Skip to main content
SpringerLink
Log in

The genesis and significance of N-MORB sub-types

  • Published:
Contributions to Mineralogy and Petrology Aims and scope Submit manuscript

Abstract

A global compositional dichotomy for N-MORB magma (N1/N2) is recognized on the basis of Na2O, TiO2, CaO, and Al2O3 contents, and their respective ratios. We have characterized the two magma sub-types by means of their trace element patterns, and attempted to explain the differences in major and trace element contents in terms of a partial melting model, using data from DSDP/IPOD Leg 82. Mass balance calculations for N-MORB glass and rock compositions indicate that differences between N1-and N2-MORB are consistent with simple differences (5%–10%) in the degree of partial melting of a plagioclase-(±spinel) lherzolite, at pressures <10 kbar, rather than their respective derivation from plagioclase- and spinel-lher-zolite sources. Based on published and calculated partition coefficients, and calculated source magmaphile trace element compositions, the calculations indicate that the overall range of N-MORB compositions may be derived by between approximately 8% and 20% partial melting of a fertile lherzolite source. Fluid dynamic and melt kinematic considerations will probably necessitate refinement of the model, but should also take account of its qualitative precepts.

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

Access this article

Log in via an institution

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

Referneces

  • spinel lherzolite at 10 kbar and the genesis of MORBs. Contrib Mineral Petrol 90:18–28

  • Fujimaki H, Tatsumoto M, Aoki K (1984) Partition coefficients of Hf, Zr and REE between phenocrysts and groundmass. Proc Lunar Sci Conf 14th, J Geophys Res B89:662–672

    Google Scholar 

  • Gast PW (1965) Terrestrial ratio of potassium to rubidium and the composition of the Earth's mantle. Science 147:858–860

    Google Scholar 

  • Gast PW (1968) Trace element fractionation and the origin of tholeiitic and alkaline magma types. Geochim Cosmochim Acta 32:1057–1086

    Google Scholar 

  • Green DH, Hibberson WO, Jaques AL (1979) Petrogenesis of mid-ocean ridge basalts. In McElhinny MW (ed) The Earth. Its origin, structure and evolution. Academic Press, London, pp 265–299

    Google Scholar 

  • Grutzek M, Kridelbaugh S, Weill D (1974) The distribution of Sr and REE between diopside and silicate liquid. Geophys Res Lett 1:273–275

    Google Scholar 

  • Hamlyn PR, Bonatti E (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 48:65–79

    Google Scholar 

  • Hart SR (1984) A large scale isotope anomaly in the southern hemisphere mantle. Nature 28:753–757

    Google Scholar 

  • Haskin LA, Paster TP (1979) Geochemistry and mineralogy of the rare earths. In Gschneider Jr KA, Eyring L (eds) Handbook on the physics and chemistry of rare earths, 3. North-Holland, Amsterdam:1–80

    Google Scholar 

  • Henderson P (1982) Inorganic geochemistry. Pergamon, Oxford New York, pp 353

    Google Scholar 

  • Hertogen J, Gijbels R (1976) Calculation of trace element fractionation during partial melting. Geochim Cosmochim Acta 40:313–322

    Google Scholar 

  • Hertogen J, Sachtleben T, Schmincke HU, Jenner GA (1985) Trace element geochemistry and petrogenesis of Leg 82 basalts. In Bougault H, Cande SC et al. (eds) Init Repts DSDP 82. US Govt Printing Office, Washington, pp 449–457

    Google Scholar 

  • Irving AJ (1978) A review of experimental studies of crystal/liquid trace element partitioning. Geochim Cosmochim Acta 42:743–770

    Google Scholar 

  • Irving AJ, Frey FA (1984) Trace element abundances in megacrysts and their host basalts: Constraints on partitioning coefficients and megacryst genesis. Geochim Cosmochim Acta 48:1201–1221

    Google Scholar 

  • Jaques AL, Green DH (1980) Anhydrous melting of peridotite at 0–15 kb pressure and the genesis of tholeiitic basalts. Contrib Mineral Petrol 73:287–310

    Google Scholar 

  • Jenner GA, Hertogen J, Sachtleben T, Schmincke HU (1985) Isotopic and trace element composition of Leg 82 basalts: constraints on some processes affecting their composition. In Bougault H, Cande SC et al. (eds) Init Repts DSDP 82. US Govt Printing Office, Washington, pp 501–507

