"Sample Number (Well, depth)" Lithology Formation Stratigraphic age Age (Ma) 143Nd/144Nd Epsilon Nd Mekong River sand Modern 0 0.512118 ± 11 -10.1 Red River sand Modern 0 0.512047 ± 9 -11.5 "LK 64, 741 m" silty shale Tien Hung Upper Miocene 6.8 0.512027 ± 4 -11.9 "LK 81, 1108 m" sandstone Tien Hung Upper Miocene 9.1 0.512094 ± 6 -10.6 "LK 41, 444 m" sandstone Phu Cu Middle Miocene 12.0 0.512057 ± 6 -11.3 "LK 108, 1344 m" siltstone Phu Cu Middle Miocene 13.7 0.512021 ± 3 -12.0 "LK 200, 2643 m" sandstone Phu Cu Middle Miocene 17.0 0.512159 ± 2 -9.3 "LK 203, 2511 m" shale Phong Chau Lower Miocene 17.2 0.512103 ± 4 -10.4 "LK 203, 2846 m" sandstone Phong Chau Lower Miocene 24.0 0.51206 ± 3 -11.3 "LK 81, 1986 m" shale Dinh Cao Oligocene 28.0 0.51203 ± 6 -11.9 "LK 81, 2250 m" shale Dinh Cao Oligocene 31.5 0.511949 ± 5 -13.4 "LK 104, 3590 m" conglomerate Phu Tien Eocene 34.8 0.51178 ± 12 -16.7 "LK 106, 3910 m" shale Phu Tien Eocene 37.0 0.511862 ± 8 -15.1