Boron isotope geochemistry of Bangor Co Salt Lake(central Tibet): implications for boron origin and

• 作者: Bin-Kai Li Mao-Yong He Hai-Zhou Ma Huai-De Cheng Lian-Min Ji
• 来源期刊: 地球化学学报(英文）
• 学科: 地球科学
• 关键词: Tibet Bangor Co salt lake Boron isotope Origin Fractionation processes
• 年，卷（期）: 2023,（5）
• 页码范围: 731-740
• 页数: 9页
• 语种: 英文
• DOI: 10.1007/s11631-022-00542-1

摘要

Boron is an essential, widely used, micronutrient element and is abundant in salt lakes on the Qinghai-Tibet Plateau. The origin and distribution of boron brine deposits on the Qinghai-Tibet Plateau is an important foundation for B resource formation, evolution, and enrichment, which have long been the subject of debate. The boron isotope system is a sensitive geochemical tracer, making it useful for effectively and precisely tracking a wide range of geological processes and sources. This study investigates the major cations, [B], and δ11 B values of samples (lake brine, river waters, and cold spring water) from the Bangor Co Lake which is a typical salt lake rich in boron in Tibet, China. There are magnitude-scale differences in [B] among different sample types: river samples < cold spring water << brine lakes. [B] values vary from 0.73 to ~ 1113 mg/L. Similar to [B], the δ11 B values of the samples exhibit magnitude-scale variations as [B], ranging from - 7.35‰ to + 7.66‰. There are also magnitude-scale differences in δ11 B among different sample types. The δ11 B values of cold spring water are relatively low, and the values range from - 1.26‰ to -7.75‰. However, the river water samples and saline lakes have higher values, from 0.38‰ to 4.62‰, and the δ11 B values of river water samples are basically in the distribution range of those of Bangor Co Lake. This indicates that the sources of boron in Bangor Co Lake are mainly the recharge water with higher δ11 B values and spring water with lower δ11 B values, and the boron sources and the uneven mixing of lake water are two reasons that account for the large change in the δ11 B value of Bangor Co Lake.