Journal of Asian Earth Sciences 97 (2015) 393–405

Contents lists available at ScienceDirect

Journal of Asian Earth Sciences

journal homepage: www.elsevier .com/locate / jseaes

Early Cretaceous high-Mg diorites in the Yanji area, northeastern China:Petrogenesis and tectonic implications

http://dx.doi.org/10.1016/j.jseaes.2014.07.0101367-9120/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding author.E-mail addresses: rcao2007cug@qq.com (R. Cao), wpzhu@pku.edu.cn (W.-P. Zhu).

Xing-Hua Ma a, Rui Cao b,⇑, Zhen-Hua Zhou a, Wen-Ping Zhu c

a Key Laboratory of Metallogeny and Mineral Assessment, Chinese Academy of Geological Sciences, Beijing 100037, Chinab College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, Chinac Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China

a r t i c l e i n f o

Article history:Received 21 March 2014Received in revised form 4 July 2014Accepted 6 July 2014Available online 16 July 2014

Keywords:High-Mg dioriteSubductionDehydrationSediment meltingNE China

a b s t r a c t

Mesozoic granitic rocks are widely distributed in northeast (NE) China. However, high-Mg dioritic rocksare considerably rare. Here, we report a newly recognized high-Mg diorite (the Xintun diorite) in theYanji area, NE China, to constrain its origin and implications for the tectonic evolution of eastern Asiancontinental margin. Zircon U–Pb dating yields a crystallization age of 128 ± 1 Ma for the Xintun diorite.The diorites are characterized by high MgO (4.4–6.6 wt.%), Cr (119–239 ppm), Ba (419–514 ppm) and Sr(649–747 ppm) contents and Mg# values (59–64), but low FeOtotal/MgO ratios (1.2–1.4), with geochem-ical features similar to those of sanukitic high-Mg andesites (HMAs). They show moderate radiogenic Sr(ISr = 0.7047–0.7050) and Nd (eNd = 0.3–1.1), with high La/Sm ratios, which are indicative of contributionsfrom sediment components. The mineral assemblage of euhedral hornblende, magnetite and titanite,implies a water-rich and oxidized signature for their primitive magmas. These features suggest thatthe Xintun high-Mg diorites were probably formed via partial melting of the subducting sedimentsand subsequent interaction of mantle peridotites with both melts and aqueous fluids. Geochemical mod-eling reveals that hornblende-dominated fractional crystallization under water-sufficient conditionsenabled the evolved magmas to acquire adakitic signatures. We believe that the Paleo-Pacific subductionbeneath eastern Asian continental margin caused large-scale back-arc extension of NE China in the EarlyCretaceous, and, consequently, induced the asthenospheric flow toward the mantle wedge, reheatingsubducting sediments enough to cause melting. Therefore, the occurrence of the Xintun high-Mg dioritessignifies the onset of extensive back-arc extension of eastern Asian continental margin at ca. 128 Ma.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

High-Mg andesites (HMAs) and their intrusive equivalents are aminor group with unique geochemical characteristics in the familyof intermediate igneous rocks. They are usually characterized byhigh MgO (>5%), Mg# (100 �Mg/(Mg + Fe)>45), but low CaO(<10%), FeOtotal/MgO ratios (<1.5), and enrichment in large ionlithophile element (LILE, e.g., Ba and Sr) as well as compatible ele-ments (e.g., Cr and Ni) relative to typical arc andesites (Tatsumiand Ishizaka, 1982; Kelemen, 1995; Shimoda et al., 1998;Heilimo et al., 2010; Tang and Wang, 2010). The HMAs are consid-ered to have contributed greatly to continental-crust formation inEarth’s early history (e.g., the Archean) (Smithies and Champion,2000; Halla, 2005). However, they are volumetrically limited inthe modern Earth (Tatsumi, 2001), and mainly found at convergent

plate margins, such as the Setouchi volcanic belt of Japan (Tatsumiand Ishizaka, 1982), Aleutian arc (Kay, 1978) and volcanoes fromBaja California (Rogers et al., 1985), and generally classified intofour types, as Sanukitoids, Boninites, Adakites and Bajaites(Kamei et al., 2004). There is a broad consensus that the HMAsare indicative of subduction-zone related melting under relativelyhigh temperature conditions in arc systems (Furukawa andTatsumi, 1999; Hanyu et al., 2006), therefore, they could provideimportant insights into the thermal structure, tectonic settingand interaction between slab-derived fluids/melts and peridotitesin the mantle wedge (Kelemen, 1995; Shimoda et al., 1998; Rappet al., 1999; Hanyu et al., 2006; Tatsumi, 2006).

In this paper, we present zircon U–Pb ages, and petrological,geochemical and Sr–Nd isotopic data for an Early Cretaceoushigh-Mg diorite from the Yanji area, northeast (NE) China. Ourresults reveal that the high-Mg diorites were essentially derivedfrom a mantle source metasomatized by both fluids and sedi-ment-derived melts. Their occurrence indicates an abnormally

Fig. 1. (a) Simplified geological map showing the location of Yanji area, NE China, modified after Jahn et al. (2000). (b) Distribution of granitoids in the Yanji area, modifiedafter Wu et al. (2011). (c) Geological map showing the Xintun diorite in the Yanji area. NCC, North China Craton.

Fig. 2. Representative photographs of the Xintun diorites showing (a) field outcrop, (b) euhedral hornblende, biotite and subhedral to anhedral plagioclase, (c) magnetitewrapped in the hornblende, and (d) euhedral titanite as early-stage phase. Hb, hornblende; Bt, biotite; Pl, plagioclase; Qz, quartz; Mag, magnetite; Ttn, titanite. The length ofhammer is 50 cm.

394 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

high thermal field in the mantle wedge related to the upwelling ofasthenosphere caused by the Paleo-Pacific subduction, and signi-fies the onset of extensive back-arc extension of NE China in theEarly Cretaceous.

2. Geological background

NE China is located in the easternmost segment of the CentralAsian Orogenic Belt (CAOB) that separates the Siberian Craton inthe north from the Tarim and North China Cratons in the south

(Fig. 1a). This area has traditionally been regarded as an importantjunction of two different tectonic regimes, as the EW-trendingPaleo-Asian oceanic domain and the NNE-trending Paleo-Pacificdomain, respectively (Fig. 1a). Overall, the tectonic evolution ofNE China may be divided into two stages (Maruyama et al.,1997; Xiao et al., 2003; Wu et al., 2011): (1) During the Neoprote-rozoic to Paleozoic, multi-arc systems and accretion complexes(e.g., Ulan, Baolidao island arcs and Ondor Sum accretion complex)were developed as a result of subduction of Paleo-Asian oceanicslabs (Windley et al., 2007; Lehmann et al., 2010), which was

Fig. 3. CL images of representative zircons and U–Pb concordia diagrams of theXintun diorites. In the CL images, spots on zircons represent analyzed locations forU–Pb dating and data listed above zircons are 206Pb/238U ages.

Table 1LA-ICP-MS U–Pb data of zircons from the Xintun diorites.

Spot no. U (ppm) 207Pb/206Pb 1r 207Pb/235U

YJ24.1 62 0.0488 0.0149 0.1402YJ24.2 64 0.0486 0.0181 0.1331YJ24.3 167 0.0489 0.0065 0.1363YJ24.4 162 0.0488 0.0047 0.1353YJ24.5 181 0.0487 0.0042 0.1306YJ24.6 142 0.0486 0.0066 0.1299YJ24.7 129 0.0486 0.0086 0.1331YJ24.8 101 0.0491 0.0099 0.1353YJ24.9 75 0.0485 0.0131 0.1317YJ24.10 171 0.0489 0.0043 0.1359YJ24.11 94 0.0490 0.0098 0.1365YJ24.12 104 0.0487 0.0090 0.1315YJ24.13 119 0.0489 0.0076 0.1386YJ24.14 161 0.0487 0.0072 0.1349YJ24.15 57 0.0487 0.0176 0.1369YJ24.16 125 0.0493 0.0081 0.1405YJ24.17 43 0.0489 0.0362 0.1379YJ24.18 138 0.0488 0.0059 0.1359YJ24.19 307 0.0489 0.0037 0.1346YJ24.20 77 0.0488 0.0124 0.1352YJ24.21 116 0.0491 0.0098 0.1380YJ24.22 146 0.0488 0.0062 0.1386YJ24.23 74 0.0487 0.0127 0.1377YJ24.24 116 0.0489 0.0084 0.1340YJ24.25 164 0.0488 0.0074 0.1343YJ24.26 273 0.0487 0.0049 0.1314YJ24.27 248 0.0491 0.0039 0.1333YJ24.28 194 0.0487 0.0055 0.1374YJ24.29 75 0.0488 0.0119 0.1356YJ24.30 63 0.0487 0.0181 0.1382

Note: 204Pb has been corrected.

