Mineral chemistry and genetic significance of clinopyroxenes in the basement basalts from the southern Kyushu-Palau Ridge
-
摘要: 九州−帕劳脊是古伊豆−小笠原−马里亚纳弧的重要组成,对其上基底岩石开展矿物学和岩石学研究可为理解洋内岛弧演化早期的岩石成因和岩浆活动特点提供重要线索。本文对九州−帕劳脊南段基底玄武岩中的单斜辉石斑晶和微晶开展详细的岩相学和原位主微量元素分析,结果表明,单斜辉石斑晶与微晶整体上具有相似的化学组分,为普通辉石及透辉石等种属,且亏损轻稀土元素,Eu负异常不明显。多数单斜辉石斑晶具有环带结构,可划分为简单环带及韵律性环带两类;从辉石核部到边部,MgO、FeO、Al2O3、TiO2含量与核部镁指数Mg#等呈现复杂的高低变化,指示了多期次的岩浆混合与补给事件。单斜辉石的结晶温度、压力分别为1 151~1 210℃和1.3×108~4.2×108 Pa。通过单斜辉石组分反演获得的母岩浆含水量为0.8%~2.3%(以湿质量计)。最后,我们提出,形成于典型的洋内岛弧背景下的九州−帕劳脊南段熔岩的母岩浆为亚碱性岛弧拉斑玄武质熔体,具有高温、中压、高氧逸度的特征,岩浆房深度较浅并存在多期次原始岩浆的补给和混合。Abstract: The Kyushu-Palau ridge (KPR) is an important part of the proto-Izu-Bonin-Mariana arc. The mineralogical and petrological studies of the arc basement rocks can provide significant insights for understanding the petrogenesis and magmatism characteristics of the early stage of intra-oceanic island arc evolution. In this paper, we performed petrographic and detailed mineral geochemical analyses including in situ major-trace elements of clinopyroxene (Cpx) phenocrysts and microcrystals from the basement basalts from the southern KPR. The results show that clinopyroxenes are mainly augites and diopside, which generally have similar chemical components for the phenocrysts and microcrystals. These clinopyroxenes are depleted in light rare earth elements with weak Eu negative anomalies. Most of the Cpx macrocrysts display zoning structures, which can be classified into basic and oscillatory zoning. The MgO, FeO, Al2O3, TiO2 and Mg# contents show complex high-low variations from the pyroxene core to the rim, indicating multi-period magma mixing and replenishment events. The crystallization temperature and pressure of Cpx phenocrysts are 1 151−1210℃ and 1.3×108−4.2×108 Pa, respectively. In addition, the water content of parent magma obtained by the inversion calculated from Cpx components is 0.8%−2.3% (wet weight). Conclusively, we suggested that the parent magma of the southern KPR lavas that formed within a typical intra-oceanic island-arc setting is a sub-alkaline island-arc tholeiite basaltic melt with high temperature, medium pressure, and high oxygen fugacity. The magma chambers were shallow in depth and there existed multi-period replenishment and mixing of primitive magma.
