Skip to main content
SpringerLink
Log in

Multiple ways of producing intermediate and silicic rocks within Thingmúli and other Icelandic volcanoes

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

Abstract

Major and trace element compositions of rocks and coexisting phenocrysts of the Thingmúli volcano suggest a revision of the existing models for the formation of intermediate and silicic melts in Iceland. The new data define two compositional tholeiitic trends with a significant gap between them. A high-iron trend (HFe) contains 6–14 wt% total FeO in silicic rocks with c. 1 wt% MgO, as well as sodic plagioclase and hedenbergite phenocrysts. A low-iron trend (LFe) contains 3–5 wt% FeO at c. 1 wt% MgO, which is typical of Iceland but higher than MORB compositions. The most evolved phenocrysts of the LFe trend do not reach iron-rich end members. The HFe trend is interpreted as a result of fractional crystallization; numerical modelling using the MELTS algorithm suggests that crystallization took place under redox conditions constrained to one-log unit below the fayalite-magnetite-quartz oxygen buffer (FMQ-1). The LFe trend is explained by a combination of mixing between rhyolite and ferrobasalt, assimilation of hydrated crust and fractional crystallization under higher redox conditions (FMQ). The two trends and the gap are best defined in a plot of Mg# versus SiO2 that is useful to unravel petrogenetic processes. For example, intermediate and silicic rocks of the Holocene volcanic systems of spreading rifts (e.g. Krafla), propagating rifts (e.g. Hekla) and off-rifts (Öræfajökull) also fall into high- and low-iron fields and outline a gap similar to Thingmúli. The identification of two compositional trends in erupted intermediate and silicic volcanic products shows that processes in the deep roots of single volcanic systems are highly diverse and likely controlled by local variations in the thermal gradients and the extend of hydrothermal alteration. Generalizations about the relationship between the compositions of intermediate and silicic rocks and plate tectonic setting, therefore, should be avoided.

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

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

References

  • Akselsson J (1946) A contribution to the geology of the Kerlingarfjöll. Acta Nat Island 1:1–15

    Google Scholar 

  • Annen C, Sparks RJS (2002) Effects of repetitive emplacement of basaltic intrusions on thermal evolution and melt generation in the crust. Earth Planet Sci Lett 203(3–4):937–955

    Article  Google Scholar 

  • Arculus R (2003) Use and abuse of the terms calcalkaline and calcalkalic. J Petrol 44(5):929–935

    Article  Google Scholar 

  • Asimow A, Ghiorso M (1998) Algorithmic modifications extending MELTS to calculate subsolidus phase relations. Am Mineral 83:1127–1131

    Google Scholar 

  • Beard J, Lofgren G (1991) Dehydration melting and water-saturated melting of basaltic and andesitic greenstones and amphibolites at 1.3 and 6.9 kb. J Petrol 32(2):365–401

    Article  Google Scholar 

  • Bourgeois O, Dauteuil O, Hallot E (2005) Rifting above a mantle plume: structure and development of the Iceland plateau. Geodin Acta 1:1–22

    Google Scholar 

  • Brophy JG (2009) La–SiO2 and Yb–SiO2 systematics in mid-ocean ridge magmas: implications for the origin of oceanic plagiogranite. Contrib Mineral Petrol 158(1):99–111

    Article  Google Scholar 

  • Carmichael ISE (1964) The petrology of Thingmúli, a tertiary volcano in eastern Iceland. J Petrol 5(3):435–460

    Article  Google Scholar 

  • Carmichael ISE (1967) The mineralogy of Thingmúli, a tertiary volcano in eastern Iceland. Am Mineral 52(11–1):1815–1841

    Google Scholar 

  • Carmichael ISE (1991) The redox states of basic and silicic magmas: a reflection of their source regions? Contrib Mineral Petrol 106(2):129–141

    Article  Google Scholar 

  • Charreteur G (2012) Intermediate and silicic rocks in accretion context: studies of the Thingmúli volcanic system and of the Rauðafell composite complex, eastern Iceland. Ph.D. Thesis, Aarhus University, Denmark

  • Charreteur G, Tegner C (2013) Magmatic emulsion texture formed by mixing during extrusion, Rauðafell composite complex, Breiðdalur volcano, eastern Iceland. Bull Volcan

