A study of fluid inclusion planes in the Gongga granite, Western Sichuan province China

摘要

Fluid inclusion planes (FIP) result from the healing of former open cracks and appear to be fossilized fluid pathways (Roedder, 1984). Microcracks should provide valuable information about the local stress in rocks and can be assumed to be (σ_1-σ_2) planes (Wise, 1964; Lespinasse, 1986, 1999). The FIP are mode I cracks that occur in sets with a predominant orientation perpendicular to the least principal compressive stress axis, σ_3. FIP are usually observed and characterized in minerals which crack according to the stress field, independently of their crystallographic properties (special in quartz. Lespinasse, 1990). A second generation of FIP generally cross-cuts the first one, thus, FIP are good records of successive episodes of crack initiation. In order to understand the relation between FIP and structural deformation, a study ofrnoccurrence, orientation of FIP microstructures and microthermometric works have been undertaken on Gongga granitic massif.