Spatial and temporal variability in crystallization of celadonites within the Troodos Ophiolite, Cyprus: implications for low- temperature alteration of the oceanic crust

Abstract

Celadonite, a low-temperature (<30°C) hydrothermal alteration mineral, is a predominant fracture and void-filling phase within the volcanic rocks of the Troodos ophiolite. The combined chemical and structural properties of celadonite, along with its common occurrence, provide a valuable tracer for studying the temporal and spatial variability of low-temperature hydrothermal fluid circulation and alteration within this ancient oceanic crust. Some 54 new K/Ar age determinations of celadonites from the extrusive rocks of Troodos yield crystallization ages ranging from 90.9 ± 1.0 to 49.8 ± 0.5 Ma. Correlations between celadonite ages and field relationships suggest that low-temperature hydrothermal fluid circulation and secondary mineral precipitation are controlled by the local alteration conditions, such as intrinsic permeability, degree of fracturing, and water/rock ratios, and are independent of time and space. -from Authors