-
Key words:
- clinopyroxene /
- mineral chemistry /
- zoning structure /
- magmatic process /
- island-arc basalt /
- Kyushu-Palau Ridge
-
图 2 九州−帕劳脊南段玄武岩及主要矿物岩相学特征
a. CJ09-123-3-1样品正交偏光镜下图像,可见单斜辉石斑晶及斜长石斑晶,斜长石内部有熔蚀结构,部分单斜辉石裂理发育;b和c. 样品中典型矿物斑晶及微晶的背散射电子(BSE)图像,可见单斜辉石斑晶内部明暗相间分布的环带结构,局部有熔蚀痕迹,矿物微晶无明显颜色及环带变化。cpx:单斜辉石;pl:斜长石
Fig. 2 Petrographic characteristics of the basalt in the KPR and the major minerals phenocrysts
a. Photomicrographs showing clinopyroxene and resorption textures of plagioclase phenocrysts in sample CJ09-123-3-1(crossed polarized light), some Cpx phenocrysts showing cleavage structure; b and c. the backscattered electron (BSE) images of the typical mineral phenocrysts and microcrystals in the sample, the cpx phenocrysts have alternately dark and bright zones with local resorption texture, the cpx microcrystals show no distinct color and zoned variations. cpx: clinopyroxene, pl: plagioclase
图 4 九州−帕劳脊南段代表性单斜辉石背散射图像及剖面成分特征
a. 代表性深色核部单斜辉石;b. 代表性浅色核部单斜辉石;c. 具有韵律性复杂环带的单斜辉石斑晶CJ09-123-5;d. 简单环带辉石剖面元素变化;e. 复杂环带辉石剖面元素变化。图像中红线指示测试剖面
Fig. 4 Compositional profiles for the major elements and backscattered electron (BSE) images of representative pyroxene phenocrysts from the southern KPR
a. Representative cpx with dark core; b. representative cpx with bright core; c. the cpx named CJ09-123-5 with complex rhythmically zoning; d. variation of important elements in the sections of simple zoned clinopyroxenes; e. variation of important elements in the section of complex zoned clinopyroxene. The red lines in the images indicate the test sections
图 6 岩浆系列判别图解
a. 单斜辉石Si-Al关系图(据文献[42];b. 单斜辉石Ti-Ca+Na图解;c. 单斜辉石Ti-Al图解(据文献[38]);d.单斜辉石Al2O3-SiO2图解(据文献[41]);图a−c中各元素含量以单位分子原子数(apfu)表示,图d中以湿质量百分比表示
Fig. 6 Discriminant diagrams of magma series
a. Si-Al diagram of Clinopyroxenes (from reference [42]);b. Ca + Na vs. Ti; c. Ti vs. Al(total) diagrams (from reference [38]); d. Al2O3 vs. SiO2 diagram of Clinopyroxenes (from reference [41]). The contents of each elements are expressed in terms of atoms per formula unit (apfu) in figures a-c, and in terms of wet mass percentage in figure d
图 8 单斜辉石‒熔体平衡对分布图
图a中灰色区域代表平衡区间,寄主全岩Mg#值为67.1(未发表数据);图b‒d中虚线及黑色细线分别指示1σ和2σ;DiHd(透辉石+钙铁辉石),EnFs(顽辉石+斜铁辉石),CaTs(钙契尔马克分子)
Fig. 8 Diagrams of clinopyroxene-melt pairs in equilibrium conditions
a. Comparison of measured Mg# values of Cpx phenocrysts and their host whole-rocks. Gray fields define the equilibrium curves between Cpx and melt. The Mg# value of the host whole-rock is 67.1(unpublished data). Fig. b‒d are plots of the predicted compositions (DiHd) of Cpx compared to the observed compositions. The dashed lines and the thin black lines indicate 1σ and 2σ, respectively. DiHd = diopside + hedenbergite, EnFs = enstatite + ferrosilite and CaTs = Ca-Tschermak
