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Precise Dating and Geological Significance of the Caledonian Shangyou Pluton in South Jiangxi Province
Author(s) -
Jianren MAO,
Qingtao ZENG,
Zilong LI,
Qing HU,
Xilin ZHAO,
Haimin YE
Publication year - 2008
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2008.tb00590.x
Subject(s) - geology , zircon , geochemistry , pluton , partial melting , continental crust , biotite , crust , proterozoic , subduction , mantle (geology) , geochronology , petrology , tectonics , quartz , paleontology
The zircon SHRIMP dating age for the Shangyou granites is 464±11 Ma. The geological feature of the pluton is consistent with the isotopic age, which shows that it is a product of Caledonian orogenesis. The Shangyou granites are regarded as peraluminous crust‐derived granites to possess the typical geochemical characteristics of calc‐alkaline rocks on the active continental margin with enriched Si, K, Al (A/CNK = 1.11 on average), HREE, Rb, U, Th and heavily depleted V, Cr, Co, Ni, as well as Ti‐Y, Nb‐Ta, Zr, Sr, P and Ba, to be commonly corundum normative (av C = 1.44). The Shangyou granites with higher 87 Sr/ 86 Sr ratios (0.707126‐0.712186), ε Nd ( t ) values (‐7.29 to −10.22) and ( t DM ) values (1.52‐1.63 Ga), which are considered to result from partial melting of continental crust metamorphic sedimentary rocks with relatively low of crust maturation degree corresponding to the Middle Proterozoic, to have some possible contributions of mantle‐derived components. The Shangyou granites are regarded as post‐collision granites, which were formed in a transitional tectonic setting from compression to extension in the Middle Ordovician period after the Yangtze plate was subducted beneath the Cathaysian plate. The Ar‐Ar total ages of K‐feldspar and biotite are 292.1 Ma and 295.5 Ma respectively, which have recorded information of a late‐stage thermal alteration event.