Bulletin of Volcanology

, Volume 74, Issue 1, pp 47–66 | Cite as

Remobilization of granitoid rocks through mafic recharge: evidence from basalt-trachyte mingling and hybridization in the Manori–Gorai area, Mumbai, Deccan Traps

  • Georg F. ZellmerEmail author
  • Hetu C. Sheth
  • Yoshiyuki Iizuka
  • Yi-Jen Lai
Research Article


Products of contrasting mingled magmas are widespread in volcanoes and intrusions. Subvolcanic trachyte intrusions hosting mafic enclaves crop out in the Manori–Gorai area of Mumbai in the Deccan Traps. The petrogenetic processes that produced these rocks are investigated here with field data, petrography, mineral chemistry, and whole rock major, trace, and Pb isotope chemistry. Local hybridization has occurred and has produced intermediate rocks such as a trachyandesitic dyke. Feldspar crystals have complex textures and an unusually wide range in chemical composition. Crystals from the trachytes cover the alkali feldspar compositional range and include plagioclase crystals with anorthite contents up to An47. Crystals from the mafic enclaves are dominated by plagioclase An72–90, but contain inclusions of orthoclase and other feldspars covering the entire compositional range sampled in the trachytes. Feldspars from the hybridized trachyandesitic dyke yield mineral compositions of An80–86, An47–54, Ab94–99, Or45–60, and Or96–98, all sampled within individual phenocrysts. We show that these compositional features are consistent with partial melting of granitoid rocks by influx of mafic magmas, followed by magma mixing and hybridization of the partial melts with the mafic melts, which broadly explains the observed bulk rock major and trace element variations. However, heterogeneities in Pb isotopic compositions of trachytes are observed on the scale of individual outcrops, likely reflecting initial variations in the isotopic compositions of the involved source rocks. The combined data point to one or more shallow-level trachytic magma chambers disturbed by multiple injections of trachytic, porphyritic alkali basaltic, and variably hybridized magmas.


Remobilization Igneous protoliths Trachytes Mafic enclaves Feldspar mineralogy FE-EPMA mapping Deccan volcanism 



HCS thanks A. Ghosh, B. Jana, and B. Singh for their field assistance during one of his many visits to these outcrops. We are grateful to C-Y Lee and S-L Chung for access to XRF and ICPMS facilities at National Taiwan University, and to I-J Lin for assistance with the ICMPS analyses. We thank G. Gualda, JG Shellnutt, SF Sethna, S. Viswanathan, and GK Upadhya for useful discussions and comments on an earlier version of this work. The manuscript benefitted from constructive reviews by S. Seaman and NJ McMillan, and the thorough editorial comments of M. Clynne. This study was partially supported by the National Science Council (96WIA0100363 to GFZ and 97-2116 M001008 to YI) and by Academia Sinica.

Supplementary material

445_2011_498_MOESM1_ESM.doc (38 kb)
ESM 1 (DOC 38 kb)
445_2011_498_MOESM2_ESM.xls (354 kb)
ESM 2 (XLS 354 kb)


