Early Cretaceous volcanic-arc magmatism in the Dalat-Kratie Fold Belt of eastern Cambodia: implications for the lithotectonic evolution of the Indochina terrane

Mesozoic granitic plutons are found throughout the Indochina terrane of eastern Cambodia and southern Vietnam. The rocks range in age from Early Triassic (240 Ma) to Late Cretaceous (80 record distinct tectonomagmatic periods associated with subduction Paleotethys Paleo-Pacific oceans. Samples collected Snoul pluton, composed silicic intermediate dioritic rocks, basalt. quartz diorites magnesian, metaluminous, calcic calc-alkalic, similar volcanic-arc granitoids whereas basaltic compositionally within-plate Zircon U-Pb geochronology Lu-Hf isotopes whole rock Sr-Nd show that Albian isotopically juvenile (107.5 ± 0.3 Ma, 109.1 0.4 Ma; ε Hf ( t ) = +7.0–+17.0; 87 Sr/ 86 Sr i 0.704313–0.707681; Nd +3.1–+4.9). Fractional crystallization modeling using a composition as parental magma demonstrates it is possible generate diorite compositions under oxidizing (ΔFMQ +1) hydrous (H 2 O wt%) conditions suggesting they consanguineous. nature their compositional similarity (SiO ≥ 56 wt%, Al 3 15 400 ppm, Y ≤ 18 Yb 1.9 ppm) adakitic indicates magmas pluton were likely derived by partial melting mafic basement terrane. Moreover, plutonic tectonic setting Vietnam there could be lithotectonic domain boundary within Southern In contrast, temporally period magmatism Cenozoic tensional plate stress.