图 9 单斜辉石结晶压力判别图
图a 中AlIV-AlVI界线据文献[65];图b中Xpt、Ypt计算公式分别为:Xpt = 0.446SiO2 + 0.187TiO2 ‒ 0.404Al2O3 + 0.346FeO ‒ 0.052MnO + 0.309MgO + 0.431CaO ‒ 0.446Na2O; Ypt = ‒0.369SiO2 + 0.535TiO2 ‒ 0.317Al2O3 + 0.323FeO +0.235MnO ‒ 0.516MgO ‒ 0.167CaO ‒ 0.153Na2O;图中相关界线据文献[59];apfu: 单位分子原子数
Fig. 9 Determination of crystallization pressures of studied clinopyroxenes
a. AlIV vs. AlVI diagram for Cpx (from reference [65]); b. Xpt-Ypt diagram of clinopyroxene crystallization P-T conditions (from reference [10], Xpt = 0.446SiO2 + 0.187TiO2 ‒ 0.404Al2O3 + 0.346FeO ‒ 0.052MnO + 0.309MgO + 0.431CaO ‒ 0.446Na2O; Ypt = ‒0.369SiO2 + 0.535TiO2 ‒ 0.317Al2O3 + 0.323FeO +0.235MnO ‒ 0.516MgO ‒ 0.167CaO ‒ 0.153Na2O). apfu: atoms per formula unit
图 11 单斜辉石化学组分构造背景判别图解
图a中WPA:板内碱性玄武岩,WPT:板内拉斑玄武岩,VAB:火山弧玄武岩,OFB:洋底玄武岩,F1、F2计算公式据文献[40];图b底图资料据文献[69];apfu: 单位分子原子数
Fig. 11 Tectonic discrimination diagrams of clinopyroxenes components
a. F1 vs. F2 discriminant diagram (from reference [40]) (WPA = Within-Plate Alkali basalt, WPT = Within-Plate Tholeiitic basalt, VAB = Volcanic Arc Basalt, OFB = Ocean Floor Basalt); b. Si vs. Fe diagram for the clinopyroxenes of volcanic rocks from different structural backgrounds (from reference [69]). apfu: atoms per formula unit
表 1 九州−帕劳脊南段基底玄武岩中单斜辉石主要氧化物含量
Tab. 1 Major oxides contents of clinopyroxenes from the southern KPR basalt
样品编号 分析点位 氧化物含量/% SiO2 TiO2 Al2O3 FeO MnO MgO NiO Cr2O3 CaO Na2O K2O 总量 Wo En Fs 123px-1 c 52.97 0.27 2.14 6.29 0.20 16.81 0.00 0.81 20.36 0.23 0.00 100.08 41.35 47.51 10.28 m 52.37 0.26 2.41 6.74 0.29 16.00 0.05 0.41 21.01 0.25 0.00 99.80 42.70 45.23 11.15 r 52.50 0.19 2.43 5.89 0.15 16.62 0.06 0.30 21.49 0.19 0.00 99.82 43.28 46.57 9.47 123px-2 c 51.89 0.39 2.15 9.09 0.39 15.39 0.17 0.10 20.33 0.28 0.00 100.19 40.97 43.15 14.85 m 52.19 0.05 2.97 4.22 0.15 16.73 0.03 1.34 21.99 0.19 0.00 99.85 44.85 47.49 6.94 r 52.12 0.29 2.42 6.53 0.26 16.31 0.10 0.69 20.85 0.23 0.00 99.80 42.33 46.08 10.74 123px-3 c 52.10 0.41 1.70 9.53 0.47 14.91 0.00 0.05 20.36 0.26 0.00 99.80 41.25 42.02 15.77 c 52.44 0.40 1.74 9.56 0.32 14.90 0.02 0.08 20.03 0.30 0.00 99.80 40.87 42.30 15.73 m 52.45 0.27 2.61 6.13 0.28 16.79 0.05 0.88 20.12 0.22 0.00 99.80 41.16 47.79 10.23 r 52.07 0.31 2.75 7.09 0.27 16.35 0.02 0.39 20.32 0.23 0.00 99.80 41.29 46.21 11.65 123px-4 m 52.17 