Dolomite genesis and reservoir-cap rock assemblage in carbonate-evaporite paragenesis system

HU Anping,SHEN Anjiang,YANG Hanxuan,ZHANG Jie,WANG Xin,YANG Liu,MENG Shaoxing

Fig. 5. Experiment on the precipitation of original dolomite induced by halophilic archaea. Experimental results from State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences. (a) Original spherical dolomite formed after 72 h action of Natrinemas sp.; (b) Spindle-shaped original dolomite formed after 72 h action of Haloferax volcanii; (c) Spherical original dolomite formed after 48 h action of Haloferax volcanii; (d) Scanning electron microscopy photograph and energy spectrum test results of loose sediments of the modern salt lakes in Tunbul, Inner Mongolia, and the results of the energy spectrum test, spherical dolomite; (e) Well Shi 49-1, 3 764.20 m, algae limestone from the upper member (E32) of the Paleogene Lower Ganchaigou Formation, in honeycomb shape, with algae framework pores and a porosity of 20%; (f) Well Gaoshen 1, 5 880 m, core, the Mesoproterozoic Wumishan Formation in the Jixian System, the microbial dolomite reformed by the karstification of Phanerozoic, with a porosity of up to 15%; (g) Well Yaha 10, core 4-10/25, Lower Cambrian, micrite dolomite, with gypsum molded pores; (h) Well Longgang 001-11, 6 086.50 m, Lower Triassic Feixianguan Formation, oolitic dolomite, with oolitic molded pores, but no calcite or dolomite cements, cast thin section, single polarized light; (i) Well Longgang 001-11, 6 088.50 m, Feixianguan Formation, micrite psammitic bioclastic limestone, stylolite, intergranular pores and body vugs fully filled with sparry calcite, single polarized light.