  1. Annen C, Blundy JD, Sparks RSJ (2006) The genesis of intermediate and silicic magmas in deep crustal hot zones. J Petrol 47:505–539CrossRefGoogle Scholar
  2. Bacon CR (1986) Magmatic inclusions in silicic and intermediate volcanic rocks. J Geophys Res 91:6091–6112CrossRefGoogle Scholar
  3. Beane JE (1988) Flow stratigraphy, chemical variation and petrogenesis of Deccan flood basalts from the Western Ghats, India. PhD thesis, Washington State University, USAGoogle Scholar
  4. Clynne MA (1999) A complex magma mixing origin for rocks erupted in 1915, Lassen Peak, California. J Petrol 40:105–132CrossRefGoogle Scholar
  5. Devey CW, Stephens WE (1991) Tholeiitic dykes in the Seychelles and the original spatial extent of the Deccan. J Geol Soc 148:979–983CrossRefGoogle Scholar
  6. Eichelberger JC, Izbekov PE, Browne BL (2006) Bulk chemical trends at arc volcanoes are not liquid lines of descent. Lithos 87:135–154CrossRefGoogle Scholar
  7. Feeley TC, Wilson LF, Underwood SJ (2008) Distribution and compositions of magmatic inclusions in the Mount Helen dome, Lassen Volcanic Center, California: insights into magma chamber processes. Lithos 106:173–189CrossRefGoogle Scholar
  8. Humphreys MCS, Christopher T, Hards V (2009) Microlite transfer by disaggregation of mafic inclusions following magma mixing at Soufrière Hills volcano, Montserrat. Contrib Mineral Petrol 157:609–624CrossRefGoogle Scholar
  9. Ionov DA, Dupuy C, O'Reilly SY, Kopylova MG, Genshaft YS (1993) Carbonated peridotite xenoliths from Spitsbergen: implications for trace element signature of mantle carbonate metasomatism. Earth Planet Sci Lett 119:283–297CrossRefGoogle Scholar
  10. Irvine TN, Baragar WRA (1971) A guide to the chemical classification of common rocks. Can J Earth Sci 8:523–548CrossRefGoogle Scholar
  11. Ishizaki Y (2007) Dacite-basalt magma interaction at Yakedake volcano, central Japan: petrographic and chemical evidence from the 2300 years B. P. Nakao pyroclastic flow deposit. J Mineral Petrol Sci 102:194–210CrossRefGoogle Scholar
  12. Kshirsagar PV, Sheth HC, Shaikh B (2011) Mafic alkalic magmatism in central Kachchh, India: a monogenetic volcanic field in the northwestern Deccan Traps. Bull Volcanol. doi: 10.1007/s00445-010-0429-9
  13. Lai Y-M, Song S-R, Iizuka Y (2008) Magma mingling in the Tungho area, coastal range of eastern Taiwan. J Volc Geotherm Res 178:608–623CrossRefGoogle Scholar
  14. Le Bas MJ, Le Maitre RW, Streckeisen A, Zanettin P (1986) A chemical classification of volcanic rocks based on the total alkali–silica diagram. J Petrol 27:745–750Google Scholar
  15. Lightfoot PC, Hawkesworth CJ, Sethna SF (1987) Petrogenesis of rhyolites and trachytes from the Deccan Trap: Sr, Nd and Pb isotope and trace element evidence. Contrib Mineral Petrol 95:44–54CrossRefGoogle Scholar
  16. Lightfoot PC, Hawkesworth CJ, Devey CW, Rogers NW, van Calsteren PWC (1990) Source and differentiation of Deccan Trap lavas: implications of geochemical and mineral chemical variations. J Petrol 31:1165–1200Google Scholar
  17. Macdonald GA, Katsura T (1964) Chemical composition of Hawaiian lavas. J Petrol 5:82–133Google Scholar
  18. Mahoney JJ (1988) Deccan Traps. In: Macdougall JD (ed) Continental flood basalts. Kluwer Academic Publishers, Dordrecht, pp 151–194Google Scholar
