Field Studies in the Sakoli and Sausar Belts of the Central Indian Tectonic Zone, 1999-2000
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Journal or Geosciences, Osaka City University Vol. 44, Art. 2, p. 17-39, March, 2001 Field Studies in the Sakoli and Sausar Belts of the Central Indian Tectonic Zone, 1999-2000 1 2 3 KANO Takashi , YOSHIDA Masaru , WADA Hideki , SATISH-KUMAR M.3, Roy Abhinaba4, BANDHOPADYAY B.K.4, KHAN A.S4., PAL T.4, HUIN A.K.4, BHOWMIK S.K.4 and CHATTOPADHYAY A4. I Department of Earth Sciences, Yamaguchi U ni versity, Yamaguchi 753-85 I2, Japan 2Department of Geosciences, Faculty of Science, Osaka City University, Osaka 558-8585, Japan (Present address: Gondwana Institute for Geology and Environment, Hashimoto 648-0091, Japan, E-mail: [email protected]) 3Department of Biology and Geology, Faculty of Science, Shizuoka University, Shizuoka 422-8529 4Geological Survey of India, Central Region, Nagpur, India Abstract Field observations in the Sakoli and Sausar belts around Nagpur, central India were conducted from December 28th 1999 to January 8th 2000, by a Japanese and Indian joint project team. Both the belts are Proterozoic mobile belts consisting of supracrustal sequences and reworked basement gneissic complex, and form an integral part of the central portion of the Central Indian Tectonic Zone (CITZ). Field work covered the typical occurrences of metarhyolite, metabasalt and metasediments of the Sakoli Belt, and metasediments, syngenetic manganese deposits, granulite facies rocks and reworked basement gneisses in the Sausar Belt, in order to obtain the general view of the tectonic history of the CITZ. Observations were focused also in the tectonic boundaries between both belts and their basements. Deformations consisting of D I, D2 and D3 folds affect the Sakoli supracrustals and basements, forming the eastern and western marginal shear zones. The Sausar supracrustals are also deformed, and their basement Tirodi Gneiss is re-folded and found as several tectonized intercalations within the Sausar Belt. This paper reports the outline of geology and lithological and structural features of observed outcrops in two belts, with comments for several potential problems that were identified during the field works. Key-words: Central Indian Tectonic Zone, Proterozoic, Nagpur, Sakoli Belt, Sausar Belt interpreted by Radhakrishna and Naqvi (1986) as the Introduction northwestern and southeastern extension of the CITZ respectively (Fig. I). The Sakoli and Sausar belts form the central part The major part of the ClTZ has a width of about of the Central Indian Tectonic Zone (CITZ) which is 200- to 250-km and a length of more than 1000-km, a Proterozoic mobile belt running between the North running E-W at the neck of Peninsular India. The Indian cratonic block (the Bundelkand craton) and the Narmada-Son Lineament bounds the northern margin, South Indian cratonic blocks (the Singhbhum, Baster and the Central Indian Shear Zone (CISZ) - Singhb and Dharwar cratons). The Aravalli-Delhi mobile hum Shear Zone forms the southern margin of this belt fringing the western margin of the Bundelkand extensive tectonic zone. The Phanerozoic. Deccan Craton, and the Eastern Ghats Granulite Belt running Trap covers a considerable part of the eastern part of along the SE coast of the Peninsular India, have been the zone, and the Gondwana sediments and Quater- 18 Field Studies in the Sakoli and SousaI' Belts of Central India, 1999-2000 / I I \ \ \ ~I \ EL:±J 2 o:TI 3 CLIJ 4 UllJ 5 LtLQ) 6 ~7 CIJ 8 ~9 c=J 10 200km ! I Fig. I The Central Indian Tectonic Zone (CITZ), and location of the survey area (modified after Radhakrishna and Naqvi; 1986). KN: Karnataka nucleus, SN: Singhbhum nucleus, BN: Bastar nucleus, EPMB: Early Proterozoic Mobile Belt, MPMB: Middle Proterozoic Mobile Belt, ADMB: Aravalli-Delhi Mobile Belt, CGC: Chotonagupur Gneiss Complex, EGMB: Eastern Ghats Granulite Belt, (I): Narmada-Son Lineament, (2): Central Jndian Shear Zone Singhbhum Shear Zone. Legend; I: Schist belt in nucleii, 2: Tonalitic gneisses, 3: Granodior ites- granulites of EPMB, 4: K- granites of EPMB, 5: Granulites and gneisses of MPMB, 6: Middle Proterozoic sedimentary basin, 7: Gondwana sediments, 8: Anorthosites, 9: Eastern Ghats-Sukinda Singhbhum thrust, 10: Deccan Trap. The arrow indicates the obser ved area (see Fig. 2). nary sequence overlie in the central and eastern parts of The Precambrian units comprising the central region the zone. In the remaining areas, there occur base of the CITZ are, from west to east, the Sausar and ment Precambrian rocks characteristic of the CITZ. Sakoli belts along the CISZ, the Mahakoshal Belt KANa Takashi and others 19 Table 1 List of observed outcrops in the Sakoli and Sausar belts, during the 1999-2000 field survey. (1228-1 to 108-3 No. of localities in Fig. 2) December 26 [Arrive in Nagpur] December 27 [Introductory talks and lectures for the CITZ, Sakoli and Sausar belts at GSI in Nagpur] December 28 [Nagpur <=t Bhiwapur <= Pawni <=t Nagpur] 1228-1 Metarhyolite of the Bhiwapur Formation 1228-2 Metarhyolite at Gothangaon 