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Gajapathi Rao, R.
- Geochemistry of Shales from the Proterozoic Intracratonic Kaladgi- Badami Basin, Karnataka, Southern India as an Indicator of Palaeoweathering and Evolution of the Dharwar Craton
Abstract Views :203 |
PDF Views:4
Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Begumpet, Hyderabad - 500 016, IN
2 Atomic Minerals Directorate for Exploration and Research, Madhavadhara, Visakhapatnam - 530 018, IN
3 Atomic Minerals Directorate for Exploration and Research, Department of Geological Sciences, Jadavpur University, Kolkata - 700 032, IN
1 Atomic Minerals Directorate for Exploration and Research, Begumpet, Hyderabad - 500 016, IN
2 Atomic Minerals Directorate for Exploration and Research, Madhavadhara, Visakhapatnam - 530 018, IN
3 Atomic Minerals Directorate for Exploration and Research, Department of Geological Sciences, Jadavpur University, Kolkata - 700 032, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 71, No 4 (2008), Pagination: 483-501Abstract
Shales of the Proterozoic Kaladgi Supergroup, occupying the intracratonic Kaladgi-Badami Basin in the Dharwar craton, are analyzed for mineralogical as well as major and trace element compositions. Field setting and elemental ratios, critical to provenance, indicate (1) major contribution from highly weathered Archaean silicic source rocks like Peninsular Gneiss and Closepet Granite, (2) the shales lack any systematic time-dependent variation of composition and (3) they record normal weathering history. Compared to the middle Archaean cratonic shales of the Dharwar craton, the Kaladgi shales are enriched in K2O, Th, La, Ce and Yb and depleted in MgO, Cr and Ni suggesting secular change in the Cpper crustal composition towards more felsic nature. The middle Archaean shales document acid leaching as an important weathering process, whereas the Kaladgi shales reflect intense weathering of the source similar to that of present day warm humid climate. In contrast to the extreme variability of the middle Archaean shales, the Kaladgi shales show smaller compositional variation suggesting development of Iarger platformal environment suitable for repeated recycling and efficient mixing. During late Archaean crustal growth, emplacement of juvenile granites into the crust and subsequent intracrustal melting has transferred huge amount of incompatible elements into the upper continental crust. The effect of ths change is clearly imprinted in the evolved composition of the Kaladgi shales.Keywords
Shale, Geochemistry, Proterozoic, Kaladgi Supergroup, Palaeoweathering, Upper Crustal Composition.- Geochemistry and Origin of Northern Closepet Granite from Gudur-Guledagudda Area, Bagalkot District, Karnataka
Abstract Views :187 |
PDF Views:2
Authors
Sukantadey
1,
R. Gajapathi Rao
1,
R. A. Gorikhan
1,
D. Veerabhaskar
1,
Sunil Kumar
1,
Mary K. Kumar
1
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Bangalore - 560 072, IN
1 Atomic Minerals Directorate for Exploration and Research, Bangalore - 560 072, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 62, No 2 (2003), Pagination: 152-168Abstract
The late Archaean Closepet Granite of the Gudur-Guledagudda area consists of equigranular pink and grey biotite granites, and porphyntic pink biotite granodionte to quartz-monzodionte. The granitoids exhibit intrusive relation with the Hungund-Kushtagi schist belt at places. The equigranular granites show limited range of major oxide compositions and compared to the porphyntic granodionte and quartz-monzodionte, are enriched in Si02, K20 and Rb but depleted in Al203, FeO, Fe203, CaO, MgO, P205, Sr, Ba, Y, Nb and REE. The granitoids fall near the boundary between peraluminous and metaluminous granitoids with the A/CNK ratios around one Fractionated LREE and flat HREE patterns and a negative Eu anomaly characterize all the samples Field evidences indicate mainly post-kinematic nature of the granitoids. The equigranular granites appear to be minimum melt derived from anatexis of Peninsular Gneiss without fractional crystallization. The porphyntic granodionte and quartz-monzodionte represent non-minimum melt derived from a different source enriched in REE Geochemical signatures indicate that the Closepet Granite of Gudur-Guledagudda area is the product of melting at shallower level compared to the southern Closepet Granite.Keywords
Petrography, Geochemistry, Northern Closepet Granite, Gudur-Guledagudda Area, Karnataka.- Controls on Formation of Beach Sand Deposits along Andhra Pradesh Coast: a Study on Heavy Mineral Distribution Pattern, Size Characteristics, some Beneficiation Problems and Coastal Zone Management Plan
Abstract Views :175 |
PDF Views:163
Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Bangalore - 560 072, IN
1 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Bangalore - 560 072, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 60, No 4 (2002), Pagination: 472-473Abstract
No Abstract.- Palaeo-Coastal Morphology of the Neoproterozoic Badami Basin - some Field Evidences from Khanapur, Bagalkot District, Karnataka
Abstract Views :194 |
PDF Views:164
Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Bangalore - 560 072, IN
1 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Bangalore - 560 072, IN