Table A10.

Detrital zircon age and isotope data for Mesozoic sediments in the Central Valley (Fig. A1)

Lithology (sample number) (number of mineral grains analysed)LocationDating methodAge ± error (Ma)ϵNd (T)ReferencesNotes
Cretaceous
Amber Noije Bum hillZircons collected from the matrix surrounding (Group 1 zircons n = 6 interiors)26° 15′ N, 96° 34′ ESIMS 206Pb/238U102–108Shi et al. (2012)Dacite and andesite clasts present
Hukawng ValleyAmber in 1 m thick blue-grey volcaniclastic mudstones. (Group 2 zircons n = 25)206Pb/238U concordia98.79 ± 0.62c. +7.8 to +10.8Shi et al. (2012)Maximum age of the burmite (amber) and a volcanic eruption in the Hukawng Valley
Triassic
Pane Chaung FormationMicaceous sandstone interbedded with shale (ISWB 42) (zircons n = 105)23.25103° N, 93.98612° EICP-MSAve of 3 youngest zircons is 199 ± 13Sevastjanova et al. (2016)Detrital zircons age ranges 3445 ± 52 to 195 ± 4 Ma; 23–36% 1.4–0.7 Ma; 1–5% 360–300 Ma (Carboniferous); 4–9% 300–250 Ma (Permian); 5–12% 25–200 Ma (Triassic), also Archean1–8% (>2.5 Ga except ISWB 10)
Chin Hills near KalaymioMicaceous sandstone interbedded with shale (ISWB 57) (zircons n = 146)22.9812° N, 93.97023° E(Min age of Pane Chaung Formation)
Chin Hills near Mont VictoriaMicaceous sandstone interbedded with shale (ISWB 13) (zircons n = 108)20.84° N, 94.086° ESmall no. of 2.1–1.4 Ga and 410–320 Ma aged zircons present but no significant populations
Micaceous sandstone interbedded with shale (ISWB 25) (zircons n = 114)20.98168° N, 94.1353° E29/39 volcanic? Zircons 100–80 Ma (Cretaceous)
Micaceous sandstone interbedded with shale (ISWB 10) (zircons n = 74)21.1514° N, 94.1334° ESevastjanova et al. (2016) conclude that the weighted average age of the Pane Chaung Formation based on the three youngest zircons is 119 ± 13 Ma, placing its deposition on the Triassic–Jurassic boundary
Thick-bedded yellow sandstone (ISWB 15) (zircons n = 113)20.85061° N, 94.0865° EAve of 3 youngest zircon 255 ± 7
Marlstone (ISWB 06) (zircons n = 39)20.84269° N, 94.08665° E81–97 age range of volcanic zirconsThe presence of Permian and Triassic zircons, apart from in ISWN15 (no Triassic volcanic zircons; weighted average age of 3 youngest zircons is 255 ± 7 Ma) is argued to indicate that West Burma was a part of SE Asia since before the Mesozoic as Permian and Triassic zircons are not known from the West Australia Gondwana margin and were likely derived from the SE Asia Tin belt granitoids. Marlstone (SWB 05) indicates calm-water deposition in Cenomanian–Turonian accompanied with volcanicity, which is difficult to reconcile with a major continental collision during the Cretaceous (see Mitchell et al. 2012, 2015).