GeoScienceWorld Lithosphere Volume 2020, Article ID 8875012, 28 pages https://doi.org/10.2113/2020/8875012 Research Article Coexisting Late Cenozoic Potassic and Sodic Basalts in NE China: Role of Recycled Oceanic Components in Intraplate Magmatism and Mantle Heterogeneity 1,2,3 1,2,3 1,2,3 1,2,3,4 1,2,3 Ming Lei, Zhengfu Guo , Wenbin Zhao, Maoliang Zhang, and Lin Ma 1Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China 3University of Chinese Academy of Sciences, Beijing 100049, China 4Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China Correspondence should be addressed to Zhengfu Guo; [email protected] Received 23 July 2019; Revised 28 May 2020; Accepted 24 June 2020; Published 1 September 2020 Academic Editor: Sarah M. Roeske Copyright © 2020 Ming Lei et al. Exclusive Licensee GeoScienceWorld. Distributed under a Creative Commons Attribution License (CC BY 4.0). This study presents an integrated geochemical study of the Wudalianchi-Erkeshan potassic basalts and Halaha sodic basalts of NE China, and uses these data to further our understanding of the petrogenetic relationships between the coeval potassic and sodic basalts in this region. The potassic basalts with high concentrations of K2O have arc-like trace-element compositions and 206 204 enriched Sr-Nd-Hf isotopic compositions with unradiogenic Pb/ Pb values (16.77–16.90). In contrast, the sodic basalts with high concentrations of Na2O have OIB-like trace-element compositions and depleted Sr-Nd-Hf isotopic compositions with radiogenic 206Pb/204Pb values (18.27–18.40). These data suggest that the potassic and sodic basalts were derived from mixed depleted mid-ocean-ridge basalt mantle (DMM) and enriched mantle source end-members, where the enriched end-members are ancient sediment for the potassic basalts and Pacific oceanic crust for the sodic basalts. The combined geophysical and geochemical data indicate that these two enriched end-members are located in the mantle transition zone. We propose that partial melting of upwelling asthenospheric mantle comprising ambient DMM and recycled materials shifting from the ancient sediment to the Pacific oceanic crust could have produced the coeval potassic and sodic basalts in NE China. The proposed mantle sources for the potassic and sodic basalts indicate that the upper mantle beneath NE China was highly heterogeneous during late Cenozoic. 1. Introduction [10]. According to Bonin [11, 12], potassic basalts are usually formed in postcollisional or postorogenic settings, whereas Continental alkali basalts including potassic basalts (K2O/ sodic basalts are normally formed within continental and Na2O>1) and sodic basalts (Na2O/K2O>1) are particularly oceanic lithosphere associated with rift systems, hot spots, important because they preserve geochemical features that or mantle plumes (e.g., [13]). likely reflect the nature of their mantle source (e.g., [1]). Pre- Intriguingly, coeval spatially and temporally related vious studies have suggested that potassic basalts are the potassic and sodic basalts are also reported in some places, result of the low degree of melting of phlogopite-bearing including the Basin-and-Range Province (e.g., the Rio peridotite (or pyroxenite) in the subcontinental lithospheric Grande Rift) [14–17], the East African Rift [18], and the mantle (SCLM) or asthenospheric mantle ([2–9], 2016), Hong’an-Dabie orogen, China [19–21]. Previous studies whereas sodic basalts are generally the result of decompres- have proposed two main models to explain the coeval potas- sion melting of asthenospheric mantle or mantle plumes sic and sodic basalts as follows: Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/doi/10.2113/2020/8875012/5293662/8875012.pdf by guest on 29 September 2021 2 Lithosphere (1) In the lithospheric thinning or delamination model, relationship of these two suites of basalts, and (3) character- potassic basalts are formed by the partial melting of ize the upper mantle beneath NE China. a previously enriched lithospheric mantle, whereas sodic basalts are presumed to be formed by the 2. Geological Setting and Samples decompressional melting of sublithospheric material (asthenospheric mantle or mantle plume) when the The Xing’an-Mongolia Orogenic Belt is the eastern segment local lithospheric mantle is thinning [14, 15, 17, 18]. of the Central Asian Orogenic Belt, which lies between the Alternatively within this model, potassic basalts Siberia and Baltica cratons to the north and the Tarim and could be produced by the melting of a delaminated North China cratons to the south (e.g., [43]). NE China lies lithospheric mantle veined by a mica-bearing, Al- within the eastern