Bat guano minerals and mineralization processes in Chameau Cave, Eastern Morocco

The decay of bat guano deposits in caves produces mineral accumulations, mainly phosphates and secondary sulfates. Chameau Cave, Eastern Morocco, is located the semi-arid Bni Snassen Mountains. It composed semi-active dry passages, featured by strong condensation-corrosion on walls, presence fluvial sediments, old corroded flowstones. Due to forced convective airflow, cave generally very dry, with some damp sites related condensation. Samples collected surface different passages along two sediment profiles yielded minerals decay. On recent or fresh guano, precursor correspond sulfate (gypsum), phosphate-sulfate (ardealite) phosphate (brushite). Phosphates (hydroxylapatite, fluorapatite) occur at interface host rock carbonate speleothems. At contact phyllosilicates contained allogenic shale partings, pyrite-rich various (Al-rich strengite, Fe-rich variscite, phosphosiderite, leucophosphite, spheniscidite, crandallite, minyulite, strengite), latter being stable end-members. Black seams oxyhydroxides (goethite, hematite, birnessite) line between weathered deposits. After “digestion” acidic leachates, only display most resistant (quartz, muscovite, K-feldspars Na-plagioclases) weathering byproducts (kaolinite). We discuss origin a pure gypsum particle cone, possibly evaporation edge wet cupola subsequent detachment particles. Among environmental conditions, humidity required for In this cave, originates from either permanent seasonal Dust advection seems be essential providing compounds that are not present clay minerals). Bat phosphatization has probably occurred since >100 ka. Cave appears as an outstanding site guano-related (n = 12), including rare (spheniscidite minyulite).