caa a22 4500 445300191 CHVBK 20180317142555.0 cr unu---uuuuu 170323e20100301xx s 000 0 eng 10.1007/s11430-010-0028-9 doi (NATIONALLICENCE)springer-10.1007/s11430-010-0028-9 Hydrothermal recrystallization of the Lower Ordovician dolomite and its significance to reservoir in northern Tarim Basin [Elektronische Daten] [DongYa Zhu, ZhiJun Jin, WenXuan Hu] Discovered in S15 and some other wells, the Lower Ordovician in the northern Tarim Basin consists mainly of brown gray-dark gray very fine-fine crystalline dolomite, with a minor portion of locally light gray-white medium-coarse crystalline dolomite. Silicification can be observed in the medium-coarse dolomite, and some euhedral drusy quartz can also be found in pores and fractures of the dolomite. The homogenization temperature of the fluid inclusions in the medium-coarse dolomite is between 110 and 200°C with maximum between 140 and 190°C, and the salinity is between 10.7 and 18.5 wt.% NaCl Eq. The homogenization temperature and salinity of the fluid inclusions in the medium-coarse dolomite are similar to those in the drusy quartz. Compared with the very fine-fine dolomite, the medium-coarse phase contains relatively high Fe and Mn. The average concentration of FeO and MnO in the medium-coarse dolomite is 1.917% and 0.323%, respectively. The medium-coarse dolomite has a remarkable negative Eu anomaly, consistent with the REE pattern of the intermediate-felsic igneous rocks in the Tarim Basin. The oxygen isotopic composition of the medium-coarse dolomite is relatively lighter than that of the very fine-fine dolomite. The δ18OPDB values of the medium-coarse dolomite are between −10.35‰ and −7.31‰. The δ18OSMOW values of the fluid associated with the medium-coarse dolomite can be calculated according to homogenization temperature and oxygen isotope fractionation factor between dolomite and fluid, and the calculated values are between +4‰ and +10‰, consistent with those of the hydrothermal fluid. The medium-coarse dolomite has relatively high 87Sr/86Sr ratios as well, indicating an origin associated with intermediate-felsic igneous rock. The homogenization temperature, element composition, REE pattern, oxygen and strontium isotopes demonstrate that the medium-coarse dolomite is the result of recrystallization of very fine-fine dolomite under hydrothermal environment. The hydrothermal dolomite recrystallization is a special event but exists extensively in the Tarim Basin. The recrystallized dolomite becomes well reservoir bed for many intercrystalline pores and dissolution pores are produced in this event, so that more attention should be paid to the altered dolomite during the petroleum exploration in the lower Paleozoic in the Tarim Basin. Science China Press and Springer-Verlag Berlin Heidelberg, 2010 Tarim nationallicence hydrothermal nationallicence dolomite nationallicence recrystallization nationallicence reservoir nationallicence Zhu DongYa Petroleum Production and Exploration Institute of China Petroleum and Chemical Corporation, 100083, Beijing, China aut Jin ZhiJun Petroleum Production and Exploration Institute of China Petroleum and Chemical Corporation, 100083, Beijing, China aut Hu WenXuan Department of Earth Sciences, Nanjing University, 210093, Nanjing, China aut Science China Earth Sciences SP Science China Press 53/3(2010-03-01), 368-381 1674-7313 53:3<368 2010 53 11430 https://doi.org/10.1007/s11430-010-0028-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11430-010-0028-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhu DongYa Petroleum Production and Exploration Institute of China Petroleum and Chemical Corporation, 100083, Beijing, China aut NATIONALLICENCE 700 1- Jin ZhiJun Petroleum Production and Exploration Institute of China Petroleum and Chemical Corporation, 100083, Beijing, China aut NATIONALLICENCE 700 1- Hu WenXuan Department of Earth Sciences, Nanjing University, 210093, Nanjing, China aut NATIONALLICENCE 773 0- Science China Earth Sciences SP Science China Press 53/3(2010-03-01), 368-381 1674-7313 53:3<368 2010 53 11430 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer