## 1 Introduction  
The Jiaodong Peninsula, located in the eastern continental margin of East China (Figure 1A), is divided into the Sulu terrane in the southeast and the Jiaobei terrane in the northwest by the crustal-scale ENE-to NE-trending WQYF (i.e., the Wulian-Qingdao-Yantai Fault) (Figure 1B) [1, 2, 3]. It is considered to result from the collision of the Yangtze Craton (YC) with the North China Craton (NCC) during the Middle-Late Triassic [4]. The Paleo-Pacific subduction beneath East China initiated at ca. 180 Ma [5, 6, 7] led to the large-scale magmatism in the eastern NCC between the Late Jurassic and the Early Cretaceous [8, 9, 10], and is associated with a great number of Early Cretaceous gold deposits developed in the Jiaodong Peninsula [1]. So far, over 260 gold deposits, with a total proved reserve of more than 5000 t Au [11], have been reported in the Jiaodong Peninsula, the first largest gold producer in China (Figure 1B) [12,13]. They are clustered in the three gold metallogenic belts, which are Muping-Rushan, Penglai-Qixia and Zhaoyuan-Laizhou, located in eastern, central and western Jiaodong, respectively (Figure 1B) [14]. It has been widely recognized that the gold deposits in the Jiaodong Peninsula occur as the disseminated and stockwork pyrite-sercite-quartz-altered ones (i.e., the \"Jiaojia-type\" mineralization), represented by the Taishang, Jiaojia and Sanshandao gold mines (Figure 1B), or the gold-bearing quartz-vein ores (i.e., the \"Linglong-type\" mineralization), represented by the Wang'ershan, Linglong and Rushan gold mines (Figure 1B) [1, 16, 17]. Both of them are controlled by either the regional or the lower-order NNE- to NE-striking faults and are hosted within mineralogically altered rocks, which consist of the Guojialing-type granitoids (middle Early Cretaceous), the Linglong-type granitoids (late Jurassic) and the high-grade metamorphic rocks (Precambrian) [16, 17]. The dominant ore mineralogies are pyrite, chalcopyrite, sphalerite, galena, gold and tetrahedrite, with sercite, quartz, calcite and chlorite being the main altered mineralogies [1, 18]. However, the Xiawolong gold mine, newly found in 2012-2017 by the No.6 Geological Exploration Team of Shandong Province, China [19] in the northeast of the Muping-Rushan gold metallogenic belt within  
Figure 1: (**A**) Tectonic sketch map of eastern continent of East China, showing the location of the Jiaodong Peninsula. Adapted with permission from Ref. [3], 2012, Elsevier. (**B**) A simplified geological map of the Jiaodong Peninsula showing the distribution of basement rocks, Mesozoic igneous rocks, main faults and representative gold deposits. Adapted with permission from Ref. [1], 2015, Elsevier. The location for sample SD-11 is from Ref. [15]. Abbreviations: WQYF, Wulian-Qingdao-Yantai Fault; TLE, Tan–Lu Fault; ZPF, Zhaoping Fault; MRF, Muping–Rushan Fault. Typical gold deposits: 1 Sanshandao; 2 Jiaojia; 3 Wang’ershan; 4 Linglong; 5 Taishang; 6 Rushan; 7 Xiawolong; 8 Xiadian; 9 Zhuangzi; 10 Daliuhang; 10 Hushan. eastern Jiaodong, i.e., Sulu terrane (Figure 1B), is hosted within the non-deformed fresh fine-grained granite (late Early Cretaceous) [20]. The ores occur as the disseminated and stockwork-style pyrite, generally associated with molybden and magnetite, within the fine-grained granite, where neither fracture nor hydrothermal alteration occurred [19; 20]. So far, no other research work on this deposit has been reported except for the basic geological and geochemical research [19; 20]. The geochemical study on the stable isotope and fluid inclusion of the Xiawolong reported by [PERSON] et al. [20] suggests that distinct from the traditional gold deposits for the \"Jiaojia-type\" and \"Linglong-type\" deposits, the ore-forming process for the Xiawolong gold deposit is the result of the fluid release, which could take place during the magmatic-hydrothermal transition stage.