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 395

followed by consolidation of multiple terranes with the closure ofPaleo-Asian Ocean until the Late Permian (Ruzhentsev andPospelov, 1992; Chen et al., 2000, 2009); (2) Since the Mesozoic,NE China was dominated by the continental margin accretionrelated to the northwestward subduction of Paleo-Pacific plates(Zhao et al., 1994; Maruyama et al., 1997; Wu et al., 2002; Niu,2005). Therefore, NE China ultimately became a tectonic collageof several micro-continental blocks and/or terranes, including theErguna in the northwest, the Xing’an and Songliao in the center,Jiamusi and Nadanhada in the east, and the Liaoyuan Terrane inthe southeast (Zhou et al., 2009; Wu et al., 2011).

During the multiple-stage plate interactions, voluminous Phan-erozoic (mostly the Mesozoic) granitoids were developed in thecollaged terranes of NE China. They are mainly distributed in thewestern Erguna Massif, Great Xing’an Range, Lesser Xing’an Range,Zhangguangcai Range and Yanji–Suifenhe area (Jahn et al., 2000;Zhang et al., 2004; Ma et al., 2009; Wu et al., 2011). Coeval man-tle-derived mafic to intermediate intrusions are subordinate andsparsely distributed along the suture zones between the terranes,such as the Hongqiling, Qinglinzi, Faku gabbros, and the Liukesong,Taipinggou diorites (Wu et al., 2011). Geochemical investigationsindicate that the granitoids in NE China (as well as other parts ofthe CAOB), are mostly I- and A-types, with minor S-type, whichhave consistently been considered as significant growth of juvenilecrust for their low initial 87Sr/86Sr ratios, high eNd(t) values andyoung TDM ages (Wu et al., 2000; Jahn et al., 2001, 2004;Kovalenko et al., 2004; Chen and Arakawa, 2005).

The Yanji–Suifenhe area, located at the border of China, Russiaand North Korea, is the most southeastern part of NE China(Fig. 1b). Its basement is mainly composed of Palaeozoic stratawhich have undergone variable degrees of metamorphism anddeformation (Shao and Tang, 1995). Massive granitoids, occupying�70% of the exposed rocks in this region (JBGMR, 1988), wereemplaced at three distinct stages, as the Permian (285–245 Ma),

1r 206Pb/238U 1r 206Pb/238U (Ma) 1r

0.0348 0.0208 0.0004 132.9 2.70.0292 0.0199 0.0004 126.7 2.50.0172 0.0202 0.0002 129.1 1.30.0132 0.0201 0.0002 128.4 1.30.0112 0.0194 0.0002 124.1 1.20.0175 0.0194 0.0002 123.7 1.30.0231 0.0199 0.0002 126.8 1.50.0253 0.0200 0.0003 127.6 2.20.0296 0.0197 0.0003 125.6 2.20.0123 0.0202 0.0002 128.7 1.20.0253 0.0202 0.0003 129.0 1.80.0233 0.0196 0.0003 124.9 1.90.0203 0.0206 0.0002 131.3 1.50.0192 0.0201 0.0003 128.3 2.00.0434 0.0204 0.0004 130.0 2.50.0239 0.0207 0.0003 131.9 2.20.0455 0.0204 0.0006 130.5 3.80.0162 0.0202 0.0003 129.0 1.70.0133 0.0200 0.0002 127.6 1.40.0286 0.0201 0.0003 128.2 2.20.0256 0.0204 0.0003 130.0 2.00.0177 0.0206 0.0002 131.6 1.30.0302 0.0205 0.0004 130.9 2.20.0236 0.0199 0.0003 126.9 1.80.0295 0.0200 0.0005 127.5 3.00.0131 0.0196 0.0002 124.9 1.10.0104 0.0197 0.0002 125.6 1.00.0156 0.0204 0.0002 130.5 1.30.0281 0.0201 0.0003 128.5 1.80.0401 0.0206 0.0004 131.2 2.3

Table 2Whole rock chemical compositions of the Xintun diorites.

Sample YJ-24 YJ-25 YJ-26 YJ-27 YJ-28 YJ-29 YJ-30

Major elements (wt.%)SiO2 54.4 53.9 53.3 53.3 56.3 53.4 54.9Al2O3 16.1 16.0 16.6 15.8 17.3 17.0 17.0Fe2O3

total 8.1 8.1 8.4 8.5 7.1 8.3 7.7CaO 7.7 7.6 7.8 7.9 7.4 7.9 7.6MgO 6.1 6.1 5.6 6.6 4.4 5.8 4.9K2O 1.1 1.1 1.2 1.1 1.2 1.0 1.1Na2O 3.6 3.6 3.6 3.5 3.7 3.7 3.6MnO 0.1 0.1 0.1 0.1 0.1 0.1 0.1TiO2 1.1 1.1 1.1 1.2 0.8 1.0 0.9P2O5 0.3 0.3 0.2 0.3 0.2 0.2 0.2LOI 1.2 1.3 2.0 1.3 1.5 1.4 1.6Total 99.6 99.3 99.8 99.5 100.1 99.8 100.0Na2O/K2O 3.2 3.2 3.1 3.1 3.2 3.8 3.2FeOtotal/MgO 1.2 1.2 1.3 1.2 1.4 1.3 1.4Mg# 64 64 61 64 59 62 60

Trace elements (ppm)Sc 19.6 20.6 23.3 23.6 15.0 20.4 18.7Ti 5987 5987 5715 7099 4444 5620 5064V 169 186 178 196 139 178 161Cr 213 222 190 239 119 159 149Mn 970 1050 1117 1078 1071 1039 1081Co 27.8 29.0 27.9 32.6 20.9 27.9 24.4Ni 74.1 84.0 48.6 78.9 32.3 55.6 41.6Cu 26.8 32.7 24.9 79.0 14.7 31.2 20.9Ga 18.3 19.6 19.5 19.8 18.4 18.9 18.9Rb 23.1 23.5 24.4 23.1 27.2 19.1 24.9Sr 650 678 684 649 725 747 699Y 16.1 17.3 18.1 18.7 9.5 16.6 11.5Zr 75.5 68.3 85.5 116.0 51.3 80.5 67.6Nb 6.5 7.0 5.9 7.2 5.2 6.1 5.6Ba 469 500 514 478 436 419 459La 15.7 17.7 14.1 16.2 13.6 14.6 13.9Ce 36.6 40.9 33.6 38.2 27.0 34.8 30.5Pr 4.8 5.3 4.3 5.1 3.0 4.6 3.7Nd 20.2 22.2 18.7 21.2 11.9 19.5 15.4Sm 4.6 4.8 4.3 4.8 2.5 4.4 3.5Eu 1.4 1.5 1.4 1.5 0.9 1.4 1.2Gd 4.1 4.3 4.3 4.4 2.3 4.0 3.3Tb 0.6 0.6 0.6 0.7 0.3 0.6 0.5Dy 3.5 3.7 3.7 3.9 1.9 3.5 2.8Ho 0.7 0.7 0.7 0.7 0.4 0.7 0.5Er 1.6 1.7 1.8 1.9 0.9 1.6 1.3Tm 0.2 0.3 0.3 0.3 0.2 0.3 0.2Yb 1.5 1.7 1.6 1.8 0.9 1.6 1.3Lu 0.3 0.3 0.3 0.3 0.2 0.2 0.2Hf 2.5 2.4 2.6 3.2 1.7 2.7 2.2Ta 0.4 0.4 0.4 0.4 0.3 0.4 0.3Pb 5.3 5.5 6.0 5.3 6.3 4.9 6.0Th 1.9 2.0 2.3 1.9 1.8 1.8 2.0U 0.3 0.4 0.8 0.4 0.3 0.3 0.5dEu 1.01 1.00 1.01 0.99 1.18 1.01 1.07Sr/Y 40.4 39.2 37.8 34.7 76.4 45.0 60.8(La/Yb)N 7.4 7.7 6.0 6.5 10.4 6.6 8.3

Note: LOI, loss on ignition; Mg# = 100 Mg/(Mg + Fe2+); dEu = EuN/[(1/2) * (SmN + -GdN)]; N = chondrite-normalized concentrations.

396 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

Late Triassic-Middle Jurassic (210–155 Ma) and Early Cretaceous(135–100 Ma), respectively (Wu et al., 2011, and referencestherein). Of which, the Permian granitoids are rarely exposed inthe west along northern margin of the North China Craton(Fig. 1b), and generally considered to be associated with the termi-nal evolution of the CAOB. In contrast, the Late Triassic-MiddleJurassic and Early Cretaceous granitic rocks are widely distributedalong the NNE-trending Dunhua–Mishan fault (Fig. 1b). These LateMesozoic granitoids, combined with those from other areas of NEChina (e.g., the Zhangguangcai Range and Lesser Xing’an Range),Far East Russia and Japan Islands, have been increasingly regardedas a magmatic arc belt formed by the subduction of Paleo-Pacificplates beneath eastern Asian continental margin (Maruyamaet al., 1997; Zhang et al., 2004; Zhou et al., 2009; Guo et al.,2010; Wu et al., 2011).

