## 1 Introduction  
The Central Asian Orogenic Belt (CAOB) is one of the largest accretionary orogens structurally located between the Siberian and Europe cratons to the north and the Tarim and North China cratons to the south (Figure 0(a)). The East Junggar is a key constituent of the CAOB, which located in the northeast of the Junggar block. It is characterized by Paleozoic island arcs, ophiolitic melanges, granites, and sedimentary units [1, 2], which comprises Paleozoic accretionary complexes that formed during northward subduction and accretion/collision related to the Paleo-Asian Ocean [3, 4, 5]. In recent decades, the U-Pb ages of the Cambrian to Carboniferous ophiolite belts show that the southern Karamaili ophiolite, the middle Zhaheba ophiolite, and the northern Kuerti ophiolite have a wide range of ages from 417 to 330 Ma, 503 to 406 Ma, and 389 to 332 Ma, respectively [6, 7, 8]. The Yemaquan arc and Dulate arc are clamped between the Karamaili ophiolite and the northern Kuerti ophiolite, which are separated by the Zhaheba ophiolite. Some studies inferred a continental island arc setting for the Yemaquan arc [2, 9]. On the other hand, others suggested that the compositions of volcanic and plutonic rocks from the Yemaquan arc are consistent with an intra-oceanic island arc setting during the early Paleozoic [10, 11]. The Dulate magmatic arc was thought to be formed as a result of the southward subduction of the Ocean plate, whereas the formation time remains controversial [12, 13]. The Carboniferous sedimentary rocks were interpretedto form in back-arc setting, which was related to the rollback of the Ocean subduction zone [14; 15].  
Moreover, the basement nature of the Junggar terrane was highly controversial for a long time, which hampered us from the tectonic evolution of the East Junggar area. Some authors suggested that the crust of the Junggar block is composed of the Precambrian basement [16; 17; 18; 19]. In contrast, others maintained that its formation is related to multiple Paleozoic subduction-accretion systems [20; 21; 22; 23]. The gravity and magnetic study revealed that the southwestern Chinese Altai and the northeastern Junggar Basin seem to contain the mafic basement [24]. Additionally, the comprehensive geophysical research showed that the ultramafic rocks may have squeezed into the crust, which are characterized by high seismic velocity, high density, and high magnetic intensity [25]. [PERSON] reported that the basement of the East Junggar has two layers, i.e., an upper layer comprising a Hercynian folded basement, and a lower layer composed of a paleocrystalline basement [26]. The elastic wave velocities of the granitoids from Eastern Junggar show that the upper crust of the Eastern Junggar is composed of the alkali feldspar granite, alkali granite, and monozgranite, while the middle crust is composed of quartz diorite [27]. Due to the lack of high-resolution geophysical data, the understanding of the basement has not been unified. In addition, the Magnetotelluric research in the study area is still rare, which is commonly used to analyze the deep structure of the crust [28].  
Figure 1: **(a)** Location of the Junggar terrains in the Central Asian Orogenic Belt. **(b)** Distribution of the West Junggar, Junggar Basin, and East Junggar. **(c)** Geological map of the East Junggar showing MT line locations. F1: the Erqis Fault, F2: the Zhaheba-Armantai Fault, F3: the Kelameili Fault, F4: Fuyun Fault (modified from [23]).  
This paper studied the electrical structure of the East Junggar crust by setting up a magnetotelluric profile with a length of 105 km. We estimated geoelectric strike directions by the tensor decomposition method to analyze the structural orientation in the study area. The result of MT inversion was interpreted to reveal the crustal structure and basement of the East Junggar. In addition, we discussed the relationship between high conductivity in crust and mineralization.