A geochronological and geochemical study on the granodiorite porphyry and its implication for the mineralization in the
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ORIGINAL ARTICLE
A geochronological and geochemical study on the granodiorite porphyry and its implication for the mineralization in the Dayaoshan metallogenic belt, Southeastern China Panfeng Liu1,2 • Jiali Zhang1 • Zhiqiang Wu2 • Qingwei Zhang1 • Meilan Wen1 • Xianrong Luo1 • Chaojie Zheng1 • Wenbin Huang1
Received: 22 April 2020 / Revised: 5 July 2020 / Accepted: 10 August 2020 Ó Science Press and Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A systematic study combining U-Pb zircon dating, lithogeochemical and Sr–Nd isotopic analyses was carried out upon the Xinping granodiorite porphyry in the Dayaoshan metallogenic belt to understand its petrogenesis and tectonic significance. LA-ICP-MS U–Pb zircon dating yielded a 442.7 ± 5.8 Ma age, indicating that the granodiorite porphyry was emplaced during the Llandovery Silurian of the Early Paleozoic. The granodiorite porphyry shares the same geochemical characteristics such as Eu negative anomaly as other syn-tectonic granite plutons in the region, including the granodiorite porphyry in Dawangding and granite porphyries in the Dali Cu–Mo deposit and Longtoushang old deposit, indicating a similar magma evolution process. The Xinping granodiorite porphyry has high contents of SiO2 (67.871.8%) and K2O (1.78–3.42%) and is metaluminous–peraluminous with A/CNK ratios ranging from 0.97 to 1.06, indicative of high-potassium calc-alkaline to calc-alkaline affinity. It is a I-type granite enriched in large ion lithophile elements Rb, Sr, while depleted in Ba and high field-strength element Nb. Tectonically, a collision between the Yunkai Block from the south and the Guangxi Yunnan-North Vietnam Block from the north during the Early Paleozoic was followed by uplifting of the Dayaoshan terrane. The Xinping granodiorite porphyry was likely emplaced during the & Panfeng Liu [email protected] & Jiali Zhang [email protected] 1
College of Earth Science, Guilin University of Technology, Guilin 541006, China
2
College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China
collision. Sr–Nd isotopic analyses show that the granodiorite porphyry has initial 87Sr/86Sr ratios (Isr) of 0.7080–0.7104, eNd(t) range from - 0.08 to - 4.09, and t2DM between 1.19 and 1.51 Ga, well within the north-east low-value zone of the Cathaysia block, indicating a Paleoproterozoic Cathaysia basement source and an involvement of under plating mantle magma. Field observations, geochronological data, and 3D spatial distribution all lead to the conclusion that the Early Paleozoic Xinping granodiorite porphyry does not have any metallogenic and temporal relationships with the Xinping gold deposit (which has a Jurassic-Early Cretaceous age based on previous studies) but a close metallogenic relation to W–Mo mineralization. Keywords U–Pb zircon geochronology Lithogeochemistry Sr–Nd isotopes Granodiorite porphyry The Dayaoshan metallogenic belt
1 Introduction The Dayaoshan metallogenic belt is loca
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