International Journal of Coal Geology ( IF 5.6 ) Pub Date : 2022-09-03 , DOI: 10.1016/j.coal.2022.104097 Jing Li, Yuan Wang, Xuanphu Nguyen, Xinguo Zhuang, Jiancheng Li, Xavier Querol, Baoqing Li, Natalia Moreno, Vanlong Hoang, Patricia Cordoba, Vanthuat Do
This paper represents the first integrated research on the mineralogical, geochemical and stable isotope characteristics of the Upper Triassic high‑sulfur coals from the Khanh Hoa open-pit mine, Thai Nguyen Coalfield, NE Vietnam. Formed in a marine-influenced carbonate succession, the Khanh Hoa coal is characterized by medium ash yield, low volatile matter yield, and high sulfur content. Minerals in the Khanh Hoa coal are predominantly composed of authigenic calcite in the upper portion; and pyrite, quartz, with minor amounts of tobelite ([(NH4), K] (Si, Al)4Al2O10(OH)2), gypsum in the middle and lower portions. The high‑sulfur Khanh Hoa coal is enriched in an As-Mo-Sb-U-Cs-P assemblage, which presents both an organic and inorganic mode of occurrence, and is largely ascribed to hydrothermal fluids. The δ13C values of the Khanh Hoa coal range from −24.77‰ to −22.80‰ (avg. −23.33‰), reflecting a change in sedimentation pattern (from transgressive to high stand system upwards). The δ15N values of the Khanh Hoa coal range from 2.41‰ to 3.73‰ (avg. 3.30‰), possibly resulted from influenced by seawater influence and a redox environment. The mineralogical, geochemical and isotopic characteristics reflected that the high‑sulfur Khanh Hoa coal was formed/preserved in marine-influenced anoxic environment, with low detrital input, and strong activities of multi-stage hydrothermal solutions.
中文翻译:
对来自越南东北部 Thai Nguyen 煤田的上三叠统高硫煤的矿物学、地球化学和同位素特征的首次见解
本文是对来自越南东北部 Thai Nguyen 煤田庆和露天矿的上三叠统高硫煤的矿物学、地球化学和稳定同位素特征的首次综合研究。庆和煤形成于受海洋影响的碳酸盐岩层序中,具有中等灰分产量、低挥发分产量和高硫含量的特点。庆和煤中的矿物主要由上部的自生方解石组成;和黄铁矿,石英,含有少量的托必利石 ([(NH 4 ), K] (Si, Al) 4 Al 2 O 10 (OH) 2),中部和下部的石膏。高硫庆和煤富含 As-Mo-Sb-U-Cs-P 组合,具有有机和无机两种赋存模式,主要归因于热液流体。庆和煤的δ 13 C 值范围为 -24.77‰ 至 -22.80‰(平均为 -23.33‰),反映了沉积模式的变化(从海进到高位系统向上)。δ 15 _庆和煤的 N 值在 2.41‰ 到 3.73‰ 之间(平均 3.30‰),可能是受海水影响和氧化还原环境的影响。矿物学、地球化学和同位素特征反映了高硫庆和煤形成/保存在受海洋影响的缺氧环境中,碎屑输入量低,多级热液活性强。