Evidence of rodingitization process within Ophiolite Units (Liguride Units, Southern Apennines - Italy)

New petrological data of the ophiolitic sequences from the Liguride Units (Southern Apennine Chain) are herepresented in order to investigate some rodingite dykes preserved within un-sheared low strain domains. Liguride Unitsshows indeed pervasive shear deformations, developed during subduction process reaching HP/LT conditions typical ofblueschist facies (Cirrincione & Monaco, 1996). Nevertheless, local low strain domains are preserved and within these,rodingite dikes occur. The rodingite dikes is composed of garnet, prehnite, chlorite, pumpellyite, and quartz.Hydrogrossularite, prehnite, epidote, calcite, and titanite replace plagioclase and produce Ca-rich basic rocks duringhydrothermal alteration of sub-greenshist to greenschist facies metabasalts (Sansone et al., 2011).The process usually is initialized during the early stage of ocean crust evolution and can continue at later stages ofthe oceanic crust history (Charlou et al., 1998). It is catalyzed by metasomatism, triggered by injection of Ca2+ ionsfrom high alkaline content fluids, probably released during the ocean-floor metamorphism.In order to extrapolate new quantitative petrological data from this process, after propaedeutic optical and electronmicroprobeanalytical sessions, a multivariate statistical data handling of X-ray maps, representative for some garnetreplacingplagioclase microdomains have been carried out by means of X-Ray Micro Analyzer software (Ortolano etal., in press). Obtained results were then used for the computation of useful phase diagrams, able to reconstruct thesequence of the metamorphic reactions evolved during the rodingitization process as a tracer of the original ocean floormetamorphic conditions of the Liguride ocean, today merged into the southern sector of the Apennine chain, evaluatingat the same time the potential metamorphic effects operating during the following tectonic staking activity of the FridoUnit (Sansone et al., 2011).