Skip to main content
Log in

Petrography and mineral chemistry of neovolcanics occurring between Pacific and Nazca Plate boundaries

  • Published:
Journal of the Geological Society of India

Abstract

Mid-Oceanic Ridge Basalt (MORB) samples collected from southern East Pacific Rise (SEPR) have been investigated. These highly phyric plagioclase basalts (HPPB) and moderately phyric plagioclase basalts (MOPB) show rare cumulate and vitrophyric textures with plagioclase (>10% as phenocryst) and abundant glass (>72%). Electron Probe Micro Analysis (EPMA) showed large compositional variations in the megacrysts as well as microcrysts of plagioclase (An62 to An82), olivine (Fo78 to Fo87), pyroxene (ferroaugite to augite) and iron oxides, mostly titaniferous magnetite. Olivine grains show high Mg# (>80%) and distinctly low in NiO (0.01–0.2%). Ferroan trevorite (NiO =16.22 and FeO(t) =83.06) a characteristic meteoritic mineral has been identified from the olivine megacrysts of MORB, possibly attributed to Ni-enrichment, resulted from heterogeneity of the lower mantle. Wide range of An composition in plagioclase is indicative of large pressure range of crystal nucleation under decompression at a depth of ∼70 km (An82) up to the ocean spreading centre. Absence of zoning observed in all the minerals present in the MORB samples, possibly attributed to unmixing and dominant fractionation process.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Arai, S. and Fujii, T. (1978) Petrology of ultramafic rocks from site 395. Initial Rep. Deep Sea Drilling Project, v.45, pp.587–598.

    Google Scholar 

  • Bachw. Hegnere. Erzingerj. and Satarm. 1994 Chemical and isotopic variation along the superfast spreading east pacific rise from 6° to 30°s. Contrib. Mineral. Petrol. v. 116pp. 365–380.

    Article  Google Scholar 

  • Best, M.G. and Christiansen, E.H. (2001) Igneous Petrology. Blackwell Sci. Publ., Oxford, 458p.

    Google Scholar 

  • Danyushevsky, L.H., Perfit, M.R., Eggins, S.M. and Falloon, T.J. (2003) Crustal origin of coupled ultra-depleted and Plagioclase signatures in MORB olivine-hosted melt inclusions: evidence from the Siqueiros Transform Fault, East Pacific Rise. Contrib. Mineral Petrol., v.144, pp.619–637.

    Google Scholar 

  • Detrick, R.S., Harding, A.J., Kent, G.M., Orcutt, J.A., Mutter, J.C. and Buhl, P. (1993) Seismic structure of the southern East Pacific Rise. Science, v.259, pp.499–503.

    Article  Google Scholar 

  • de Waal, S.A. (1969) Nickel mineral from Barberton, South Africa: I. Ferroan Trevorite. Amer. Mineral., v.54, pp.1204–1208.

    Google Scholar 

  • de Waal, S.A. (1972) Nickel mineral from Barberton, South Africa:V.Trevorite redescribed. Amer. Mineral., v.27, pp.1527–1530.

    Google Scholar 

  • Deer, W.A., Howie, R.A. and Zussman, J. (1963) Rock forming minerals, 2. Chain Silicates. Longmans. Green and Co., London, p.379.

    Google Scholar 

  • Dick, H.J.B., Fisher, R.L. and Bryan, W.B. (1984) Mineralogic variability of the upper most mantle along mid-oceanic ridges. Earth Planet. Sci. Lett., v.69, pp.88–106.

    Article  Google Scholar 

  • Dixon, J.E., Clague, D.A. and Eissen, J.P. (1986) Gabbroic xenoliths and host ferrobasalt from the southern Juan de Fuca Ridge. Jour. Geophys. Res., v.91, pp.3795–3820.

    Article  Google Scholar 

  • Droop, G.T.R. (1987) A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineral. Mag., v.51, pp.431–435.

