Detailed Petrological And Petrochemical Studies Of Ultramafic Rocks In And Around Mallanayakkanpalaiyam Area, Mettupalaiyam Ultramafic Complex (Muc), Tamil Nadu With Special Significance To Pge Mineralization

• Main Author: Dr. A. Balukkarasu
• Format: Text
• Language: unknown
• Published: Zenodo 2018
• Subjects: Ultramafic Complex, Cauvery Suture Zone, Pegmatites & Pegmatoidal; Greenland; Vidal
• Online Access: https://dx.doi.org/10.5281/zenodo.1194909; https://zenodo.org/record/1194909

The area has been named with reference to the nearest village Mallanayakkanpalaiyam. Also this area is called as "M" area for report writing and convenience to presentation. The general trend of the block is N 70 ° E – S 70 ° W with 70 ° – 80 ° dipping towards south. In this block chromiferous meta-pyroxenite band has been traced for about 400m strike length with width 10-15m. Chromite is found as cryptic layering within meta-pyroxenite. Garnetiferous-gabbro and about one meter width of hornblende-ferrous amphibolite are inter-banded with ultramafic rocks in the northern side of Mallanayakkanpalaiyam block. A total number of 13 chip samples have been collected along 4 lkm traverse. In Mallanayakkanpalaiyam bands of ultramafic rocks have been traced 1) ultramafic band is southern side and co-banded with gabbro showing cumulus nature, hard and compact; 2) another in northern ultramafic band having 10-15m width with presence of actinolite-tremolite. The general trend is ENE 80°-85°WSW with 75°-85° dip towards northern direction. Hornblende biotite gneiss and banded magnetite quartzite have also been observed and sampled in these areas. Gabbroic rocks can be graded into anorthosites and pyroxenites with increasing amount of plagioclase and pyroxene respectively. Such gradations have been observed to take place respectively through leucogabbros and melanogabbros in field of Ayyampalaiyanm area, where mineral cumulation plays an important role to interpret the genesis. Garnet grains have been observed occurring as concentrated in the margins of gabbro / gabbroic bodies. Collected chip/groove samples for further studies. Metagabbros are medium to coarse grained and mesocratic, massive, hard and compact in hand specimen. The major rocks types exposed in this area are pyroxenite, amphibolites, meta- gabbro, and gabbroic anorthosite. The ultramafic rocks are inter-banded with meta-gabbro. The general trend of the rock is ENE –WSW with steep (75°-85°) dip towards south. The Meta pyroxenite bands are occurring as detached and discontinuous nature. : {"references": ["1.\tHaskin,L.A., Haskin,M.A., Frey, F.A. and Wildeman, T.R., 1968, Relative and absolute terrestial aboundances of the REE. In: L.H. Ahrens (Editor), Origins and Distribution of Elements, Pergamon, New York, N.Y.,pp.889-912. 2.\tJanardhan.A.S and Peucat.J.J, 1996, Geochronological frame work of southern India. The Archaean and Proterozoic terrain of southern India within east gondwana. Gondwana research group memoir no.3, pp.53-76. 3.\tMahabaleswar,B, 1986, Mineral chemistry of the silicate mineral phases of banded iron \u2013 formation of high-grade region, Karnataka, Jour. Geol. Soc. India, v.28,pp.165-178. 4.\tShanmugam, P and Srinivasan, B.V. 1989, Concept oriented second generation mapping in parts of Namakkal and Tiruchengodu Taluks, Salem District, Tamil Nadu, Geol. Surv. India. Prog. Rept. F.S.1987-88. 5.\tShrivastave, S.K. and Kanishkan,B., 1979, Geology of parts of Bhavani Taluk, Periyar District and Mettur Taluk, Salem District, G,S.I. Unpublished progress report. F.S. 1978-79. 6.\tPeucat,J.J, Vidal,P., Bernard-Griffiths,J. and , Condie,K.C, 1989, Sr, Nd and Pb isotope systematics in the Archaean low to high-grade transition zone of Southern India: syn-accretion vs post \u2013 accretion granulites, Jour. Geol., v.97,pp.537 \u2013 550. 7.\tSinha, A.L., and Krishna Rao, A.V., 1979, Geological of parts of Manaparai Taluk, Tiruchinopoly district and Dindigal taluk, Madurai District, Tamil Nadu, Geol. Surv. India. Prog. Rept. F.S. 1977-78. 8.\tSrikantappa, C. and Hensen, B.J., 1992, Metamorphic conditions and characterization of fluids in the MM hill granulites, Karnataka, India, N.Jb. Mineral, Mh, H, v.11,pp.498-506. 9.\tWELLS, P.R.A., (1979). Chemical and thermal evolution of archaean sialic crust. Southern West Greenland Jour. Petrol., Vol. 20, pp. 187-226. 10.\tZIRKEL, F., (1973). Die mikroskopische beschaffenheit der Mineralien und Gesteine. Wilhelm Engelmann, Leipzig, 502."]}