  • Chekol TA, Kobayashi K, Yokoyama T, Sakaguchi C, Nakamura E (2011) Timescales of magma differentiation from basalt to andesite beneath Hekla Volcano, Iceland: constraints from U-series disequilibria in lavas from the last quarter-millennium flows. Geochim Cosmochim Acta 75:256–283

    Article  Google Scholar 

  • Daly RA (1925) The geology of Ascension Island. Proc Am Acad Arts Sci 60:1–80

    Article  Google Scholar 

  • Dick HJB, Ozawa K, Meyer PS, Niu Y, Robinson PT, Constantin M, Hebert R, Maeda J, Natland JH, Hirth JG and Mackie SM (2002). Primary silicate mineral chemistry of a 1.5-km section of very slow spreading lower ocean crust: ODP Hole 735B, Southwest Indian Ridge. In: Natland JH, Dick HJB, Miller DJ and Von Herzen RP (eds.). Proc ODP Sci Results, vol 176, pp 1–61

  • Elders WA, Fridleifsson GO, Zierenberg RA, Pope EC, Mortensen AK, Gudmundsson A, Lowenstern JB, Marks NE, Owens L, Bird DK, Reed M, Olsen NJ, Schiffman P (2011) Origin of a rhyolite that intruded a geothermal well while drilling at the Krafla volcano Iceland. Geology 39(3):231–234

    Article  Google Scholar 

  • Flude S, Mcgarvie DW, Burgess R, Tindle AG (2010) Rhyolites at Kerlingarfjoll, Iceland: the evolution and lifespan of silicic central volcanoes. Bull Volcanol 72:523–538

    Article  Google Scholar 

  • Foulger GR, Du Z, Julian BR (2003) Icelandic-type crust. Geophys J Int 155:567–590

    Article  Google Scholar 

  • Fridleifsson IB, Gibson IL, Hall JM, Johnson HP, Christensen NI, Schmincke HU, Schönharting G (1982) The Iceland research drilling project. J Geophys Res 87(B8):6359–6361

    Article  Google Scholar 

  • Frost BR, Lindsley DH (1992) Equilibria among Fe-Ti oxides, pyroxenes, olivine, and quartz: part II application. Am Mineral 77:1004–1020

    Google Scholar 

  • Geist D, Howard KA, Larson P (1995) The generation of oceanic rhyolites by crystal fractionation—the basalt-rhyolite association at volcan-alcedo, galapagos-archipelago. J Petrol 36(4):965–982

    Article  Google Scholar 

  • Ghiorso MS, Sack O (1995) Chemical mass transfer in magmatic processes. IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid-solid equilibria in magmatic systems at elevated temperatures and pressures. Contrib Mineral Petrol 119:197–212

    Article  Google Scholar 

  • Grönvold K (1972) Structural and petrochemical studies in the Kerlingarfjoll region, Central Iceland. Ph.D. Thesis, Oxford University

  • Grönvold K, Mäkipä H (1978) Chemical composition of Krafla lavas 1975–1977. Nordic Volcanological Institute Report vol 7816, pp 49

  • Haase KM, Stroncik NA, Hékinian R, Stoffer P (2005) Nb-depleted andesites from the Pacific-Antarctic Rise as analogs for early continental crust. Geology 33(12):921–924

    Article  Google Scholar 

  • Hards VL, Kempton PD, Thompson RN, Greenwood PB (2000) The magmatic evolution of the Snaefell volcanic centre; an example of volcanism during incipient rifting in Iceland. J Volcanol Geoth Res 99(1–4):97–121

    Article  Google Scholar 

  • Hémond C, Arndt NT, Lichtenstein U, Hofmann AW, Oskarsson N, Steinthorsson S (1993) The heterogeneous Iceland plume: Nd-Sr-O isotopes and trace element constraints. J Geophys Res 98(B9):15833–15850

    Article  Google Scholar 

  • Jakobsson SP, Jónasson K, Sigurdsson IA (2008) The three igneous rock series of Iceland. Jokull 58:117–138

    Google Scholar 

  • Jerram DA, Martin VM (2008) Understanding crystal populations and their significance through the magma plumbing system. Geol Soc Lond Special Publ 304(1):133–148. doi:10.1144/SP304.7

    Article  Google Scholar 

  • Jónasson K (1994) Rhyolite volcanism in the Krafla central volcano, north-east Iceland. Bull Volcanol 56(6):516–528

