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塔中地区奥陶系碳酸盐岩经历了多期构造运动,具有复杂的埋藏史和地热史,且受深部流体作用改造,成岩作用比较复杂。本文通过对塔中地区6口井奥陶系碳酸盐岩样品开展详细的显微镜岩矿鉴定、流体包裹体岩相学研究及包裹体均一温度和盐度的测定,结合塔中地区构造、地层埋藏史及热演化史等资料,对塔中地区奥陶系成岩作用及深部流体作用进行了探讨。塔中地区奥陶系包裹体大致可以分为4期:第1期包裹体形成于晚加里东-早海西期早成岩期的同生-准同生或表生暴露阶段,温度接近地表温度,包裹体均一温度<60℃;第2期形成于晚海西期浅埋藏阶段,包裹体均一温度为90～105℃;第3期包裹体形成于波动埋藏-深埋藏阶段,包裹体均一温度变化范围较大,为120～186℃;第4期包裹体均一温度较高,多分布在192～235℃之间,这期高温流体包裹体的形成应该与岩浆-火山或深部热流体作用有关。另外,包裹体的盐度随均一温度升高而发生变化,这可能反映了塔中地区奥陶系在后期受深部热流体影响。
The Ordovician carbonate rocks in Tazhong area underwent multiple tectonic movements with complicated burial history and geothermal history. Due to the deep fluid effect, diagenesis was complicated. In this paper, six wells in Tarim Basin Ordovician carbonate rock samples for detailed microscopic rock and mine identification, fluid inclusions and facies fluid inclusions temperature and salinity measurements, combined with the structure of the Tazhong area, buried stratigraphy History and thermal history of diagenesis and so on. The diagenesis and deep fluid function of Ordovician in Tazhong area are discussed. The Ordovician inclusions in the Tazhong area can be roughly divided into four phases: the first phase inclusions formed in the synoptic-epigenetic or epigenetic exposures during the late Caledonian-Early Hercynian diagenetic stage, the temperature was close to the surface temperature , The homogenization temperature of the inclusions is <60 ℃. The second phase is formed in the shallow-burial stage of Late Hercynian. The homogenization temperature of the inclusions is 90 ~ 105 ℃. The third-phase inclusions are formed during the fluctuating burial-deep burial stage. The homogenization temperature The range of temperature ranged from 120 ℃ to 186 ℃. The homogenization temperatures of the fourth inclusions were higher and ranged from 192 ℃ to 235 ℃. The formation of high-temperature fluid inclusions should be related to the magmatic-volcanic or deep thermal fluids . In addition, the salinity of the inclusions changed with the increase of the homogenization temperature, which may reflect that the Ordovician in the Tazhong area was affected by the deep thermal fluid in the later period.