Post-collision, Shoshonitic Volcanism on the Tibetan Plateau: Implications for Convective Thinning of the Lithosphere and the Source of Ocean Island Basalts

Turner, Simon; Arnaud, Nicolas; Liu, J.; Rogers, Nick; Hawkesworth, Chris J.; Harris, Nigel; Kelley, S. P.; Calsteren, Peter van; Deng, Wenfeng

doi:10.1093/petrology/37.1.45

Cited by 927 publications

(626 citation statements)

References 64 publications

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“…The localities are as follows (from east to west): 1, Linzhi (Chung et al, 2003); 2, Jiama (Hou et al, 2004, the present study); 3, Qulong (Hou et al, 2004); 4, Lakang'e (Hou et al, 2004, the present study); 5, Nanmu (Hou et al, 2004); 6, Nemu (Hou et al, 2004, the present study); 7, Maquiang (Turner et al, 1996); 8, Xigaze (Chung et al, 2003); 9, Daggyaio Tso (Williams et al, 2004); 10, Manasarowar and Gegar (Miller et al, 1999); 11, Bangba (the present study); 12, Shiduo (Cai et al, 2005); 13, Shiquanhe (Guo et al, 2007); and 14, Ritu (Cai et al, 2005). The adakitic rocks in the Tethyan Himalayan tectonic zone are as follows: 15 Mayum and 16 Kuday (King et al, 2007).…”

Section: Analytical Techniquesmentioning

confidence: 57%

Geochemical variations in Miocene adakitic rocks from the western and eastern Lhasa terrane: Implications for lower crustal flow beneath the Southern Tibetan Plateau

Chen

Zhao

et al. 2011

Lithos

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Section: Analytical Techniquesmentioning

confidence: 57%

Geochemical variations in Miocene adakitic rocks from the western and eastern Lhasa terrane: Implications for lower crustal flow beneath the Southern Tibetan Plateau

Chen

Zhao

et al. 2011

Lithos

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“…One of the most studied collisional orogens is the Tethyan belt (Şengör & Kidd, 1979;Turner et al 1996;Gao et al 2010) extending from the Alps to the Himalayas. Large portions of this belt are characterized by complex collisional processes involving continental blocks that were separated from the northern Gondwana margin (Stocklin, 1974;Berberian & King, 1981;Stampfli, 2000).…”

Section: Post-collisional Shaivar Dagh Pluton Iranmentioning

confidence: 99%

“…The so-called post-collisional magmatism is the most characteristic petrologic feature of many, but not all, orogenic environments related to continent-continent collision. The establishment (Venturelli et al 1984), Hercynian (Ajaji et al 1998;López-Moro & López-Plaza, 2004) and Himalayan (Turner et al 1996;Williams et al 2004;Gao et al 2010) belts. Several studies have been performed on the Zagros belt supplying valuable information about petrogenesis and age relationships of magmatism (Haschke et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

et al. 2011

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-The petrological and geochronological study of the Cenozoic Shaivar Dagh composite intrusion in the Alborz Mountain belt (NW Iran) reveals important clues to decipher complex relations between magmatic and tectonic processes in the central sectors of the Tethyan (Alpine-Himalayan) orogenic belt. This pluton is formed by intrusion at different times of two main magmatic cycles. The older (Cycle 1) is formed by calc-alkaline silicic rocks, which range in composition from diorites to granodiorites and biotite granites, with abundant mafic microgranular enclaves. The younger cycle (Cycle 2) is formed by K-rich monzodiorite and monzonite of marked shoshonitic affinity. The latter form the larger volumes of the exposed plutonic rocks in the studied complex. Zircon geochronology (laser ablation ICP-MS analyses) gives a concordia age of 30.8 ± 2.1 Ma for the calc-alkaline rocks (Cycle 1) and a range from 23.3 ± 0.5 to 25.1 ± 0.9 Ma for the shoshonitic association (Cycle 2). Major and trace element relations strongly support distinct origins for each magmatic cycle. Rocks of Cycle 1 have all the characteristic features of active continental margins. Shoshonitic rocks (Cycle 2) define two continuous fractionation trends: one departing from a K-rich basaltic composition and the other from an intermediate, K-rich composition. A metasomatized-mantle origin for the two shoshonitic series of Cycle 2 is proposed on the basis of comparisons with experimental data. The origin of the calc-alkaline series is more controversial but it can be attributed to processes in the suprasubduction mantle wedge related to the incorporation of subducted mélanges in the form of silicic cold plumes. A time sequence can be established for the processes responsible of the generation of the two magmatic cycles: first a calc-alkaline cycle typical of active continental margins, and second a K-rich cycle formed by monzonites and monzodiorites. This sequence precludes the younger potassic magmas as precursors of the older calc-alkaline series. By contrast, the older calc-alkaline magmas may represent the metasomatic agents that modified the mantle wedge during the last stages of subduction and cooked a fertile mantle region for late potassic magmatism after continental collision.

