We report the occurrence of primary apatite crystals in association with graphite within alkaline pegmatite dykes in the Kerala Khondalite Belt (KKB). Petrologic and X-ray diffraction studies identify the mineral to be fluorapatite. Fluid inclusion studies show that the fluorapatites contain abundant CO2-rich inclusions with densities in the range of 0.85-0.72 gcm-3. A subsequent generation of trail-bound CO2-H2O inclusions with low salinity were entrapped along hydraulic cracks. The abundance of CO2-rich inclusions, and the intimate association of fluorapatite with fluid-precipitated graphite suggest that the pegmatite dykes hosting fluorapatite were rich in CO2-dominated fluids. We identify that among the magmatic conduits proposed for the transfer of CO2-rich fluids in granulite processes in the KKB, the fluorapatite and graphite bearing pegmatites reported in this study form important examples.
|Number of pages||10|
|Journal||Journal of the Geological Society of India|
|Publication status||Published - Dec 1996|
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences (miscellaneous)
- Earth and Planetary Sciences(all)
- Environmental Science(all)