3. Petrological description

The Xintun dorites occurred in the southeast of Yanji area(Fig. 1b), intruding into the Palaeozoic strata and the Jurassic grani-toids (Fig. 1c). They appear gray to dark green (Fig. 2a), medium-grained, and show equigranular texture (Fig. 2b). The mineralassemblage consists of hornblende (38–50%), plagioclase (32–45%), biotite (5–8%) and quartz (�5%), with minor amounts ofpyroxene (<3%). Accessory phases are apatite, titanite, epidote, zir-con and magnetite (Figs. 2c and d).

Hornblende occurs as euhedral and hexagonal crystals (Fig. 2b),suggesting that it formed very early. Biotite is often euhedral tosubhedral, and locally replaced by chlorite (Fig. 2b). Magnetite isan earlier phase, wrapped in the hornblende and biotite (Fig. 2band c). Plagioclase is mostly subhedral to anhedral (Fig. 2b andc), and commonly shows compositional and textural zoning.Quartz is a late-stage phase, interstitial to the cleavage of earlycrystallized minerals (Fig. 2b and c). Moreover, apatite is oftenstubby. Titanite usually shows wedge-shape and euhedral(Fig. 2d), indicating its early crystallization.

4. Analytical methods

4.1. Zircon U–Pb dating

Zircon grains were extracted by the combination of heavy-liquid and magnetic methods after crushing the fresh rocks, andfurther purified by hand-picking under a binocular microscope.Zircons were set in an epoxy mount which was polished, and thenvacuum-coated with a layer of 50 nm high-purity gold. Micropho-tographs and Cathodoluminescence (CL) images were taken toexamine the internal structure of individual grain for situ U–Pb iso-topic analyses.

Zircons were dated by the Laser ablation ICP-MS method, con-ducted on a Thermo Fisher NEPTUNE ICP-MS equipped with a193 nm laser (1–200 Hz, 15 J/cm2) at the Tianjin Institute of Geol-ogy and Mineral Resources, China Geological Survey. The analyticalprocedures have been described in detail by Wu et al. (2002). Thespot diameter was 35 lm. Zircon Plesovice (Slama et al., 2008) wasused as the standard and the standard glass NIST610 was used tooptimize the machine. GLITTER program (Jackson et al., 2004)was used to calculate the U–Pb isotopic compositions. Measuredcompositions were corrected for common Pb using the measurednon-radiogenic 204Pb (Andersen, 2002). The age calculations andConcordia plots were done using ISOPLOT 3.0 (Ludwig, 2003).

4.2. Major and trace element analyses

Whole-rock geochemical analyses were performed at NationalResearch Center for Geoanalysis. Major elements were determinedby X-ray fluorescence (XRF) using fused glass disks on ARLADVANT’ XP+ with accelerating voltage of 50 kV, acceleratingcurrent of 50 mA. The analytical errors are less than 2%. Traceelements were measured by inductively coupled plasma-mass(ICP-MS). The analytical uncertainties are 10% for elements withabundances 610 ppm and better than 5% for those P10 ppm.International standards, GSR-1 (granite) and GSR-9 (diorite), wereused during data acquisition.

4.3. Sr–Nd isotopes analyses

Separation of Sr and Nd was performed at Key Laboratory ofOrogenic Belts and Crustal Evolution, Peking University. Sampledissolution was carried out using acid digestion (HNO3 + HF) in asealed Savillex beaker on a hot plate (80 �C). Separation of Rb, Sr

Fig. 4. Plots of major elements against MgO for the Xintun diorites.

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 397

and light REE was done through a cation-exchange column (packedwith Bio-Rad AG50Wx8 resin). Sm and Nd were further purifiedusing a second cation-exchange column, conditioned and cleanedwith dilute HCl as described by Chen et al. (2000).

Sr–Nd isotope ratios were measured on a negative thermal ion-ization mass spectrometer (NTIMS) by TRITON, at the Tianjin Insti-tute of Geology and Mineral Resources, China Geological Survey.87Sr/86Sr ratios were normalized to 86Sr/88Sr = 0.1194. 143Nd/144Ndratios were normalized to 146Nd/144Nd = 0.7219. 87Sr/86Sr ratioswere adjusted to NBS-987 SrCO3

87Sr/86Sr = 0.710250, and the143Nd/144Nd ratios to JMC Nd2O3

143Nd/144Nd = 0.511122. Theuncertainty (2r) in concentration measurement by isotope dilu-tion is 1–2% for Rb, 0.5% for Sr, and 0.2–0.5% for Sm and Nd depend-ing on concentrations. Average procedural blanks are: Rb = 100 pg,Sr = 400 pg, Sm = 50 pg, Nd = 50–100 pg. The decay constants usedin age calculations are 0.0142 Ga�1 for 87Rb and 0.00654 Ga�1

for 147Sm. Nd model ages were calculated based on depleted

mantle assuming a linear revolution of isotopic composition fromeNd(t) = 0 at 4.56 Ga to +10 at the present time.

5. Results

5.1. Zircon U–Pb ages

Cathodoluminescence (CL) images of representative zirconsfrom the Xintun diorites are shown in Fig. 3a. Zircons are euhedral,short prismatic, with pyramidal terminations and clear oscillatoryzones, which are indicative of a magmatic origin. Thirty grainswere analyzed by LA-ICP-MS method. The zircon U–Pb isotopicresults are presented in Table 1 and graphically shown in the Con-cordia diagram (Fig. 3b). Thirty spots yield 206Pb/238U ages rangingfrom 123.7 ± 1.3 to 132.9 ± 2.7 Ma, with a weighted mean206Pb/238U age of 127.9 ± 0.9 Ma (MSWD = 2.4), which representsthe crystallization age of the Xintun diorites.

Fig. 5. Plots of trace elements against MgO for the Xintun diorites.

Fig. 6. Chondrite-normalized REE patterns (a) and primitive mantle-normalized trace element spidergrams (b) for the Xintun diorites. Normalization values of chondrite andprimitive mantle are from Sun and McDonough (1989).

398 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

Table 3Sr–Nd isotopic compositions of the Xintun diorites.

Sample Rb(ppm)

Sr(ppm)

87Rb/86Sr 87Sr/86Sr ±2r ISr(t) Sm(ppm)

Nd(ppm)

147Sm/144Nd 143Nd/144Nd ±2r eNd(0) fSm/Nd (143Nd/144Nd)t eNd(t) TDM

(Ma)

YJ-24 23.1 663 0.101 0.705039 0.000006 0.7049 4.64 20.2 0.1389 0.512612 0.000001 �0.5 �0.29 0.51250 0.4 886YJ-25 23.5 678 0.101 0.705028 0.000012 0.7048 4.8 22.2 0.1307 0.512613 0.000002 �0.5 �0.34 0.51250 0.6 873YJ-26 24.4 684 0.103 0.705145 0.000013 0.7050 4.29 18.7 0.1387 0.512646 0.000002 0.2 �0.29 0.51253 1.1 831YJ-27 23.1 649 0.103 0.705049 0.000004 0.7049 4.78 21.2 0.1363 0.512623 0.000002 �0.3 �0.31 0.51251 0.7 865YJ-28 27.2 725 0.109 0.704979 0.000010 0.7048 2.52 11.9 0.1280 0.512626 0.000021 �0.2 �0.35 0.51252 0.9 850YJ-29 19.1 681 0.081 0.704968 0.000005 0.7048 4.43 19.5 0.1373 0.512604 0.000328 �0.7 �0.30 0.51249 0.3 896YJ-30 24.9 699 0.103 0.704842 0.000006 0.7047 3.5 15.4 0.1352 0.512626 0.000003 �0.2 �0.31 0.51251 0.8 859

Note: eNd = ((143Nd/144Nd)S/(143Nd/144Nd)CHUR � 1) � 10,000, fSm/Nd = (147Sm/144Nd)S/(147Sm/144Nd)CHUR � 1, TDM1 = 1/k � ln(1 + ((143Nd/144Nd)S � (143Nd/144Nd)DM)/((147Sm/144Nd)S-(147Sm/144Nd)DM)), TDM2 = TDM1 � (TDM1 � t)((�0.4 � fSm/Nd)(�0.4 � 0.08592)), 143Nd/144NdCHUR = 0.512638, 147Sm/144NdCHUR = 0.1967, 143Nd/144NdDM =0.51315, 147Sm/144NdDM = 0.2137; kRb = 1.42 � 10�11/year, kSm = 6.54 � 10�12/year.

