Finding of the spore Coniopteris and pollen Classopollis in the Hòn Gai Formation
in the Đồng Pagoda area, Yên Tử Mt
Bùi Phú Mỹ, Đoàn Nhật Trưởng, Hoàng Đình Khảm,
Nghiêm Nhật Mai, Nguyễn Chí Hưởng, Nguyễn Văn Hoành
Recently, in the Yên Tử Mt, a spores and pollens assemblage containing the Jurassic genera Coniopteris and Classopollis has been found in coal-bearing sediments belonging to the Hòn Gai Formation of Late Triassic, Norian-Rhaetian age.
The sediments containing the above spores and pollens consist of siltstone interbedded with coarse-grained beds, mainly of conglomerate, about 300 m thick, distributed from Bảo Sái to Đồng Pagodas, lying in the summit of the Yên Tử Mt. They belong to the uppermost part of the coal-bearing section of this locality. They have been described as “Chùa Đồng Conglomerate, of Early Jurassic age”. So, the Hòn Gai Formation in the Yên Tử Mt has a thickness of 1150-1300 m and has an age of Late Triassic - Early Jurassic (T3n-J1 hg).
Người biên tập: GS. TSKH Vũ Khúc