云南江城勐野井组钾盐成矿时代及其古环境研究

研究云南江城勐野井组的成钾时代, 对于分析兰坪—思茅盆地与老挝沙空那空、呵叻盆地含盐系地层对应关系, 以及在云南开展钾盐找矿工作具有重要意义, 但勐野井组的地层学年代至今仍存在较大分歧。本文通过对江城宝藏乡泰裕矿区含盐系地层的孢粉分析, 得到孢粉组合: Psophophaera-Exesipollenites- Classopollis, 且发现单沟类Monocolpopollenites和三沟类Tricopite等被子植物花粉, 此被子植物花粉时代分别为晚巴列姆期—阿普第期和早、中阿尔必期。因此, 笔者将江城勐野井组钾盐成矿时代确定为阿普第期—阿尔必期; 同时, 孢粉反映矿区成盐期气候呈炎热干旱的热带-亚热带特征。

The Ore-forming Age and Palaeoenvironment of the Mengyejing Formation in Jiangcheng, Yunnan Province

Research on the potash metallogenic epoch in the Mengyejing Formation is of important significance for the analysis of the corresponding relationships of the salt-bearing strata between Lanping-Simao Basin in Yunnan, Sakhon Nakhon Basin in Laos, and Khorat Basin in Thailand, and is also helpful to the prospecting for potassium deposits in Yunnan. However, there has long been controversial concerning the chronostratigraphy of this formation. Based on pollen analysis of samples collected from the Jiangcheng mining area, the authors defined the main sporopollen assemblage as Psophophaera-Exesipollenites-Classopollis assemblage, with the discovery of the index angiosperms pollen fossils like Monocolpopollenites and Tricopite, indicating an arid tropical and subtropical climate. Thus, the age of sporopollen assemblage in Mengyejing Formation should be between Aptian and Albian of late Early Cretaceous.