  19. Mahoney JJ, Macdougall JD, Lugmair GW, Murali AV, Sankar Das M, Gopalan K (1982) Origin of the Deccan Trap flows at Mahabaseshwar inferred from Nd and Sr isotopic and chemical evidence. Earth Planet Sci Lett 60:47–60CrossRefGoogle Scholar
  20. Middlemost EAK (1989) Iron oxidation ratios, norms and the classification of volcanic rocks. Chem Geol 77:19–26CrossRefGoogle Scholar
  21. Murphy MD, Sparks RSJ, Barclay J, Carroll MR, Lejeune A-M, Brewer TS, Macdonald R, Black S, Young S (1998) The role of magma mixing in triggering the current eruption at the Soufriere Hills volcano, Montserrat, West Indies. Geophys Res Lett 25:3433–3436CrossRefGoogle Scholar
  22. Murphy MD, Sparks RSJ, Barclay J, Carroll MR, Brewer TS (2000) Remobilization of andesite magma by intrusion of mafic magma at the Soufriere Hills volcano, Montserrat, West Indies. J Petrol 41:21–42CrossRefGoogle Scholar
  23. Pande K (2002) Age and duration of the Deccan Traps, India: a review of radiometric and palaeomagnetic constraints. Proc Ind Acad Sci (Earth and Planet Sci) 111:115–123Google Scholar
  24. Raczek I, Stoll B, Hofmann AW, Jochum KP (2001) High-precision trace element data for the USGS reference materials BCR-1, BCR-2, BHVO-1, BHVO-2, AGV-1, AGV-2, DTS-1, DTS-2, GSP-1 and GSP-2 by ID-TIMS and MIC-SSMS. Geostand Newslett 25:77–86CrossRefGoogle Scholar
  25. Ray R, Shukla AD, Sheth HC, Ray JS, Duraiswami RA, Vanderkluysen L, Rautela CS, Mallik J (2008) Highly heterogeneous Precambrian basement under the central Deccan Traps, India: direct evidence from xenoliths in dykes. Gondwana Res 13:375–385CrossRefGoogle Scholar
  26. Reubi O, Blundy J (2009) A dearth of intermediate melts at subduction zone volcanoes and the petrogenesis of arc andesites. Nature 461:1269–1273CrossRefGoogle Scholar
  27. Sethna SF (1999) Geology of Mumbai and surrounding areas and its position in the Deccan volcanic stratigraphy, India. J Geol Soc India 53:359–365Google Scholar
  28. Sethna SF, Battiwala HK (1974) Metasomatised basalt xenoliths in the trachyte of Manori-Goria, Bombay, and their significance. Geological, Mining and Metallurgical Society of India Golden Jubilee Volume: 337–346Google Scholar
  29. Sethna SF, Battiwala HK (1976) Hybridization effects in contemporaneous eruption of trachytic and basaltic magmas in Salsette Bombay. Neues Jahrb Mineral 11:495–507Google Scholar
  30. Sethna SF, Battiwala HK (1977) Chemical classification of the intermediate and acid rocks (Deccan Trap) of Salsette Island, Bombay. J Geol Soc India 18:323–330Google Scholar
  31. Sethna SF, Battiwala HK (1980) Major element geochemistry of the intermediate and acidic rocks associated with the Deccan Trap basalts. In: Proceedings of the 3rd Indian Geological Congress. Pune, pp 281–294Google Scholar
  32. Sethna SF, Battiwala HK (1984) Hybrid quartz-monzonite dyke near Dongri, Salsette island, Bombay. The Indian Mineralogist, pp 124–129Google Scholar
  33. Sheth HC, Melluso L (2008) The Mount Pavagadh volcanic suite, Deccan Traps: geochemical stratigraphy and magmatic evolution. J Asian Earth Sci 32:5–21CrossRefGoogle Scholar
  34. Sheth HC, Ray JS (2002) Rb/Sr-87Sr/86Sr variations in Bombay trachytes and rhyolites (Deccan Traps): Rb-Sr isochron, or AFC process? Int Geol Rev 44:624–638CrossRefGoogle Scholar
  35. Sheth HC, Pande K, Bhutani R (2001a) 40Ar-39Ar age of a national geological monument: the Gilbert Hill basalt, Deccan Traps, Bombay. Curr Sci 80:1437–1440Google Scholar
