Geochemical constraints on the evolution of the lithospheric mantle beneath central and southern Vietnam

Characterizing Peridotite Xenoliths From Southern Vietnam: Insight Into the Underlying Lithospheric Mantle

“…(b) Clinopyroxene REE concentrations for Xuan Loc peridotites, where type‐R peridotites are shown by dashed and type‐F peridotites by solid red lines; Dalat xenoliths from Anh et al. (2021) and C. Nguyen and Kil (2020) are shown as solid (type‐F) and dashed (type‐R) gray lines for comparison. (c) Clinopyroxene trace element concentrations for Pleiku peridotite xenoliths from this study; (d) cpx trace element concentrations of Xuan Loc peridotites from this study; and (e) opx trace element concentrations of both Pleiku and Xuan Loc peridotites from this study; the gray field represents the detection limits for each element.…”

“…The diffuse igneous province of Indochina is a collision‐adjacent, complex tectonic region with extensive basaltic magmatism (Hoang & Flower, 1998; Hoang et al., 1996). Vietnamese Cenozoic plateau basalts record two‐stage eruptive cycles that initiated ∼17 Ma, and consist of large volumes of tholeiitic basalt followed by smaller quantities of alkaline basalt eruptions, several of which host crustal and lithospheric mantle xenoliths (e.g., Anh et al., 2021; Hoang & Flower, 1998; Hoang et al., 1996; T. C. Nguyen & Kil, 2019; C. Nguyen & Kil, 2020). Prior geochemical analysis of Vietnamese basalts has included major element and trace element compositions and 87 Sr/ 86 Sr, 143 Nd/ 144 Nd, 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb isotopes, and suggests that early stage tholeiitic volcanism may record partial melt contributions from a subcontinental lithospheric mantle (SCLM) source, while later‐stage volcanism derives from an asthenospheric source (Hoang & Flower, 1998; Hoang et al., 1996).…”

Bilateral Heterogeneity in an Upwelling Mantle via Double Subduction of Oceanic Lithosphere

“…Isotopic compositions of peridotite xenoliths in Vietnamese basalts are from Anh et al. (2020), Huong and Hoang (2018), and Nguyen and Kil (2020). The circles labeled C1 and C2 are hypothetical end‐member components proposed in this study to explain isotopic variability in mafic volcanic rocks in Vietnam and the adjacent regions (Text S7 in Supporting Information S1 and Table S6).…”

“…The lithospheric origin of EM1‐and EM2‐like components (Hoang et al., 1996) is ruled out as the isotopic compositions of lithosphere‐derived xenoliths in Vietnamese basalts are distinctly different from the compositions postulated for these end‐member components (Figure 5; Anh et al., 2020; Huong & Hoang, 2018; C. Nguyen & Kil, 2020). Alternatively, subducted sediments have been considered sources of EM1 and EM2‐like components (Kuritani et al., 2011).…”

“…Also shown are isotopic compositions of seamount basalts (denoted as "Indian seamount") from Eastern Wharton Basin Volcanic Province (Figure 10a; Hoernle et al, 2011), seafloor basalts in Indian and Pacific Oceans (I-MORB and P-MORB, Gale et al, 2013), and (seafloor) sediment (Gasparon & Varne, 1998;Ben Othman et al, 1989;Plank & Langmuir, 1998). Isotopic compositions of peridotite xenoliths in Vietnamese basalts are from Anh et al (2020), Huong and Hoang (2018), and Nguyen and Kil (2020). The circles labeled C1 and C2 are hypothetical end-member components proposed in this study to explain isotopic variability in mafic volcanic rocks in Vietnam and the adjacent regions (Text S7 in Supporting Information S1 and Table S6).…”