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“…Discussion 9.1. Relationships between the cumulate, high-K ankaramites and associated mafic shoshonites Shoshonitic magmas are widespread in continental arc settings such as the Aeolian Volcanic Arc (Francalanci et al, 2007), the Eastern Rhodopes, Bulgaria (Marchev et al, 2004), the Tibetan Plateau (Turner et al, 1996), the Mexican Volcanic Belt (Blatter et al, 2001) and, more rarely, in back-arc settings or oceanic island arcs (e.g. Izu-BoninMariana arc; Sun and Stern, 2001).…”

Section: Diffusion Of Fe and Ca From The Melt Inclusions Into Olivinementioning

confidence: 99%

High-K ankaramitic melt inclusions and lavas in the Upper Cretaceous Eastern Srednogorie continental arc, Bulgaria: Implications for the genesis of arc shoshonites

Marchev

Georgiev

Zajacz

et al. 2009

Lithos

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The Upper Cretaceous Yambol-Burgas region of the Eastern Srednogorie continental arc is characterized by unusually large volumes of mafic shoshonitic and ultra-K magmatism represented by high-Mg cumulitic rocks, and nepheline-normative ankaramites, absarokites and shoshonitic (high-alumina) basalts. The cumulitic rocks consist of phenocrysts of clinopyroxene and olivine ) with inclusions of spinel (Cr#75-78). Olivine high-Fo cores and clinopyroxene host glassy melt inclusions which have nephelinenormative compositions with ankaramitic CaO/Al 2 O 3 ratios (N 1), low SiO 2 (47.4-50.0 wt.%), high MgO (7.5-10.8 wt.%), high total alkalis and shoshonitic K 2 O/Na 2 O ratios (N1). Electron microprobe and LA-ICPMS analyses demonstrate that parental magma was a high-Ca primitive mantle melt. Melt inclusions from the less Fo 85 rim approach absarokite composition with CaO/Al 2 O 3 ratios b 1, lower MgO (5.2 wt.%), and higher total alkalis and K 2 O/Na 2 O ratio. The ankaramitic rocks are strongly porphyritic, composed of phenocrysts of altered olivine with spinel inclusions and large clinopyroxene. Their major and trace element compositions are similar to those of melt inclusions hosted in the high-Fo 91-90 cores and clinopyroxene of the cumulitic rock. The absarokites differ from the high-K ankaramites by slightly higher SiO 2 (50.6-52.7 wt.%), Al 2 O 3 and alkali-oxide contents, lower FeO and MgO and particularly low CaO/Al 2 O 3 (0.6-0.9) ratio. Compared to the absarokites, shoshonitic basalts have similar SiO 2 (50.2-52.8 wt.%) at lower MgO contents and CaO/Al 2 O 3 ratios (0.37-0.53). The presented extensive set of major and trace element data on melt inclusions and whole rocks, along with their main phenocryst compositions, is used to constrain the crystallization temperatures and pressures of the most primitive ankaramites. We suggest that ankaramite compositions are formed by melting of a garnet-free metasomatized mantle source rather than by melting of lower crustal cumulates. Numerical modelling demonstrates that the generation of absarokites and shoshonitic basalts is compatible with fractionation of olivine and clinopyroxene from ankaramitic magma. The high-Mg chemistry of cumulitic rocks is explained as the result of accumulation of these minerals.

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Post-collision, Shoshonitic Volcanism on the Tibetan Plateau: Implications for Convective Thinning of the Lithosphere and the Source of Ocean Island Basalts

Cited by 927 publications

References 64 publications

Geochemical variations in Miocene adakitic rocks from the western and eastern Lhasa terrane: Implications for lower crustal flow beneath the Southern Tibetan Plateau

Geochemical variations in Miocene adakitic rocks from the western and eastern Lhasa terrane: Implications for lower crustal flow beneath the Southern Tibetan Plateau

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

High-K ankaramitic melt inclusions and lavas in the Upper Cretaceous Eastern Srednogorie continental arc, Bulgaria: Implications for the genesis of arc shoshonites

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