0.25 3.05 6.28 0.14 15.79 0.05 0.44 21.86 0.20 0.00 100.22 44.43 44.66 10.17 m 51.62 0.20 3.22 6.36 0.16 15.61 0.11 0.46 21.57 0.20 0.00 99.51 44.27 44.57 10.43 c 52.73 0.19 2.86 3.81 0.00 16.84 0.04 0.80 22.37 0.16 0.00 99.80 45.60 47.76 6.07 c 51.84 0.25 3.26 5.55 0.22 15.91 0.00 0.62 21.91 0.23 0.00 99.80 44.75 45.22 9.19 r 52.19 0.18 2.82 4.68 0.12 16.83 0.05 0.95 21.84 0.14 0.00 99.80 44.33 47.55 7.60 r 52.48 0.37 2.40 6.90 0.28 16.34 0.06 0.69 20.34 0.26 0.00 100.11 41.40 46.27 11.40 r 52.71 0.13 2.48 5.34 0.26 17.66 0.04 0.83 20.17 0.20 0.00 99.80 40.78 49.67 8.83 r 52.30 0.23 2.57 7.45 0.29 16.28 0.00 0.57 19.91 0.22 0.00 99.80 40.64 46.23 12.31 r 52.09 0.25 3.04 6.73 0.16 15.33 0.00 0.39 21.59 0.22 0.00 99.80 44.35 43.81 11.03 123px-5 c 53.06 0.08 2.20 3.78 0.17 17.61 0.00 0.71 22.03 0.15 0.00 99.80 44.15 49.10 6.18 r 52.48 0.29 2.54 6.57 0.35 16.05 0.08 0.50 20.65 0.28 0.00 99.80 42.25 45.67 11.06 c 52.41 0.17 2.61 5.25 0.12 16.14 0.00 1.16 21.75 0.19 0.00 99.80 44.63 46.07 8.61 c 52.56 0.10 2.63 5.16 0.18 16.34 0.03 0.96 21.87 0.17 0.00 100.00 44.57 46.33 8.49 c 51.90 0.20 3.11 4.87 0.20 16.55 0.00 1.00 21.82 0.11 0.00 99.75 44.55 46.99 8.05 c 53.83 0.04 1.72 4.05 0.18 17.37 0.00 0.89 21.76 0.16 0.00 99.99 43.94 48.79 6.67 c 52.05 0.14 1.83 3.81 0.18 17.12 0.00 3.32 21.15 0.18 0.00 99.80 43.69 49.20 6.44 c 53.61 0.10 1.81 4.16 0.14 17.13 0.06 0.90 21.86 0.11 0.00 99.88 44.37 48.38 6.84 m 53.02 0.07 2.01 5.27 0.12 16.53 0.02 0.79 21.73 0.23 0.00 99.80 44.03 46.60 8.53 m 52.01 0.13 3.17 6.34 0.28 15.85 0.00 0.47 21.38 0.18 0.00 99.80 43.71 45.09 10.54 m 52.28 0.31 2.92 6.98 0.18 15.61 0.08 0.40 20.81 0.23 0.00 99.80 42.88 44.76 11.52 m 51.82 0.21 2.97 6.52 0.25 15.55 0.01 0.52 21.47 0.19 0.00 99.50 44.07 44.41 10.83 m 52.28 0.25 3.05 6.59 0.20 15.33 0.00 0.41 21.55 0.15 0.00 99.81 44.47 44.02 10.95 m 52.17 0.23 2.93 6.45 0.29 15.77 0.07 0.43 21.57 0.16 0.00 100.07 43.98 44.71 10.71 m 51.47 0.29 2.96 6.53 0.26 15.60 0.00 0.64 21.89 0.16 0.00 99.80 44.53 44.13 10.74 m 51.72 0.17 3.12 7.10 0.29 15.42 0.00 0.55 21.27 0.18 0.00 99.82 43.59 43.96 11.78 m 50.04 0.15 2.74 6.80 0.23 14.94 0.06 4.47 20.61 0.19 0.00 100.23 43.64 44.04 11.61 m 51.73 0.22 2.72 6.00 0.25 15.68 0.00 0.37 21.64 0.17 0.00 98.77 44.49 44.85 10.01 m 51.94 0.28 2.66 6.26 0.16 15.89 0.09 1.17 21.12 0.23 0.00 99.80 43.41 45.43 10.29 m 52.33 0.28 2.67 6.30 0.22 16.34 0.03 0.48 21.41 0.26 0.00 100.32 43.08 45.76 10.20 m 51.68 0.27 3.06 6.31 0.30 15.74 0.00 0.50 21.84 0.19 0.00 99.88 44.37 44.49 10.44 r 53.70 0.05 1.42 3.98 0.23 