Juliette Forneris:
Experimental study of dehydration processes of hydrous
minerals in subducting oceanic crust Deep Earth Processes: current research projects
Juliette Forneris:
Experimental study of dehydration processes of hydrous
minerals in subducting oceanic crust
The focus of my Ph.D. research is the study of dehydration processes that occur in subducting slabs. The transport of H2O from the subducting slab is an essential factor in understanding the deep water cycle of the Earth. This mechanism needs to be understood and quantified to get a better knowledge of recycling of H2O in subduction zones and transport of H2O at deeper levels in the mantle. My research is focused on the dehydration of some of the most important hydrous phases contained in the subducting oceanic crust.
Recent experiments show that the dehydration process involves several hydrous minerals, other than amphibole, as potential water reservoirs in the subducting basaltic crust. It is thus important to determine the different phase stability at the P-T conditions of interest (in the region where a subducting slab intersects the solidus curve). These studies also seem to agree on the fact that the dehydration of the slab occurs by both continuous and discontinuous reactions as opposed to the "single dehydration front" model of Tatsumi (1986).
Some of the previous studies of dehydration reactions of minerals typical of the crustal component (amphibole, chlorite, epidote, chloritoid, lawsonite) have led to conflicting conclusions. Results obtained by Liu et al. (1996) on basaltic compositions under H2O saturated conditions differ considerably from those of Pawley and Holloway (1993), and Schmidt and Poli (1998). In their experiments, important phases like epidote and phengite are not observed. As opposed to the other sets of experiments, Liu et al. (1996) found that chloritoid was not a stable intermediate phase between the amphibole and the lawsonite stability fields. Chloritoid, if it is present, in the subducting oceanic crust would play a important role in the dehydration process by carrying water from the amphibole to the lawsonite stability field. Thus, the discrepancy in the experimental results motivates a new series of experiments using piston-cylinders to further investigate the stability of chloritoid and its relationship with other hydrous phases present in the crustal section of the slab.
If you want to learn more about my research or who I am,, check out my personal web page.
Darren Locke:
Trace element partitioning between silicate melts and nominally anhydrous
minerals
This material is based upon work supported by the National Science Foundation under Grant No. 9973066.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
Page last updated April 19, 2002. Comments and Suggestions to Darren Locke