    Article  Google Scholar 

  • Jónasson K (2005) Magmatic evolution of the Heidarspordur ridge NE-Iceland. J Volcanol Geoth Res 147:109–124

    Article  Google Scholar 

  • Jónasson K (2007) Silicic volcanism in Iceland: composition and distribution within the active volcanic zones. J Geodynamics 43(1):101–117

    Article  Google Scholar 

  • Keiding JK, Sigmarsson O (2012) Geothermobarometry of the 2010 Eyjafjallajökull eruption: new constraints on Icelandic magma plumbing systems. J Geophys Res 117. doi:10.1029/2011JB008829

  • Kelemen PB (1995) Genesis of high Mg# andesites and the continental crust. Contrib Mineralog Petrol 120(1):1–19

    Article  Google Scholar 

  • Kelley DF, Barton M (2008) Pressures of crystallization of Icelandic magmas. J Petrol 49(3):465–492

    Article  Google Scholar 

  • Kitagawa H, Kobayashi K, Makishima A, Nakamura E (2008) Multiple pulses of the mantle plume: evidence from Tertiary icelandic lavas. J Petrol 49(7):1365–1396

    Article  Google Scholar 

  • Koepke J, Feig ST, Snow J, Freise M (2004) Petrogenesis of oceanic plagiogranites by partial melting of gabbros: an experimental study. Contrib Mineral Petrol 146(4):414–432

    Article  Google Scholar 

  • Kuritani T, Yokoyama T, Kitagawa H, Kobayashi K, Nakamura E (2011) Geochemical evolution of historical lavas from Askja Volcano, Iceland: implications for mechanisms and timescales of magmatic differentiation. Geochim Cosmochim Acta 75:570–587

    Article  Google Scholar 

  • Le Bas MJ, Le Maitre RW, Wooley AR (1992) The construction of the total alkali-silica chemical classification of volcanic rocks. Mineral Petrol 46(1):1–22

    Article  Google Scholar 

  • Macdonald R, Sparks RSJ, Sigurdsson H, Mattey DP, Mcgarvie DW, Smith RL (1987) The 1875 eruption of Askja volcano, Iceland: combined fractional crystallization and selective contamination in the generation of rhyolitic magma. Mineral Mag 51(2):183–202

    Article  Google Scholar 

  • Maclennan J, McKenzie D, Gronvöld K, Slater L (2001) Crustal accretion under northern Iceland. Earth Planet Sci Lett 191(3–4):295–310

    Article  Google Scholar 

  • Macpherson CG, Hilton DR, Day JMD, Lowry D, Grönvold K (2005) High-3He/4He depleted mantle and low-∂18O, recycled oceanic lithosphere in the source of central Iceland magmatism. Earth Planet Sci Lett 233:411–427

    Article  Google Scholar 

  • Martin E, Sigmarsson O (2007) Crustal thermal state and origin of silicic magma in Iceland: the case of Torfajokull, Ljosufjoll and Snaefellsjokull volcanoes. Contrib Mineral Petrol 153(5):593–605

    Article  Google Scholar 

  • Martin E, Sigmarsson O (2010) Thirteen million years of silicic magma production in Iceland: links between petrogenesis and tectonic settings. Lithos 116(1–2):129–144

    Article  Google Scholar 

  • Martin E, Martin H, Sigmarsson O (2008) Could Iceland be a modern analogue for the Earth’s early continental crust? Terra Nova 20:463–468

    Article  Google Scholar 

  • McBirney AR (1989) The Skaergaard layered series: I Structure and average compositions. J Petrol 30(2):363–397

    Article  Google Scholar 

  • Moorbath S, Sigurdsson H, Goodwin R (1968) K-Ar ages of the oldest exposed rocks in Earth Planet. Sci Lett 4(3):197–205

    Google Scholar 

  • Muehlenbachs K, Anderson AT, Sigavaldason GE (1974) Low-18O basalts from Iceland. Geochim Cosmochim Acta 38:577–588

    Article  Google Scholar 

  • Nichols ARL, Carroll MR, Horskuldsson Á (2002) Is the Iceland hot spot also wet? Evidence from the water contents of undegassed submarine and subglacial pillow basalts. Earth Planet Sci Lett 202(1):77–87