18.04 0.05 0.68 21.55 0.10 0.00 99.80 43.00 50.08 6.56 r 53.95 0.15 1.69 3.59 0.11 17.61 0.00 0.80 21.64 0.15 0.00 99.70 43.89 49.70 5.87 r 53.73 0.06 1.83 3.96 0.17 17.75 0.03 0.70 21.62 0.10 0.00 99.94 43.49 49.67 6.48 r 53.67 0.06 1.95 3.86 0.09 17.85 0.05 0.85 21.74 0.10 0.00 100.23 43.62 49.83 6.20 r 53.75 0.12 2.08 4.45 0.16 17.57 0.00 0.45 21.11 0.12 0.00 99.80 42.75 49.52 7.30 123px-5 r 53.39 0.11 2.30 4.75 0.19 17.41 0.15 0.35 21.17 0.12 0.00 99.95 42.78 48.97 7.82 r 53.00 0.05 2.56 4.80 0.20 16.94 0.09 0.49 21.94 0.10 0.00 100.15 44.24 47.54 7.87 r 52.25 0.18 3.37 5.34 0.18 16.08 0.03 0.57 22.08 0.20 0.00 100.28 44.95 45.56 8.75 r 53.63 0.09 2.08 4.32 0.15 17.09 0.07 0.69 21.49 0.19 0.00 99.80 43.76 48.42 7.12 r 52.82 0.27 2.06 6.90 0.30 16.58 0.14 0.29 20.29 0.19 0.00 99.84 41.13 46.77 11.40 r 51.22 0.23 1.89 6.80 0.36 16.40 0.00 3.11 19.59 0.19 0.00 99.80 40.54 47.21 11.55 r 52.53 0.19 2.15 6.24 0.31 16.97 0.13 0.52 20.19 0.27 0.00 99.51 40.87 47.80 10.33 r 53.12 0.20 2.27 5.84 0.26 16.76 0.00 0.78 20.41 0.26 0.00 99.89 41.69 47.63 9.74 r 52.91 0.18 1.96 6.73 0.19 16.89 0.00 0.76 19.92 0.27 0.00 99.80 40.40 47.66 10.96 r 52.63 0.25 2.17 6.90 0.15 16.40 0.10 0.37 20.60 0.23 0.00 99.80 41.77 46.26 11.14 r 52.42 0.26 2.39 6.95 0.25 15.99 0.03 0.46 20.79 0.26 0.00 99.80 42.32 45.29 11.43 r 52.42 0.27 2.33 7.16 0.28 16.02 0.00 0.39 20.69 0.24 0.00 99.80 42.05 45.29 11.80 r 52.25 0.30 2.48 7.12 0.20 15.71 0.05 0.51 20.95 0.23 0.00 99.80 42.82 44.66 11.68 123px-6 r 52.56 0.21 2.06 6.43 0.27 17.18 0.03 0.80 20.10 0.24 0.00 99.88 40.48 48.15 10.51 m 52.03 0.19 3.05 4.66 0.25 16.78 0.10 0.90 21.56 0.22 0.00 99.73 43.88 47.53 7.77 c 52.49 0.14 2.53 6.06 0.22 16.98 0.05 0.51 20.65 0.16 0.00 99.80 41.75 47.76 9.90 r 52.10 0.23 2.17 6.24 0.23 16.49 0.15 0.84 21.12 0.22 0.00 99.80 42.68 46.35 10.17 123px-7 r 52.75 0.30 2.51 6.21 0.27 16.40 0.00 0.84 20.74 0.26 0.00 100.27 42.26 46.49 10.32 m 51.88 0.34 2.30 8.64 0.25 15.13 0.18 0.00 20.79 0.21 0.00 99.71 42.30 42.85 14.08 m 51.29 0.17 3.68 6.27 0.22 15.41 0.00 0.83 21.64 0.18 0.00 99.68 44.65 44.23 10.44 c 53.24 0.17 2.15 5.28 0.15 17.04 0.02 0.29 21.59 0.10 0.00 100.05 43.42 47.69 8.52 r 52.06 0.21 2.77 6.43 0.17 16.55 0.04 1.18 20.17 0.23 0.00 99.80 41.37 47.22 10.55 123px-8 c 52.38 0.13 2.76 4.24 0.17 16.64 0.00 1.29 21.78 0.22 0.00 99.61 44.65 47.46 7.06 m 51.86 0.26 2.75 7.47 0.31 15.42 0.01 0.28 21.19 0.24 0.00 99.80 43.12 43.65 12.33 m 52.38 0.13 3.00 4.46 0.16 16.82 0.00 1.25 21.64 0.18 0.00 100.01 44.19 47.78 7.36 r 52.26 0.26 2.36 6.37 0.22 