1228-3 Metarhyolite 1228-4 Abandoned Au-eu mine in the upper margin of the metarhyolite December 29 [Nagpur -> Bhiwapur -> Gondia] 1229-1 Abandoned chromite mine in ultramafic rocks in the basement 1229-2 Basement biotite gneiss 1229-3 Muscovite schist with andalusite porphyroblast in the Pawni Group 1229-4 Two mica pink granite and gabbro December 30 [Gondia <= Eastern Sakoli Shear Zone] 1230-1 Amgaon gneiss (augen gneiss, schistose granite) 1230-2 Schistose granite, cord ierite gneiss 1230-3 Amphibolite and pyroxenite in sheared granite (augen gneiss with strong lineation) 1230-4 Garnet amphibolite (ultramafic rock) in Borunda village 1230-5 Banded and fine-grained granite mylonite December 31 [Gondia -> Bhandra -> Nagpur] 1231-1 Sillimanite quartzite (I km north of Gangajhari) 1231-2 Staurolite-kyanite schsit in pre-Sakoli basement 1231-3 BIF (garnet-grunerite) in Sakoli Group 1231-4 Carbonaceous phylite 1231-5 Metabasalt 1231-6 Coarse-grained quartzite, peblly quartzite 1231-7 Granite mylonite January I [Lecture and discussion at GSI in Nagpur] January 2 [Nagpur <= Ramtek <=(Seoni Road)<= Deolapar] [The southern part of the cross section of the SausaI' Belt including reworked basement of the Tirodi gneiss] 102-1 Satak mine (stratiform manganese ore and gondite) 102-2 Ramtek fold in quartzite at Ramtek dam 102-3 Foliated fine-grained granite (Ramatek granite) 102-4 Phyllite and lenz or boudin of schistose at NH-7 Road 102-5 Coarse-grained biotite gneiss (Tirodi gneiss;reworked basement) 102-6 Calc-silicate rock in the Tirodi gneiss January 3 [Nagpur <= Deolapar <=(Seoni Road)<= Pindkapar] [The northern half of the cross section of the Sausar Belt, and the Tirodi gneiss] 103-1 Pauni granite (Iate- or post-kinematic granite in the Sausar Belt) 103-2 Thin band of reworked gneiss layer and calc-silicate gneiss 103-3 Highly deformed biotite gneiss 103-4 Pelitic to psammitic gneiss or tonalitic gneiss 103-5 Pel itic to psammitic gneiss incl ud ing garnet-beari ng mafic band 103-6 L-tectonite (sillimanite rods) in pelitic gneiss 103-7 Dolomitic marble contuied 20 Field Studies in the Sako/i and Sausar Belts of Central India, 1999-2000 Table 1 List of observed outcrops in the Sakoli and Sausar belts, during the 1999-2000 field survey. (1228-1 to 108-3: No. of localities in Fig. 2) January 4 [Nagpur <=t Sausar <=t(Chhindwara Road)] [The northern granulite belt of the Sausar belt] 104-1 Ramakona granulite (dolomitic marble) 104-2 Garnet granulite, charnockite 104-3 Dolomitic marble January 5 [Nagpur -> Ramtek -> Tumsar Katangi -> Tumsar -> Bhandara] [The northeastern margin of the northern granulite belt] 105-1 Calc-silicate gnei s (Lohangi F. on the hill top) 105-2 Garnet amphibolite in biotite gneiss and augen gneiss 105-3 Metamorphosed dolerite January 6 [Bhandara <=t Tumsar <=t Katangi <=t Waraseoni] [The northeastern end of the southern granulite belt] 106-J Tectonized biotite gneiss at Lingmala village (augen gneiss including amphibolite) 106-2 Metamorphosed mafic-ultramafic rock (metagabbro ?) 106-3 Garnet cordierite rock (granulite of pelitic origin) 106-4 Metadiorite (or .dolerite to microgabbro) 106-5 Meta-quartzite or BIF in granulite facies January 7 [Bhandara <=t Tumsar <=t(Katangi)] [Tirodi gneiss, and the contact between Sausar supracrustals and the basemen Tirodi gneiss] 107-1 Banded gneiss (basement Tirodi gneiss) 107-2 Tirodi mine (contact of Sausar supracrustals-basemen gneiss), manganese ore and cherty rock, quartzite, micaceous schist, cataclastic gneiss, migmatitic gneiss, injection gneiss by pink granite, banded gneiss. January 8 [Bhandara -> Sakoli -> Bhandara -> Nagpur] [A marginal zone of the Sakoli belt and the southern granulite belt] 108-1 Quarzite mylonite at the eastern marginal shear zone of the Sakoli Belt including tourmalinite, BIF 108-2 Metabasalt of the Dhabetekri F. 108-3 Garnet two-pyroxene granulite (metagabbro ?) January 9 [Nagpur] Discussion at GSI in Nagpur January 10 [ agpur -> Mumbai -> Osaka] along the armada-Son Lineament, the Singhbhum The members of the IGCP-368 (Study of the Fold Belt along the CISZ, and the Chotanagpur Proterozoic Events in East Gondwana) have been Gneiss Complex in the northeastern part. conducting systematic field surveys in the CITZ, which More than 10 years of studies by a group of have been financially supported by the Grant-in-Aid geologists from the Central Region of the Geological for International Scientific Research Program of the Survey of India (GSI) located in Nagpur have been MONBUSHO (Ministry of Education, Science, Sports conducted. They recently summarized the geology, and Culture of Japan), such as in the Eastern Ghats structure, metamorph ism and mineral izatio n of the Belt and in the Aravalli-Delhi Belt in January 1999 Sakoli Belt. Some of these results have already been (Kano et aI., 2000). Subsequently, we focussed the published (e.g., Roy Abhinaba et aI., 1992; Band central domain of the CITZ consisting of the Sakoli hopadyay et aI., 1995; Acharyya and Roy Abhinaba, in and Sausar belts around Nagpur, and carried out about press) and some are in progress.