The characteristics and genesis of the calcite veins in Carboniferous basalt in the east slope of Mahu Sag, Junggar Basin are investigated based on observation of cores and thin sections; analyses of X-ray fluorescence, in situ major, trace and rare earth elements (REE), carbon, oxygen and strontium isotopes, fluid inclusions, as well as basin modeling. There are three periods of calcite fillings. The Period I calcite is characterized by low Mn content, flat REE pattern, strong negative cerium (Ce) anomaly, weak to moderate negative Eu anomaly, and light carbon isotopic composition, indicating the formation of the calcite was affected by meteoric water. The Period II calcite shows higher Mn and light REE contents, weak positive Ce anomaly and slight positive europium (Eu) anomaly, and a little heavier carbon isotopic composition and slightly lower strontium isotope ratio than the Period I calcite, suggesting that deep diagenetic fluids affected the formation of the Period II calcite to some extent. The Period III calcite is rich in iron and manganese and has REE pattern similar to that of the Period II calcite, but the cerium and europium enomalies vary significantly. The Period I and II calcites were formed in shallow diagenetic environment at approximately 250–260 Ma, corresponding to Late Hercynian orogeny at Late Permian. The Period III calcite was probably formed in the Indo-China movement during Late Triassic. It is believed that the precipitation of calcite in basalt fractures near unconformity was related to leaching and dissolution of carbonates in the overlying Lower Permian Fengcheng Formation by meteoric water, which destructed the Carboniferous weathering crust reservoirs in early stage. Relatively high quality reservoirs could be developed in positions with weak filling and strong late dissolution, such as structural high parts with Fengcheng Formation missing, distant strata from Fengcheng Formation vertically, buried hills inside lake basin, etc.

在岩心和薄片观察的基础上，研究了准噶尔盆地玛湖凹陷东坡石炭系玄武岩方解石脉的特征及成因；X 射线荧光分析、原位主要、痕量和稀土元素 (REE)、碳、氧和锶同位素、流体包裹体以及盆地建模。方解石充填分为三个时期。Ⅰ期方解石Mn含量低，稀土元素分布平缓，铈（Ce）负异常强，Eu负异常弱至中，碳同位素组成轻，表明方解石的形成受大气水的影响。第二期方解石显示出较高的 Mn 和轻 REE 含量，微弱的 Ce 正异常和轻微的铕 (Eu) 正异常，且碳同位素组成较Ⅰ期方解石稍重，锶同位素比略低，说明深成岩流体对Ⅱ期方解石的形成有一定影响。III 期方解石富含铁和锰，稀土元素分布与 II 期方解石相似，但铈和铕的含量差异很大。I期和II期方解石形成于约250-260 Ma的浅层成岩环境，对应于晚二叠世晚期海西造山运动。III期方解石可能形成于晚三叠世的印度支那运动。认为近不整合面玄武岩裂缝中方解石的沉淀与大气水对上覆下二叠统凤城组碳酸盐岩的淋溶作用有关，早期破坏了石炭系风化壳储层。在缺少丰城组的构造高部位、垂直远离丰城组地层、湖盆内潜山等充填弱、晚期溶蚀作用强的部位可发育相对优质的储集层。