RELATIONSHIP BETWEEN ORIGIN AND DISTRIBUTION OF DOLOMITES IN LOWER PALEOZOIC, JIZHONG DEPRESSION, NORTH CHINA

Yan, Wei ✉; Jin, Zhenkui; Yao, Mengzhu; Zhao, Wenlong

Angol nyelvű Tudományos Szakcikk (Folyóiratcikk)
Megjelent: FRESENIUS ENVIRONMENTAL BULLETIN 1018-4619 28 (5) pp. 3946-3962 2019
  • SJR Scopus - Pollution: Q3
Azonosítók
Szakterületek:
    The origin and distribution of the Lower Paleozoic dolomites in the Jizhong Depression, North China, are related and affect the distribution of the reservoir. The Lower Paleozoic dolomites can be divided into four types: Type-A is gypsiferous mud silt -sized crystalline dolomites; Type-B is non-gypsiferous mud-silt-sized crystalline dolomites; Type C is silt-fine-sized crystalline dolomites; Type-D is medium-coarse-sized crystalline dolomites. Type-A dolomites contains gypsum, with stratiform stromatolites, bird's eye structures and brecciated structures. The ordering of dolomites averages 0.56. delta C-13 averages -0.155 parts per thousand (PDB) and delta O-18 averages -5.669 parts per thousand (PDB). Type-B dolomites are gypsum-free and not associated with gypsum bed. delta C-13 averages -2.114 parts per thousand (PDB). The rest of the characteristic are similar to type A. Type-C dolomites are subhedral and euhedral. Metasomatic relict structure are common. The ordering of dolomites averages 0.75. delta C-13 averages -0.693 parts per thousand (PDB) and delta O-18 averages -6.079 parts per thousand (PDB). Cathodoluminescence is orange and represents zonal structure. Type-D dolomites are subhedral or anhedral. Mosaic structure, recrystallization and residual porphyritic features are common. The ordering of dolomites averages 0.86. delta C-13 averages -1.433 parts per thousand (PDB) and delta O-18 averages -0.149 parts per thousand (PDB). The homogenization temperature of inclusions ranges between 90-330 degrees C. Cathodoluminescence is dark brown. Type-A dolomites and Type-B dolomites are thin, with a small horizontal distribution, but the number of dolomite layer is more. Type-C dolomites have large thickness and large horizontal distribution. It is generally distributed under Type-A and Type-B dolomites. Type-D dolomites have a massive distribution with a large vertical thickness. The range of horizontal distribution is relatively small. These characteristics can be used to analyze the original rock of dolomite, dolomitization temperature, strati graphic burial history, the occurrence time of dolomitization, and the source of magnesium ions. It is indicated that Type-A and Type-B dolomites are formed in tidal flat environment. Type-A dolomites are formed as a result of evaporative pumping. The origin of T-B dolomites are similar to that of dolomite in Andros Island, Bahamas. Type-C dolomites are formed as a result of seepage reflex dolomitization, and have a sandwich structure. Type-D dolomites are formed as a result of burial hydrothermal dolomitization, closely related to the deep faults of the Himalayan Movement and Cenozoic magmatic rocks. These dolomitizations result in different patterns of dolomite distribution. Type-A, Type-B and Type-D dolomites underwent dissolution during the formation process, and could form good reservoirs for oil and gas.
    Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSLMásolásNyomtatás
    2020-09-30 20:19