Geochronology and geochemistry of late Paleozoic–early Mesozoic igneous rocks of the Erguna Massif, NE China: Implications for the early evolution of the Mongol–Okhotsk tectonic regime

2017 ◽  
Vol 144 ◽  
pp. 205-224 ◽  
Author(s):  
Yu Li ◽  
Wen-Liang Xu ◽  
Feng Wang ◽  
Jie Tang ◽  
Shuo Zhao ◽  
...  
Keyword(s):  
Early Evolution ◽  
Igneous Rocks ◽  
Late Paleozoic ◽  
Ne China ◽  
Tectonic Regime ◽  
Early Mesozoic ◽  
Erguna Massif

Late Paleozoic igneous rocks in the Xing’an Massif and its amalgamation with the Songnen Massif, NE China

2020 ◽  
Vol 197 ◽  
pp. 104407
Author(s):  
Yu Li ◽  
Wen-Liang Xu ◽  
Jie Tang ◽  
Chen-Yang Sun ◽  
Xiao-Ming Zhang ◽  
...  
Keyword(s):  
Igneous Rocks ◽  
Late Paleozoic ◽  
Ne China

Late Paleozoic- Early Mesozoic tectonics of Hainan Island: Key to understanding Paleotethyan geology

2020 ◽  
Author(s):  
Huiying He ◽  
Peter Cawood ◽  
Yuejun Wang
Keyword(s):  
South China ◽  
Tectonic Evolution ◽  
Hainan Island ◽  
Igneous Rocks ◽  
Late Paleozoic ◽  
Calc Alkaline ◽  
Early Mesozoic ◽  
History Of ◽  
Back Arc ◽  
T Values

<p>In Southeast Asia, establishing the origin and associated tectonic setting of Late Paleozoic-Early Mesozoic igneous rocks is complicated by structural overprinting and the complex tectonic evolution of the Paleotethyan regime. Hainan Island, located at the south-eastern margin of the Paleotethys, and lacking significant tectonic overprints is a key to understand amalgamation history of the Indochina and South China blocks and to constraining the tectonic evolution of Paleotethys ocean in southeast Asia.</p><p>The Late Paleozoic-Early Mesozoic record of igneous rocks on Hainan Island includes the following. 1) ca. 350 Ma island arc andesites and ca. 330 Ma metabasites, the latter with both MORB- and arc-like geochemical affinities, positive ε<sub>Nd</sub>(t) values of +5.86 – +9.85 and rare inherited zircons with a zircon age of 1400 Ma inferred to be derived from a MORB source with the input of a slab-derived component. Together with the ~350 Ma island arc andesites, the Carboniferous tectonic environment is supposed to be a continental back-arc basin setting. 2) Late Permian gneiss granitoids (272-252 Ma) characterized by a gneissic foliation and calc-alkaline I-type geochemical affinities with negative Nb-Ta and Ti anomalies, related to metasomatized mantle wedge modified by the sediment-derived component in a continental arc setting. 3) ca. 257 Ma arc-like andesites, which further validate a subduction-related setting. 4) Peraluminious Early-Middle Triassic massive granitoids (251–243 Ma) with slightly high A/CNK ratios, δ<sup>18</sup>O values (up to 11.75 ‰) and Sr/Y ratios, inferred to have formed in a compressive regime from a mixed source of greywacke and metabasite. 5) Middle-Late Triassic (242–225 Ma) high-K calc-alkaline granitoids with high zircon temperatures (842–867°C) and geochemical signatures of A-type granites. They show slightly low whole-rock ε<sub>Nd</sub>(t) and zircon ε<sub>Hf</sub>(t) values, suggestive of the derivation from a metabasite–greywacke source in an extensional setting. 6) ca. 240 Ma gabbro-dolerites showing enrichment in LILEs, depletion in HFSEs, negative ε<sub>Nd</sub> (t)-ε<sub>Hf</sub> (t) values (−8.45 to −1.05 and −5.9 to −2.7, respectively) and crustal-like δ<sup>18</sup>O values (7.26–8.70‰), it is implied that the Hainan Island entered into post-collisional environment in response to the asthenosphere upwelling shortly after the closure of back-arc basin.</p><p>Thus, Hainan Island provides a record of Carboniferous back-arc basin opening, followed by an extended Permian–Triassic history of subduction-related consumption leading to orogenic assembly and extensional collapse between the South China and Indochina blocks. Such a tempo-spatial pattern is consistent with that along the Song Ma–Ailaoshan suture zone rather than the magmatic history of eastern South China and indicates that the Paleotethys extended west to at least Hainan Island in the Late Paleozoic-Early Mesozoic.</p>

Paleomagnetism of Late Paleozoic igneous rocks from southern Portugal

1985 ◽  
Vol 12 (1) ◽  
pp. 45-48 ◽  
Author(s):  
H. Perroud ◽  
N. Bonhommet ◽  
A. Ribeiro
Keyword(s):  
Igneous Rocks ◽  
Late Paleozoic ◽  
Southern Portugal
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