Zircon SHRIMP U–Pb ages of the Gangdese Batholith and implications for Neotethyan subduction in southern Tibet

Wen, Da Ren; Liu, Dunyi; Chung, Sun‐Lin; Chu, Mei Fei; Ji, Jianqing; Zhang, Qi; Song, Biao; Lee, Tung Yi; Yeh, Meng Wan; Lo, Ching–Hua

doi:10.1016/j.chemgeo.2008.03.003

Cited by 445 publications

(348 citation statements)

References 71 publications

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“…Although the Napuri adakitic magmas are contemporary with the Gangdese peak activities at ca. 50 Ma (e.g., Ji et al, 2009;Lee et al, 2009Lee et al, , 2012Wen et al, 2008a), their higher SiO 2 (66.4-73.9 wt.%) and lower MgO (0.4-1.0 wt.%) and compatible element (Cr = 2.9-7.4 ppm; 5 55 60 65 70 75 80 45 0 5 55 60 65 70 75 80 45 0 5 55 60 65 70 75 80 45 0 5 55 60 65 70 75 80 45 0 5 55 60 65 70 75 Ni = 1.6-4.5 ppm) contents also do not accord with a mantle origin (Martin et al, 2005). Their relatively enriched Sr-Nd isotopic compositions also argue against such a source (Fig.…”

Section: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

“…4d). In addition, the relatively low ε Nd (t) and ε Hf (t) isotopic values of the Napuri adakitic rocks compared to Gangdese Jurassic-Eocene granitoids (e.g., Ji et al, 2009Ji et al, , 2012Wen et al, 2008a) further rules out this possibility. The Group I samples are also characterized by positive Eu and Sr anomalies, which contradicts a model of partial melting of arc-type tonalites with amphibole and plagioclase as residual phases (Kamei et al, 2009).…”

Section: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

“…2012; Wen et al, 2008a). Here we use the slab break-off model to account for both the formation of the Napuri adakitic rocks and the associated magmatic "flare-up" event (e.g., Chung et al, 2005;Ji et al, 2009Ji et al, , 2012Lee et al, 2009Lee et al, , 2012Wen et al, 2008a;Zhu et al, 2011).…”

Section: Early Eocene Neo-tethyan Slab Break-offmentioning

confidence: 99%

“…Magma mixing generally requires mantle-derived basaltic and crust-derived felsic endmembers (e.g., Streck et al, 2007). In southern Lhasa, the candidates for mantle-derived basaltic and crust-derived felsic end-members are most plausibly represented by the 65-40 Ma Linzizong mafic magmas (e.g., Lee et al, 2012;Mo et al, 2007) and the synchronous (45-53 Ma) Gangdese granites (e.g., Ji et al, 2009Ji et al, , 2012Wen et al, 2008a), respectively. However, the ε Nd (t) and ε Hf (t) values of the Napuri adakitic rocks are lower than those of both the felsic and basaltic end-members, Defant and Drummond (1990) and Petford and Atherton (1996).…”

Section: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

“…Here we use the slab break-off model to account for both the formation of the Napuri adakitic rocks and the associated magmatic "flare-up" event (e.g., Chung et al, 2005;Ji et al, 2009Ji et al, , 2012Lee et al, 2009Lee et al, , 2012Wen et al, 2008a;Zhu et al, 2011). When two continents collide, the tensile stresses between the buoyant continental lithosphere and previously subducted oceanic lithosphere lead to the separation of the oceanic slab from the continental lithosphere (e.g., Davies and von Blanckenburg, 1995;van Hunen and Allen, 2011;von Blanckenburg and Davis, 1995).…”

Section: Early Eocene Neo-tethyan Slab Break-offmentioning

confidence: 99%

See 4 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: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

