The reconstruction of such a belt is critical for understanding the tectonomagmatic evolution of the western block of the North China Craton.Vol.04 No.10(2014), Article ID:50978,12 pages 10.4236/ojg.2014.410037 Do U/Pb-SHRIMP Dating and Pb Stepwise Leaching (Pb SL) Analyses Confirm the Lack of Precambrian Basement Outcrops in Thailand? [email protected] © 2014 by authors and Scientific Research Publishing Inc.
The Nd isotopic analyses of the three samples emphasize the polycyclic evolution of the batholith, which is much more complex than previously realized.
The evolution is marked by two successive Paleoproterozoic accretionary orogenic events at about 2200–2175 Ma and by a crustal melting event at about 2000 Ma, which had an Archaean source (Sm-Nd depleted mantle model age, T = 2860 Ma).
Introduction In 1939,  were the first to publish a description on the occurrence of gneisses in Thailand.
These high-grade metamorphic rocks are generally overlain by fossiliferous sedimentary rocks of all periods of phanerozoic strata.
The zircon population displays complex internal structures in three of the four dated samples.
The complex crystals have well-preserved magmatic cores and altered rim domains.The zircons from both samples exhibit magmatic growth pattern.The shapes of the zircons suggest that the zircons should crystallize from a granitic of felsic volcanic terrain.The Neoproterozoic Florianópolis batholith provides the major clue for unraveling the pre-Brasiliano Cycle evolution of Santa Catarina State, southern Brazil, because it contains septa of basement units such as the Camboriú and Águas Mornas complexes reactivated during the younger Brasiliano orogeny at about 600 Ma.We establish precise U-Pb zircon SHRIMP ages and Nd isotopic evolution of four key samples from the septa.The core populations were dated at about 2180 Ma (Águas Mornas complex), about 2160 Ma (Camboriú complex amphibolite xenolith), and 2000 Ma (Camboriú complex orthogneiss), whereas the ages of the measured rims and altered domains are about 590 Ma in all three samples.