#Cascadea subduction series#
Previous studies have been performed by petrologic observations, analogue experiments and numerical simulations for exhumation processes and mechanisms of deeply subducted crustal rocks, and a series of important results have been achieved. However, exhumation mechanism of the deeply subducted crustal rocks has been a hot topic in geodynamic community and remains controversial. The discovery of ultrahigh-pressure (UHP) index minerals such as coesite and micro-diamond in supracrustal rocks indicate that a large amount of crustal rocks were subducted to mantle depths and subsequently returned to the Earth’s surface. Temperature (100-150☌) meteoric component is also predicted by the models. AOC-derived fluids are not the unique source of fluids since a low That New Caledonia serpentines were mainly formed in equilibrium with fluids releasedīy the dehydration of altered oceanic crust (AOC) during subduction between 250☌Īnd 350☌. Values (88‰ to 106‰) of all serpentine species through Monte-Carlo simulations show The modeling of δ18O values (1.9‰ to 13.9‰) and δD Then, the development of lizardite 2 yields an enrichment in fluid-mobileĮlements such as Cs, Rb, Ba, U and light rare-earth elements and an apparent The transition from primary/magmatic minerals to lizardite 1 is almost The relative chronologyĪppears as follows: lizardite 1 → lizardite 2 → antigorite → chrysotile → polygonal Veins of other serpentine species in the serpentinite sole. More than 80% of the entire serpentine content of the ophiolite. Using mineralogical and geochemical approaches and modeling.Lizardite represents Result of several superimposed serpentinisation events. Serpentinite sole of the Peridotite Nappe of New Caledonia (Southwest Pacific) is the
Therefore, the characterization of serpentine minerals,Īnd the possible occurrence of multiple serpentine generations in mantle rocks provideĮssential constraints on the conditions of fluid-rock interactions in the mantle. Serpentine minerals form according to temperature and pressure conditions, and Subduction and obduction, where mantle rocks interact with water. Serpentinization processes occur at geological settings notably during oceanic
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