The Himalayan collision zone carbonatites in western Sichuan, SW China: Petrogenesis, mantle source and tectonic implication

Hou, Zhiyuan; Tian, Senlin; Zhong, Yuan; Xie, Yuling; Yin, Shuping; Yi, Liang; Fei, Hongcai; Yang, Zhiming

doi:10.1016/j.epsl.2006.01.052

Cited by 173 publications

(66 citation statements)

References 54 publications

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“…1.97-1.95 Ga Gabbros, syenogranites and carbonatites in Daqingshan Complex (Wan et al, 2008(Wan et al, , 2013aMa et al, 2012;Liu et al, 2013). The carbonatites have characteristic enrichments in Sr, Ba and REE combined with depletions in HFSE, similar to other carbonatites emplaced in post-collisional settings (Hou et al, 2006;Chakmouradian et al, 2008). This period of magmatism was accompanied by regional ca.…”

Section: Source Components For S-type Granitesmentioning

confidence: 89%

Paleoproterozoic S-type granites in the Helanshan Complex, Khondalite Belt, North China Craton: Implications for rapid sediment recycling during slab break-off

Wei

Wang

et al. 2014

Precambrian Research

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a b s t r a c t S-type granites, typically derived from the rapid recycling of sedimentary rocks, are sometimes accompanied by contemporary mafic magmatism and granulite metamorphism. However, the geodynamic context for such rock suites is often highly disputed, with various model proposed, including back-arc basin opening, lithospheric delamination, mantle plume and continental rifting. The Paleoproterozoic Khondalite Belt in the North China Craton provides an example of synchronous mafic and felsic magmatism that was accompanied by granulite-facies metamorphic events for which the tectonic affinities of these rocks remains unclear. This study integrates in situ zircon Hf-O isotope analyses, whole-rock geochemistry and Nd isotope results for the earliest two-mica granites (ca. 1.95 Ga) in order to provide constraints on the above issues. The granites are strongly peraluminous (A/CNK value >1.1), and characterized by high zircon ␦18 O values of 7.3-10.6‰, corresponding to calculated magmatic ␦ 18 O values of 9.1-12.3‰, similar to those of typical S-type granites. They have relatively high and homogeneous ε Nd (t) values of −1.1 to +0.9 and highly variable zircon ε Hf (t) values ranging from −1.0 to +8.3. In situ zircon Hf-O isotopic compositions indicate that the S-type granites may contain some mantle or juvenile crustal components in addition to a sediment component. Based on the new results and published data, a slab break-off model is proposed to explain the rapid recycling of sedimentary precursors and the generation of the ca. 1.95 Ga S-type granites.

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Section: Source Components For S-type Granitesmentioning

confidence: 89%

Paleoproterozoic S-type granites in the Helanshan Complex, Khondalite Belt, North China Craton: Implications for rapid sediment recycling during slab break-off

Wei

Wang

et al. 2014

Precambrian Research

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“…This belt of syenite-carbonatite igneous complexes, intruded into a Cenozoic collisional zone, is associated with several REE deposits including the giant Maoniuping deposit (Hou et al 2006(Hou et al , 2009Xu et al 2008). The syenite and associated carbonatite intrusions in this area have high Ba, Sr and LREE contents, but are low in the HFSE and are isotopically enriched (low e Nd , high 87 Sr/ 86 Sr).…”

Section: Discussionmentioning

confidence: 99%

“…They thus provide an excellent analogue for the Loch Loyal Syenite Complex and other enriched members of the CPMA. A component of subducted carbonate-rich pelagic sediment has been proposed as the source of the chemical characteristics of these Chinese magmas and hence also of the major REE deposits (Hou et al 2006). This igneous belt is thus a good analogue for the Northern Highlands igneous suite.…”

Section: Discussionmentioning

confidence: 99%

Enrichment of Rare Earth Elements during magmatic and post-magmatic processes: a case study from the Loch Loyal Syenite Complex, northern Scotland