    Article  Google Scholar 

  • Elthon, D. (1987a) Mineral chemistry of gabbroic rocks from the Mid-Cayman Rise spreading center. Jour. Geophys. Res., v.92, pp.58–682.

    Article  Google Scholar 

  • Elthon, D.H. (1989) Pressure of origin of primary mid-oceanic ridge basalts, Geol. Soc. London, Spec. Publ., v.42, pp.125–136.

    Article  Google Scholar 

  • Elthon, D.H. (1992) Chemical Trends in Abyssal Peridotites: Refertilization of Depleted Suboceanic Mantle, Jour. Geophys. Res., v.97, pp.9,015–9,026.

    Google Scholar 

  • Elthon, D., Stewart, M. and Ross, D.K. (1992) Compositional Trends of Minerals in Oceanic Cumulates, Jour. Geophys. Res. v.97, pp.15,189–15,200.

    Google Scholar 

  • Francheteau, J. and Ballard, R.D. (1983) The East Pacific Rise near 21°N, 13°N and 20°S: Inferences for along-strike variability of axial processes of the mid-ocean ridge. Earth Planet. Sci. Lett., v.64, pp.93–116.

    Article  Google Scholar 

  • Green, D.H. and Ringwood, A.E. (1967) The genesis of basaltic magmas. Contrib. Mineral. Petrol., v.15, pp.103–190.

    Article  Google Scholar 

  • Hamlyn, P.R. and Bonatti (1980) Petrology of mantle-derived ultramafics from the Owen fracture zone, northwest Indian Ocean: Implications for the nature of the oceanic upper mantle. Earth Planet. Sci. Lett., v.48, pp.65–79.

    Article  Google Scholar 

  • Hebert, R., Bideau, D. and Hekinian, R. (1983) Ultramafic and mafic rocks from the Garrett Transform fault near 13°30′S on the East Pacific Rise: Igneous Petrology. Earth Planet. Sci. Lett., v.65, pp.107–125.

    Article  Google Scholar 

  • Hebert, R., Constantin, M. and Robinson, P.T. (1991) Primary mineralogy of Leg 118 gabbroic rocks and their place in the spectrum of oceanic mafic igneous rocks. In: R.P. Von Herzen, P.T. Robinson et al., Proc. ODP, Sci. Results, 118: College Station, TX (Ocean Drilling Program), pp.3–20.

  • Hekinian, R. (1982) Petrology of the ocean floor, Elsevier, Amsterdam, Oceanographic series: 33

    Book  Google Scholar 

  • Hekinian, R. and Walker, D. (1987) Diversity and special zonation of volcanic rocks from the East Pacific Rise near 21°N. Contrib. Mineral. Petrol.. v.96, pp.265–280.

    Article  Google Scholar 

  • Hess, P.C. (1992) Phase Equilibria Constraints on the Origin of Ocean Floor Basalts. In: J. Phipps Morgan, D.K. Blackman and J.M. Sinton (Eds.), Mantle Flow and Melt Generation at Mid-Ocean Ridges. Amer. Geophys. Union Monogr. Ser., v.71, pp.67–102.

  • Hoges, F.N. and Papike, J.J. (1976) Deep Sea Drilling Project site 334: Magmatic cumulates from oceanic layer3. Jour. Geophys. Res., v.81, pp.4135–4151.

    Article  Google Scholar 

  • Hughes, C.J. (1982) Igneous Petrology: Developments in Petrology. Elsevier, New York, 551p.

    Google Scholar 

  • Lonsdale, P. (1977) Regional shape and tectonics of the equatorial East Pacific Rise. Marine Geophys. Res., v.3, pp.313–327.

    Google Scholar 

  • Mahoney, J.J., Sinton, J.M., Kurz, M.D., Macdougall, J.D., Spencer, K.J. and Lugmair, G.W. (1994) Isotope and trace element characteristics of a super-fast spreading ridge: East Pacific Rise, 13°–23°S, Earth Planet. Sci. Lett., v.121, pp.173–193.