Section: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

Section: Early Eocene Neo-tethyan Slab Break-offmentioning

confidence: 99%

Section: Adakitic (Groups I and Ii) Rocksmentioning

confidence: 99%

Section: Early Eocene Neo-tethyan Slab Break-offmentioning

confidence: 99%

See 3 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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A Cretaceous-Eocene depositional age for the Fenghuoshan Group, Hoh Xil Basin: Implications for the tectonic evolution of the northern Tibet Plateau

et al. 2014

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The Fenghuoshan Group marks the initiation of terrestrial deposition in the Hoh Xil Basin and preserves the first evidence of uplift above sea level of northern Tibet. The depositional age of the Fenghuoshan Group is debated as are the stratigraphic relationships between the Fenghuoshan Group and other terrestrial sedimentary units in the Hoh Xil Basin. We present new radiometric dates and a compilation of published biostratigraphic data which are used to reinterpret existing magnetostratigraphic data from the Fenghuoshan Group. From these data, we infer an 85-51 Ma depositional age range for the Fenghuoshan Group. U-Pb detrital zircon age spectra from this unit are compared to age spectra from Tibetan terranes and Mesozoic sedimentary sequences to determine a possible source terrane for Fenghuoshan Group strata. We propose that these strata were sourced from the Qiangtang Terrane and may share a common sediment source with Cretaceous sedimentary rocks in Nima Basin. Field relationships and compiled biostratigraphic data indicate that the Fenghuoshan and Tuotuohe Groups are temporally distinct units. We report late Oligocene ages for undeformed basalt flows that cap tilted Fenghuoshan Group strata. Together, our age constraints and field relationships imply exhumation of the central Qiangtang Terrane from the Late Cretaceous to earliest Eocene, followed by Eocene-Oligocene deformation, and shortening of the northern Qiangtang and southern Songpan-Ganzi terranes. Crustal shortening within the Hoh Xil Basin ceased by late Oligocene time as is evident from flat-lying basaltic rocks, which cap older, deformed strata.

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Late Cretaceous back‐arc extension and arc system evolution in the Gangdese area, southern Tibet: Geochronological, petrological, and Sr‐Nd‐Hf‐O isotopic evidence from Dagze diabases

Wang

Wyman

et al. 2015

JGR Solid Earth

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Back‐arc extension and asthenosphere upwelling associated with oceanic lithospheric subduction affect the structure and thermal regime of the arc lithosphere, which often triggers widespread extension‐related mafic magmatism. Although it is commonly accepted that the Neo‐Tethyan oceanic lithosphere subducted beneath the southern Lhasa block, resulting in the well‐known Late Mesozoic Gangdese magmatic arc, the possible role of contemporary back‐arc extension and asthenosphere upwelling has been disputed due to a lack of evidence for extension‐related mafic magmatism. Here, we report detailed petrological, geochronological, geochemical, and Sr‐Nd‐Hf‐O isotopic data for the Dagze diabases located in the north of the Gangdese district, southern Lhasa block. The zircon U‐Pb analyses indicate that they were generated in the Late Cretaceous (ca. 92 Ma) instead of the Eocene (42–38 Ma) as previously believed. These mafic rocks are characterized by variable MgO (4.0–12.2 wt %) and Mg# (42 to 71) values combined with flat to slightly enriched ([La/Yb]N = 1.87–5.23) light rare earth elements (REEs) and relative flat heavy REEs ([Gd/Yb]N = 1.36–1.87) with negative Ta, Nb, and Ti anomalies (e.g., [Nb/La]PM = 0.16–0.51). They also have slightly variable εNd(t) (−1.25 to +4.71) and low initial 87Sr/86Sr (0.7045–0.7058) values with strong positive igneous zircon εHf(t) (+8.0 to +12.1) and low δ18O (5.31–6.12‰) values. The estimated primary melt compositions are similar to peridotite‐derived experimental melts. Given their high melting temperature (1332 to 1372°C) and hybrid geochemical characteristics, we propose that the Dagze mafic magmas likely represent mixtures of asthenospheric and enriched lithospheric mantle‐derived melts that underwent minor crustal assimilation and fractional crystallization of clinopyroxene. Taking into account the spatial and temporal distribution of Mesozoic mafic‐felsic magmatic rocks and regional paleomagnetic and basin data, we suggest that the Dagze mafic rocks resulted from asthenospheric upwelling associated with intracontinental back‐arc extension during the rollback of subducted Tethyan oceanic lithosphere in the Late Cretaceous.

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Zircon SHRIMP U–Pb ages of the Gangdese Batholith and implications for Neotethyan subduction in southern Tibet

Cited by 445 publications

References 71 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

A Cretaceous-Eocene depositional age for the Fenghuoshan Group, Hoh Xil Basin: Implications for the tectonic evolution of the northern Tibet Plateau

Late Cretaceous back‐arc extension and arc system evolution in the Gangdese area, southern Tibet: Geochronological, petrological, and Sr‐Nd‐Hf‐O isotopic evidence from Dagze diabases

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