Back-arc basin evolution in the southern Lhasa sub-terrane, southern Tibet: Constraints from U-Pb ages and in-situ Lu-Hf isotopes of detrital zircons

2019 ◽  
Vol 185 ◽  
pp. 104026 ◽  
Author(s):  
Yuanku Meng ◽  
Walter D. Mooney ◽  
Yuan Ma ◽  
Han Xu ◽  
Rongzhen Tang
Keyword(s):  
Detrital Zircons ◽  
Hf Isotopes ◽  
Basin Evolution ◽  
Southern Tibet ◽  
Back Arc

scholarly journals Significant Zr isotope variations in single zircon grains recording magma evolution history

2020 ◽  
Vol 117 (35) ◽  
pp. 21125-21131 ◽  
Author(s):  
Jing-Liang Guo ◽  
Zaicong Wang ◽  
Wen Zhang ◽  
Frédéric Moynier ◽  
Dandan Cui ◽  
...  
Keyword(s):  
Isotopic Fractionation ◽  
Major Type ◽  
Strong Temperature Dependence ◽  
Calc Alkaline ◽  
Southern Tibet ◽  
Rayleigh Distillation ◽  
Single Zircon ◽  
Magmatic History ◽  
Fractionation Factors

Zircons widely occur in magmatic rocks and often display internal zonation finely recording the magmatic history. Here, we presented in situ high-precision (2SD <0.15‰ for δ94Zr) and high–spatial-resolution (20 µm) stable Zr isotope compositions of magmatic zircons in a suite of calc-alkaline plutonic rocks from the juvenile part of the Gangdese arc, southern Tibet. These zircon grains are internally zoned with Zr isotopically light cores and increasingly heavier rims. Our data suggest the preferential incorporation of lighter Zr isotopes in zircon from the melt, which would drive the residual melt to heavier values. The Rayleigh distillation model can well explain the observed internal zoning in single zircon grains, and the best-fit models gave average zircon–melt fractionation factors for each sample ranging from 0.99955 to 0.99988. The average fractionation factors are positively correlated with the median Ti-in-zircon temperatures, indicating a strong temperature dependence of Zr isotopic fractionation. The results demonstrate that in situ Zr isotope analyses would be another powerful contribution to the geochemical toolbox related to zircon. The findings of this study solve the fundamental issue on how zircon fractionates Zr isotopes in calc-alkaline magmas, the major type of magmas that led to forming continental crust over time. The results also show the great potential of stable Zr isotopes in tracing magmatic thermal and chemical evolution and thus possibly continental crustal differentiation.

scholarly journals Supplemental Material: Protracted northward drifting of South China during the assembly of Gondwana: Constraints from the spatial-temporal provenance comparison of Neoproterozoic–Cambrian strata

2020 ◽  
Author(s):  
Qiong Chen ◽  
Guochun Zhao ◽  
et al.
Keyword(s):  
South China ◽  
Detrital Zircons ◽  
Isotopic Data

Table S1: In-situ U-Pb ages and Hf isotopic data of detrital zircons from the Neoproterozoic–Cambrian samples from the western and eastern margins of South China.

The continental crust contributes to magmatic hydrothermal gold deposit in Ciemas, West Java, Indonesia: Constraints from Hf isotopes of zircons and in situ Pb isotopes of sulfides

2019 ◽  
Vol 112 ◽  
pp. 103010 ◽  
Author(s):  
Chengquan Wu ◽  
Zhengwei Zhang ◽  
Mega Fatimah Rosana ◽  
Qiao Shu ◽  
Chaofei Zheng ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Continental Crust ◽  
Pb Isotopes ◽  
Hf Isotopes ◽  
West Java

Early Carboniferous Back‐Arc Rifting‐Related Magmatism in Southern Tibet: Implications for the History of the Lhasa Terrane Separation From Gondwana

Tectonics ◽  
2020 ◽  
Vol 39 (10) ◽  
Author(s):  
Xuhui Wang ◽  
Xinghai Lang ◽  
Juxing Tang ◽  
Yulin Deng ◽  
Qing He ◽  
...  
Keyword(s):  
Early Carboniferous ◽  
Southern Tibet ◽  
Lhasa Terrane ◽  
History Of ◽  
Back Arc

The petrogenesis of back-arc magmas, constrained by zircon O and Hf isotopes, in the Frontal Cordillera and Precordillera, Argentina

2020 ◽  
Vol 175 (9) ◽  
Author(s):  
Gregory H. Poole ◽  
Anthony I. S. Kemp ◽  
Steffen G. Hagemann ◽  
Marco L. Fiorentini ◽  
Heejin Jeon ◽  
...  
Keyword(s):  
Hf Isotopes ◽  
Arc Magmas ◽  
Back Arc

scholarly journals Detrital Zircon U-Pb-Hf Isotopes of Middle Neoproterozoic Sedimentary Rocks in the Altyn Tagh Orogen, Southeastern Tarim: Insights for a Tarim-South China-North India Connection in the Periphery of Rodinia

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 1-10
Author(s):  
Qian Liu ◽  
Guochun Zhao ◽  
Jianhua Li ◽  
Jinlong Yao ◽  
Yigui Han ◽  
...  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
North India ◽  
Hf Isotopes ◽  
Altyn Tagh ◽  
Tarim Craton ◽  
Rodinia Supercontinent ◽  
New Perspective