    Article  Google Scholar 

  • Meyer, P.S., Dick, H.J.B. and Thomson, G. (1989) Cumulate gabbros from the Southwest Indian Ocean Ridge, 54°S–7°16′E: Implication for the magmatic processes at a slow spreading ridge. Contrib. Mineral. Petrol., v.103, pp.44–63.

    Article  Google Scholar 

  • Naar, D.F. and Hey, R.N. (1991) Tectonic evolution of Easter Microplate. Jour. Geophys. Res., v.96, pp.7961–93.

    Article  Google Scholar 

  • Natland, J.H., Adamson, A.C., Laverne, C., Melson, W.G. and O’hearn, T. (1983) A compositionally nearly steady state magma chamber at the Costa Rica Rift: Evidence from basalt glass and mineral data, Initial Rep. Deep Sea Drill. Proj., v.69, pp.811–858.

    Google Scholar 

  • Niu, Y.L. and Hékinian R. (1997) Spreading rate dependence of the extent of mantle melting beneath ocean ridges. Nature, v.385, pp.326–329.

    Article  Google Scholar 

  • Niu, Y., Gilmore, T., Mackie, S., Greig, A. and Bach, W. (2002) Mineral chemistry, whole rock composition and petrogenesis of Leg 176 gabbros: data and discussion. In: J.H. Natland, H.J.B. Dick, D.J. Miller and R.P. Von Herzen (Eds.), Proc. ODP, Sci. Results, v.176, pp.1–60.

  • Osborn, E.F. and Tait, D.B. (1952) The system diopside-forsteriteanorthite. Amer. Jour. Sci. (Bowen Volume), v.413, pp.413–433.

    Google Scholar 

  • Pandey, S.K. (2008) Petrology and Geochemistry of the MORB from the Fast Spreading Southern East Pacific Rise. PhD Thesis (unpublished), Delhi University, 219p.

  • Pandey, S.K., Shrivastava, J.P. and Roonwal, G.S. (2008) Occurrence of ferroan trevorite in the olivine megacryst from the fast spreading southern East Pacific Rise. Curr. Sci., v.95, no.10, pp.1468–1473.

    Google Scholar 

  • Perfit, M.R., Saunders, A.D. and Fornari, D.J. (1982) Phase chemistry, fractional crystallization and magma mixing in basalts from the Gulf of California, Deep Sea Drill. Project, leg 64. Initial Rep. DSDP leg 64: pp.649–666.

    Google Scholar 

  • Perfit, M.R., Fornari, D.J. Smith, M.C. Bender, J.F. Langmuir, C.H. and Haymon, R.M. (1994) Small-scale spatial and temporal variations in mid-ocean ridge crest magmatic processes. Geology, v.22, pp.375–379.

    Article  Google Scholar 

  • Perfit, M.R., Fornari, D.J., Ridlay, W.I., Kirk, P.D., Casey, J., Kastens, K.A., Reynolds, J.R., Edwards, M., Desonie, D., Shuster, R. and Paradis, S. (1996) Recent volcanism in the Siqueiros transform fault: picritic basalts and implications for MORB magma genesis. Earth Planet. Sci. Lett., v.141, pp.91–108.

    Article  Google Scholar 

  • Perfit, M.R. (2001) Mid-ocean ridge geochemistry and petrology. Academic Press, University of Florida, www.clas.ufl.edu/users/emartin/GLY5736F07/literature/midoceanridgePerfitpdf.pdf

  • Pluger, W.L. and All Cruise Participants (1988) Fahrtbericht SO28 and Wissenshzftlicher Bericht GEMINO I: Geothermal Metallogenesis Indian Ocean. Inst. Mineral. Lagerstattenlehrk. Techn. Hochschule Aachen, Aachen, 274.

