüller 1987; Steinmüller and Wauschkuhn 1987; Vidal 1987). The deposits are hosted by the volcano-sedimentary Casma Group, which was deposited during the mid-Cretaceous in an aborted ensialic marginal basin (Atherton et al. 1983). The deposits occur to the west as well as to the east of the coastal batholith. This chapter deals with Palma, one of the eastern stratabound massive Zn-Ba occurrences, located 55 km SE of Lima in the Río Lurin valley (Fig. 1). Here are mainly described the geological, mineralogical and geochemical features of the deposit. A detailed genetic discussion is presented in Steinmüller (1987).