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 cont...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.展开更多
文摘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.
