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始新世是西藏特提斯消亡的时期,因此在该地史时期形成了最年轻的海相沉积即最高海相层。最高海相层的时代代表了残留海盆消亡的时间。藏南亚东地区保存着最年轻的海相沉积,即遮普惹组。通过对亚东堆纳地区日阿东剖面遮普惹组中灰岩段的上部和砂页岩段的中下部灰白色块状生物碎屑灰岩夹层中的钙藻化石进行详细的分析和研究,共鉴定出18属27种(包括红藻门6属9种,绿藻门12属18种),据其分布特征划分出3个化石组合:1 Jania denotata-Amphiroa iraquensis组合,2 Ovulites margaritula-Fucoporella diplopora组合,3 Lithoporella melobesioides-Polygonella minima组合。根据所含钙藻化石组合的相关特征,推测堆纳地区在始新世处于浅海陆棚环境,海水深度最深不超过30m。
Eocene was the period of the demise of Tethys in Tibet. Therefore, the youngest marine deposit, the highest marine phase, was formed during the history of this area. The era of the highest marine layer represents the time of the disappearance of the remaining basins. Southeast Asia holds the youngest marine deposits in southern Asia, namely the Punjab group. Based on the detailed analysis and research on the calcareous fossils in the upper part of the limestone section of the Zhupujao Formation and the limestone block in the middle and lower shale of the Zhudong Formation in the Yadongdu area, A total of 27 genera and 18 genera were identified from 18 genera (including 6 genera and 6 genera of the genus Chlorophyta) and 3 genera and 12 genera of the genus Chlorophyta. According to their distributional characteristics, 3 fossil assemblages were identified: 1 Jania denotata-Amphiroa iraquensis combination, 2 Ovulites margaritula-Fucoporella diplopora combination, 3 Lithoporella melobesioides-Polygonella minima combination. According to the related characteristics of the algae-fossil assemblages, it is speculated that the stalagmite region was in the shallow sea shelf environment during the Eocene, and the deepest seawater depth does not exceed 30m.