    Google Scholar 

  • Jenner GA, Hertogen J (1986) Constraints on processes affecting the origin of oceanic crust: geochemical evidence from the 0–35 Ma age basalts, between 30 N and 40 N, MAR. J Geodynamics 5:49–78

    Google Scholar 

  • Klein EM, Langmuir CH (1988) Ocean ridge basalt chemistry, axial depth, crustal thickness and temperature variations in the mantle. J Geophys Res 92:8089–8115

    Google Scholar 

  • Langmuir CH, Bender JF, Bence AE, Hanson GN, Taylor SR (1977) Petrogenesis of basalts from the FAMOUS area: Mid-Atlantic Ridge. Earth Planet Sci Lett 36:133–156

    Google Scholar 

  • Langmuir CH, Hanson GN (1980) An evaluation of major element heterogeneity in the mantle sources of basalts. Phil Trans Soc Lond A297:383–407

    Google Scholar 

  • Langmuir CH, Bender JF (1984) The geochemistry of oceanic basalts in the vicinity of transform faults: observations and implications. Earth Planet Sci Lett 69:107–127

    Google Scholar 

  • Langmuir CH, Plank T (1988) Quantitative reevaluation of magma chamber processes and melting regime shape. Chem Geol 70:153

    Google Scholar 

  • Le Roex AP, Dick HJB, Erlank AJ, Reid AM, Frey FA, Hart SR (1983) Geochemistry, mineralogy and petrogenesis of lavas erupted along the Southwest Indian Ridge between the Bouvet triple junction and 11 degrees East. J Petrol 24:267–318

    Google Scholar 

  • Le Roex AP (1988) Source regions of mid-ocean ridge basalts: evidence for enrichment processes. In: Menzies MA, Hawkesworth CJ (eds) Mantle metasomatism. Academic Press, London, pp 389–422

    Google Scholar 

  • Matsui A, Onuma N, Nagasawa H, Higuchi H, Banno S (1977) Crystal structure control in trace element partition between crystal and magma. Bull Soc Fr Mineral Cristallogr 100:315–324

    Google Scholar 

  • McKenzie DP (1984) Generation and compaction of partially molten rock. J Petrol 25:713–765

    Google Scholar 

  • McKenzie DP (1985) The extraction of magma from the crust and mantle. Earth Planet Sci Lett 74:81–91

    Google Scholar 

  • Melson WG, Hart SR, Thompson G (1972) St Paul's Rocks, equatorial Atlantic: petrogenesis, radiometric ages and implications on sea-floor spreading. Geol Soc Am Mem 132:241–272

    Google Scholar 

  • Melson WG, O'Hearn T (1979) Basaltic glass erupted along the Mid-Atlantic Ridge between 0–37°N: relationship between composition and latitude. In Talwani M, Harrison CG, Hayes DE (eds) Deep drilling results in the Atlantic Ocean: ocean crust. Maurice Ewing Series 2, Washington. Am Geophys Union, pp 249–261

    Google Scholar 

  • Michael PJ, Bonatti E (1985) Peridotite composition from the North Atlantic: regional and tectonic variations and implications for partial melting. Earth Planet Sci Lett 73:91–104

    Google Scholar 

  • Morel JM, Hekinian R (1980) Compositional variations of volcanics along segments of recent spreading ridges. Contrib Mineral Petrol 72:425–436

    Google Scholar 

  • Nagasawa H, Schreiber HD, Morris RV (1980) Experimental mineral/liquid partition coefficients of the rare earth elements (REE), Sc and Sr for perovskite, spinel and melilite. Earth Planet Sci Lett 46:431–437

    Google Scholar 

  • O'Hara MJ (1977) Geochemical evolution during fractional crystallization of a periodically refilled magma chamber. Nature 266:503–507

    Google Scholar 

  • O'Hara MJ (1985) Importance of the ‘shape’ of the melting regime during partial melting of the mantle. Nature 314:58–62

    Google Scholar 

  • O'Hara MJ, Mathews RE (1981) Geochemical evolution in an advancing, periodically replenished, periodically tapped, continously fractionated magma chamber. J Geol Soc Lond 138:237–277

    Google Scholar 

  • Ottonello G (1980) Rare earth abundances and distribution in some spinel peridotite xenoliths from Assab (Ethiopia). Geochim Cosmochim Acta 44:1885–1901

