## 1 Introduction  
The Jiaodong Peninsula, situated at the southeastern edge of the North China Craton (NCC) (Figure 1) [1], is endowed with a total proved reserve of over 5000 t Au [2], which makes it one of the most important gold provinces worldwide, and the number one gold producer in China (Figure 1) [3,4]. The giant Jiaodong gold province is composed of the Zhaoyuan-Laizhou, Penglai-Qixia, and Muping-Rushan gold metallogenic belts situated in the western, central, and eastern Jiaodong Peninsula, respectively (Figure 1) [5]. Since the 1980s, a large number of studies have been performed on the Jiaodong gold deposits in terms of the source of ore-forming fluids [7,8], the timing of gold deposition [9, 10, 11], the structural environment controlling the airferous fluid migration [12,13], the hydrothermal alteration [14,15], and the metallogenic geodynamic setting [16, 17, 18]. The gold deposits, with the Precambrian high-grade metamorphic rocks of the NCC, the late Jurassic Linglong-type granitoids, and the middle Early Cretaceous Guojialing-type granitoids being the gold-hosting rocks, are considered to occur as two types of mineralization, i.e., the \"Jiaojia-type\" and the \"Linglong-type\" [1]. The former is represented by the gold-bearing quartz veins, and the latter is represented by stockwork and disseminated pyrite-sericite-quartz altered ores [19,20]. The \"Jiaojia-type\" gold deposit is generally hosted in the regional NNE- to NE-trending faults along the lithologic contacts between Linglong granite and Precambrian metamorphic rock or between Linglong granite and Guojialing-type granitoid, such as the Sanshandao, Jiaojia, and Zhaoping faults (Figure 1b) [21], and \"Linglong-type\" deposit is usually hosted in the lower-order NNE- to NE-trending faults that cut the Mesozoic granitoids or the Precambrian metamorphic rocks (Figure 1b) [22]. Both of the two types of orebodies are surrounded by the zoned hydrothermal alteration  
Figure 1: (**a**) A simplified tectonic map of the North China craton showing the location of the Jiaodong Peninsula. Adapted with permission from Ref. [6]. 2012, Elsevier. (**b**) A simplified geological map of the Jiaodong Peninsula showing the distribution of crystalline basement, Mesozoic volcanic-sedimentary sequence and granitoids, major structures, and typical gold deposits. Adapted with permission from Ref. [1]. 2015, Elsevier. Main faults: WQYF, Wulian–Qingdao–Yantai Fault; TLF, Tan–Lu Fault; ZPF, Zhaoping Fault; SSDF, Sanshandao Fault; JJF, Jiaojia Fault; MRF, Muping–Rushan Fault. Typical gold deposits: (  
characterized by strong sericitization in the inner domain and silicification in the outer. The thickness of the alteration envelope is usually between 10 and several hundred meters for the \"Jiaojia-type\" gold deposit, and less than 2 m for the \"Linglong-type\" deposit [23]. However, a special case is the Xiawolong gold deposit, situated at the Muping-Rushan gold metallogenic belt (Figure 1). It was newly discovered by the Shandong Provincial No.6 Exploration Institute of Geology and Mineral Resources, China during 2012-2017 [24]. Based on the primary geological survey work, the deposit is different from both the \"Linglong-type\" and \"Jiaojia-type\" gold deposits in terms of host rock, gold mineralization style, structural controls, and hydrothermal alteration [24]. Furthermore, so far, no more information has been published on this deposit. More interestingly, it is noted that the deposit developed in the late Early Cretaceous as fine-grained granite. Fine-grained granite is considered to be the late-stage product of granitic magmatic crystallization and is usually rich in Be-Li-Nb-Ta-Sn-Bi-W-Mo-Cu-Zn-U elements [25; 26; 27; 28], which has resulted in the close spatial and temporal relationship between fine-grained granites and orebodies in many deposits [29], such as the W-Mo deposit [28; 30; 31], copper deposit [32], uranium deposit [25; 33; 34], and Pb-Zn deposit [35].