Abstract
The Panghazjilga igneous complex in the eastern part of the Central Pamirs is one of the few Cambrian intrusive formations in the region. In our study, we address a number of questions that contribute to understanding the nature of the rocks in the complex. The quartz diorites and granodiorites of the Panghazjilga complex, which constitute the eponymous massif, are products of crystallization from a single parent andesitic magma. The fact that mafic microgranular enclaves (MME), isotopically similar to the rocks of the complex and represented by monzodiorites, are present in quartz diorites and granodiorites, as well as the rock association itself, indicates the involvement of mafic and acid magmas in the process of magma generation. The predominance of amphibole crystals and the absence of pyroxene in the quartz diorites, granodiorites and monzodiorites from the enclaves suggest that amphibole was the principal early-crystallizing mineral, and the dominant role of amphibole and biotite in the rocks indicates a significant influence of H 2 O on crystallization. The composition of the rocks from this igneous complex, as well as that of the monzodiorites from the enclaves, demonstrates their close connection with melting of a mantle source that interacted with crustal rocks (or their melts). In particular, this hybrid nature of the source explains the variable and enriched isotopic composition of Hf–Nd–Sr in the rocks that were considered earlier. We believe that the generation of magmas, which serve as a parent material for quartz diorites and granodiorites, involved heterogeneous sources: heterogeneous crustal source (predominantly subducted sedimentary material) and magmas that formed through partial melting of enriched mantle material altered during subduction. The formation of magmas, which are the source of granitoids of the Panghazjilga complex, was associated with the subduction of the oceanic crust of the Proto-Tethys beneath the northern margin of Gondwana.