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 399

5.2. Whole-rock geochemistry

Major and trace element compositions are listed in Table 2 andpresented in Figs. 4 and 5. The Xintun diorites have relatively highcontents of SiO2 (53.3–56.3 wt.%), Al2O3 (15.8–17.3 wt.%) and TiO2

(0.8–1.2 wt.%), and are characterized by high MgO (4.4–6.6 wt.%)and Mg# (59–64), but low CaO (7.4–7.9 wt.%) and FeOtotal/MgOratios (1.2–1.4), which are approximately equivalent to the compo-sitions of typical HMAs (Tatsumi and Ishizaka, 1982; Kelemen,1995). Na2O and K2O abundances are 3.5–3.7 wt.% and 1.0–1.2 wt.%, respectively, with considerably high Na2O/K2O ratios(3.1–3.8). They show mediate-K calc-alkaline characteristics. Inthe major element Harker diagrams, the SiO2 and Al2O3 are nega-tively correlated with MgO (Fig. 4a and b), while CaO, FeO, P2O5

and Na2O + K2O show opposite trends (Fig. 4c–e).The Xintun diorites have remarkably high Ba (419–514 ppm)

and Sr (649–747 ppm) contents (Fig. 5), and show significantenrichment in light rare earth element (LREE) and LILE (e.g., Pb,Rb and Th), and depletion in high field strength elements (HFSE;e.g., Nb, Ta, Ti and Zr) (Fig. 6). Compatible elements, such as Cr(119–239 ppm) and Ni (32–84 ppm), are relative high, which areconsistent with their high MgO contents and Mg# values (Table 2).Moreover, they have strong fractionated LREE, but weak fraction-ated medium rare earth element (MREE) relative to heavy rareearth element (HREE), displaying concave chondrite-normalizedREE patterns with negligible Eu anomalies (dEu = 0.99–1.18)(Fig. 6a).

5.3. Sr–Nd isotope data

Sr and Nd isotopic analyses are presented in Table 3 and Fig. 7.The Xintun diorites have homogeneous and slightly depletedSr–Nd isotopic compositions, with ISr = 0.7047–0.7050, andeNd(128 Ma) = +0.3 to +1.1, respectively. Nd model ages (TDM) ofthe Xintun diorites are relatively young, ranging from 831 to896 Ma. As shown in Fig. 7, the isotopic compositions of the Xintundiorites are different from the Cenozoic adakites of the Yanji area(Guo et al., 2009). All samples plot on the extension of the subcon-tinental mantle of that time, overlapping with the Setouchi HMAsfrom NE Japan arcs (Hanyu et al., 2006).

Fig. 7. 143Nd/144Nd(t) vs. 87Sr/86Sr(i) plot for the Xintun diorites. Sr–Nd isotopicdata of the Yanji adakites are from Guo et al. (2009). Data of the Setouchi HMAs,altered oceanic crust and sediments are from Tatsumi (2006) and Hanyu et al.(2006).

6. Discussion

6.1. Analogy to high-Mg andesites

The Xintun diorites are characterized by abundance of euhedralhornblende (Fig. 2b), primary magnetite and titanite (Fig. 2c and d),which imply a H2O-rich (P4 wt.%; Ridolfi et al., 2010) and rela-tively oxidized (Foley and Wheller, 1990) signature of their initialmagmas. Geochemically, they are enriched in LREE as well as LILE

(e.g., Sr, Ba and Pb) and, depleted in HFSE (e.g., Nb, Ta and Ti)(Fig. 6). These features indicate an arc-related magma series forthe Xintun diorites. However, the high MgO (4.4–6.6%), Mg#(59–64), and low CaO (7.4–7.9%) and FeOtotal/MgO ratios (1.2–1.4) make them quite akin to typical HMAs. As shown in the dia-gram of SiO2 vs. MgO (Fig. 4a), all the samples fall in the HMAs fielddue to higher MgO contents than that of normal andesites at equiv-alent SiO2. Further evidence comes from their considerably high Srand Ba contents. In addition, high concentrations of compatibleelements, such as Cr and Ni are also common features of HMAs.Therefore, the Xintun diorites have geochemical affinities to thetypical HMAs, probably representing the intrusive equivalents ofthe HMAs.

As mentioned earlier, the HMAs can be divided into four sub-types according to their unique geochemical characteristics. Thesanukitic HMAs are characterized by high LILE, Cr, Ni contentsand Mg# (>60) (Martin et al., 2005), and relatively high Y(>10 ppm), Yb (>0.8 ppm), and low Sr/Y (<40), (La/Yb)N (<10) ratios(Kamei et al., 2004). They are believed to be generated by equilib-rium reaction of mantle peridotites with silicic melts derived frompartial melting of subducting slab/sediments (Yogodzinski et al.,1994; Shimoda et al., 1998; Tatsumi, 2001). Adakitic HMAs showsignificantly higher Sr (>400 ppm), Sr/Y and (La/Yb)N ratios, lowerlow Y (<18 ppm) and Yb (<1.9 ppm) (Kay, 1978; Defant andDrummond, 1990; Martin, 1999) than sanukitic HMAs, and areusually derived from melting of a subducting oceanic slab(Defant and Drummond, 1990) or over-thickened lower crust

Fig. 8. TiO2 vs. MgO/(MgO + FeOT), Sr/Y vs. Y, and (La/Yb)N vs. YbN discriminationdiagrams for the Xintun high-Mg diorites (after Kamei et al., 2004).

400 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

(Atherton and Petford, 1993). Bajaites have extremely high Sr (upto 4000 ppm), Ba (>1000 ppm) and Sr/Y ratios, which are widelyconsidered to be generated by disequilibrium reaction of mantleperidotites with slab-derived melts (Saunders et al., 1987). Boni-nites contain very low TiO2 (<0.5 wt.%), Y (<10 ppm) and Yb(<0.8 ppm), but high SiO2 (>52 wt.%) and MgO (>8 wt.%), and areusually generated by hydrous melting of depleted residual mantlein supra-subduction zone setting (Crawford et al., 1989; Tayloret al., 1994; Macpherson and Hall, 2001). Discrimination diagrams

of TiO2 vs. MgO/(MgO + FeOtotal), Sr/Y vs. Y, and (La/Yb)N vs. YbN

can effectively distinguish them from each other (Kamei et al.,2004). As shown in Fig. 8, the Xintun diorites possess relativelyhigh TiO2 (0.8–1.2 wt.%), Y (10–19 ppm), and Yb (0.9–1.8) contents,but low Sr/Y (35–76) and (La/Yb)N (6–10) ratios, which are analo-gous to those of sanukite from the Setouchi Volcanic Belt.

6.2. Origin of the Xintun high-Mg diorites

The origin of HMAs remains a subject of considerable debate(Kelemen, 1995; Shimoda et al., 1998; Tatsumi, 2001; Hanyuet al., 2006). Proposed possible processes of HMAs magma genera-tion include: (1) partial melting of a subducting oceanic crust andsubsequent melt–mantle interaction (Yogodzinski et al., 1994;Kelemen, 1995); (2) partial melting of subducting sediments fol-lowed by equilibration with mantle peridotites (Shimoda et al.,1998; Tatsumi, 2001); (3) direct hydrous melting of mantle perido-tites by addition of fluids released from the dehydrating slab(Kushiro, 1969; Crawford et al., 1989; Hirose, 1997). In this case,it is crucial to identify the nature of metasomatic agents over-printed in the mantle wedge.

The model of oceanic crust melting is not favored for the Xintunhigh-Mg diorites due to the following reasons. First of all, trace ele-ment characteristics of the Xintun high-Mg diorites are quite dif-ferent from those of oceanic crust-derived melts, which possesshigher Sr/Y ratios and lower Y (<18 ppm) as well as Yb(<1.9 ppm) concentrations than the former (Defant andKepezhinskas, 2001; Kelemen et al., 2003). Moreover, althoughthe Xintun high-Mg diorites are enriched in LREE relative to HREE,few show strong MREE enrichments relative to HREE (Fig. 6a), pre-cluding their origination from partial melting of an eclogite-facesource region where oceanic crust melts are generally produced(Defant and Drummond, 1990; Richards and Kerrich, 2007). Thisis also supported by their high contents of Al2O3 (15.8–17.3 wt.%)and Sc (15–24 ppm) (preferably hosted in the garnet) which couldbe indicative of a garnet-free residue in the source. Furthermore,the Ba/Th ratios should be markedly increased if oceanic crust-derived melts are involved in the production of magmas(Tatsumi, 2006), which is inconsistent with their low Ba/Th ratios(226–256) (Fig. 9a). Besides, the Xintun high-Mg diorites havemoderate radiogenic Sr (ISr = 0.7047–0.7050) and Nd(143Nd/144Nd(t) = 0.51249–0.51253) (Fig. 7), rather than strikinglydepleted isotopic compositions of the MORB and oceanic crust(Tatsumi, 2006).

