Methodology and thematic studies of geological mapping of intrusions

Geological mapping of intrusions in China has experienced different stages. Now, researchers should explore methods for medium-large scale mapping (1:50000~1:25000). Based on previous mapping experience, especially that obtained from the pilot mapping of cogenetic granitoids, magmatic mixing granitoid, and intermediate-mafic and ultramafic intrusions, this paper presents mapping methodology of intrusive rocks. No matter what kinds of petrogenesis they are, mapping of intrusions should establish different grades of mapping units, such as intrusive body-unit-suite-supersuite-supersuite association, probably responding to plutonbatholith-magmatic belt-huge magmatic belt respectively. Previously, pedigree unit mapping method was widely applied in congenetic granites. These intrusive body-unit-suite-supersuite result from evolution of one magmatic cycle. Mixing or mingling granitoid pluton can be divided into units by different mixing degrees and merging suites. Mapping of intermediate mafic-ultramafic rocks can also refer to the methods introduced above. The establishment of mapping units according to different grades of intrusive rocks are helpful to understanding the magma system and its constraints. Furthermore, intrusive rocks such as granitoids contain abundant geodynamic information, and hence it is necessary to launch thematic mapping and research.