Geological mapping approach to hybrid type granitic batholiths:A case study of the Jialuhe complex from East Kunlun orogen

Mafic enclaves are widespread in the granitic rocks of Eastern Kunlun orogen. They provide essential evidence for mixing events of magmas from the mantle and the crust, and thus the Eastern Kunlun granite belt is considered to be a natural laboratory of magma mixing. In recent years, arguments appear in applying comagmatic granitical mapping method to hybrid type granitic batholiths in an orogen environment. In this paper, the authors studied the Jialuhe hybrid type granite complex from East Kunlun orogen, aiming to shed some new lights on mapping methods of hybrid type granites. Based on field work, petrography, mineral and rock chemistry information, it is concluded that the Jialuhe granodiorite and the mafic enclaves inside resulted from magma mixing event under open systems. During the work, the authors divided the igneous rocks into two supper units, i.e., hybrid unit and un-hybrid unit. Based on the theory of magma mixing, three sub-units were further established:mafic end-member, felsic end-member and hybrid products. The basic unit for end-member rocks is pluton according to differences in mineral assemblages and textures of rocks. Likewise, the hybrid products could be further divided into different mixing units based on the different degrees of mixing or on the variations of enclave distributions. This mapping method is somehow similar to the traditional comagmatic granitical mapping method, and provides a preliminary exploration scheme for mapping work of hybrid type granite batholiths.