Journal of GEOLOGY, Series B, No.47-48/2018.
Unit 4: Events on climate change of Young Dryas, Dansgaard-Oeschger and Heinrich recorded by high-resolution dO18, dC13 stable isotope analysis of stalagmite in Ngườm Hậu cave, Cao Bằng province, Vietnam
Nguyễn Đại Trung, Phạm Thị Thúy, Trần Tân Văn
Vietnam Institute of Geosciences and Mineral Resources
Received: 13/5/2018
Accepted: 23/8/2018
Abstract: Stalagmite specimen (CPTP5), which is 11 cm in length with the weight of 2 kilograms, was collected in Ngườm Hậu limestone cave, Phong Nậm commune, Trùng Khánh district, Cao Bằng province of Vietnam to analyze stable isotope composition of oxygen and carbon (dO18, dC13) and U/Th dating. The analytical results are used to interpret the climate changes in the north of Vietnam during the late Pleistocene - Holocene (approximately 30.000 years ago). A total of 72 samples were collected along both the growth layers and growth axis of stalagmites to determine stable isotope while 10 samples were gathered only along growth axis to dating. The results showed that stalagmites ages were from 271 to 28,700 years. Isotope analysis indicated that dO18, dC13 ranged from 10.317 to -9.407 ‰ and -11.951 to -11.391 ‰, respectively. These results gave illustrated the paleoclimate conditions exist the cold and warm period intertwining under 28,700 year ago. There were four climate events marked the world climate changes in the last glacial period as known as Dansgaard/Oeschger (D/O) 1-2, Heinrich 1(H1) and global cold Young Dryas (YD). Besides, study area’s climate had changed to cold period in the nearly year of 8,200 and regional the cold and warm period intertwining.
Keywords: Stalagmites, YD, D/O Heinrich events, dO18, Vietnam