  36. Sheth HC, Pande K, Bhutani R (2001b) 40Ar-39Ar ages of Bombay trachytes: evidence for a Palaeocene phase of Deccan volcanism. Geophys Res Lett 28:3513–3516CrossRefGoogle Scholar
  37. Sheth HC, Choudhary AK, Bhattacharyya S, Cucciniello C, Laishram R, Gurav T (2011) The Chogat–Chamardi subvolcanic complex, Saurashtra, northwestern Deccan Traps: geology, petrochemistry, and petrogenetic evolution. J Asian Earth Sci. doi: 10.1016/j.jseaes.2011.02.012
  38. Snyder D (1997) The mixing and mingling of magmas. Endeavour 27:19–22CrossRefGoogle Scholar
  39. Snyder D (2000) Thermal effects of the intrusion of basaltic magma into a more silicic magma chamber and implications for eruption triggering. Earth Planet Sci Lett 175:257–273CrossRefGoogle Scholar
  40. Snyder D, Tait S (1998) The imprint of basalt on the geochemistry of silicic magmas. Earth Planet Sci Lett 160:433–445CrossRefGoogle Scholar
  41. Sparks RSJ, Marshall LA (1986) Thermal and mechanical constraints on mixing between mafic and silicic magmas. J Volc Geotherm Res 29:99–124CrossRefGoogle Scholar
  42. Straub SM, Gomez-Tuena A, Stuart FM, Zellmer GF, Cai Y, Espinasa-Perena R (2011) Formation of hybrid arc andesites beneath thick continental crust. Earth Planet Sci Lett 303:337–347CrossRefGoogle Scholar
  43. Sun SS, McDonough WF (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: Saunders AD, Norry MJ (eds) Magmatism in ocean basins. Geological Society Special Publications, London, pp 313–345Google Scholar
  44. Thomas N, Tait SR (1997) The dimensions of magmatic inclusions as a constraint on the physical mechanism of mixing. J Volc Geotherm Res 75:167–178CrossRefGoogle Scholar
  45. Verma SP, Torres-Alvarado IS, Sotelo-Rodrigues ZT (2002) SINCLAS: standard igneous norm and volcanic rock classification system. Comput Geosci 28:711–715CrossRefGoogle Scholar
  46. Walker GPL, Skelhorn RR (1966) Some associations of acid and basic igneous rocks. Earth Sci Rev 2:93–109CrossRefGoogle Scholar
  47. Yoder HS Jr (1973) Contemporaneous basaltic and rhyolitic magmas. Am Mineral 58:153–171Google Scholar
  48. Zellmer GF (2009) Petrogenesis of Sr-rich adakitic rocks at volcanic arcs: insights from global variations of eruptive style with plate convergence rates and surface heat flux. J Geol Soc 166:725–734CrossRefGoogle Scholar
  49. Zellmer GF, Turner SP (2007) Arc dacite genesis pathways: evidence from mafic enclaves and their hosts in Aegean lavas. Lithos 95:346–362CrossRefGoogle Scholar
  50. Zellmer GF, Sparks RSJ, Hawkesworth CJ, Wiedenbeck M (2003) Magma emplacement and remobilization timescales beneath Montserrat: insights from Sr and Ba zonation in plagioclase phenocrysts. J Petrol 44:1413–1431CrossRefGoogle Scholar
  51. Zellmer GF, Rubin KH, Grönvold K, Jurado-Chichay Z (2008) On the recent bimodal magmatic processes and their rates in the Torfajökull–Veidivötn area, Iceland. Earth Planet Sci Lett 269:387–397CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Georg F. Zellmer
    • 1
    • 2
    Email author
  • Hetu C. Sheth
    • 3
  • Yoshiyuki Iizuka
    • 1
  • Yi-Jen Lai
    • 4
  1. 1.Institute of Earth SciencesTaipeiRepublic of China
  2. 2.Lamont-Doherty Earth ObservatoryPalisadesUSA
  3. 3.Department of Earth SciencesIndian Institute of Technology Bombay (IITB)MumbaiIndia
  4. 4.Department of Earth SciencesUniversity of BristolBristolUK

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