Table A2.

Isotopic ages and data for intrusions in the north and south Shan States (Fig. A2)

Lithology (sample number) (number of mineral grains analysed)LocationDating methodAge ± error (Ma)MSWDPlateau ageIsochron ageTotal ageΦ age (Ma)Mean track length (µm)87Sr/86SrϵNd (T)Zircon ϵHfZircon δ18OReferencesNotes
Shan States (North)
Tawng Peng (Taung Peng)
GraniteRb–Sr errorchron340 ± 34Mitchell et al. (1977)Apparent age
DoleriteMile post 71 Kyaukme-Namhsam roadK–Ar whole rock834 ± 15Mitchell et al. (1977)
Diorite982 ± 20Mitchell et al. (1977)
Coarse foliated pegmatitic granite (8276A)22° 59″ N, 97° 7′ EK–Ar biotite156 ± 30.7916Brook & Snelling (1976)
Coarse foliated pegmatitic granite (8276A)22° 59′ N, 97° 7′ EK–Ar K-feldspar253 ± 5Brook & Snelling (1976)
Coarse foliated pegmatitic granite (8276B)K–Ar Biotite156 ± 30.792Brook & Snelling (1976)
Coarse foliated pegmatitic granite (8276B)22° 59′ N, 97° 7′ EK–Ar K-feldspar140 ± 3Brook & Snelling (1976)
Crushed foliated granite (8276C)K–Ar plagioclase142 ± 30.8423Brook & Snelling (1976)
Crushed foliated granite (8276C)22° 59′ N, 97° 7′ EK–Ar K-feldspar44 ± 1Brook & Snelling (1976)
Granites (2 samples)22° 59′ N, 97° 7′ ERb–Sr errorchron341 ± 175.60.739Brook & Snelling (1976)2-point errorchron
Dolerite (8276E)22° 59″ N, 97° 7′ EK–Ar whole rock834 ± 15Brook & Snelling (1976)
Diorite (8276F)22° 59″ N, 97° 7′ EK–Ar whole rock982 ± 20Brook & Snelling (1976)
Bawdwin Mine
Rhyolite and volcanoclastic sediments; intense sericitization23° 7′ N, 97° 18′ ERb–Sr isochron212 ± 40.75532 ± 0.0016Lenz & Müller (1981)Triassic age indicates later Sr homogenization of Late Cambrian rocks.
Shan States (South)
Kyaing Tong Granite
Granite (MY55) (zircons n = 8)21.3639° N, 99.62167° EU–Pb concordia219.3 ± 1.31c. −10.5Gardiner et al. (2015)
Granite (MY56) (zircons n = 10)21.29222° N, 99.57417° EU–Pb concordia220.1 ± 1.10.66c. −12.4Gardiner et al. (2015)Kyaing Tong granite within northern extension of Main Range Granites
Plot of ϵHf v. inferred crystallization ages for MY55 and MY56 (zircons n = 18)
Biotite granite (53221B) (apatite n 26) (elevation 800 m)21° 27.238′ N, 99° 39.883′ EApatite fission track20.4 ± 1.2Myo Min (2007)
Biotite granite (53221A) (apatite n = 10) (elevation 800 m)21° 27.238′ N, 99° 39.883′ EApatite fission track21.3 ± 0.613.97 ± 0.08 (n = 257)Myo Min (2007)
Biotite granite (53221A) (apatite n = 3)21° 27.238′ N, 99° 39.883′ EApatite (U–Th)/ He method20.7Myo Min (2007)
Biotite granite (53221A)21° 27.238′ N, 99° 39.883′ E40Ar/39Ar biotite101.6 ± 1.1Myo Min (2007)
Biotite granite (53226B) (apatite n = 63) (elevation 820 m)21° 16.871′ N, 99° 33.797′ EApatite fission track20.0 ± 0.9Myo Min (2007)
Granite (53265A)21° 00.297′ N, 99° 48.956′ E40Ar/39Ar biotite208.0 ± 2.47.4208.1 ± 2.5219.7 ± 2.6208.0 ± 2.4Myo Min (2007)40Ar/36Ar age of 306 ± 68 Ma
Biotite granite (53232A) (apatite n = 10) (elevation 906 m)21° 00.297′ N, 99° 48.956′ EApatite fission track46.8 ± 1.213.19 ± 0.09 (n = 250)Myo Min (2007)
Biotite granite (53232A) (apatite n = 7)21° 00.297′ N, 99° 48.956′ EApatite (U-Th)/He method33.2 ± 4.8 ± 1σMyo Min (2007)
Sandstone (53233B) (apatite n = 47) (elevation 752 m)21° 00.019′ N, 99° 50.064′ EApatite fission track24.0 ± 1.3Myo Min (2007)
Subvolcanic rock (53235B) (apatite n = 71) (elevation 679 m)20° 59.424′ N, 99° 51.009′ EApatite fission track27.6 ± 1.5Myo Min (2007)
Gabbro (53236B) (apatite n = 88) (elevation 424 m)20° 42.971′ N, 100° 04.877′ EApatite fission track16.7 ± 0.614.26 ± 0.17 (n = 70)Myo Min (2007)
Gabbro (53236B) (apatite n = 11)20° 42.971′ N, 100° 04.877′ EApatite (U–Th)/ He method15.3 ± 2.9 ± 1σMyo Min (2007)
Mong Kan Noi
Altered biotite granite (zircon)20° 35′ N, 98° 45′ ELA-MC-ICP-MS214 ± 1.5Than Htun et al. (2014)
Tachileik Granite
Undeformed granite (MY53) (zircons n = 9)20.561473° N, 99.977197° EU–Pb concordia265.8 ± 2.11.9c. −9.6Gardiner et al. (2015)Tachiliek granite suggested to be part of Sukhothai Volcanic Arc.
Granite (SP-11)20° 25.324′ N, 99° 18.166′ EAr–Ar biotitec. 90–110Myo Min (2007)