Stable isotope compositions (δ13C, δ 18O) of calcite within the veins hosted by the Sanbagawa metamorphic rocks in the Nagatoro area, Kanto mountains, Japan gave clues on movement of fluids during exhumation. The host rock calcite shows the nearly uniform δ18O values ranging from +14.5 to +16.5‰ (V-SMOW), and wide δ13C variation from -12.1 to +1.3‰ (V-PDB). The δ13C values of calcite within the exhumation--related veins also have wide variation, and the Δhost-vein (= δ 13Chost rock-δ 13Cvein) value vary depending on vein thickness and textures. Thin stretched crystal veins contain calcite with δ13C value close to that of the host rock calcite (Δhost-vein < ±2‰). In contrast, calcite grains within the thick blocky veins have homogenous δ 13C values with large variations with host rock (Δhost-vein = +3.5 - -3.0‰). The latter types of sealed cracks may have played as dominant pathways of regional fluid flow.
|Number of pages||4|
|Journal||Journal of Mineralogical and Petrological Sciences|
|Publication status||Published - 2008|
- Calcite veins
- Carbon and oxygen stable isotopes
- Sanbagawa metamorphic belt
ASJC Scopus subject areas