Comparative studies on carbon origin of dawsonite between Hailaer Basin in China and Bowen-Gunnedah-Sydney basin system in Australia  

作　　者：Yuqiao GAO Li LIU Qi＇an MENG Yan XU Xiyu QU Xianmei JIN 

机构地区：[1]College of Earth Sciences, Jilin University, Changchun 130061, China [2]Exploration and Development Research Institute of Daqing Oilfield Ltd Co. , Daqing 163712, Heilon~iang, China [3]Exploration and Development Research Institute of Northwest Branch of SINOPEC, Urumchi 830011, China

出　　处：《Global Geology》2007年第2期148-155,共8页世界地质（英文版）

基　　金：Project of NSFC (No.40372060)

摘　　要：Dawsonite, NaAtCO3 （OH）2, is widespread as a cement, replacement and cavity filling in Hailaer Basin in China and Bowen-Gunnedah-Sydney （BGS） basin system in Australia. The origin of dawsonite is emphatically contrasted and analyzed through stable isotopic composition. Dawsonite δ^13C values ranging from -4. 0 × 10 -3 to 4. 1 × 10 -3 are remarkably consistent through the BGS basin system. The calculated 813C values of CO2 gas in isotopic equilibrium with dawsonite range from - 11.3 × 10 -3 to -4. 6 × 10 -3. These values indicate carbon of dawsonite came from inorganic CO2 gas accompanied by magmatie activity. In Hailaer Basin, the Dawsonite δ^13C values ranging from -4. 64×10 -3 to 2. 12 × 10 -3 are also consistent. The calculated δ^13 C values of CO2 gas in isotopic equilibrium with dawsonite range from - 11.82 × 10 -3 to -5. 11 ×10 -3. According to the coincidence of dawsonite-bearing well and CO2 gas well with mantle source, lying along deep fracture within or adjacent to Yanshanian granite, it is concluded that CO2 gas forming dawsonite is derived from mantle related to magmatie process during the Yanshanian. A little biologic origin carbon owing to petroleum charging intervened when dawsonite formed.Dawsonite, NaAlCO3(OH)2, is widespread as a cement, replacement and cavity filling in Hailaer Basin in China and Bowen-Gunnedah-Sydney (BGS) basin system in Australia. The origin of dawsonite is emphatically contrasted and analyzed through stable isotopic composition. Dawsonite δ13C values ranging from -4.0×10-3 to 4.1×10-3 are remarkably consistent through the BGS basin system. The calculated δ13C values of CO2 gas in isotopic equilibrium with dawsonite range from -11.3×10-3 to -4.6×10-3. These values indicate carbon of dawsonite came from inorganic CO2 gas accompanied by magmatic activity. In Hailaer Basin, the Dawsonite δ13C values ranging from -4.64×10-3 to 2.12×10-3 are also consistent. The calculated δ13C values of CO2 gas in isotopic equilibrium with dawsonite range from -11.82×10-3 to -5.11×10-3. According to the coincidence of dawsonite-bearing well and CO2 gas well with mantle source,lying along deep fracture within or adjacent to Yanshanian granite,it is concluded that CO2 gas forming dawsonite is derived from mantle related to magmatic process during the Yanshanian. A little biologic origin carbon owing to petroleum charging intervened when dawsonite formed.

关 键 词：DAWSONITE isotope composition source for carbon Hailaer Basin BGS basin system 

分 类 号：P54[天文地球—构造地质学]