Holzheid, Astrid (2012) Gain and loss of volatile and fluid-mobile elements in subduction zones: a combined fieldbased and experimental approach. [Talk] In: The Lübeck Retreat, Collaborative Research SFB 574 Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters. , 23.-25.05.2012, Lübeck . The Lübeck Retreat: final colloquium of SFB 574; May 23-25, 2012: program & abstracts. ; p. 12 .

Abstract

Understanding the exchange of volatiles between mantle, crust and atmosphere represents a central
issue of terrestrial geodynamics. Studies of uplifted tracts of subduction related metamorphic rocks
can provide detailed information regarding the extent of loss of volatile and fluid-mobile elements
during prograde metamorphism. Studies within SFB 574 have shown that in many cases fluid flow is
channelized rather than penetrative. The study of vein systems and metasomatic reaction zones is
therefore the key to understand fluid-related processes and mass transfer in subduction zones, as
they track pathways of migrating fluids and record fluid compositions. These processes were studied
in distinct parts of the subduction zones, representing (i) an accretionary wedge (e.g., Coastal
Cordillera Accretionary Complex, Chile), (ii) the subduction mélange (e.g., Cyclades, Greece;
Tianshan, China) and (iii) the subducted oceanic slab with serpentinized lithospheric mantle, highpressure
metamorphic oceanic crust and sediments (e.g., Raspas Complex, Ecuador; Bantimala
Complex, Sulawesi; Zambesi Belt, Zambia). Case studies of all three mentioned parts of subduction
zones will be presented.
Furthermore, the role and evolution of fluids released during subduction were experimentally studied.
Instead of conducting single point analysis at a given P/T or single crystal analyses, to derive
partitioning data, we tracked a more dynamic approach and investigated the evolution, and thus the
change in the composition of basalts, gabbros and their respective fluids, when moving down along
the subducting slab.

Actions (login required)

View Item