16.80 0.07 0.79 20.42 0.25 0.00 99.80 41.36 47.33 10.38 123px-9 r 53.30 0.16 1.93 5.48 0.20 17.48 0.09 0.65 20.60 0.18 0.00 100.08 41.47 48.95 8.94 c 52.01 0.35 1.95 8.42 0.39 15.92 0.02 0.20 20.29 0.26 0.00 99.80 40.78 44.53 13.77 m 53.24 0.15 1.92 5.36 0.23 17.59 0.00 0.45 20.59 0.19 0.00 99.71 41.37 49.19 8.76 123px-10 c 51.93 0.35 2.27 9.33 0.34 15.20 0.00 0.04 20.02 0.28 0.00 99.75 40.68 42.98 15.29 m 53.37 0.16 2.54 4.57 0.19 16.85 0.06 0.79 21.66 0.19 0.00 100.37 44.05 47.70 7.57 m 52.18 0.36 2.07 8.65 0.24 15.14 0.10 0.06 20.66 0.33 0.00 99.80 41.96 42.79 14.06 r 52.18 0.20 2.36 6.49 0.23 16.67 0.00 0.66 20.74 0.23 0.00 99.76 41.83 46.77 10.55 123px-b1 b 52.73 0.26 2.09 6.39 0.25 16.89 0.07 0.72 20.04 0.21 0.00 99.64 40.81 47.86 10.55 b 53.02 0.23 1.83 7.10 0.27 17.03 0.00 0.52 19.76 0.19 0.00 99.95 39.88 47.82 11.60 123px-b2 b 48.23 0.20 2.10 6.29 0.31 15.15 0.08 8.33 18.86 0.23 0.02 99.80 41.45 46.33 11.31 b 52.21 0.22 2.09 6.63 0.21 16.55 0.05 1.49 20.12 0.24 0.00 99.80 41.14 47.08 10.91 123px-b3 b 52.72 0.27 2.22 6.20 0.23 16.65 0.14 0.86 20.56 0.23 0.00 100.07 41.82 47.12 10.21 b 51.85 0.26 2.80 6.94 0.23 16.09 0.11 0.88 20.42 0.22 0.00 99.80 41.85 45.88 11.44 b 51.29 0.33 2.26 5.88 0.25 16.19 0.07 4.24 19.62 0.20 0.00 100.33 41.48 47.64 10.14 注:c代表斑晶核部,m代表斑晶幔部,r代表斑晶边部,b代表矿物微晶。 表 2 单斜辉石的稀土元素分析结果
Tab. 2 LA-ICPMS results for rare earth elements of pyroxene phenocrysts from the southern Kyushu-Palau ridge basalt
测点号 矿物
类型位置 稀土元素含量/10−6 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ∑REE LREE/
HREEδEu 123px-1-1 斑晶 r 0.10 0.83 0.21 1.71 1.14 0.33 1.59 0.27 2.04 0.48 1.21 0.20 1.31 0.18 11.60 0.59 0.76 123px-1-2 斑晶 m 0.28 1.80 0.47 3.63 2.34 0.72 2.65 0.61 3.83 0.77 2.29 0.34 1.99 0.28 22.00 0.72 0.88 123px-1-3 斑晶 c 0.10 0.72 0.20 1.92 0.77 0.27 1.75 0.26 1.75 0.36 1.08 0.12 0.94 0.17 10.40 0.62 0.69 123px-2-1 斑晶 − 0.37 2.70 0.68 6.31 3.61 1.18 6.42 1.14 7.67 1.55 4.47 0.57 4.52 0.54 41.73 0.55 0.74 123px-2-2 斑晶 − 0.16 1.03 0.25 2.01 1.05 0.37 1.83 0.34 2.75 0.46 1.61 0.23 1.16 0.16 13.39 0.57 0.80 123px-3-1 斑晶 c 0.24 1.80 0.55 4.10 2.29 0.74 3.18 0.71 4.62 1.08 2.64 0.32 2.59 0.34 25.21 0.63 0.84 123px-3-2 斑晶 m 0.08 0.38 0.10 0.72 0.20 0.17 0.87 0.17 0.82 0.22 0.57 0.05 0.50 0.07 4.92 0.51 1.06 123px-3-3 斑晶 r 0.16 1.01 0.24 2.26 1.14 0.37 1.58 0.35 2.41 0.58 1.48 0.24 1.44 0.14 13.41 0.63 0.84 123px-4-1 斑晶 c 0.12 0.79 0.20 1.74 0.79 0.25 1.11 0.24 1.79 0.25 1.02 0.09 0.56 0.13 9.09 0.75 0.82 123px-4-2 斑晶 m 0.03 0.37 0.10 0.62 0.33 0.18 0.44 0.10 0.92 0.18 0.37 0.01 0.43 0.09 4.18 0.65 