Origin of basal dolomitic claystone in the Marsili Basin, Tyrrhenian Sea

摘要: Abstract Red–brown dolomitic claystones overlay the Marsili Basin basaltic basement at ODP Site 650. Sequential leaching experiments reveal that most of elements considered to have a hydrothermal or hydrogenous origin in marine environment, such as Fe, Cu, Zn, Pb, Co, Ni, are present mainly aluminosilicate fraction claystones. Their vertical distribution, content and partitioning chemistry trace elements, REE patterns suggest enhanced terrigenous input during dolomite formation, but no significant influence from underlying basement. Positive correlations C O isotopes dolomites reflect complex conditions dolomitization. The stable can be controlled part by temperature variations Majority samples, however, form trend is steeper than expected for only control on isotopes. latter indicates possible isotopic heterogeneity proto-carbonate related arid climatic formation basal In addition, dolostones characteristics influenced diagenetic release heavier δ18O clay dehydration and/or alteration siliciclastic material. Strontium Pb data non-carbonate fraction, “dye” claystones, Saharan dust (75%–80%) material with similar Aeolian Arc volcanoes (20%–25%). calcareous ooze overlying has Sr composition identical indicating change sources sedimentary basin occurred after dolomitization event. Combination climato-tectonic factors probably resulted suitable nearby Vavilov Basins. claystone sequence was formed initiation opening (∼ 2 Ma), which coincided consecutive glacial stage. glaciation caused climate evaporation possibly contributed isotope proto-carbonate. conductive cooling young lithosphere produced high heat flow region, causing low-temperature passive convection pore waters sediment. We this pumping process major mechanism since it capable driving large volumes seawater (the source Mg2+) through red–brown hue contribution glacially induced eolian influx not hydrothermally derived detailed geochemical investigation tectono-climatic set initial stages glaciation.