Abundances and isotopic compositions of noble gases (He, Ne, Ar, Kr) with various existence states in carbonate rocks from the Tacanl Well have been investigated by means of the stepwise heating technique. The element...Abundances and isotopic compositions of noble gases (He, Ne, Ar, Kr) with various existence states in carbonate rocks from the Tacanl Well have been investigated by means of the stepwise heating technique. The elemental abundance patterns of noble gases in the samples show the enrichment of heavy noble gases and depletion of 20Ne relative to the atmosphere, which are designated as type-I and are similar to that observed in water, natural gases and sedimentary rocks. The 3He/4He ratios of deep carbonate samples at lower and medium temperature (300-700°C) and a majority of samples at higher temperature (1100-1500°C) steps are very similar to those of natural gases in the same strata in this area, this feature of radiogenic crustal helium shows that the Tazhong Uplift is relatively stable. However, significant helium and argon isotopic anomalies are found at the 1100°C step in the Middle-Upper Ordovi-cian carbonate rock, suggesting the incorporation of mantle-derived volatiles, this may be due to minor展开更多
基金This work was supported by "Light of the West" Project of the Chinese Academy of Sciences (CAS)the Important Direction Projects of Knowledge Innovation in Resource and Environment Field, CAS (Grant No. KZCX2- 111).
文摘Abundances and isotopic compositions of noble gases (He, Ne, Ar, Kr) with various existence states in carbonate rocks from the Tacanl Well have been investigated by means of the stepwise heating technique. The elemental abundance patterns of noble gases in the samples show the enrichment of heavy noble gases and depletion of 20Ne relative to the atmosphere, which are designated as type-I and are similar to that observed in water, natural gases and sedimentary rocks. The 3He/4He ratios of deep carbonate samples at lower and medium temperature (300-700°C) and a majority of samples at higher temperature (1100-1500°C) steps are very similar to those of natural gases in the same strata in this area, this feature of radiogenic crustal helium shows that the Tazhong Uplift is relatively stable. However, significant helium and argon isotopic anomalies are found at the 1100°C step in the Middle-Upper Ordovi-cian carbonate rock, suggesting the incorporation of mantle-derived volatiles, this may be due to minor