    Google Scholar 

  • Pearce JA (1983) Role of the sub-continental lithosphere in magma genesis at active continental margins. In Hawkesworth CJ, Norry MJ (eds) Continental basalts and mantle xenoliths. Shiva, Cheshire, pp 230–272

    Google Scholar 

  • Pearce JA, Norry MJ (1979) Petrogenetic implications of Ti, Zr, Y and Nb variations in volcanic rocks. Contrib Mineral Petrol 69:33–47

    Google Scholar 

  • Pearce JA, Harris NBW, Tindle AG (1984) Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J Petrol 25:956–983

    Google Scholar 

  • Presnall DC, Dixon JR, O'Donnell TH, Dixon SA (1979) Generation of mid-ocean ridge tholeiites. J Petrol 20:3–35

    Google Scholar 

  • Presnall DC, Hoover JD (1984) Composition and depth of origin of primary mid-ocean ridge basalts. Contrib Mineral Petrol 87:170–178

    Google Scholar 

  • Rhodes JM, Dungan MA (1979) The evolution of ocean-floor basaltic magmas. In: Talwani M, Harrison CG, Hayes DE (eds) Deep drilling results in the Atlantic Ocean: ocean crust. Maur-ice Ewing Series 2, Washington. Am Geophys Union, pp 262–272

    Google Scholar 

  • Ribe NM (1985) The generation and composition of partial melts in the earth's mantle. Earth Planet Sci Lett 73:361–376

    Google Scholar 

  • Richter FM, McKenzie DP (1984) Dynamical models for melt segregation from a deformable matrix. J Geol 92:729–740

    Google Scholar 

  • Ringwood AE (1975) Composition and petrology of the earth's mantle. McGraw-Hill, New York, pp 618

    Google Scholar 

  • Roeder PL, Emslie RF (1970) Olivine-liquid equilibrium. Contrib Mineral Petrol 29:275–289

    Google Scholar 

  • Saunders AD, Tarney J, Marsh NG, Wood DA (1979) Ophiolites as ocean crust or marginal basin crust: a geochemical approach. In: Panayiotou A (ed) Ophiolites. Proc Intern Ophiolite Symp Cyprus 1979:193–204

  • Schilling JG (1973) Iceland mantle plume, geochemical evidence along Reykjanes Ridge. Nature 242:565–571

    Google Scholar 

  • Schilling JG (1975) Rare earth variations across ‘normal’ ridge, 29 S, and East Pacific Rise, 2–19 S, and evidence on the composition of the underlying low-velocity layer. J Geophys Res 80:1459–1473

    Google Scholar 

  • Schilling JG, Kingsley R, Bergeron M (1977) Rare earth abundances in DSDP Sites 332, 334 and 335, and inferences on the Azores mantle blob activity with time. In: Aumento F, Melson WG et al. (eds) Init Repts DSDP 37. US Govt Printing Office, Washington, pp 591–598

    Google Scholar 

  • Schilling JG, Meyer PS, Kingsley RH (1982) Evolution of the Iceland Hotspot. Nature 296:313–320

    Google Scholar 

  • Schilling JG, Zajac M, Evans R, Johnston T, White W, Devine JD, Kingsley R (1983) Petrologic and geochemical variations along the Mid-Atlantic Ridge from 29 N to 73 N. Am J Sci 283:510–586

    Google Scholar 

  • Shibata T, Delong SE, Walker D (1979) Abyssal tholeiites from the Oceanographer Fracture Zone I. Petrology and fractionation. Contrib Mineral Petrol 70:89–102

    Google Scholar 

  • Shido F, Miyashiro A (1973) Compositional difference between abyssal tholeiites from north and south of the Azores on the Mid-Atlantic Ridge. Nature 245:59–60

    Google Scholar 

  • Shimizu H (1980) Experimental study on rare-earth element partitioning in minerals formed at 20 and 30 kb for basaltic systems. Geochem J 14:185–202

    Google Scholar 

  • Sigurdsson H (1981) First-order major element variation in basaltic glasses from the Mid-Atlantic Ridge: 29 N–73 N, J Geophys Res 86:9483–9502