Walters

Goodenough

Hughes

et al. 2013

Contrib Mineral Petrol

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Concern about security of supply of critical elements used in new technologies, such as the Rare Earth Elements (REE), means that it is increasingly important to understand the processes by which they are enriched in crustal settings. High REE contents are found in syenitedominated alkaline complexes intruded along the Moine Thrust Zone, a major collisional zone in north-west Scotland. The most northerly of these is the Loch Loyal Syenite Complex, which comprises three separate intrusions. One of these, the Cnoc nan Cuilean intrusion, contains two mappable zones: a Mixed Syenite Zone in which mafic melasyenite is mixed and mingled with leucosyenite and a Massive Leucosyenite Zone. Within the Mixed Syenite Zone, hydrothermal activity is evident in the form of narrow altered veins dominated by biotite and magnetite; these are poorly exposed and their lateral extent is uncertain. The REE mineral allanite is relatively abundant in the melasyenite and is extremely enriched in the biotite-magnetite veins, which have up to 2 % total rare earth oxides in bulk rock analyses. An overall model for development of this intrusion can be divided into three episodes: (1) generation of a Light Rare Earth Element (LREE)-enriched parental magma due to enrichment of the mantle source by subduction of pelagic carbonates; (2) early crystallisation of allanite in melasyenite, due to the saturation of the magma in the LREE; and (3) hydrothermal alteration, in three different episodes identified by petrography and mineral chemistry, generating the intense enrichment of REE in the biotite-magnetite veins. Dating of allanite and titanite in the biotite-magnetite veins gives ages of c. 426 Ma, overlapping with previously published crystallisation ages for zircon in the syenite.

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“…The observation that OIB are more enriched in the porogressively more incompatible elements (Figure 6) requires that the metasomatic agents are incipient H 2 O-and CO 2 -rich silicate melts. It is important to note that carbonatite melt as a metasomatic agent has become popular in the last few years [70−72] , but carbonatite melts have variably different trace element systematics from OIB [73,74] and would be compositionally unsuitable as metasomatic agents for OIB.…”

Section: The Nature Of Metasomatic Agentsmentioning

confidence: 99%

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

Niu

2009

Chin. Sci. Bull.

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Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm] PM <1) to be source material for highly enriched (e.g., [La/Sm] PM >> 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm] PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H 2 O and CO 2 rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2) the melt layer, and (3) assimilation of the metasomatic vein lithologies formed earlier in the growing/grown lithosphere. It is probable that the fertile source material from depth may be (or contain) recycled ancient metasomatized deep portions of oceanic lithosphere. In any attempt to explain the origin of mantle isotopic end-members as revealed from global OIB data, we must (1) remember our original assumptions that the primitive mantle (PM) soon after the core separation was compositionally uniform/homogeneous with the core playing a limited or no role in causing mantle isotopic heterogeneity; (2) not use OIB isotopes to conclude about the nature and compositions of ultimate source materials without understanding geochemical consequences of subduction zone metamorphism; and (3) ensure that models and hypotheses are consistent with the basic petrology and major/trace element geochemistry. ocean islands, intra-plate magmatism, mantle source heterogeneity, mantle metasomatism, seismic low velocity zone processesThe above is a widely circulated attribution to Albert Einstein without a known source. T...

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The Himalayan collision zone carbonatites in western Sichuan, SW China: Petrogenesis, mantle source and tectonic implication

Cited by 173 publications

References 54 publications

Paleoproterozoic S-type granites in the Helanshan Complex, Khondalite Belt, North China Craton: Implications for rapid sediment recycling during slab break-off

Paleoproterozoic S-type granites in the Helanshan Complex, Khondalite Belt, North China Craton: Implications for rapid sediment recycling during slab break-off

Enrichment of Rare Earth Elements during magmatic and post-magmatic processes: a case study from the Loch Loyal Syenite Complex, northern Scotland

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

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