**2. Geological structure of the Bureya-Jiamusi superterrane**

The northern border of the Bureya-Jiamusi superterrane is situated directly at the territory of Amur region (Russia) and correlates with its border with Mongol-Okhotsk orogenic belt [26]. According to [25], superterrane borders with Paleozoic early Mesozoic orogenic belts on west and south: South Mongol-Khingan, Solonker, Wundurmiao and China-Korea plate

As the author states [19], the southern border of superterrane is cut by Suolunshan-Central Jilin orogenic belt, which is an intermediate suture between the superterrane and the China-Korea plate. Li [19] suggests that Solonker orogenic belt includes the Bureya-Jiamusi superterrane in its structure. But there are also other ideas of the location of the Bureya-Jiamusi

**Figure 1.** Scheme of the structurally tectonical composition of the Mongol-Okhotsk orogenic belt and its southern framing according to [25]. BJ – Bureya-Jiamusi superterrane and its forming terrains: I – Bureya, II – Jiamusi, III – Khanka. The outlines of the Bureya-Jiamusi superterrane are according to the data: 1 – [12]; 2 – [43]; 3 – [39]. 4 – The outline of Mudanjianiang belt is according to the data [31]. Adacitic fields with age 55.5 Myr are according to the data [2] – 5. Other alphabetic designations: MO – Mongol-Okhotsk orogenic belt, AR – Argun superterrane, SM – South Mongolian-Khingan orogenic belt, SL – Solonker orogenic belt, WD – Wundurmiao orogenic belt, BD – Badzhal terrain,

(**Figure 1**). The Bureya-Jiamusi superterrane situation by [19] is the same as by [25].

superterrane (**Figure 1**).

34 Tectonics - Problems of Regional Settings

SA – Honshu-Sikhotealin orogenic belt.

It is considered that the Bureya-Jiamusi superterrane is formed with the comparable in geological structure terrains (**Figure 1**): I – Bureya, II – Jiamusi, III – Khanka [16, 25–27].

Previously, it was stated that the foundations of these terrains are the metamorphic complexes of the Archean-Proterozoic [17, 22]. But at this time, data on the age of protoliths of metamorphic rocks of these complexes are obtained.

According to the data, the formation of the foundation occurred not earlier than late Proterozoic. Superimposed structural-metamorphic transformations are connected not with the Precambrian events but are the result of processes that occurred in the territory of Bureya-Jiamusi superterrane in Paleozoic-Mesozoic [34, 35, 40, 41].

Significant part of the Bureya-Jiamusi superterrane territory (more than 50%) is built with granitoids of Paleozoic age [17].

It is believed that the Paleozoic granites along with Devonian, Permian, and Silurian volcanogenic and terrigenous formations played a "stitching" and overlapping role in the structure of the studied terrains.

They built up more ancient formations. In turn, they were blocked and injected with Mesozoic rocks (Triassic and Cretaceous) [16]. According to the research results of the biota characteristics from terrigenous deposits of early Mesozoic (Triassic-Jurassic) of Bureya-Jiamusi superterrane, it was stated that the rocks were formed in the sea basin under conditions of significant climate changes. Such changes are characteristic of mid-latitude [21]. The formations of the Sikhote-Alin terrains that are the neighboring territory at the east were formed under tropical conditions of the marine environment of low latitudes. With all that, it was shown that the sedimentation accumulation of the rocks occurred in the single oceanic basin [21]. As the authors consider, the fact is "an important, evidence in favor of the interpretations, according to which, a number of Sikhote-Alin terrains, experienced large-scale displacement in the northern direction" [21]. Shallow marine sediments, which are replaced by coarse continental material, begin to form in Jurassic. The end of Jurassic is marked with magmatic activity in the region.
