Granulite complex on the left side of the Bol. Kuonamka River, below the mouth of the Khapchan River, is composed of melanocratic and mesocratic orthopyroxene–clinopyroxene crystalline schists and leucocratic orthopyroxene and orthopyroxene–clinopyroxene plagiogneisses. The granulites formed after mafic to felsic volcanoplutonic rocks with rare sedimentary interlayers. In terms of chemical composition, the mafic and ultramafic rocks correspond to pyroxenites, gabbronorites, and gabbro-diorites of the tholeiite series. The plagioschists and plagiogneisses were formed after rocks similar to diorites, tonalities, and trondhjemites or their volcanic analogs, and are distinguished by increased contents of Ba, Zr, Y, REE, Nb, and Ta. The concordant U-Pb age of zircon from the diorite protolith of orthopyroxene–clinopyroxene plagioschists is 2095 ± 10 Ma. The Lu-Hf isotopic composition of the zircon (ε_Hf (T) = 6.5–12, T_Hf(DM) = 1.98–2.22 Ga) indicates the correspondence of its source to the Paleoproterozoic depleted mantle. Two-pyroxene plagiogneisses with a concordant U-Pb zircon age of 2030 ± 17 Ma were formed after tonalites of the calc-alkaline series. They are characterized by well-pronounced negative Ti, Nb, Ta, P anomalies characteristic of subduction magmatism. All studied rocks of the Khapchan Belt have positive ε_Nd(T) values from +2.3 to +4.2 and are interpreted as a juvenile suprasubduction complex. It is assumed that the subduction of oceanic crust of this age is associated with the formation of eclogitic diamond, which was noted earlier and widespread in placer deposits in the northeastern Siberian platform.

Bol左侧为花岗石复合体。库普卡河河口下方的库纳姆卡河是由黑克拉通和中克拉正统的邻苯二茂基-斜py石晶体片岩和白垩系的邻苯二茂基和邻苯二茂基-斜石斜片组成的。由镁铁质到长英质的火山成岩后，形成了具有稀少沉积夹层的花岗石。在化学组成方面，镁铁质和超镁铁质岩石分别对应于黄铁矿系列的辉石岩，辉长岩和辉长岩闪长岩。斜长石和斜长片麻岩是在类似于闪长岩，色调和长生硬石或其火山类似物的岩石之后形成的，其特征是Ba，Zr，Y，REE，Nb和Ta的含量增加。邻辉石-斜辉石斜生辉长岩闪长岩原石的锆石U-Pb年龄一致为2095±10 Ma。_Hf（T）= 6.5–12，T _Hf（DM）= 1.98–2.22 Ga）表示其来源与古元古代贫化地幔的对应关系。在钙-碱性系列的色调剂之后，形成了具有2030±17 Ma一致的U-Pb锆石年龄的两py斜长片麻岩。它们的特征是俯冲岩浆作用具有明显的负Ti，Nb，Ta，P异常。在Khapchan带的所有研究岩石有积极的ε_的Nd（T）值从+2.3 +4.2到和被解释为俯冲少年复杂。据推测，该年龄的洋壳俯冲与火山岩的形成有关，该岩体较早被发现并广泛分布在东北西伯利亚平台的砂矿中。