Abstract:

Regional uplift and denudation is one of the main factors that have effect on the changes and preservation after deposit formation. Mineral geobarometer can quantitatively obtain the initial crystallization pressure of granitic magma, which is also one of the effective methods to reflect granitic intrusion depth and uplift history. In this paper, we apply biotite ^TAl geobarometer to calculate the emplacement depth of typical ore-forming porphyries in Geza magmatic belts in Indosinian and to estimate the crust uplift-denudation rates. Also, we discuss the changes and preservation after deposit formation. The results indicate that the denudation rate of ore-bearing intrusion is rather slow with an average value of 0.018 mm/a, which is favorable to preserve the deposit after its formation. Our study also provides a quantitative reference for the tectonic uplift and denudation of the western Yunnan plateau since Indosinian.

Key words: crust uplift, denudation rate, change and preservation, crust-mantle interaction, Geza arc, Yunnan