Abstract The location of the Tarim craton during the assembly and breakup of the Rodinia supercontinent remains enigmatic, with some models advocating a Tarim-Australia connection and others a location at the heart of the unified Rodinia supercontinent between Australia and Laurentia. In this study, our new zircon U-Pb dating results suggest that middle Neoproterozoic sedimentary rocks in the Altyn Tagh orogen of the southeastern Tarim craton were deposited between ca. 880 and 760 Ma in a rifting-related setting slightly prior to the breakup of Rodinia at ca. 750 Ma. A compilation of existing Neoproterozoic geological records also indicates that the Altyn Tagh orogen of the southeastern Tarim craton underwent collision at ca. 1.0-0.9 Ga and rifting at ca. 850-600 Ma related to the assembly and breakup of Rodinia. Furthermore, in order to establish the paleoposition of the Tarim craton with respect to Rodinia, available detrital zircon U-Pb ages and Hf isotopes from Meso- to Neoproterozoic sedimentary rocks were compiled. Comparable detrital zircon ages (at ca. 0.9, 1.3-1.1, and 1.7 Ga) and Hf isotopes indicate a close linkage among rocks of the southeastern Tarim craton, Cathaysia, and North India but exclude a northern or western Australian affinity. In addition, detrital zircons from the northern Tarim craton exhibit a prominent age peak at ca. 830 Ma with minor spectra at ca. 1.9 and 2.5 Ga but lack Mesoproterozoic ages, comparable to the northern and western Yangtze block. Together with comparable geological responses to the assembly and breakup of the Rodinia supercontinent, we offer a new perspective of the location of the Tarim craton between South China and North India in the periphery of Rodinia.

Resistance of zircons to U–Pb resetting in a prograde metamorphic sequence of Caledonian age in East Greenland

1985 ◽  
Vol 22 (3) ◽  
pp. 330-338 ◽  
Author(s):  
J. J. Peucat ◽  
D. Tisserant ◽  
R. Caby ◽  
N. Clauer
Keyword(s):  
Source Area ◽  
Detrital Zircons ◽  
Metamorphic Event ◽  
Great Resistance ◽  
East Greenland ◽  
Geological Interpretation ◽  
Source Areas ◽  
Metasedimentary Rocks ◽  
Sedimentary Source

In the Alpefjord area, Caledonian metamorphism from the chlorite zone to the sillimanite zone is seen to cut across the sedimentary pile of the lower Eleonore Bay Group. Zircons have been collected from quartzite layers enriched in heavy minerals.U–Pb zircon dating in the chlorite and the sillimanite zones does not reveal the Caledonian event but, instead, previous episodes at 1100 and 2500 Ma ago. The Caledonian event can be recognized in anatectic gneisses where detrital zircons are surrounded by overgrowths, K–Ar and Rb–Sr methods yield 1030–410 Ma ages on micas, with a positive correlation between the degree of apparent reselling of mica ages and the grade of the Caledonian metamorphism.The following geological interpretation of the age data is proposed. (1) A major metamorphic event occurred around 1100 Ma ago in the source area for the lower Eleonore Bay Group sediments. During this Grenvillian event, Archaean detrital zircons were affected by an episodic lead loss and a muscovite phase recorded the cooling and uplift of a basement source area. (2) Erosion of this source area occurred after 1100 Ma, followed by sedimentation of the lower Eleonore Bay Group [Formula: see text]. The 2500–1100 Ma U–Pb system remained nearly a closed system during Caledonian metamorphism up to and including sillimanite-zone conditions.This example shows the great resistance or inherited zircons to an important secondary Pb loss during Caledonian metamorphism and consequently shows that the lower-intercept ages of zircons from metasedimentary rocks do not always record the last metamorphic event observed in situ, but retain memories of previous geological events in the sedimentary source areas. By contrast, zircons separated from quartzitic xenoliths in migmatitic gneisses have recorded a disturbance in their U–Pb systems that corresponds to Caledonian partial melting.

scholarly journals Hidden Archaean and Palaeoproterozoic crust in NW Ireland? Evidence from zircon Hf isotopic data from granitoid intrusions

2009 ◽  
Vol 146 (6) ◽  
pp. 903-916 ◽  
Author(s):  
M. J. FLOWERDEW ◽  
D. M. CHEW ◽  
J. S. DALY ◽  
I. L. MILLAR
Keyword(s):  
Source Region ◽  
Isotope Analysis ◽  
Isotopic Signature ◽  
Detrital Zircons ◽  
Metasedimentary Rocks ◽  
Deep Crust ◽  
Gneiss Complex ◽  
Granitoid Rocks ◽  
Granitoid Intrusions

AbstractThe presence of major crystalline basement provinces at depth in NW Ireland is inferred from in situ Hf isotope analysis of zircons from granitoid rocks that cut structurally overlying metasedimentary rocks. Granitoids in two of these units, the Slishwood Division and the Tyrone Central Inlier, contain complex zircons with core and rim structures. In both cases, cores have average ϵHf values that differ from the average ϵHf values of the rims at 470 Ma (the time of granitoid intrusion). The Hf data and similarity in U–Pb age between the inherited cores and detrital zircons from the host metasedimentary rocks suggests local contamination during intrusion rather than transport of the grains from the source region at depth. Rims from the Slishwood Division intrusions have average ϵHf470 values of −7.7, consistent with a derivation from juvenile Palaeoproterozoic crust, such as the Annagh Gneiss Complex or Rhinns Complex of NW Ireland, implying that the deep crust underlying the Slishwood Division is made of similar material. Rims from the Tyrone Central Inlier have extremely negative ϵHf470 values of approximately −39. This isotopic signature requires an Archaean source, suggesting rocks similar to the Lewisian Complex of Scotland, or sediment derived wholly from it, occurs at depth in NW Ireland.

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