    Article  Google Scholar 

  • Nicholson KN, Condomines M, Fitton JG, Fallick AE, Gronvold K, Rogers G (1991) Geochemical and isotopic evidence for crustal assimilation beneath Krafla Iceland. J Petrol 32(5):1005–1020

    Article  Google Scholar 

  • Óskarsson N, Sigvaldason GE, Steinthorsson S (1982) A dynamic model of rift zone petrogenesis and the regional petrology of Iceland. J Petrol 23(1):28–74

    Article  Google Scholar 

  • Prestvik T (1980) Petrology of hybrid intermediate and silicic rocks from Öræfajökull, southeast Iceland. Föreningens i Stockholm Förhandlingar 101:299–307

    Article  Google Scholar 

  • Prestvik T, Goldberg S, Karlsson HR, Grönvold K (2001) Anomalous strontium and lead isotope signatures in the off-rift Öræfajökull central volcano in south-east Iceland: evidence for enriched endmember(s) of the Iceland mantle plume? Earth Planet Sci Lett 199(1):211–220

    Article  Google Scholar 

  • Rollinson H (2009) New models for the genesis of plagiogranites in the Oman ophiolite. Lithos 112(3–4):603–614

    Article  Google Scholar 

  • Sæmundsson K (1979) Outline of the geology of Iceland. Jökull 29:7–28

    Google Scholar 

  • Selbekk RS, Trønnes RG (2007) The 1362 AD Öraefajökull eruption, Iceland: petrology and geochemistry of large-volume homogeneous rhyolite. J Volcanol Geoth Res 160(1–2):42–58

    Article  Google Scholar 

  • Sigmarsson O, Hémond C, Condomines M, Fourcade S, Oskarsson N (1991) Origin of silicic magma in Iceland revealed by Th isotopes. J Geophys Res 19(6):621–624

    Google Scholar 

  • Sigmarsson O, Condomines M, Fourcade S (1992) A detailed Th, Sr and O isotope study of Hekla: differentiation processes in an Icelandic volcano. Contrib Mineral Petrol 112(1):20–34

    Article  Google Scholar 

  • Sigmarsson O, Karlsson HR, Larsen G (2000) The 1996 and 1998 subglacial eruptions beneath the Vatnajökull ice sheet in Iceland: contrasting geochemical and geophysical inferences on magma migration. Bull Volcanol 61(7):468–476

    Article  Google Scholar 

  • Sigurdsson H, Sparks SJ (1981) Petrology of rhyolitic and mixed magma ejecta from the 1875 eruption of Askja Iceland. J Petrol 22(1):41–84

    Article  Google Scholar 

  • Sigvaldasson GE (1969) Chemistry of basalts from Icelandic rift zone. Contrib Mineral Petrol 20:357–370

    Article  Google Scholar 

  • Sigvaldasson GE (2002) Volcanic and tectonic processes coinciding with glaciation and crustal rebound: an early Holocene rhyolitic eruption in the Dyngjufjoll volcanic centre and the formation of the Askja caldera, north Iceland. Bull Volcanol 64(3–4):192–205

    Article  Google Scholar 

  • Spulber SD, Rutherford MJ (1983) The origin of rhyolite and plagiogranite in oceanic crust: an experimental study. J Petrol 24(1):1–25

    Article  Google Scholar 

  • Steinthorsson S, Hardarson BS, Ellam RM, Larsen G (2000) Petrochemistry of the Gjálp-1996 subglacial eruption, Vatnajökull SE Iceland. J Volcanol Geoth Res 98(1–4):79–90

    Article  Google Scholar 

  • Stevenson JA, Mcgarvie DW, Smellie JL, Gilbert JS (2006) Subglacial and ice-contact volcanism at the Öræfajökull stratovolcano Iceland. Bull Volcanol 68(7):737–752

    Article  Google Scholar 

  • Sverrisdottir G (2007) Hybrid magma generation preceding Plinian silicic eruptions at Hekla, Iceland: evidence from mineralogy and chemistry of two zoned deposits. Geol Mag 144(4):643–659

    Article  Google Scholar 

  • Tegner C, Cawthorn RG, Kruger FJ (2006) Cyclicity in the main and upper zones of the Bushveld complex, South Africa: crystallization from a zoned magma sheet. J Petrol 47(11):2257–2279