Instead, sediment components, as a major metasomatic agent,may have played an important role in the formation of Xintunhigh-Mg diorites, based on the facts below: (1) In the ISr vs.143Nd/144Nd diagram (Fig. 7), the Xintun high-Mg diorites showisotopic trends toward the sediments, suggesting significant con-tribution of sediment components. (2) Addition of sediment-derived melts could notably enhance La/Sm ratios of the magma(Fig. 9a), but could not change Ba/Th ratios (Tatsumi, 2006), whichare consistent with features of the Xintun high-Mg diorites. (3)Geochemical modeling by Tatsumi (2001) and Hanyu et al.(2006) has demonstrated that sediment melts could be producedat 1050 �C and 1.0 GPa and subsequent interaction of such meltswith overlying mantle peridotites could result in element compo-sitions close to the Setouchi HMAs (Imaoka et al., 1993; Shimodaet al., 1998; Kamei et al., 2004). The Xintun high-Mg diorites areakin to the sanukitic HMAs; therefore, they are likely to share com-mon generation mechanism.

However, in addition to sediment-derived melts, we proposethat H2O-rich fluids are another metasomatic agent also involvedin the production of the Xintun dioritic magmas. As mentionedabove, the common presence of hydrous minerals (hornblendeand biotite) suggests that primitive parental melts are hydrous. This

Fig. 9. Ba/Th vs. (La/Sm)N and Th/Yb vs. Ba/La discrimination diagrams for metasomatic agents added to the mantle wedge. Data of Choshi, Setouchi HMAs and normal arcrocks are from Tatsumi (2006) and Hanyu et al. (2006).

Fig. 10. SiO2 vs. Th/La and U/Nb (a and b), and MgO vs. eNd(t) and ISr(t) (c and d) diagrams for the Xintun diorites. CC, crustal contamination. FC, fractional crystallization.

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 401

is further supported by the observation that plagioclase crystallizedlater than hornblende; because experimental results indicate thatearly crystallization of plagioclase is suppressed by high water con-tent of the melts (Müntener et al., 2001). Such H2O-rich magmasusually solidify upon ascent as the Xintun high-Mg dioritic pluton,rather than reach the surface. Moreover, addition of sediment com-ponents to the mantle wedge could elevate the Th/Yb ratios due tohigh Th/Yb in sediments. Meanwhile the Ba/La ratios would also beelevated accordingly if additional fluids were involved, because Bais more soluble in aqueous fluids than La (Hanyu et al., 2006). As

presented in Fig. 9b, the Xintun diorites possess trace element sig-natures transitional between the two trends. Therefore, we inferthat not only sediment-derived silicic melts but also aqueous fluidshave been overprinted in the original mantle wedge and subse-quently involved in the magma generation.

6.3. Magmatic evolution

High MgO contents, Mg# values (mostly over 60), and high con-centrations of compatible elements (e.g., Cr and Ni) indicate that

Fig. 11. Sr/Y vs. Y (a) and (La/Yb)N vs. YbN (b) discrimination diagrams for adakites and typical arc rocks (after Drummond and Defant (1990) and Martin (1986)). Thecalculated trend line in (a) represents residual liquids after variable proportions of fractionation of Hb (46%) + Cpx (42%) + Ttn (5%) + Ap (4%) + Mag (3%), based on theRayleigh law, and the partition coefficients are from Rollinson (1993). Cpx, clinopyroxene; Hb, hornblende ; Ttn, titanite ; Ap, apatite; Mag, magnetite.

Fig. 12. Possible petrogenetic model of the Xintun high-Mg diorites in the Yanji area, NE China (modified after Hanyu et al., 2006 and Wu et al., 2011). (a) Slab dehydrationand partial melting of the lithospheric mantle were major processes to form normal arc magmas during 210–155 Ma. (b) Long-lasting subduction of the Paleo-Pacific Plateinduced the initiation of back-arc extension in the Xing’an area at 155–130 Ma. (c) Since the 130 Ma, extensive upwelling and injection of asthenospheric materials resultedin high-temperature conditions in the whole mantle wedge, reheating the subducted sediments enough to cause melting.

402 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 403

the most primitive parental magmas to the Xintun high-Mg dior-ites were in equilibrium with mantle peridotites. Even so, mag-matic differentiation may have taken place during the ascent ofmagmas from the subarc mantle to the upper crust, as revealedby the regular chemical compositions variations in Harker dia-grams (Figs. 4 and 5).

Crustal contamination and fractional crystallization are twopossible processes responsible for the chemical variations. Chenet al. (2013) have ever presented petrological and isotopic data ofthe high-Mg dioritic rocks from the North China Craton andproposed a process of magma mixing between mantle- and crust-derived magmas for their origin. However, mixing and contamina-tion evidence cannot be observed for the Xintun diorites, such asthe presence of enclaves or xenoliths, textural and compositionaldisequilibrium in plagioclase phenocrysts (Chen et al., 2013). More-over, from primitive mantle-normalized trace element spidergrams(Fig. 6b), it can be seen that Th and U are mostly depleted relative tothe LREE, precluding significant involvement of crustal componentsduring the magma ascent (Taylor and McLennan, 1985). This issupported by the constant Th/La and U/Nb ratios with increasingSiO2 content (Fig. 10a and b). Furthermore, the diagrams of eNd(t)and ISr vs. MgO are constructed to evaluate the role of crustalcontamination for the Xintun high-Mg diorites (Fig. 10c and d).However, the eNd(t) and ISr values do not show remarkablevariations and linear trends with MgO contents, also suggestingthat the magmas were not notably affected by crustal materials.

Instead, a process of fractional crystallization may have played adominated role during the magmatic evolution. In Harker dia-grams, the positive correlations of CaO, FeO (Fig. 4c and d), Coand Sc (Fig. 5a and b) with MgO indicate a significant fractionationof ferromagnesian phases such as clinopyroxene and hornblende,which is well verified by the concave REE patterns (Fig. 6a),because clinopyroxene and hornblende show preference for MREEover HREE (Rollinson, 1993). Moreover, experimental studiesreveal that hornblende crystallization from basaltic to intermedi-ate magmas shifts the residual melts toward high SiO2 andNa2O + K2O contents (Foden and Green, 1992), which is consistentwith the negative correlations of SiO2 and Na2O + K2O with MgO(Fig. 4a and f). The presence of Ti anomalies in the primitive man-tle-normalized spidergrams (Fig. 6b) and positive correlationbetween Ti and MgO (Fig. 5c) are possibly attributed to the earlyprecipitation of titanite under high fO2 conditions (Foley andWheller, 1990). In addition, the positive correlations of V and Crwith MgO (Fig. 5d) imply a significant fractionation of magnetite.Simultaneous apatite fractionation is also important as revealedby the depletion of Y (strong enrichment in apatite) (Fig. 5e) andthe positive correlation between P2O5 and MgO (Fig. 4e). However,the absence of negative Eu anomalies (Fig. 6a) indicates that segre-gation of plagioclase is negligible, which coincides with theincreasing Sr contents with decreasing MgO (Fig. 5f). So, fractionalcrystallization of assemblage of hornblende, clinopyroxene, as wellas accessory minerals such as apatite and titanite, has controlledthe magmatic differentiation of the Xintun high-Mg diorites.

More importantly, the magmas of Xintun high-Mg dioritesevolve following curved trends in Sr/Y vs. Y and (La/Yb)N vs.(Yb)N diagrams (Figs. 8 and 11), and appear an adakitic signatureprogressively. For example, two evolved samples (YJ-28 and YJ-30) possess high Sr (699–725 ppm) but low Y (9.5–11.5 ppm)and Yb (0.9–1.3 ppm) concentrations, with high Sr/Y and (La/Yb)N

ratios (60–76 and 8–10, respectively), which are comparable tothose of typical adakitic rocks (Martin, 1986, 1999). Trace elementmodeling results, based on Rayleigh law, suggest that fractionation(10–25%) of combined phases of hornblende (46%) + clinopyroxene(42%) + titanite (5%) + apatite (4%) + magnetite (3%), has contrib-uted to the high Sr/Y ratios and low Y of the evolved samples.Therefore, we propose that hornblende-dominated fractional

crystallization under water-sufficient conditions could readilyyield melts with adakitic signatures. It is therefore concluded thatoceanic crust melting is not required to produce those adakiticrocks (e.g., adakites or adakitic HMAs) which usually accompanywith the sanukitic HMAs.