    Google Scholar 

  • Prinz, M., Keil. K., Green. J.A., Reid, A.M., Bonatti, E. and Honnorez, J. (1976) Mineralogy and petrology of some ultramafic and mafic dredge samples from the equatorial Mid-Atlantic Ridge and fracture zones. Jour. Geophys. Res., v.81, pp.4087–4103.

    Article  Google Scholar 

  • Ragland, P.C. (1993) Basic Analytical Petrology, Oxford Univ. Press, 369p.

  • Ray, D. Iyer, S.D., Banerjee, R., Mishra, S. and Widdowson, M. (2007) A petrogenetic model of basalts from Northern Central Indian Ridge: 3-11°S. Geol. Sinica Acta, v.81-1, pp.99–112.

    Google Scholar 

  • Rea, D.K. (1981) Tectonics of the Nazca-Pacific divergent plate boundary Nazca Plate: crustal formation and Andean convergence. Geol. Soc. Am. Mem., v.154, pp.27–62.

    Google Scholar 

  • Reynolds, J.R., Langmuir, C.H., Bender, J.F., Kastens, K.A. and Ryan, W.B.F. (1992) Spatial and temporal variability in the geochemistry of basalts from the East Pacific rise. Nature, v.359, pp.493–499.

    Article  Google Scholar 

  • Rollinson, H. (1993) Using geochemical data: Evaluation, Presentation, Interpretation. Harlow, Longman, 352p.

    Google Scholar 

  • Roonwal, G.S., Marchig, V., Rosch, H., Milovanovic, D. and Bellieni, G. (1996) A gabbroic xenolith in recent mid-oceanic ridge basalt from the East Pacific Rise at 14°S. Curr. Sci., v.70(8), pp.724–729.

    Google Scholar 

  • Sato, H. (1977) Nickel content of basaltic magmas: Identification of primary magmas and a measure of the degree of olivine fractionation. Lithos, v.10, pp.112–120.

    Article  Google Scholar 

  • Sato, H. (2004) Mineral composition of the MORB from the Australian Antarctic Discordance (AAD): Implication for mantle source characteristics. In: R.B. Pedersen, D.M. Christie and D.J. Miller (Eds.), Proc. ODP, Sci. Results, v.187, pp.1–26.

  • Sims, K.W.W., Goldstein, S.J., Blicher-Toft, J., Perfit, M.R., Kelemen, P., Fornari, D.J., Murrell, M.T., Hart, S.R. Depaolo, D.J., Layne, G., Ball, L., Jull, M. and Bender, J. (2002) Chemical and Isotopic constraints on the generation and transportation of magma beneath the East Pacific Rise. Geochim. Cosmochim. Acta, v.66(19), pp.3481–3504.

    Article  Google Scholar 

  • Sinton, J.M., Smaglik, S.M., Mahoney, J.J. and Macdonald, K.C. (1991) Magmatic Processes at Superfast Spreading Mid-Ocean Ridges: Glass Compositional Variations along the East Pacific Rise 13°-23°S. Jour. Geophys. Res., v.96, pp.6133–6155.

    Article  Google Scholar 

  • Spiegelman, M. and Reynolds, J. (1999) Combined dynamic and geochemical evidence for convergent melt flow beneath the East Pacific Rise. Nature, v.402, pp.282–285.

    Article  Google Scholar 

  • Wendt, J.I., Regelous, M., Niu, Y., Hekinian, R. and Collerson, K.D. (1999) Geochemistry of the lavas from the Garret Transform Fault: Insights from the mantle heterogeneity beneath the eastern Pacific. Earth Planet. Sci. Lett., v.173, pp.271–284.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to J. P. Shrivastava.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Pandey, S.K., Shrivastava, J.P. & Roonwal, G.S. Petrography and mineral chemistry of neovolcanics occurring between Pacific and Nazca Plate boundaries. J Geol Soc India 74, 559–572 (2009). https://doi.org/10.1007/s12594-009-0169-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12594-009-0169-7

Keywords

Navigation