    Google Scholar 

  • Stakes DS, Shervais JW, Hopson CA (1984) The volcanic-tectonic cycle of the FAMOUS and AMAR valleys, mid-Atlantic Ridge 36° 48′N: evidence from basalt glass and phenocryst compositional variations for a steady state magma chamber beneath the valley midsections, AMAR 3. J Geophys Res 89:6995–7028

    Google Scholar 

  • Stolper E (1980) A phase diagram for mid-ocean ridge basalts: preliminary results and implications for petrogenesis. Contrib Mineral Petrol 74:13–27

    Google Scholar 

  • Stosch HG (1982) Rare earth element partitioning between minerals from anhydrous spinel peridotite xenoliths. Geochim Cosmochim Acta 46:793–811

    Google Scholar 

  • Stosch HG, Seck HA (1980) Geochemistry and mineralogy of two spinel peridotite suites from Dreiser Weiher, West Germany. Geochim Cosmochim Acta 44:457–470

    Google Scholar 

  • Sun SS (1980) Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs. Phil Trans R Soc London A297:409–446

    Google Scholar 

  • Sun SS, Nesbitt RW (1977) Chemical heterogeneity of the Archean mantle, composition of the earth and mantle evolution. Earth Planet Sci Lett 35:429–448

    Google Scholar 

  • Sun SS, Nesbitt RW, Sharaskin A (1979) Geochemical characteristics of mid-ocean ridge basalts. Earth Planet Sci Lett 44:119–138

    Google Scholar 

  • Takahashi E, Kushiro I (1983) Melting of a dry peridotite at high pressures and basalt magma genesis. Am Mineral 68:859–879

    Google Scholar 

  • Tanaka T, Nishizawa O (1975) Partitioning of REE, Ba and Sr between crystal and liquid phases for a natural silicate system at 20 kb pressure. Geochem J 9:161–166

    Google Scholar 

  • Weaver BL, Tarney J, Saunders AD (1985) Geochemistry and mineralogy of basalts recovered from the Central North Atlantic. In: Bougault H, Cande SC et al. (eds) Init Repts DSDP 82. US Govt Printing Office, Washington, pp 395–420

    Google Scholar 

  • Weill DF, McKay GA (1975) The partitioning of Mg, Fe, Sr, Ce, Sm, Eu and Yb in lunar igneous systems and a possible origin of KREEP by equilibrium partial melting. Proc Lunar Sci Conf 6th: 1143–1158

    Google Scholar 

  • White MW, Schilling JG (1978) The nature and origin of geochemical variation in Mid-Atlantic Ridge basalts from the Central North Atlantic. Geochim Cosmochim Acta 42:1501–1506

    Google Scholar 

  • Wood DA (1979) A variably veined suboceanic upper mantle — genetic significance for mid-ocean ridge basalts from geochemical evidence. Geol 7:499–503

    Google Scholar 

  • Wright TL (1984) Origin of Hawaiian tholeiite: a metasomatic model. J Geophys Res 89:3233–3252

    Google Scholar 

  • Wright TL, Doherty PC (1970) A linear programming and least squares computer method for solving petrology mixing problems. Geol Soc Am Bull 81:1995–2008

    Google Scholar 

  • Yoder HS (1976) Generation of basaltic magma. National Academy of Sciences, Washington, DC, pp 265

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Institut für Mineralogie, Ruhr Universität Bochum, Postfach 102148, D-4630, Bochum, Germany

    L. G. Viereck & H. -U. Schmincke

  2. Department of Geological Sciences, University of Illinois, Box 4348, 60680, Chicago, Ill, USA

    M. F. J. Flower

  3. Fysico-chemische geologie, Universiteit Leuven, Celestijnenlaan 200 C, B-3030, Leuven, Belgium

    J. Hertogen

  4. Department of Earth Sciences, Memorial University Newfoundland, A1B 3X5, St. John's, Newfoundland, Canada

    G. A. Jenner

  5. Hygiene Institut des Ruhrgebiets, Rotthauserstrasse 19, D-4650, Gelsenkirchen, Germany

    L. G. Viereck

Authors
  1. L. G. Viereck
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. F. J. Flower
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. J. Hertogen
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. H. -U. Schmincke
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. G. A. Jenner
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Viereck, L.G., Flower, M.F.J., Hertogen, J. et al. The genesis and significance of N-MORB sub-types. Contr. Mineral. and Petrol. 102, 112–126 (1989). https://doi.org/10.1007/BF01160195

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01160195

Keywords

Search

Navigation