A great amount of quartz was found filling vugs of the dolomite strata of Upper Cambrian-Lower Ordovician in Keping(柯坪) outcrop area of Tarim basin,China,which is widely distributed with obvious impact on dolomite reservoirs.The quartz’s genesis and environment were studied based on careful field observation and indoor comprehensive analysis.The abnormal high temperature of the primary saline aqueous inclusions of quartz minerals might reach as high as 578 ℃,showing the characteristics of basin abnormal heat events.The quartz-rare earth element(REE) pattern is similar to those of the granite,diabase,and basalt of Permian in Tabei(塔北) area.According to the regional geological setting and quartz’s distribution as well as its occurrence,the genesis of quartz is attributed to Permian magmatic activity-related hydrothermal liquid instead of the primary marine sedimentary genesis or regional metamorphic genesis.The δ 13 C values of CO 2 in the quartz inclusions range from-1.4‰ to-4.6‰,which might derive from the mantle,while δ 18 O of SiO 2 indicates a hot fluid genesis of meteoric precipitation,which consists of the meteoric precipitation diagenetic setting of C and O isotopes in the dolomite host rocks and the low-medium salinity freshwater condition in the inclusions.REEs must have experienced clear differentiation,since the values of LREE/HREE are all over 1,clearly indicating the characteristic of enrichment of LREE and decrement of HREE.Ce has no obvious anomaly and Eu has clear negative anomalies,which suggests a reducing environment when the quartz crystallized.After the comprehensive analysis,we believe that quartz is a product of siliceous hydrothermal liquids in combination with meteoric precipitation under a reducing environment.Additionally,the precipitation hydrothermal fluid mixture might have also mixed thoroughly with the formation water and exchanged material with the host dolomites.The significance of siliceous hydrothermal fluids for dolomite reservoirs as well as oil-gas exploration is finally discussed in this article. A great amount of quartz was found filling vugs of the dolomite strata of Upper Cambrian-Lower Ordovician in Keping outcrop area of ​​Tarim basin, China, which is widely distributed with obvious impact on dolomite reservoirs. Quartz’s genesis and environment were studied based on careful field observation and indoor comprehensive analysis. The abnormal high temperature of the primary ammonium aqueous inclusions of quartz minerals might reach as high as 578 ° C, showing the characteristics of basin abnormal heat events. The quartz-rare earth element (REE) pattern is similar to those of the granite, diabase, and basalt of Permian in Tabei area.According to the regional geological setting and quartz’s distribution as well as its occurrence, the genesis of quartz is attributed to Permian magmatic activity-related hydrothermal liquid instead of the primary marine sedimentary genesis or regional metamorphic genesis. The δ 13 C values ​​of CO 2 in the quartz inclusions range from-1.4 ‰ t o-4.6 ‰, which might derive from the mantle, while δ 18 O of SiO 2 indicates a hot fluid genesis of meteoric precipitation, which consists of the meteoric precipitation diagenetic setting of C and O isotopes in the dolomite host rocks and the low- medium salinity freshwater condition in the inclusions .REEs must have experienced clear differentiation, since the values ​​of LREE / HREE are all over 1, clearly indicating the characteristic of enrichment of LREE and decrement of HREE. Ce has no obvious anomaly and Eu has clear negative anomalies, which suggests a reducing environment when the quartz crystallized. After the comprehensive analysis, we believe that quartz is a product of siliceous hydrothermal liquids in combination with meteoric precipitation under a reducing environment. Additionally, the precipitation hydrothermal fluid mixture might have also mixed mixed thoroughly with the formation water and exchanged material with the host dolomites. the significance of siliceous hydrothermal fluids for do lomite reservoirs as well as oil-gas exploration is finally discussed in this article.