Using a mineralogy method to reflect climate evolution is a new approach to research Cenozoic environmental progression of the Qaidam Basin. In this paper, we present the chemical composition and crystallographic para...Using a mineralogy method to reflect climate evolution is a new approach to research Cenozoic environmental progression of the Qaidam Basin. In this paper, we present the chemical composition and crystallographic parameter of atacamite, nantokite, and tenorite in cryptocrystalline aggregates from the Kaerqueka copper deposit of Qimantag metallogenic belt by means of electron microprobe and in-situ X-ray diffraction analyses. Atacamite and nantokite occur in an intimate intergrowth as the secondary precipitation of chalcopyrite and bornite filling in the interstitial space of andradite in the Kaerqueka copper deposit, with an average composition of Cl： 12.38 wt.%, Cu： 63.76 wt.%, O： 21.46 wt.%. X-ray microdiffraction shows that the intergrowth contains nantokite with a cubic unit cell a=5.403（2） ？ and atacamite with an orthorhombic unit cell a=6.030（3）, b=6.883（2）, c=9.114（1） ？. XRD quantitative calculation shows that the nanometric aggregate contains 36.07 wt.% tenorite, 18.41 wt.% atacamite, and 45.52 wt.% nantokite. The presence of nantokite and atacamite requires saline solutions for their formation and hyper-arid climate conditions for their preservation. Combined with the data of salt lakes and the pollen sequence of western China, we suggest that during the uplift of the Tibetan Plateau and the retreat of the Paratethys, saline water was forced to the surface through a basal fracture zone. In the hyper-arid climate of the Qaidam Basin, the recharge of groundwater by direct precipitation is negligible, and groundwater is derived from inflow from the salt lakes. Thus, atacamite is preserved. In addition, spertiniite in the edge and fractures of atacamite and nantokite may represent wetter climate after the formation of atacamite and nantokite.展开更多
We have found high-copper and high-chlorine inclusions in many species of diamond, following the discovery of silvine inclusions and salt inclusions in diamonds. The diamonds bearing high-copper and high-chlorine incl...We have found high-copper and high-chlorine inclusions in many species of diamond, following the discovery of silvine inclusions and salt inclusions in diamonds. The diamonds bearing high-copper and high-chlorine inclusions occurred in Liaoning, Shandong and Hunan provinces. They are mainly of type-Ia and a few samples are of type-Ⅱ and transitional type. The diamonds take the form of octahedral and展开更多
基金supported by the Geological Survey Program of China Geological Survey(No.1212011121220)the Construct Program of the Key Discipline in Hunan Province,China(No.2016001)
文摘Using a mineralogy method to reflect climate evolution is a new approach to research Cenozoic environmental progression of the Qaidam Basin. In this paper, we present the chemical composition and crystallographic parameter of atacamite, nantokite, and tenorite in cryptocrystalline aggregates from the Kaerqueka copper deposit of Qimantag metallogenic belt by means of electron microprobe and in-situ X-ray diffraction analyses. Atacamite and nantokite occur in an intimate intergrowth as the secondary precipitation of chalcopyrite and bornite filling in the interstitial space of andradite in the Kaerqueka copper deposit, with an average composition of Cl： 12.38 wt.%, Cu： 63.76 wt.%, O： 21.46 wt.%. X-ray microdiffraction shows that the intergrowth contains nantokite with a cubic unit cell a=5.403（2） ？ and atacamite with an orthorhombic unit cell a=6.030（3）, b=6.883（2）, c=9.114（1） ？. XRD quantitative calculation shows that the nanometric aggregate contains 36.07 wt.% tenorite, 18.41 wt.% atacamite, and 45.52 wt.% nantokite. The presence of nantokite and atacamite requires saline solutions for their formation and hyper-arid climate conditions for their preservation. Combined with the data of salt lakes and the pollen sequence of western China, we suggest that during the uplift of the Tibetan Plateau and the retreat of the Paratethys, saline water was forced to the surface through a basal fracture zone. In the hyper-arid climate of the Qaidam Basin, the recharge of groundwater by direct precipitation is negligible, and groundwater is derived from inflow from the salt lakes. Thus, atacamite is preserved. In addition, spertiniite in the edge and fractures of atacamite and nantokite may represent wetter climate after the formation of atacamite and nantokite.
基金Project supported by the National Natural Science Foundation of China.
文摘We have found high-copper and high-chlorine inclusions in many species of diamond, following the discovery of silvine inclusions and salt inclusions in diamonds. The diamonds bearing high-copper and high-chlorine inclusions occurred in Liaoning, Shandong and Hunan provinces. They are mainly of type-Ia and a few samples are of type-Ⅱ and transitional type. The diamonds take the form of octahedral and
