|Blueschist evolution in Southeast Sulawesi, Indonesia|
Helmers, H.; Sopaheluwakan, J.; Surya Nila, E.; Tjokrosapoetro, S. (1989). Blueschist evolution in Southeast Sulawesi, Indonesia. Neth. J. Sea Res. 24(2-3): 373-381
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
|Authors|| || Top |
- Helmers, H.
- Sopaheluwakan, J.
- Surya Nila, E.
- Tjokrosapoetro, S.
The blueschists of Southeast Sulawesi comprise graphite-mica schists and blastophitic metabasites of MORB-affinity, the latter increasing in number southward. They are part of the north-south belt of blueschists with a length of 600 km. Based on structural data, micro-structural analysis, mineral compositions, distribution of elements over mineral pairs in equilibrium and fluid inclusion study, the metamorphic history has been reconstructed. After fast burial during subduction the rocks recrystallized at high pressure (10.5 kbar) at low temperature (slightly over 400°C). Exhumation started immediately, and before substantial increase in temperature the rocks moved to a position of 400°C at 2 to 3 kbar on a normal geothermal gradient in a few million years only. It is suggested that strong erosion due to buoyancy in respect to the heavy overburden, in combination with crustal thinning by extensional tectonics are responsible for the fast uplift. At present lack of radiometric age determinations prevents detailed geotectonic modelling.