Genetic types and distinguished characteristics of dolomite and the origin of dolomite reservoirs

Wenzhi ZHAO,Anjiang SHEN,Zhanfeng QIAO,Liyin PAN,Anping HU,Jie ZHANG

Fig. 5. Geochemical characteristics and change trends of 3 types of crystal grain dolomites during burial stage with burial depth and temperature. (a) The order degree of the dolomite is relatively high in general, and has a gradual increase trend, and the saddle dolomite has a low degree of order; (b) Oxygen isotopic value shifts from low negative to high negative gradually, carbon isotopes content can either increase or decrease; (c) The Sr isotope ratio can be close to or higher than seawater in the same period, the Sr isotope ratio (87Sr/86Sr) of saddle dolomite is much higher than its host rock; (d) The content of light REEs is greater than that of heavy REEs; (e) The inclusion homogenization temperature is relatively high; (f) The oxygen isotope temperatures (D47) and inclusion homogenization temperature of saddle dolomite are in good consistency, and much higher than the surrounding rock temperature; (g) The absolute age of dolomite is younger than the formation age.