6.4. Tectonic implications

The HMAs are generally related to the subduction of a youngand/or hot oceanic slab (e.g., ridge subduction) (Rogers andSaunders, 1989; Furukawa and Tatsumi, 1999). On the other hand,some workers have recently pointed out that the HMAs magmascould be also produced in a relatively old subduction zone if thesubducting slab is reheated by 200 �C or higher (Hanyu et al.,2006). Therefore, the existence of the Xintun high-diorites in NEChina is of great significance to understand the thermal conditionsand tectonic evolution of eastern Asian continental margin.

It is well known that NE China is a junction of the Central AsianOrogenic Belt and the Pacific margin accretion belt (Fig. 1a). Previ-ous studies have shown that the final closure of the Paleo-AsianOcean between North China Craton and Siberian Craton along theSolonker-Xra Moron suture took place in the Late Permian(Ruzhentsev and Pospelov, 1992; Chen et al., 2009; Xu et al.,2013), which was followed by the post-orogenic adjustment inthe Early Triassic (Dewey, 1988; Zhang et al., 2008). After a tectonicquiescence, NE China was significantly affected by subduction ofthe Paleo-Pacific plates since the Late Mesozoic (Zhao et al.,1994; Maruyama et al., 1997; Wu et al., 2011). Jurassic to Creta-ceous accretionary terranes and calc-alkaline I-type granitoidswere widely developed along the eastern Asian continental margin,including NE China, Far East Russia and the Japan islands(Wickham et al., 1995; Jahn et al., 2004; Wu et al., 2007; Sorokinet al., 2010). In NE China, the Heilongjiang complexes, with blue-schist facies high-pressure metamorphism ages of 185–165 Ma(Cao et al., 1992; Zhou et al., 2009), are increasingly recognizedas a mélange recording the process of Pacific margin accretion(Wu et al., 2007; Zhou et al., 2009). Moreover, according toMaruyama et al. (1997), the mid-oceanic ridge between the Pacificand Izanagi plates was not subducted beneath the NE China marginuntil the Late Cretaceous (�90 Ma). Therefore, it is unlikely that ayoung and hot slab subduction has caused the formation of theXintun high-Mg diorites in the Early Cretaceous.

We prefer a model that thermal disturbance has triggered par-tial melting of the subducting sediments under high temperatureconditions (Honda and Saito, 2003; Hanyu et al., 2006), which isassociated with a possible scenario as follows (Fig. 12): The earlyPaleo-Pacific subduction toward the Eurasia plate took place at210–155 Ma, and arc magmas were generated along the easternAsian continental margin (Fig. 12a). The long-lasting subductioncaused the initiation of extension on the back-arc side of the NEChina (e.g., the Xing’an and Songliao areas) at 155–130 Ma(Fig. 12b). During the Early Cretaceous (130–110 Ma), extensiveback-arc extension occurred (Fig. 12c) (Tatsumi and Kimura,1991; Ge et al., 2005; Ma et al., 2013), as indicated by the forma-tion of NNE-striking sedimentary basins (Liu et al., 2010; Zhanget al., 2011; Ge et al., 2012), and the occurrence of immense vol-umes of I- and A-type granites (Wu et al., 2000, 2005; Jahn et al.,2001, 2009) and metamorphic core complexes (Wang et al.,2011). Lithospheric extension induced significant passive astheno-spheric injection or upwelling (Niu, 2005; Shao et al., 2007).Asthenospheric flow from the west beneath the Xing’an areatoward the subduction zone caused high temperature conditionsin the whole mantle wedge (Fig. 12c), and finally led to a result thatthe relative cold slab was effectively reheated to cause sedimentmelting (Hanyu et al., 2006). The transition from dehydration tosediment melting corresponds to the change of metasomatic

404 X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405

agents, from prevailing fluids to sediment-derived melts. There-fore, the occurrence of the Xintun high-Mg diorites signifies hightemperature conditions in the mantle wedge and commencementof extensive back-arc extension at �128 Ma, although the back-arc opening in NE China failed later due to the heat consumptionin the Japan arc-trench system (Tatsumi and Kimura, 1991).

7. Conclusions

1. The Xintun pluton is a newly recognized high-Mg diorite in theYanji area, NE China, which is characterized by high MgO, Cr, Nicontents, and low FeO/MgO ratios, with geochemical affinitiesto sanukitic HMAs.

2. Geochemical and isotopic compositions suggest that the Xintunhigh-Mg diorites were formed via partial melting of the sub-ducting sediments and subsequent interaction of mantle peri-dotites with hydrous silicic melts. Hornblende-dominatedfractional crystallization in H2O-rich melts enabled the evolvedmagmas to possess adakitic signatures. Oceanic crust melting isnot required to produce those adakitic rocks which usuallyaccompany with the sanukitic HMAs.

3. The occurrence of the Xintun high-Mg diorites indicates a hotasthenospheric injection in the mantle wedge, signifying theonset of extensive extension on the back-arc side of NE Chinaat ca. 128 Ma, associated with the long-lasting Paleo-Pacificsubduction beneath the eastern Asian continental margin.

Acknowledgments

We would like to thank H.F. Yuan and J.W. Liu for their assis-tance in U–Pb and Sr–Nd isotopes analysis. Financially, thisresearch has been supported by the State Key Basic Research andDevelopment program (#2013CB429804), Natural Science Founda-tion of China (#41202033) and Project of China Geological Survey(#12120113093600).

References

Andersen, T., 2002. Correction of common lead in U–Pb analyses that do not report204Pb. Chem. Geol. 192, 59–79.

Atherton, M.P., Petford, N., 1993. Generation of sodium-rich magmas from newlyunderplated basaltic crust. Nature 362, 144–146.

Cao, X., Dang, Z.X., Zhang, X.Z., Jiang, J.S., Wang, H.D., 1992. The composite JiamusiTerrane. Jilin Publishing House of Science and Technology, Changchun, pp. 1–224 (in Chinese with English and Russian abstracts).

Chen, B., Arakawa, Y., 2005. Elemental and Nd–Sr isotopic geochemistry ofgranitoids from the West Junggar foldbelt (NW China), with implications forPhanerozoic continental growth. Geochim. Cosmochim. Acta 69, 1307–1320.

Chen, B., Jahn, B.M., Wilde, S., Xu, B., 2000. Two contrasting Paleozoic magmaticbelts in northern Inner Mongolia, China: petrogenesis and tectonic implications.Tectonophysics 328, 157–182.

Chen, B., Jahn, B.M., Tian, W., 2009. Evolution of the Solonker suture zone:constraints from zircon U–Pb ages, Hf isotopic ratios and whole-rock Nd–Srisotope compositions of subduction and collision-related magmas and forearcsediments. J. Asian Earth Sci. 34, 245–257.

Chen, B., Jahn, B.M., Suzuki, K., 2013. Petrological and Nd–Sr–Os isotopic constraintson the origin of high-Mg adakitic rocks from the North China Craton: Tectonicimplications. Geology 41, 91–94.

Crawford, A.J., Falloon, T.J., Green, D.H., 1989. Classification, petrogenesis andtectonic setting of boninites. In: Crawford, A.J. (Ed.), Boninites and RelatedRocks. Unwin Hyman, London, pp. 1–49.

Defant, M.J., Drummond, M.S., 1990. Derivation of some modern arc magmas bymelting of young subducted lithosphere. Nature 347, 662–665.

Defant, M.J., Kepezhinskas, P., 2001. Evidence suggests slab melting in arc magmas.Eos, Trans. Am. Geophys. Union 82, 65–69.

Dewey, J.F., 1988. Extensional collapse of orogens. Tectonics 7, 1123–1139.Foden, J.D., Green, D.H., 1992. Possible role of amphibole in the origin of andesite:

some experimental and natural evidence. Contrib. Miner. Petrol. 109, 479–493.Foley, S.F., Wheller, G.E., 1990. Parallels in the origin of the geochemical signatures

of island arc volcanics and continental potassic igneous rocks: the role ofresidual titanites. Chem. Geol. 85, 1–18.

Furukawa, Y., Tatsumi, Y., 1999. Melting of a subducting slab and production ofhigh-Mg andesite magmas: unusual magmatism in SW Japan at 13–15 Ma.Geophys. Res. Lett. 26, 2271–2274.

Ge, W.C., Wu, F.Y., Zhou, C.Y., Zhang, J.H., 2005. Zircon U–Pb ages and its significanceof the Mesozoic granites in the Wulanhaote region, central Da HingganMountain. Acta Petrol. Sin. 21, 749–762 (in Chinese with English abstract).

Ge, R.F., Zhang, Q.L., Wang, L.S., Chen, J., Xie, G.A., Wang, X.Y., 2012. Late Mesozoicrift evolution and crustal extension in the central Songliao Basin, northeasternChina: constraints from cross-section restoration and implications forlithospheric thinning. Int. Geol. Rev. 54, 183–207.