1.44 123px-4-3 斑晶 r 0.20 0.97 0.29 2.41 0.96 0.44 1.97 0.34 2.55 0.51 1.63 0.20 1.22 0.25 13.93 0.61 0.95 123px-5-1 斑晶 c 0.14 0.79 0.24 1.61 1.63 0.48 1.75 0.37 2.37 0.42 1.60 0.21 1.66 0.27 13.54 0.57 0.87 123px-5-2 斑晶 m 0.05 0.21 0.09 0.22 0.58 0.13 0.65 0.09 0.79 0.15 0.55 0.07 0.37 0.03 3.98 0.48 0.66 123px-5-3 斑晶 r 0.13 0.94 0.30 1.95 1.32 0.45 2.42 0.42 2.97 0.60 1.37 0.19 1.43 0.23 14.71 0.53 0.75 123px-6-1 斑晶 c 0.13 0.77 0.12 1.24 0.48 0.28 1.80 0.25 1.87 0.46 1.09 0.18 1.10 0.17 9.95 0.44 0.82 123px-6-2 斑晶 m 0.08 0.35 0.13 0.69 0.49 0.19 0.90 0.18 1.21 0.23 0.58 0.07 0.71 0.09 5.89 0.48 0.84 123px-6-3 斑晶 m 0.14 0.76 0.29 1.65 1.11 0.42 1.81 0.35 2.46 0.44 1.75 0.29 1.44 0.24 13.15 0.50 0.90 123px-6-4 斑晶 r 0.11 0.91 0.22 1.78 0.86 0.36 1.63 0.33 2.00 0.36 1.45 0.25 1.37 0.18 11.78 0.56 0.92 123px-7-1 斑晶 c 0.19 1.01 0.25 2.41 1.39 0.47 1.54 0.26 2.54 0.52 1.45 0.19 1.80 0.22 14.24 0.67 0.98 123px-7-2 斑晶 r 0.18 0.79 0.23 1.83 1.14 0.36 2.25 0.30 2.11 0.47 1.45 0.18 1.24 0.21 12.74 0.55 0.67 123px-8-1 斑晶 c 0.30 1.57 0.37 3.60 1.88 0.69 2.92 0.54 4.01 0.80 2.38 0.30 2.33 0.35 22.05 0.62 0.89 123px-8-2 斑晶 m 0.09 0.35 0.11 0.62 0.38 0.10 1.23 0.10 0.86 0.18 0.44 0.03 0.51 0.11 5.11 0.48 0.41 123px-8-3 斑晶 r 0.10 0.94 0.29 2.36 1.27 0.42 2.29 0.44 2.75 0.45 1.42 0.17 1.47 0.18 14.56 0.59 0.75 123px-9-1 微晶 b 0.07 0.79 0.27 1.99 1.28 0.29 2.09 0.22 1.99 0.49 1.07 0.22 1.04 0.14 11.94 0.65 0.53 SRM 610 测量值 452.69 446.21 425.99 428.31 446.49 456.31 439.83 438.43 423.16 444.40 422.27 415.67 440.63 430.49 理论值 457.00 448.00 430.00 431.00 451.00 461.00 444.00 443.00 427.00 449.00 426.00 420.00 445.00 435.00 BCR-2G 测量值 23.95 48.81 5.84 25.88 6.17 1.88 6.16 0.90 6.32 1.16 3.06 0.44 3.36 0.38 理论值 24.70 53.30 6.70 28.90 6.59 1.97 6.71 1.02 6.44 1.27 3.70 0.51 3.39 0.50 注:“−”表示测点矿物形态较小,无法区分位置。 表 3 九州‒帕劳脊岩浆温压条件及含水量的估算
Tab. 3 Estimation of temperature and pressure conditions and water content of the magma from Kyushu-Palau Ridge
-
[1] 石学法, 鄢全树. 西太平洋典型边缘海盆的岩浆活动[J]. 地球科学进展, 2013, 28(7): 737−750.Shi Xuefa, Yan Quanshu. Magmatism of typical marginal basins (or back-arc basins) in the West Pacific[J]. Advances in Earth Science, 2013, 28(7): 737−750. [2] 李春峰, 周多, 李刚, 等. 西太平洋地球动力学问题与未来大洋钻探目标[J]. 