    Article  Google Scholar 

  • Thorarinsson S (1958) The Öræfajökull eruption of 1362. Acta Nat Island., Náttúrugripsasn Íslands, Reykjavik. II, 99

  • Thy P, Beard J, Lofgren G (1990) Experimental constraints on the origin of Icelandic rhyolites. J Geol 98(3):417–421

    Article  Google Scholar 

  • Thy P, Lesher CE, Nielsen TFD, Brooks CK (2006) Experimental constraints on the Skaergaard liquid line of descent. Lithos 92:154–180

    Article  Google Scholar 

  • Thy P, Lesher CE, Nielsen TFD, Brooks CK (2008) On the Skaergaard intrusion and forward modeling of its liquid line of descent: a reply to “Principles of applied experimental igneous petrology” by Morse, 2008. Lithos 105:395–399 401–411

    Article  Google Scholar 

  • Toplis MJ, Carroll MR (1995) An experimental study of the influence of oxygen fugacity on Fe-Ti oxide stability, phase relations, and mineral-melt equilibria in ferro-basaltic systems. J Petrol 36(5):1137–1170

    Article  Google Scholar 

  • Walker GPL (1958) Geology of the Reyðarfjörðúr area, eastern Iceland. J Geol Soc 114(1–4):367–391

    Google Scholar 

  • Walker GPL (1963) The Breiðdalur central volcano, eastern Iceland. J Geol Soc 119(1–4):29–63

    Google Scholar 

  • Walker GPL (1966) Acid volcanic rocks in Iceland. Bull Volcanol 29(1):375–402

    Article  Google Scholar 

  • Watkins ND, Walker GPL (1977) Magnetostratigraphy of eastern Iceland. Am J Sci 277(5):513–584

    Article  Google Scholar 

  • Wilcox RE (1956) Petrology of Parícutin volcano, Mexico. Geological Survey Bulletin 965-C, pp 281–353

  • Willbold M, Hegner E, Stracke A, Rocholl A (2009) Continental geochemical signatures in dacites from Iceland and implications for models of early Archaean crust formation. Earth Planet Sci Lett 279(1–2):44–52

    Article  Google Scholar 

  • Wood DA (1978) Major and trace element variations in the tertiary lavas of eastern Iceland and their significance with respect to the Iceland geochemical anomaly. J Petrol 19(3):393–436

    Article  Google Scholar 

  • Wood DA (1979) Dynamic partial melting: its application to the petrogeneses of basalts erupted in Iceland, the Faeroe Islands, the Isle of Skye (Scotland) and the Troodos Massif (Cyprus). Geochim Cosmochim Acta 41:1033–1046

    Google Scholar 

  • Zellmer GF, Rubin KH, Grönvold K, Jurado-Chichay Z (2008) On the recent bimodal magmatic processes and their rates in the Torfajokull-Veidivotn area Iceland earth planet. Sci Lett 269(3–4):388–398

    Google Scholar 

Download references

Acknowledgments

Kristján E. Karlsson and Jakob K. Keiding are gratefully thanked for their help during fieldwork. We also thank Morten S. Riishuus, Erwan Hallot, Tod Waight, Valentin Troll and Peter Thy for their helpful comments on the manuscript. Funding from the Danish Agency for Science, Technology and Innovation, and from the Danish Natural Science Research Council is acknowledged. Journal reviews by Georg Zellmer and two anonymous reviewers and editorial handling by Jochen Hoefs improved the manuscript considerably and is appreciated.

Author information

Authors and Affiliations

  1. Department of Geoscience, Aarhus University, Aarhus C, Denmark

    Gilles Charreteur & Christian Tegner

  2. GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, 91054, Erlangen, Germany

    Karsten Haase

Authors
  1. Gilles Charreteur
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Christian Tegner
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Karsten Haase
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Christian Tegner.

Additional information

Communicated by J. Hoefs.

Electronic supplementary material

Rights and permissions

Reprints and permissions

About this article

Cite this article

Charreteur, G., Tegner, C. & Haase, K. Multiple ways of producing intermediate and silicic rocks within Thingmúli and other Icelandic volcanoes. Contrib Mineral Petrol 166, 471–490 (2013). https://doi.org/10.1007/s00410-013-0886-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00410-013-0886-1

Keywords

Search

Navigation