Eocene–Oligocene granitoids in southern Tibet: Constraints on crustal anatexis and tectonic evolution of the Himalayan orogen

Hou, Zhenshan; Zheng, Yuanchuan; Zeng, Lingsen; Gao, Li-E; Huang, Ke-Xian; Li, Wei; Li, Qiuyun; Fu, Qiang; Liang, Wei; Sun, Qiang

doi:10.1016/j.epsl.2012.06.030

Cited by 189 publications

(130 citation statements)

References 96 publications

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“…In addition, both Group I Napuri adakitic rocks and some Cenozoic adakitic rocks in southern Lhasa are characterized by positive Eu and Sr anomalies (Fig. 5) (Chung et al, 2003Guo et al, 2007;Hou et al, 2004Hou et al, , 2012, indicating that plagioclase was not a residual phase in the source regions of these adakitic rocks. Xiong et al (2011) used the SiO 2 versus TiO 2 plot to determine whether these adakitic magmas were saturated with TiO 2 based on experimental data (Rapp and Watson, 1995;Xiong et al, 2005Xiong et al, , 2011.…”

Section: Implications For Crustal Thickeningmentioning

confidence: 99%

“…Thus, such lower crust-derived adakitic rocks have the potential of tracing the presence of anomalously thick continental crust under the Tibetan plateau (e.g., Chung et al, 2003Chung et al, , 2005Chung et al, , 2009Guan et al, 2012;Guo et al, 2007;Hou et al, 2004Hou et al, , 2012Ji et al, 2012 and references therein), and even Cretaceous plateau formation in eastern China (e.g., Zhang et al, 2001). However, some researchers have debated whether an overthickened crust and eclogite residue are necessary for producing adakitic magmas in such a tectonic setting (Ma et al, 2012;Moyen, 2009;Qian and Hermann, 2010).…”

Section: Implications For Crustal Thickeningmentioning

confidence: 99%

“…The adakitic intrusive rocks within the Gangdese batholith are considered to have been generated in two main stages, the Jurassic-Cretaceous (160-77 Ma) and : (1) Jurassic-Cretaceous adakitic rocks generated in an arc setting were related to Neo-Tethyan subduction processes, by melting of either subducted oceanic slabs (e.g., Jiang et al, 2012;Ma et al, 2013a;Wei et al, 2007;Zhang et al, 2010b;Zhu et al, 2009) or thickened mafic continental lower crust (e.g., Guan et al, 2010;Wen et al, 2008b); (2) Cenozoic adakitic rocks occurring as small-volume plugs or dikes/sills, which intrude or crosscut the Gangdese batholith, the Linzizong volcanic successions and associated sedimentary formations, and extend~1300 km across nearly the entire southern Lhasa (Fig. 1b) (e.g., Chung et al, 2003Chung et al, , 2005Chung et al, , 2009Gao et al, 2007Gao et al, , 2010Guan et al, 2012;Guo et al, 2007;Hou et al, 2004Hou et al, , 2012Ji et al, 2012;Jiang et al, 2011Jiang et al, , 2014Pan et al, 2012;Xu et al, 2010;Zhang et al, 2010a).…”

Section: Geological Background and Rock Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet

Wang

Jiang

et al. 2014

Lithos

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Section: Implications For Crustal Thickeningmentioning

confidence: 99%

Section: Implications For Crustal Thickeningmentioning

confidence: 99%

Section: Geological Background and Rock Characteristicsmentioning

confidence: 99%

See 1 more Smart Citation

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet

Wang

Jiang

et al. 2014

Lithos

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“…This age was later confirmed by Chung et al [43] using a sensitive high-resolution ion microprobe (SHRIMP). Coeval granitic intrusions were also found in other locations around the Yaja granodiorite ( Figure 1b) and dated by Ar-Ar and zircon U-Pb methods [46][47][48][49][50]76]. The geochemical compositions of these plutons show adakitic affinities, with high SiO 2 , K 2 O, and Sr, but low Y and Yb contents [43,47,49,50,61].…”

Section: 3~30 Ma Magmatism In Southern Tibetmentioning

confidence: 99%

“…(b) Geological map of the study area (Zedong-Luobusa), modified from Aitchison et al [44]. The ~30 Ma intrusives are marked on the map based on references [43,[45][46][47][48][49][50]. RZT = Renbu-Zedong thrust.…”

