Melt source and evolution of I-type granitoids in the SE Tibetan Plateau: Late Cretaceous magmatism and mineralization driven by collision-induced transtensional tectonics

We present new U–Pb age data for granitoids in the Central Sikhote–Alin orogenic belt in SE Russia, which refute the established opinion about the absence of the Late Cretaceous magmatism at the eastern margin of the Paleo-Asian continent. It was previously thought that a period of magmatic quiescence occurred from 88 to 50 Ma, related to subduction of the Paleo-Pacific Plate under the eastern margin of the Paleo-Asian continent, although this is inconsistent with evidence from the Sikhote–Alin, Sakhalin, and Japan regions. Three suites of plutonic rocks with different ages were identified in this study. The first suite has ages of 105–92 Ma and formed in a syn-orogenic setting. The second (86–83 Ma) and third (ca. 73 Ma) suites formed during the post-orogenic stage of the Sikhote–Alin orogenic belt. The second and third suites were coeval with Late Cretaceous granitoids that formed in a suprasubduction continental arc known as the Eastern Sikhote–Alin volcanic–plutonic belt (ESAVPB). However, the studied rocks are located far inland from the ESAVPB. The ages of the studied granitoids coincide with the timing of a change in the angle of convergence between the Paleo-Pacific Plate and eastern margin of the Paleo-Asian continent. This change in motion of the oceanic plate with respect to the continental plate was probably caused by a rupture in the subducted slab (i.e., a slab tear), followed by asthenospheric upwelling and partial melting of the overlying crust, which ultimately generated post-orogenic intrusive magmatism.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5738616

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Late Cretaceous magmatism in Madagascar: palaeomagnetic evidence for a stationary Marion hotspot

Earth and Planetary Science Letters ◽

10.1016/s0012-821x(98)00206-4 ◽

1998 ◽

Vol 164 (1-2) ◽

pp. 221-232 ◽

Cited By ~ 102

Author(s):

T.H Torsvik ◽

R.D Tucker ◽

L.D Ashwal ◽

E.A Eide ◽

N.A Rakotosolofo ◽

...

Keyword(s):

Late Cretaceous ◽

Cretaceous Magmatism

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Late Cretaceous to early Eocene deformation in the northern Tibetan Plateau: Detrital apatite fission track evidence from northern Qaidam basin

Gondwana Research ◽

10.1016/j.gr.2018.04.007 ◽

2018 ◽

Vol 60 ◽

pp. 94-104 ◽

Cited By ~ 24

Author(s):

Xing Jian ◽

Ping Guan ◽

Wei Zhang ◽

Hanghai Liang ◽

Fan Feng ◽

...

Keyword(s):

Tibetan Plateau ◽

Late Cretaceous ◽

Fission Track ◽

Qaidam Basin ◽

Early Eocene ◽

Apatite Fission Track ◽

Northern Tibetan Plateau

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A Late Cretaceous felsic magmatic suite from the Tengchong Block, western Yunnan: integrated geochemical and isotopic investigation and implications for Sn mineralization

Geological Magazine ◽

10.1017/s0016756819001493 ◽

2020 ◽

Vol 157 (8) ◽

pp. 1316-1332

Author(s):

Zhuanrong Sun ◽

Guochen Dong ◽

M Santosh ◽

Xuanxue Mo ◽

Pengsheng Dong ◽

...

Keyword(s):

Late Cretaceous ◽

The Tibetan Plateau ◽

Precambrian Basement ◽

Tetrad Effect ◽

Southeastern Part ◽

Ore Formation ◽

Fine Grained ◽

Western Yunnan ◽

Cretaceous Magmatism ◽

Magmatic Suite

AbstractThe Tengchong Block within the Sanjiang Tethys belt in the southeastern part of the Tibetan plateau experienced a widespread intrusion of a felsic magmatic suite of granites in its central domain during Late Cretaceous times. Here, we investigate the Guyong and Xiaolonghe plutons from this suite in terms of their petrological, geochemical, and Sr–Nd, zircon U–Pb and Lu–Hf–O isotopic features to gain insights into the evolution of the Neo-Tethys. The Guyong pluton (76 Ma) is composed of metaluminous monzogranites, and the Xiaolonghe pluton (76 Ma) is composed of metaluminous to peraluminous medium- and fine-grained syenogranite. A systematic decrease in Eu, Ba, Sr, P and Ti concentrations; a decrease in Zr/Hf and LREE/HREE ratios; and an increase in the Rb/Ba and Ta/Nb ratios from the Guyong to Xiaolonghe plutons suggest fractional crystallization of biotite, plagioclase, K-feldspar, apatite, ilmenite and titanite. They also show the characteristics of I-type granites. The negative zircon εHf(t) isotopic values (−10.04 to −5.22) and high δ18O values (6.69 to 8.58 ‰) and the negative whole-rock εNd(t) isotopic values (−9.7 to −10.1) and high initial 87Sr/86Sr ratios (0.7098–0.7099) of the Guyong monzogranite suggest that these rocks were generated by partial melting of the Precambrian basement without mantle input. The zircon εHf(t) isotopic values (−10.63 to −3.04) and δ18O values (6.54 to 8.69 ‰) of the Xiaolonghe syenogranite are similar to the features of the Guyong monzogranite, and this similarity suggests a cogenetic nature and magma derivation from the lower crust that is composed of both metasedimentary and meta-igneous rocks. The Xiaolonghe fine-grained syenogranite shows an obvious rare earth element tetrad effect and lower Nb/Ta ratios, which indicate its productive nature with respect to ore formation. In fact, we discuss that the Sn mineralization in the region was possible due to Sn being scavenged from these rocks by exsolved hydrothermal fluids. We correlate the Late Cretaceous magmatism in the central Tengchong Block with the northward subduction of the Neo-Tethys beneath the Burma–Tengchong Block.

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