Regionally variable timing and duration of celadonite formation in the Troodos lavas (Cyprus) from Rb-Sr age distributions

Celadonite (K[Mg2+,Fe2+][Fe3+,Al3+](Si4O10)(OH2)) is a common void-filling mineral in ocean floor and ophiolite lavas that forms during low-temperature, off-axis, hydrothermal alteration. Its occurrence provides important information about the sink of K from seawater into upper oceanic crust. New age determinations for celadonitic samples ~20 km section Troodos ophiolite, along with published ages, show most celadonite formed within first Myrs after crust accretion. However, significant regional differences duration formation are observed. In comparison to region flat paleo-seafloor, paleo-seafloor topographic low started forming later continued longer. The associated abundant sediments which interpreted have played key role controlling chemical conditions required precipitation. It hypothesised longer largely because these acted as source labile Fe time than where was mainly leached silicate phases. sediment did not begin accumulating crustal accretion allowing prolonged oxidative alteration This led released by phase breakdown being incorporated stable Fe3+ containing phases, such Fe-oxyhydroxides, rather transported aqueous Fe2+ sites could form. If this model correct, uptake may be highly spatially heterogeneous intimately linked subsurface redox distribution sediments.