Thermal and chemical structure of the Iceland plume

Fitton, J. Godfrey; Saunders, Andrew D.; Norry, Michael J; Harðarson, Björn S.; Taylor, Rex N.

doi:10.1016/s0012-821x(97)00170-2

Cited by 602 publications

(499 citation statements)

References 34 publications

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“…1). While the association of positive TITAN anomalies and high 3 He/ 4 He (or plume) signatures were previously observed regionally in Hawaii (Dixon et al, 2001), Iceland (Fitton, 1997) and the Galapagos (Kurz and Geist, 1999;Saal et al, 2007), we suggest that the large, positive TITAN anomalies are a global phenomenon in high 3 He/ 4 He OIBs. The primitive-mantle normalized trace element patterns (spidergrams) of the highest 3 He/ 4 He lavas from Hawaii, Iceland, Galapagos and Samoa all share prominent, anomalous enrichment in the TITAN elements compared to elements of similar compatibility in peridotite (Fig.…”

Section: New Data and Observationssupporting

confidence: 65%

Dismantling the deep earth : geochemical constraints from hotspot lavas for the origin and lengthscales of mantle heterogeneity

Jackson¹

2008

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AcknowledgementsFirst off, I want to thank my advisor, Stan Hart, for being so generous, with his time, his resources, and his thoughts. Stan sent me to the edges of the earth to collect rocks on islands and by sea ("a happy student is a traveling student"). And the fishing trips didn't end when I got back to the lab. When I went to him for answers, I often just ended up with more questions, we'd dream up a dozen projects, and he'd send me off with more projects and questions (back in my office, I'd realize that the meeting didn't go as I'd planned)! But the questions were more important than the answers: the questions will keep me employed after I graduate! It's only now that I'm realizing that without so much independence to explore (though frightening at times), I may have never understood that I was capable of generating some fun ideas! I can't express my gratitude to Nobu Shimizu and Mark Kurz for their "open door" policy. They are always ready to give me time, sit down, and hash out new ideas. Their offices are idea factories. I don't know how I would have written this thesis without their constant input.My deepest appreciation to J. Collins for sweating it out with me in the field in Samoa, and to the rest of my committee, P. Kelemen, Erik Hauri and Fred Frey for their stimulating input and for traveling so far to attend the general exam, thesis defense, and committee meetings.J. Blusztajn has always been so optimistic and helpful, and has given me so much of his time and advice. J. Curtice and T. Atwood have also given me dollops of help, and without them I could not have accomplished much of the thesis work.I am so thankful for the friendship of my dear friends, S. Hoffmann, D. Stuebe and J. Blythe, Heidi Marcella, Carolyn Walker, Lauge Sokol-Hessner and Hannah Cole. They kept me going when the times were rough, and we shared many of the best times as well.I am also thankful for the friendship and advice that I received from the "old guard" of JP students, who left the WHOI "nest" before me.

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Section: New Data and Observationssupporting

confidence: 65%

Dismantling the deep earth : geochemical constraints from hotspot lavas for the origin and lengthscales of mantle heterogeneity

Jackson¹

2008

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“…These caveats also do not hold for Icelandic tholeiites and normal mid-ocean ridge basalts (N-MORB). Fitton et al (1997) showed that Icelandic basalts and normal mid-ocean ridge basalts (N-MORB) define parallel tight arrays on a plot of log(Nb/Y) vs. log(Zr/Y), with N-MORB relatively poor in Nb (Fig. 9).…”

Section: Identifying a Recycled Component In The Western Ghats Lavas:mentioning

confidence: 99%

“…9. The Western Ghats lavas, Deccan Traps (Beane, 1988) on the log(Nb/Y) vs. log(Zr/Y) diagram of Fitton et al (1997). The Icelandic basalt array is also shown.…”

Section: The Volume Of Eclogite and Eclogitegenerated Meltmentioning

confidence: 99%

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Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Sheth¹