Section: Introductionmentioning

confidence: 99%

Timing of Secondary Hydrothermal Alteration of the Luobusa Chromitites Constrained by Ar/Ar Dating of Chrome Chlorites

Guo

et al. 2018

Minerals

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Chrome chlorites are usually found as secondary phases formed by hydrothermal alteration of chromite deposits and associated mafic/ultramafic rocks. Here, we report the 40 Ar/ 39 Ar age of chrome chlorites separated from the Luobusa massive chromitites which have undergone secondary alteration by CO 2 -rich hydrothermal fluids. The dating results reveal that the intermediate heating steps (from 4 to 10) of sample L7 generate an age plateau of 29.88 ± 0.42 Ma (MSWD = 0.12, plateau 39 Ar = 74.6%), and the plateau data points define a concordant inverse isochron age of 30.15 ± 1.05 Ma (MSWD = 0.08, initial 40 Ar/ 36 Ar = 295.8 ± 9.7). The Ar release pattern shows no evidence of later degassing or inherited radiogenic component indicated by an atmospheric intercept, thus representing the age of the hydrothermal activity. Based on the agreement of this hydrothermal age with the~30 Ma adakitic plutons exposed in nearby regions (the Zedong area, tens of kilometers west Luobusa) and the extensive late Oligocene plutonism distributed along the southeastern Gangdese magmatic belt, it is suggested that the hydrothermal fluids are likely related to the~30 Ma magmatism. The hydrothermal fluid circulation could be launched either by remote plutons (such as the Sangri granodiorite, the nearest~30 Ma pluton west Luobusa) or by a similar coeval pluton in the local Luobusa area (inferred, not found or reported so far). Our results provide important clues for when the listwanites in Luobusa were formed.

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Eocene adakitic porphyries in the central‐northern Qiangtang Block, central Tibet: Partial melting of thickened lower crust and implications for initial surface uplifting of the plateau

Wang

Wyman

et al. 2017

JGR Solid Earth

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The time and mechanism of crustal thickening and initial surface uplift of the Tibetan Plateau remain highly controversial. Here we report on zircon U‐Pb age, and mineral, element, and Sr‐Nd isotope composition data for Eocene adakitic porphyries in the Laorite Co area of central‐northern Qiangtang Block, central Tibet. Laser ablation‐inductively coupled plasma‐mass spectrometry zircon U‐Pb age dating shows that the porphyries were generated at 42–41 Ma. All samples display adakitic geochemical characteristics, such as high SiO2 and Al2O3, and low Y and Yb contents, and high Sr/Y and La/Yb ratios with positive Sr and negligible Eu anomalies and Nb‐Ta depletion. They also have low magnesium number (Mg #) (16–45) and high K2O (4.0–4.6 wt %) values, as well as high (87Sr/86Sr)i (0.7076–0.7080) and low εNd(t) (−5.9 to −4.4) values. These adakitic rocks were most probably generated by partial melting of thickened lower crust in the stability field of garnet, amphibole, and rutile but with relatively minor plagioclase. Moreover, such a crustal thickening process beneath this block likely occurred no later than the middle Eocene and was most probably caused by the southward subduction of the Songpan‐Ganzi Block in the early Cenozoic. In addition, the occurrences of exposed adakitic porphyries unambiguously indicate that exhumation process occurred after their formation. Thus, these ~42 Ma adakitic porphyries indicate the occurrence of significant exhumation since 42 Ma. Integrated with the thermochronological and paleoelevation data, we suggest that the initial surface uplift of the Qiangtang Block, triggered by crustal thickening, was underway by the middle Eocene (~42 Ma).

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Eocene–Oligocene granitoids in southern Tibet: Constraints on crustal anatexis and tectonic evolution of the Himalayan orogen

Cited by 189 publications

References 96 publications

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet

Timing of Secondary Hydrothermal Alteration of the Luobusa Chromitites Constrained by Ar/Ar Dating of Chrome Chlorites

Eocene adakitic porphyries in the central‐northern Qiangtang Block, central Tibet: Partial melting of thickened lower crust and implications for initial surface uplifting of the plateau

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