portion of the Paleozoic Central Asian poor assemblage at high pressure (great depth), Orogenic Belt (Figure 1(a)). From Paleozoic to Mesozoic, whereas sodic basalts could be generated by the melt- NE China has experienced the amalgamation of several ing of a delaminated lithospheric mantle veined by an microcontinental blocks (e.g., Xing’an, Songliao, and Jamusi) aluminous amphibole-bearing assemblage at low along suture zones [44, 45]. Since the Late Jurassic, the tec- pressure (shallow depth) [16] tonic history of NE China has been dominated by the Paleo-Pacific plate, as evidenced by the Jurassic-Cretaceous – (2) In the recycled crustal material model [19 21], potas- accretionary complexes along the eastern Eurasian plate sic basalts are viewed as resulting from the partial melt- [46]. During the Cenozoic, NE China was in a continental ing of metasomatites that were produced by a reaction extension setting due to the Pacific slab rollback and trench between mantle-wedge peridotite and recycled conti- retreat [47], which probably resulted in asthenospheric nental crust, whereas sodic basalts are considered as upwelling and led to continental intraplate volcanism in NE resulting from the partial melting of metasomatites that China [48–50]. were produced by the reaction between mantle-wedge The Wudalianchi volcanic field and the adjacent Erke- peridotite and recycled oceanic crust shan volcanic field, which were located on the Northern mar- gin of the Songliao Basin in the Xing’an-Mongolia Orogenic Late Cenozoic intraplate volcanic rocks are widely in and Belt (Figure 1(b)), are known for producing highly potassic around the Songliao Basin and occur along the Yilan-Yitong basalts (e.g., [51]). Previous studies indicated that the Wuda- and Fushun-Mishan faults, NE China (e.g., [22]). Coeval lianchi and Erkeshan volcanic activities mainly occurred in potassic and sodic basalts have also been extensively reported – – – the middle Pleistocene (0.56 0.13 Ma) and recent (1719 in NE China (e.g., [23 34]). However, the mantle sources of 1721 AD) periods (e.g., [22, 31]). these potassic and sodic basalts are still unresolved, with var- The Halaha volcanic field lies in the center of the Greater ious proposals for their sources including (1) SCLM metaso- Xing’An Mountains (Figure 1(b)). The magmatism of the matized by delaminated ancient lower continental crust or fi – Halaha volcanic eld was mainly distributed above the valley recycled ancient sediment [26, 27, 31, 33 35], (2) interaction of Halaha River, Chaoer River, Chai River, and Dele River between asthenospheric (or carbonated asthenospheric) forming a low lava platform [32]. Previous studies have mantle and enriched (or carbonated) lithospheric mantle shown that the volcanic activities of the Halaha volcanic field [28, 36], (3) asthenospheric mantle enriched by delaminated erupted over a short period from 2.30 to 0.16 Ma [23, 52]. ancient lower continental crust or recycled oceanic materials Sixteen basalts of the Wudalianchi-Erkeshan volcanic – (oceanic crust and/or sediment; [37 42]), (4) interaction fields and fourteen basalts of the Halaha volcanic field were between depleted lithospheric mantle and recycled ancient sampled in this study. The Wudalianchi-Erkeshan basalts subducted sediment [24, 25, 29], (5) depleted mid-ocean- have typical porphyritic texture and contain 10% pheno- ridge basalt (MORB) mantle (DMM) [23, 32], and (6) crysts, which are primarily olivine and clinopyroxene. The ancient primitive mantle with recycled oceanic materials matrix primarily comprises olivine, clinopyroxene, and some [30]. Recent studies have focused on the petrogenetic rela- plagioclase (Figures 2(a) and 2(b)). The Halaha basalts also tionship among these (ultra)potassic basalts and have pro- show typical porphyritic texture and contain 10%–20% phe- posed that the geochemical variations (e.g., K2O/Na2O and nocrysts, which are primarily olivine and minor clinopyrox- Rb/Nb ratios) of these potassic basalts might result from ene. The matrix primarily comprises olivine, clinopyroxene, melt-lithosphere interaction [24, 25]. However, another and minor oxide minerals (Figures 2(c) and 2(d)). The important issue is the petrogenetic relationship of the coeval descriptions of locations and ages for the studied samples potassic and sodic OIB basalts in NE China, which is still are summarized in Supporting Information Table S1. poorly constrained. For this study, we have conducted an integrated investi- 3. Analytical Methods gation of olivine, whole-rock major- and trace-element, and Sr-Nd-Pb-Hf radiogenic isotopic compositions of potassic Major-element analyses of olivine were performed