Abstract:

Zhijin Region in Central Guizhou was a tensional basin prototype (Zhijin Basin) in Late Early Permian that is formed on carbonate platform of the early Qixia-Maokou Period and underwent following evolution stuges:1. the pre-breaking stage; 2. primary breaking stage; 3. the stable subsiding, aggrading and filling stage; 4. violent breaking stage; 5. the second stuble subsiding, aggrading and filling stage; 6. uplifting and denudation stage of the whole. The two breaking stages were resulted by tensile block structures,associated with basalt eruption and led to vertically lithologic sudden change from shallow to deep water facies. During the stable subsiding, aggrading and filling stage, sedimentary cycles from deep to shallow formed not only in platform trough, but also on platform blocks and slopes. What's more, sedimentary differentiation of shallow-water carbonate rocks and deep-water silicate-carbonate rocks is generated due to paleogeomorphic difference caused by platform breaking. "Breaking platform facies zone", named herein could be divided as sunking-aggrading isolated platform sub facies zone, deeper-water platform (fault) trough sub facies zone, slope subfacies zone and residual semirestricted-open sea platform subfacies zone. The dark silicate and carbonate rocks developed in the platform trough and slope subfacies zones are favourable for the preservation of organic matter and the generation of hydrocarbon; the sunking-aggrading isolated platform subfacies zone is a firie reserving place due to its well developed bank-reef limestones.