Traditionally volcanic arcs are considered to be the most

Traditionally, volcanic arcs are considered to be the most important sites for the recycling of subducted marine sediments into the continental crust via arc magmatism (Kay, 1978; Plank and Langmuir, 1993; Hawkesworth et al., 1997; Shimoda et al., 1998; Chauvel et al., 2008; Behn et al., 2011). Given the widespread occurrences of Neogene peraluminous magmatic rocks in the southern and northern margin of Tibet, however, we suggest that the recycling of sediments with continental affinity played an important role in the formation of these peraluminous magmatic rocks and the adenosine kinase of continental crust during the collisional orogenic process.
Acknowledgment We would like to thank Editor-in-Chief Professor Wei-Dong Sun, and an anonymous reviewer for their constructive and helpful reviews. We also thank Professor J.G. Liou and Dr. M. Satish-Kumar for their suggestions on the early edition of this paper. We appreciate the assistance of Dr. Kejun Hou for providing us with standard tourmalines IAEA B4 and IMR RB2 and Professor Zhongyuan Ren for in situ B isotopic analyzing. Financial support for this research was provided by the DREAM Program of China (No. 2016YFC0600407), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (grant no. XDB03010600), the Key Program of the Chinese Academy of Sciences (QYZDJ-SSW-DQC026), the National Natural Science Foundation of China (Nos. 41630208 and 41421062), talent project of Guangdong Province (2014TX01Z079), and GIGCAS 135 project 135TP201601. This is contribution No. IS-2371 from GIGCAS.
Introduction High-precision geochronology relies on isotope dilution thermal ionization mass spectrometry (ID-TIMS), a technique that can provide individual crystal-fragment and weighted mean isotope ratios (and interpreted ages) of ±0.1% and ±0.03% relative precision, respectively (Schmitz and Kuiper, 2013). The application of “CA (Chemical Abrasion)” pretreatment is capable of completely removing zircon domains that have lost Pb, and then analyzing residual, perfectly closed-system zircon (Mattinson, 2005). Thus, the CA-ID-TIMS is one of the most accurate and precise methods of isotopic dating techniques (Parrish and Noble, 2003; Condon et al., 2008; Schmitz and Kuiper, 2013; Schoene, 2014). In 2003, the U–Pb geochronology community started the EARTHTIME initiative (Bowring et al., 2005), which has promoted, among other things, cooperation and intercalibration of international U–Pb and Ar–Ar labs, driving significant improvements in all participating laboratories and making great progress of a highly accurate geologic timescale (Mattinson, 2013). An outstanding example is the work focus on the Permo-Triassic boundary volcanic ashes at Meishan section, the issues associated with high-precision geochronology of critical intervals in earth history. Successive publications track the evolution of high-precision U–Pb geochronological techniques that have led to increasingly precise and accurate constraints on the extinction (e.g., Bowring et al., 1998; Mundil et al., 2004; Shen et al., 2011; Burgess et al., 2014). Compared to the prosperous times of EARTHTIME, the development of high resolution geochronology in China is relatively quiet. In the past two decades, all the published data based on the high precision techniques are cooperated with foreign researchers and laboratories (e.g., Shen et al., 2011; Burgess et al., 2014). This is inconsistent with the well-developed stratigraphic record and the abundant marine sections in China. The chronological results of the crucial geological times and events have attracted the attention of worldwide geologists. There are 10 GSSPs have been defined in China (Peng, 2014), which became the major indications for global stratotype. It provides significant opportunities for domestic researchers to improve the dating techniques.
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