A topaz- and amazonite-bearing leucogranite pluton in eastern Xinjiang, NW China and its zoning

Gu, Ling; Zunzhong, Zhang; Wu, Chunping; Xiaoqin, Gou; Liao, Jingjuan; Yang, Hao

doi:10.1016/j.jseaes.2010.12.010

Cited by 32 publications

(22 citation statements)

References 59 publications

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“…Niobium and Ta form F-complexes, which explain the missing continental signature of an Nb-dip in our hypersolvus granite spidergrams (Fig. 7, Table 6; Jahn et al 2001;Gu et al 2011 and authors referenced by them). Other designs of multi-element diagrams (e.g.…”

Section: Trace Elementsmentioning

confidence: 66%

“…He calculated them as NaCl-equivalents; a recalculation into NaF-equivalents gives a significantly lower, but still high salinity. Jahn et al (2001) and Gu et al (2011) emphasise the importance of F for the element distribution in granitic melts. Gu et al (2011) specifically mentioned Ga, Hf, Nb, Fig.…”

Section: Trace Elementsmentioning

confidence: 99%

“…Jahn et al (2001) and Gu et al (2011) emphasise the importance of F for the element distribution in granitic melts. Gu et al (2011) specifically mentioned Ga, Hf, Nb, Fig. 13 Cartoon showing the proposed evolution model; not to scale.…”

Section: Trace Elementsmentioning

confidence: 99%

“…Table 6) to follow F. We may add U, Y and the HREEs to this list (Table 6). Ga and Sn form complexes with F (Gu et al 2011 and authors referenced by them), which explains why these elements follow F. The F-enriched (hypersolvus) granite has a lower Zr/Hf ratio than the subsolvus one (Tables 2, 5, 6); this is expected from the results presented by Jahn et al (2001) and from the listed elements of Gu et al (2011). Niobium and Ta form F-complexes, which explain the missing continental signature of an Nb-dip in our hypersolvus granite spidergrams (Fig.…”

Section: Trace Elementsmentioning

confidence: 99%

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A model for granite evolution based on non-equilibrium magma separation: evidence from the Gharib and Qattar fluorite-bearing granites, Eastern Desert, Egypt

Lindh

El-Rus

Mohamed

et al. 2019

Int J Earth Sci (Geol Rundsch)

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We present 77 new granite whole-rock analyses from the Qattar and Gharib areas, Eastern Desert, Egypt. Both areas include a "normal" granite and either a hypersolvus (Gharib) or an almost plagioclase-free granite (Qattar) enriched in fluorite. According to earlier results, F influences element distribution in granitic melts forming complexes with specific elements as Nb, Ta, Ga, Hf, Th, Zn, Sn, whereas F excludes Ba and Sr. We use principal component analyses to split the granite into chemical groups allowing an unbiased study of the inter-group element distribution. This adds the heavy REEs and Y to the earlier lists of elements with an affinity for F. The light REEs show a decreasing affinity with decreasing atomic mass; fluorine separates Sm from Nd, whereas Zr follows La. Opposite to some, but in accordance with other earlier results, the ratio Nb/Ta is higher in the fluorite-enriched than in the other granite. Weak tetrad effects are present. Zircon in the hypersolvus granite is high in common lead. We suggest F to be instrumental for separating Pb 2+ from Pb 4+ . Two hypotheses may explain the occurrence of the two contrasting granites: they have either different sources, or they are co-magmatic, but the magma was split into two discrete types. We apply the second hypothesis as our working hypothesis. The liquidus has a gentler slope with pressure than the diapir requiring crystallisation to be most important in the lower part of the magma chamber. Our hypothesis suggests that globules of magma, enriched in volatile components, form during crystallisation due to slow diffusion rates in the crystallizing magma. Elements accompanying F are distributed into this magma batch, which has a lowered density and viscosity than the rest of the magma due to its increased contents of volatile components. A mushroom-formed diapir rises, forming the hypersolvus (or almost plagioclase-free) granite. Due to an edge effect, it is concentrated close to the wall of the magma chamber. The size and form of the outcropping granite depend on the intersection of the diapir with the erosion surface. Fluorine only makes it possible to follow the process. The model may be generalised to explain the diversification of non-F enriched granite, since the buoyancy of a magma batch several thousand m 3 in size has a much larger impact on the system than the small negative buoyancy of crystals or small crystal aggregates. A-type granite classified merely from its trace element content may form from separated F-enriched magma batches. This may be the reason for their high frequency in the Eastern Desert.

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Section: Trace Elementsmentioning

confidence: 66%

Section: Trace Elementsmentioning

confidence: 99%

Section: Trace Elementsmentioning

confidence: 99%

Section: Trace Elementsmentioning

confidence: 99%

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A model for granite evolution based on non-equilibrium magma separation: evidence from the Gharib and Qattar fluorite-bearing granites, Eastern Desert, Egypt

Lindh

El-Rus

Mohamed

et al. 2019

Int J Earth Sci (Geol Rundsch)

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“…The rotations mentioned above might have been accommodated by Late Permian to Early Triassic strike-slip faults with a displacement estimated at 1570 ± 280 km along the Irtysh-Gornotsaev Shear Zone, 410 ± 380 km along the Nikolaiev-Nalati Tectonic Line, and 490 ± 250 km along the Chingiz-Alakol-North Tian Shan Fault since Late Permian time. Gu et al (2011) reported a topaz-and amazonite-bearing leucogranite pluton in eastern Xinjiang. This pluton exhibits five well-exposed lithological zones including, from the lowest level, leucogranite (zone-a), amazonite-bearing granite (zone-b), amazonite granite (zone-c), topaz-bearing amazonite granite (zone-d) and topaz albite granite (zone-e).…”

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confidence: 99%

Continental accretion and intra-continental deformation of the Central Asian Orogenic Belt

Zhu

Charvet

Xiao

et al. 2011

Journal of Asian Earth Sciences

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Introduction

Su¹

2014

Springer Theses

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A topaz- and amazonite-bearing leucogranite pluton in eastern Xinjiang, NW China and its zoning

Cited by 32 publications

References 59 publications

A model for granite evolution based on non-equilibrium magma separation: evidence from the Gharib and Qattar fluorite-bearing granites, Eastern Desert, Egypt

A model for granite evolution based on non-equilibrium magma separation: evidence from the Gharib and Qattar fluorite-bearing granites, Eastern Desert, Egypt

Continental accretion and intra-continental deformation of the Central Asian Orogenic Belt

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