Guo, F., Nakamura, E., Fan, W.M., Kobayashi, K., Li, C.W., Gao, X.F., 2009.Mineralogical and geochemical constraints on magmatic evolution ofPaleocene adakitic andesites from the Yanji area, NE China. Lithos 112, 321–341.

Guo, F., Fan, W., Gao, X., Li, C., Miao, L., Zhao, L., Li, H., 2010. Sr–Nd–Pb isotopemapping of Mesozoic igneous rocks in NE China: constraints on tectonicframework and Phanerozoic crustal growth. Lithos 120, 563–578.

Halla, J., 2005. Late Archean high-Mg granitoids (sanukitoids) in the southernKarelian domain, eastern Finland: Pb and Nd isotopic constraints on crust.Lithos 79, 161–178.

Hanyu, T., Tatsumi, Y., Nakai, S.I., Chang, Q., Miyazaki, T., Sato, K., Tani, K., Shibata, T.,Yoshida, T., 2006. Contribution of slab melting and slab dehydration tomagmatism in the NE Japan arc for the last 25 Myr: constraints fromgeochemistry. Geochem. Geophys. Geosyst. 7, Q08002. http://dx.doi.org/10.1029/2005GC001220.

Heilimo, E., Halla, J., Hölttä, P., 2010. Discrimination and origin of the sanukitoidseries: geochemical constraints from the Neoarchean western Karelian Province(Finland). Lithos 115, 27–39.

Hirose, K., 1997. Melting experiments on lherzolite KLB-1 under hydrous conditionsand generation of high-magnesian andesitic melts. Geology 25, 42–44.

Honda, S., Saito, M., 2003. Small-scale convection under the back-arc occurring inthe low viscosity wedge. Earth Planet. Sci. Lett. 216, 703–715.

Imaoka, T., Nakajima, K., Itaya, T., 1993. K–Ar ages of hornblendes in andesite anddacite from the Cretaceous Kanmon Group, southwest Japan. J. Miner., Petrol.Econ. Geol. 88, 265–271.

Jackson, S.E., Pearson, N.J., Griffin, W.L., Belousova, E.A., 2004. The application oflaser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pbzircon geochronology. Chem. Geol. 211, 47–69.

Jahn, B.M., Wu, F.Y., Chen, B., 2000. Massive granitoid generation in Central Asia: Ndisotope evidence and implication for continental growth in the Phanerozoic.Episodes 23, 82–92.

Jahn, B.M., Wu, F.Y., Capdevila, R., Martineau, F., Wang, Y.X., Zhao, Z.H., 2001. Highlyevolved juvenile granites with tetrad REE patterns: the Woduhe and Baerzhegranites from the Great Xing’an Mountain in NE China. Lithos 59, 171–198.

Jahn, B.M., Capdevila, R., Liu, D.Y., Vernon, A., Badarch, G., 2004. Sources ofPhanerozoic granitoids in the transect Bayanhongor-Ulaan Baatar, Mongolia:geochemical and Nd isotopic evidence, and implications for Phanerozoic crustalgrowth. J. Asian Earth Sci. 23, 629–653.

Jahn, B.M., Litvinovsky, B.A., Zanvilevich, A.N., Reichow, M., 2009. Peralkalinegranitoid magmatism in the Mongolian-Transbaikalian Belt: evolution,petrogenesis and tectonic significance. Lithos 113, 521–539.

Jilin Bureau of Geology and Mineral Resources (JBGMR), 1988. Regional Geology ofJilin Province. Geological Publishing House, Beijing, pp. 1–670 (in Chinese withEnglish abstract).

Kamei, A., Owada, M., Nagao, T., Shiraki, K., 2004. High-Mg diorites derived fromsanukitic HMA magmas, Kyushu Island, southwest Japan arc: evidence fromclinopyroxene and whole rock compositions. Lithos 75, 359–371.

Kay, R.W., 1978. Aleutian magnesian andesites: melts from subducted Pacific oceancrust. J. Volcanol. Geotherm. Res. 4, 117–132.

Kelemen, P.B., 1995. Genesis of high Mg# andesites and the continental crust.Contrib. Miner. Petrol. 120, 1–19.

Kelemen, P.B., Rilling, J.L., Parmentier, E.M., Mehl, L., Hacker, B.R., 2003. Thermalstructure due to solid-state flow in the mantle wedge beneath arcs. Geophys.Monogr. Ser. 138, 293–311.

Kovalenko, V.I., Yarmolyuk, V.V., Kovach, V.P., Kotov, A.B., Kozakov, I.K., Salnikova,E.B., Larin, A.M., 2004. Isotope provinces, mechanisms of generation and sourcesof the continental crust in the Central Asian mobile belt: geological and isotopicevidence. J. Asian Earth Sci. 23, 605–627.

Kushiro, I., 1969. The system forsterite-diopside-silica with and without water athigh pressures. Am. J. Sci. 267, 269–294.

Lehmann, J., Schulmann, K., Lexa, O., Corsini, M., Kröner, A., Sripská, P., Tomurhuu,D., Otgonbator, D., 2010. Structural constraints on the evolution of the CentralAsian Orogenic Belt in SW Mongolia. Am. J. Sci. 310, 575–628.

Liu, S., Hu, R.Z., Gao, S., Feng, C.X., Feng, G.Y., Coulson, I.M., Li, C., Wang, T., Qi, Y.Q.,2010. Zircon U–Pb age and Sr–Nd–Hf isotope geochemistry of Permiangranodiorite and associated gabbro in the Songliao Block, NE China andimplications for growth of juvenile crust. Lithos 114, 423–436.

Ludwig, K.R., 2003. User’s manual for Isoplot 3.00: a geochronological toolkit forMicrosoft Excel. Berkeley Geochronology Center, Special publication No. 4.

Ma, X.H., Chen, B., Lai, Y., Lu, Y.H., 2009. Petrogenesis and mineralization chronologystudy on the Aolunhua porphyry Mo deposit, Inner Mongolia, and its geologicalimplications. Acta Petrol. Sin. 25, 2939–2950 (in Chinese with English abstract).

Ma, X.H., Chen, B., Yang, M.C., 2013. Magma mixing origin for the Aolunhuaporphyry related to Mo–Cu mineralization, eastern Central Asian Orogenic Belt.Gondwana Res. 24, 1152–1171.

X.-H. Ma et al. / Journal of Asian Earth Sciences 97 (2015) 393–405 405

Macpherson, C.G., Hall, R., 2001. Tectonic setting of Eocene boninite magmatism inthe Izu–Bonin–Mariana forearc. Earth Planet. Sci. Lett. 186, 215–230.

Martin, H., 1986. Effect of steeper Archean geothermal gradient on geochemistry ofsubduction-zone magmas. Geology 14, 753–756.

Martin, H., 1999. Adakitic magmas: modern analogues of Archaean granitoids.Lithos 46, 411–429.

Martin, H., Smithies, R.H., Rapp, R., Moyen, J.F., Champion, D., 2005. An overview ofadakite, tonalite–trondhjemite–granodiorite (TTG), and sanukitoid:relationships and some implications for crustal evolution. Lithos 79, 1–24.

Maruyama, S., Isozaki, Y., Kimura, G., Terabayashi, M., 1997. Paleogeographic mapsof the Japanese Islands: plate tectonic synthesis from 750 Ma to the present.Island Arc 6, 121–142.

Müntener, O., Kelemen, P.B., Grove, T.L., 2001. The role of H2O during crystallizationof primitive arc magmas under uppermost mantle conditions and genesis ofigneous pyroxenites: an experimental study. Contrib. Miner. Petrol. 141, 643–658.

Niu, Y.L., 2005. Generation and evolution of basaltic magmas: some basic conceptsand a new view on the origin of Mesozoic–Cenozoic basaltic volcanism ineastern China. Geol. J. China Univ. 11, 9–46.

Rapp, R.P., Shimizu, N., Norman, M.D., Applegate, G.S., 1999. Reaction between slab-derived melts and peridotite in the mantle wedge: experimental constraints at3.8 GPa. Chem. Geol. 160, 335–356.

Richards, J.P., Kerrich, R., 2007. Special paper: adakite-like rocks: their diverseorigins and questionable role in metallogenesis. Econ. Geol. 102, 537–576.

Ridolfi, F., Renzulli, A., Puerini, M., 2010. Stability and chemical equilibrium ofamphibole in calc-alkaline magmas: an overview, new thermobarometricformulations and application to subduction-related volcanoes. Contrib. Miner.Petrol. 160, 45–66.

Rogers, G., Saunders, A.D., 1989. Magnesian andesites from Mexico, Chile and theAleutian Islands: implications for magmatism associated with ridge-trenchcollision. In: Crawford, A.J. (Ed.), Boninites and Related Rocks. Unwin Hyman,London, pp. 416–445.

