Paleotethyan tectonic evolution of the Sanjiang Orogenic Belt, SW China: Temporal and spatial distribution pattern of arc-like igneous rocks

Yang, Tiannan; Xue, Chuandong; Di, Xin; MingJuan, Liang; Liao, Cheng

doi:10.18654/1000-0569/2019.05.02

Cited by 17 publications

(11 citation statements)

References 63 publications

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“…The dioritic rocks are partial melts of metasomatized mantle wedge and the granitic rocks were mainly generated by partial melting of regional subduction-related juvenile clastic rocks. Moreover, these dioritic-granitic rocks share similar crystallization age of 251-225 Ma (Figure 3) and geochemical features (Figures 4-8) with those magmatic rocks documenting the late-stage evolution of both the Main Palaeo-Tethyan Ocean and Ailaoshan Ocean involving subduction and post-collisional processes (Deng et al, 2018;Wang, Qian, et al, 2018;Yang et al, 2019). In addition, as a typical subduction-related feature, in the field, these rocks tend to occur as packages, in which different rock types are closely associated with one another in both space and time (Figure 2a,b).…”

Section: Tectonic Background Of These Rocksmentioning

confidence: 65%

“…DM represented depleted mantle, the Hf isotopic composition of which was defined by mid‐ocean ridge basalts (Griffin et al, 2004). Data of the magmatic rocks in LSS, LTZ and ATZ are from Wang et al, (2016a); Deng et al (2018); Yang et al (2019) and references therein.…”

Section: Discussionmentioning

confidence: 99%

“…Previously reported dioritic and granitic rocks related to the late‐stage evolution of the Main Palaeo‐Tethyan Ocean from the LSS, LTZ and ATZ are ploted for comparison. Data of the magmatic rocks in LSS, LTZ and ATZ are from Wang et al, (2016a); Deng et al (2018); Yang et al (2019) and references therein.…”

Section: Discussionmentioning

confidence: 99%

“…Chondrite‐ and primitive mantle‐normalized values are from Sun and McDonough (1989). Reference data of dioritic‐granitic rocks from LSS, LTZ and ATZ are from Wang et al, (2016a); Deng et al (2018); Yang et al (2019) and references therein. Data for the OIB, N‐MORB, E‐MORB are from Sun and McDonough (1989).…”

Section: Discussionmentioning

confidence: 99%

“…However, due to the absence of ophiolites or related magmatic records in the middle‐north segment of the LTZ, regional tectonic framework division is still in controversy. Consequently, instead of the middle‐north segment of the LTZ, those magmatic rocks along the ATZ in Diancangshan and Ailaoshan area traditionally related to the evolution of the Ailaoshan Ocean were also argued as subduction records of the Main Palaeo‐Tethyan Ocean (Yang et al, 2019). The second issue relates to the nature of the Ailaoshan Ocean.…”

Section: Introductionmentioning

confidence: 99%

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Triassic magmatism along both sides of the Simao terrane, SE Tibetan Plateau: Implications for the evolution of the Main Palaeo‐Tethyan Ocean and the Ailaoshan Ocean

Chen

et al. 2023

Geological Journal

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Subduction and closure of the Palaeo‐Tethyan ocean in the south‐eastern (SE) Tibetan Plateau accounted for the amalgamation of the Indochina Block with the Sibumasu and Yangtze blocks during the Triassic, however, the spatial distribution of the Main Palaeo‐Tethyan ocean and the nature of the Ailaoshan ocean in this region remain controversial. This is partially due to the absence of related magmatic records in the middle‐north segment of the Lancangjiang tectonic belt (LTZ) and consequently, the lack of regional comparison with the Ailaoshan tectonic belt (ATZ). In this contribution, we reported for the first time the presence of subduction‐related Triassic dioritic‐granitic rocks from the Chongshan metamorphic belt (CMB) and the Diancangshan metamorphic belt (DMB) along both sides of the Simao terrane. Zircon U–Pb‐Hf isotopic and whole‐rock geochemical data for these dioritic‐granitic rocks and 135 previously published magmatic rocks in the LTZ, ATZ and the Longmu Co‐Shuanghu suture (LSS) are compared and place important constraints on (1) the spatial distribution of the Palaeo‐Tethyan ocean in this region and (2) the nature of the Ailaoshan Ocean. All these dioritic‐granitic samples from the CMB and DMB yielded Triassic crystallization ages from 225 to 251 Ma, representing late‐stage magmatic records for the Palaeo‐Tethyan evolution in the middle‐north segment of both the LTZ and ATZ in this region. These Triassic dioritic‐granitic rocks in the CMB and DMB share similar geochemical features. Dioritic samples display positive εHf(t) values and relatively high MgO, Cr, Ni contents, moderately differentiated rare earth element (REE) patterns and depletion in Nb‐Ta‐Ti, suggesting their generation from partial melts of metasomatized mantle wedge. Granitic rocks are mostly S‐type with low MgO contents but high K2O/Na2O and A/CNK ratios, mainly generated by regional clastic rocks dominant by juvenile contributions, except for granodiorite samples CS1601 and DC1734‐2, exhibiting identical geological features subduction‐derived hybridized magma from regional clastic sediments and basalts. Our discovery of the Triassic dioritic‐granitic rocks in the CMB stands as the first direct evidence for the Main Palaeo‐Tethyan evolution in the middle‐north segment of the LTZ. This discovery bridges 135 contemporaneous reported magmatic records and supports the spatial distribution of the Main Palaeo‐Tethyan ocean from the LTZ to the LSS. Our Triassic dioritic‐granitic rocks in the CMB and DMB recorded comparable late‐stage evolution involving slab break‐off of the Main Palaeo‐Tethyan ocean and the Ailaoshan Ocean, respectively. Together with previous studies, the Ailaoshan ocean should be a wide oceanic Basin that shares similar time span and evolution processes as the Main Palaeo‐Tethyan ocean.

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Section: Tectonic Background Of These Rocksmentioning

confidence: 65%