Do U/Pb-SHRIMP Dating and Pb Stepwise Leaching (PbSL) Analyses Confirm the Lack of Precambrian Basement Outcrops in Thailand?

Abstract

U/Pb-SHRIMP dating and Pb stepwise leaching (PbSL) experiments on zircons and garnets, respectively have confirmed the lack of Precambrian outcrops within the crystalline basement of Thailand. The obtained data for the high grade metamorphism show Indosinian ages ranging from 225-200 Ma as previously suggested for the vast majority of outcrops in NW-Thailand ([1] and references therein), as well as a small group of ages in the range of 445 Ma in the Lampang Province. Further, the age of a thermal imprint around 60 Ma was confirmed near Surat Thani, Peninsular Thailand, and only a few indications of older ages for the unknown source areas were detected in detrital components.

Data analysis of the U–Pb geochronology and Lu–Hf system in zircon and whole-rock Sr, Sm–Nd and Pb isotopic systems for the granitoids of Thailand

“… εNd (t) against initial Sr (Fig. 5c in [1] ) Sibumasu [37] Indochina [46] , [50] , [51] Sukhothai including Lincang and Chanthaburi [42] , [44] , [48] , [49] , [52] , [53] , [54] , [55] , [56] , [57] Inthanon Zone including Bentong Raub [44] , [47] , [49] Lhasa [58] Truong Son [59] , [60] Lead [41] , [59] , [61] , [62] , [63] . 207 Pb/ 204 Pb (i) against 206 Pb/ 204 Pb (i) (Fig.…”

“… 207 Pb/ 204 Pb (i) against 206 Pb/ 204 Pb (i) (Fig. 5d in [1] ) Grid of εNd (t) including converted εHf (t) [Published data from [9] , [37] , [38] , [40] , [44] , [46] , [48] , [49] , [51] , [52] , [55] , [60] , [64] , [65] , [66] , [67] ]. (Fig.…”

The closure of Palaeo-Tethys in Eastern Myanmar and Northern Thailand: New insights from zircon U–Pb and Hf isotope data

“…1), was inferred as being evidence for Pan-African aged crustal reworking of Sibumasu basement prior to break up of Gondwana. Within the Sukhothai zone, Hansen et al (2014) reported a SHRIMP age of 445 ± 3.8 Ma from the Muang Pan Gneiss, sited east of the Chiang Rai Line in Lampang Province. These data all imply that the basement for both Sibumasu and the Sukhothai Arc have yielded similar early Palaeozoic ages.…”