2005

Gondwana Research

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Deep mantle plumes supposedly incorporate deeply subducted eclogitized oceanic crust, and continental flood basalts (CFBs) are now thought by some to be derived from such eclogite-bearing peridotite plumes. Eclogite-peridotite mixtures have much lower solidi (and produce much greater melt fractions for a given temperature) than peridotite. Ferich (eclogite-or pyroxenite-bearing) sources have been inferred for many CFBs. However, plumes with considerable amounts of eclogite should have difficulty in upwelling owing to the high density of eclogite. Besides, CFBs are always located along pre-existing lithospheric structures (suture zones, edges of thick cratons) and commonly associated with lithospheric rifting and continental breakup. India's major late Mesozoic CFB, the Deccan Traps, erupted through rift zones and a new continental margin that had developed along ancient suture zones traversing the subcontinent. Many Deccan basalts are too Fe-rich to have been in equilibrium with a peridotite mantle source, and have commonly been considered to be significantly fractionated derivatives of picritic liquids. However, it is possible to view them as relatively less evolved liquids derived from a source with extra fertility (i.e., an Fe-rich source). A new non-plume, plate tectonic model for Icelandic hotspot volcanism involves melting of a shallowly recycled slab of eclogitized Iapetus oceanic crust formerly trapped along the Caledonian suture. The model explains the geochemical-petrological characteristics of Icelandic basalts, and is consistent with passive upper mantle upwelling under Iceland inferred from recent seismic tomography. Based on the petrological and geochemical features of the Deccan flood basalts of the type section, in the Western Ghats, I propose that old, eclogitized oceanic crust trapped in the ancient Indian suture zones could have produced voluminous basaltic melts during the Deccan event.

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“…The subalka- line mafic dyke plots on a trend toward the area above the mantle array in the arc-back-arc field. On the Zr/Y-Nb/Y diagram (Fitton et al 1997), the mafic dykes as well as all other investigated mafic rocks groups plot above the ΔNb line [ΔNb =1.74 + log (Nb / Y) −1.92 log (Zr/Y)], inside of the plume field (Condie 2005) at relatively high Zr/Y values within the OPB (oceanic plateau basalt) and OIB fields. However, the subalkaline mafic dyke plots within depleted mantle with lower Zr/Y values (Fig.…”

Section: Tectonic Implicationsmentioning

confidence: 99%

Geochemical and isotopic evidence for Carboniferous rifting: mafic dykes in the central Sanandaj-Sirjan zone (Dorud-Azna, West Iran)

Shakerardakani¹,

Neubauer²,

Bernroider³

et al. 2017

Geologica Carpathica

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Abstract:In this paper, we present detailed field observations, chronological, geochemical and Sr-Nd isotopic data and discuss the petrogenetic aspects of two types of mafic dykes, of alkaline to subalkaline nature. The alkaline mafic dykes exhibit a cumulate to foliated texture and strike NW-SE, parallel to the main trend of the region. The 40 Ar/ 39 Ar amphibole age of 321.32 ± 0.55 Ma from an alkaline mafic dyke is interpreted as an indication of Carboniferous cooling through ca. 550 °C after intrusion of the dyke into the granitic Galeh-Doz orthogneiss and Amphibolite-Metagabbro units, the latter with Early Carboniferous amphibolite facies grade metamorphism and containing the Dare-Hedavand metagabbro with a similar Carboniferous age. The alkaline and subalkaline mafic dykes can be geochemically categorized into those with light REE-enriched patterns [(La/Yb) N = 8.32-9.28] and others with a rather flat REE pattern [(La/Yb) N = 1.16] and with a negative Nb anomaly. Together, the mafic dykes show oceanic island basalt to MORB geochemical signature, respectively. This is consistent, as well, with the (Tb/Yb) PM ratios. The alkaline mafic dykes were formed within an enriched mantle source at depths of ˃ 90 km, generating a suite of alkaline basalts. In comparison, the subalkaline mafic dykes were formed within more depleted mantle source at depths of ˂ 90 km. The subalkaline mafic dyke is characterized by 87 Sr/ 86 Sr ratio of 0.706 and positive ɛ Nd (t) value of + 0.77, whereas 87 Sr/ 86 Sr ratio of 0.708 and ɛ Nd (t) value of + 1.65 of the alkaline mafic dyke, consistent with the derivation from an enriched mantle source. There is no evidence that the mafic dykes were affected by significant crustal contamination during emplacement. Because of the similar age, the generation of magmas of alkaline mafic dykes and of the Dare-Hedavand metagabbro are assumed to reflect the same process of lithospheric or asthenospheric melting. Carboniferous back-arc rifting is the likely geodynamic setting of mafic dyke generation and emplacement. In contrast, the subalkaline mafic sill is likely related to the emplacement of the Jurassic Darijune gabbro.

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Thermal and chemical structure of the Iceland plume

Cited by 602 publications

References 34 publications

Dismantling the deep earth : geochemical constraints from hotspot lavas for the origin and lengthscales of mantle heterogeneity

Dismantling the deep earth : geochemical constraints from hotspot lavas for the origin and lengthscales of mantle heterogeneity

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Geochemical and isotopic evidence for Carboniferous rifting: mafic dykes in the central Sanandaj-Sirjan zone (Dorud-Azna, West Iran)

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