Rogers, G., Saunders, A.D., Terrell, D.J., Verma, S.P., Marriner, G.F., 1985.Geochemistry of Holocene volcanic rocks associated with ridge subduction inBaja California, Mexico. Nature 315, 389–392.

Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation,Interpretation. Pearson Education Limited, London, p89.

Ruzhentsev, S.V., Pospelov, I.I., 1992. The south Mongolian Variscan fold system.Geotectonics 26, 383–395.

Saunders, A.D., Rogers, G., Marriner, G.F., Terrell, D.J., Verma, S.P., 1987.Geochemistry of Cenozoic volcanic rocks, Baja California, Mexico:implications for the petrogenesis of post-subduction magmas. J. Volcanol.Geotherm. Res. 32, 223–245.

Shao, J.A., Tang, K.D., 1995. Terranes in Northeast China and Evolution of NortheastAsia Continental Margin. Seismic Press, Beijing, pp. 1–209 (in Chinese).

Shao, J.A., Zhang, L.Q., Mu, B.L., Han, Q.J., 2007. Upwelling of Da Hinggan Mountainsand its Geodynamic Background. Geological Publishing House, Beijing, pp. 67–79 (in Chinese with English abstract).

Shimoda, G., Tatsumi, Y., Nohda, S., Ishizaka, K., Jahn, B.M., 1998. Setouchi high-Mgandesites revisited: geochemical evidence for melting of subducting sediments.Earth Planet. Sci. Lett. 160, 479–492.

Slama, J., Kosler, J., Condon, D.J., Crowley, J.L., Gerdes, A., Hanchar, J.M., Horstwood,M.S.A., Morris, G.A., Nasdala, L., Norberg, N., Schaltegger, U., Schoene, B., Tubrett,M.N., Whitehouse, M.J., 2008. Plesovice zircon – a new natural referencematerial for U–Pb and Hf isotopic microanalysis. Chem. Geol. 249, 1–35.

Smithies, R.H., Champion, D.C., 2000. The Archaean high-Mg diorite suite: links totonalite–trondhjemite–granodiorite magmatism and implications for EarlyArchaean crustal growth. J. Petrol. 41, 1653–1671.

Sorokin, A.A., Kotov, A.B., Sal’nikova, E.B., Kudryashov, N.M., Anisimova, I.V.,Yakovleva, S.Z., Fedoseenko, A.M., 2010. Granitoids of the Tyrma–Bureyacomplex in the northern Bureya–Jiamusi superterrane of the Central Asianfold belt: age and geodynamic setting. Russ. Geol. Geophys. 51, 563–571.

Sun, S.S., McDonough, W.F., 1989. Chemical and Isotopic Systematics of OceanicBasalts: Implications for Mantle Composition and Processes. Geological Society,London, Special Publications 42, pp. 313–345.

Tang, G.J., Wang, Q., 2010. High-Mg andesites and their geodynamic implications.Acta Petrol. Sin. 26, 2495–2512 (in Chinese with English abstract).

Tatsumi, Y., 2001. Geochemical modeling of partial melting of subductingsediments and subsequent melt-mantle interaction: generation of high-Mgandesites in the Setouchi volcanic belt, southwest Japan. Geology 29, 323–326.

Tatsumi, Y., 2006. High-Mg andesites in the Setouchi volcanic belt, southwesternJapan: analogy to Archean magmatism and continental crust formation? Annu.Rev. Earth Planet. Sci. 34, 467–499.

Tatsumi, Y., Ishizaka, K., 1982. Origin of high-magnesian andesites in the Setouchivolvanic belt, southwest Japan: I. Petrographical and chemical characteristics.Earth Planet. Sci. Lett. 60, 293–304.

Tatsumi, Y., Kimura, N., 1991. Backarc extension versus continental breakup:petrological aspects for active rifting. Tectonophysics 197, 127–137.

Taylor, S.R., McLennan, S.M., 1985. The Continental Crust: its Composition andEvolution. Oxford Press, Blackwell, pp. 312.

Taylor, R.N., Nesbitt, R.W., Vidal, P., Harmon, R.S., Auvray, B., Croudace, I.W., 1994.Mineralogy, chemistry and genesis of the boninite series volcanics, Chichijima,Bonin Islands, Japan. J. Petrol. 35, 577–617.

Wang, T., Zheng, Y.D., Zhang, J.J., Zeng, L.S., Donskaya, T., Guo, L., Li, J.B., 2011.Pattern and kinematic polarity of late Mesozoic extension in continental NEAsia: perspectives from metamorphic core complexes. Tectonics 30, TC6007.http://dx.doi.org/10.1029/2011TC002896.

Wickham, S.M., Litvinovsky, B.A., Zanvilevich, A.N., Bindeman, D.N., 1995.Geochemical evolution of Phanerozoic magmatism in Transbaikalia, East Asia:a key constraint on the origin of K-rich silicic magmas and the process ofcratonization. J. Geophys. Res. 100, 15641–15654.

Windley, B.F., Alexeiev, D., Xiao, W.J., Kröner, A., Badarch, G., 2007. Tectonic modelsfor accretion of the Central Asian Orogenic Belt. J. Geol. Soc. 164, 31–47.

Wu, F.Y., Jahn, B.M., Wilde, S., Sun, D.Y., 2000. Phanerozoic crustal growth: U–Pb andSr–Nd isotopic evidence from the granites in northeastern China.Tectonophysics 328, 89–113.

Wu, F.Y., Sun, D.Y., Li, H.M., Jahn, B.M., Wilde, S., 2002. A-type granites innortheastern China: age and geochemical constraints on their petrogenesis.Chem. Geol. 187, 143–173.

Wu, F.Y., Lin, J.Q., Wilde, S.A., Zhang, X.O., Yang, J.H., 2005. Nature and significance ofthe Early Cretaceous giant igneous event in eastern China. Earth Planet. Sci. Lett.233, 103–119.

Wu, F.Y., Yang, J.H., Lo, C.H., Wilde, S.A., Sun, D.Y., Jahn, B.M., 2007. The HeilongjiangGroup: a Jurassic accretionary complex in the Jiamusi Massif at the westernPacific margin of northeastern China. The Island Arc 16, 156–172.

Wu, F.Y., Sun, D.Y., Ge, W.C., Zhang, Y.B., Grant, M.L., Wilde, S.A., Jahn, B.M., 2011.Geochronology of the Phanerozoic granitoids in northeastern China. J. AsianEarth Sci. 41, 1–30.

Xiao, W.J., Windley, B.F., Hao, J., Zhai, M.G., 2003. Accretion leading to collision andthe Permian Solonker suture, Inner Mongolia, China: termination of the centralAsian orogenic belt. Tectonics 22, 1069. http://dx.doi.org/10.1029/2002TC001484.

Xu, B., Charvet, J., Chen, Y., Zhao, P., Shi, G.Z., 2013. Middle Paleozoic convergentorogenic belts in western Inner Mongolia (China): framework, kinematics,geochronology and implications for tectonic evolution of the Central AsianOrogenic Belt. Gondwana Res. 23, 1342–1364.

Yogodzinski, G.M., Volynets, O.N., Koloskov, A.V., Seliverstov, N.I., Matvenkov, V.V.,1994. Magnesian andesites and the subduction component in a strongly calc-alkaline series at Piip Volcano, far western Aleutians. J. Petrol. 35, 163–204.

Zhang, Y.B., Wu, F.Y., Wilde, S.A., Zhai, M.G., Lu, X.P., Sun, D.Y., 2004. Zircon U–Pbages and tectonic implications of ‘‘Early Paleozoic’’ granitoids at Yanbian, JilinProvince, NE China. The Island Arc 13, 484–505.

Zhang, L.C., Ying, J.F., Chen, Z.G., Wu, H.Y., Wang, F., Zhou, X.H., 2008. Age andtectonic setting of Triassic basic volcanic rocks in southern Da Hinggan Range.Acta Petrol. Sin. 24, 911–920 (in Chinese with English abstract).

Zhang, F.Q., Chen, H.L., Yu, X., Dong, C.W., Yang, S.F., Pang, Y.M., Batt, G.E., 2011.Early Cretaceous volcanism in the northern Songliao Basin, NE China, and itsgeodynamic implication. Gondwana Res. 19, 163–176.

Zhao, Y., Yang, Z.Y., Ma, X.H., 1994. Geotectonic transition from Paleo-Asian systemand Paleo-Tethyan system to Paleo-Pacific active continental margin in easternAsia. Sci. Geol. Sin. 29, 105–119 (in Chinese with English abstract).

Zhou, J.B., Wilde, S.A., Zhang, X.Z., Zhao, G.C., Zheng, C.Q., Wang, Y.J., Zhang, X.H.,2009. The onset of Pacific margin accretion in NE China: evidence from theHeilongjiang high-pressure metamorphic belt. Tectonophysics 478, 230–246.