Alkali-feldspar and Fe-Ti oxide exsolution textures as indicators of the distribution and subsolidus effects of magmatic ‘water’ in the Klokken layered syenite intrusion, South Greenland

摘要: The layered syenites in the Klokken intrusion consist of horizons fine-grained, granular-textured ferroaugite syenite showing inverted cryptic layering, interleaved with coarser, laminated, more fractionated hedenbergite syenite. Distribution hydrous mafic phases indicates build-up water parallel magmatic evolution, and druses pegmatitic segregations laminated are evidence for late development a gas phase. Feldspar bulk compositions close to minimum on Ab-Or binary, An decreasing from An7 An1 fractionation, normal zoning cryptoperthite crystals. Feldspars granular transparent coherent cryptoperthites or braid microperthites; An-content is probably main control fine-perthite coarseness. Laminated feldspars turbid, coarse patch microperthites rare relics textures. This non-coherent coarsening was caused by interactions between entrapped at temperatures which retained within original lithologies low subsolidus temperatures. Fe-Ti oxides reflect this distribution, regular trellis ilmenite-titanomagnetite intergrowths less rocks ragged granule exsolution advanced syenites. sharp change textures granular-laminated boundaries implies steep water-gradients these rock types. Water unable penetrate layers did not circulate freely cooling intrusion.