| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Petrology Volume 41 Number 7 Pages 1099-1120 2000
© Oxford University Press 2000
Geochemistry of Flood Basalts of the Toranmal Section, Northern Deccan Traps, India: Implications for Regional Deccan Stratigraphy
1SCHOOL OF OCEAN AND EARTH SCIENCE AND TECHNOLOGY, UNIVERSITY OF HAWAII, HONOLULU, HI 96822, USA
2DEPARTMENT OF EARTH SCIENCES, INDIAN INSTITUTE OF TECHNOLOGY, POWAI, BOMBAY 400 076, INDIA
Tholeiitic lavas forming a flood basalt sequence of 870 m thickness at Toranmal in the northern Deccan Traps have a large range in isotopic ratios [
Nd(t) = +2·1 to –15·7, (87Sr/86Sr)t = 0·70467–0·71416, 206Pb/204Pb = 16·699–20·246], similar to that of lavas in the well-studied southwestern part of the province. The basalts with the lowest Nd(t) values display distinctive lows at Nb, Ta, P and Ti, and large positive Pb spikes in their primitive-mantle-normalized element patterns, indicative of significant continental lithospheric influence in their petrogenesis. As in much of the southwestern Deccan, Nd(t) exhibits a rough negative correlation with Mg/Fe and SiO2 and a positive correlation with Fe, consistent with temperature-controlled assimilation. Overall, the Toranmal section appears distinct from sections in the northwestern sector of the province; however, some Toranmal basalts are isotopically and chemically similar to flows in the northeastern Deccan, and a thick pile of lavas resembling the Poladpur Fm of the southwestern Deccan, the closest type-sections of which lie 
380 km to the south, is present. If it indeed represents a northern remnant of this formation, the Poladpur Fm, which also extends far into the central and southeastern parts of the province, is one of the most widespread of Deccan formations, with a possible original extent 
3 x 105 km2. The Ambenali Fm, which forms a thick sequence lying above the Poladpur in the southwestern Deccan, is not present at Toranmal. Several flows have broad geochemical affinities with the southwestern Bushe and Mahabaleshwar formations, which respectively lie below the Poladpur and above the Ambenali; however, these flows are not in the southwestern stratigraphic order and are probably of relatively local origin as dikes compositionally very similar to these flows are present at Toranmal and elsewhere in the vicinity.
KEY WORDS: Deccan Traps; geochemical stratigraphy; flood basalts; large igneous provinces
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. E. JAY and M. WIDDOWSON Stratigraphy, structure and volcanology of the SE Deccan continental flood basalt province: implications for eruptive extent and volumes Journal of the Geological Society, January 1, 2008; 165(1): 177 - 188. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. S. Kumar, R. Menon, and G. K. Reddy Crustal geotherm in southern Deccan basalt province, India: The Moho is as cold as adjoining cratons Geological Society of America Special Papers, January 1, 2007; 430(0): 275 - 284. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.C. Sheth Plume-related regional prevolcanic uplift in the Deccan Traps: Absence of evidence, evidence of absence Geological Society of America Special Papers, January 1, 2007; 430(0): 785 - 813. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. SANO, T. FUJII, S. S. DESHMUKH, T. FUKUOKA, and S. ARAMAKI Differentiation Processes of Deccan Trap Basalts: Contribution from Geochemistry and Experimental Petrology J. Petrology, December 1, 2001; 42(12): 2175 - 2195. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. WIDDOWSON, M. S. PRINGLE, and O. A. FERNANDEZ A Post K-T Boundary (Early Palaeocene) Age for Deccan-type Feeder Dykes, Goa, India J. Petrology, July 1, 2000; 41(7): 1177 - 1194. [Abstract] [Full Text] [PDF]
|
|