地球科学, 2021, 46(3): 759−769.Li Chunfeng, Zhou Duo, Li Gang, et al. Geodynamic problems in the western pacific and future scientific drill targets[J]. Earth Science, 2021, 46(3): 759−769. [3] Stern R J, Gerya T. Subduction initiation in nature and models: a review[J]. Tectonophysics, 2018, 746: 173−198. doi: 10.1016/j.tecto.2017.10.014 [4] Yan Quanshu, Shi Xuefa, Yuan Long, et al. Tectono-magmatic evolution of the Philippine Sea Plate: a review[J]. Geosystems and Geoenvironment, 2022, 1(2): 100018. doi: 10.1016/j.geogeo.2021.100018 [5] Yan Quanshu, Shi Xuefa. Geological comparative studies of Japan arc system and Kyushu-Palau arc[J]. Acta Oceanologica Sinica, 2011, 30(4): 107−121. doi: 10.1007/s13131-011-0134-3 [6] Ishizuka O, Taylor R N, Yuasa M, et al. Making and breaking an island arc: a new perspective from the Oligocene Kyushu‐Palau arc, Philippine Sea[J]. Geochemistry, Geophysics, Geosystems, 2011, 12(5): Q05005. [7] Scott R B. Petrology and geochemistry of arc tholeiites on the Palau-Kyushu Ridge, Site 448, deep sea drilling project leg 59[J]. Initial Reports of the Deep Sea Drilling Project, 1980, 59: 681−692. [8] Brandl P A, Hamada M, Arculus R J, et al. The arc arises: the links between volcanic output, arc evolution and melt composition[J]. Earth and Planetary Science Letters, 2017, 461: 73−84. doi: 10.1016/j.jpgl.2016.12.027 [9] Stern R J. Subduction initiation: spontaneous and induced[J]. Earth and Planetary Science Letters, 2004, 226(3/4): 275−292. [10] 丁巍伟, 李家彪. 九州−帕劳海脊南段的深部结构探测及对板块俯冲起始机制的可能启示[J]. 海洋地质与第四纪地质, 2019, 39(5): 98−103.Ding Weiwei, Li Jiabiao. Seismic detection of deep structure for southern Kyueshu-Palau Ridge and its possible implications for subduction initiation[J]. Marine Geology & Quaternary Geology, 2019, 39(5): 98−103. [11] Yang H J, Frey F A, Clague D A, et al. Mineral chemistry of submarine lavas from Hilo Ridge, Hawaii: implications for magmatic processes within Hawaiian rift zones[J]. Contributions to Mineralogy and Petrology, 1999, 135(4): 355−372. doi: 10.1007/s004100050517 [12] Guo Feng, Nakamuru E, Fan Weiming, et al. Generation of Palaeocene adakitic andesites by magma mixing; Yanji Area, NE China[J]. Journal of Petrology, 2007, 48(4): 661−692. doi: 10.1093/petrology/egl077 [13] Li Xiaohui, Zeng Zhigang, Yang Huixin, et al. Integrated major and trace element study of clinopyroxene in basic, intermediate and acidic volcanic rocks from the middle Okinawa Trough: insights into petrogenesis and the influence of subduction component[J]. Lithos, 2020, 352-353: 105320. doi: 10.1016/j.lithos.2019.105320 [14] 于丽芳, 赵文霞, 陈建林, 等. 拉萨地块中南部新生代超钾质岩中单斜辉石斑晶的环带成分研究[J]. 岩石学报, 2011, 27(12): 3666−3674.Yu Lifang, Zhao Wenxia, Chen Jianlin, et al. Compositional zone investigation of clinopyroxene phenocryst in the Cenozoic ultra-potassic rocks from the middle-southern Lhasa block[J]. Acta Petrologica Sinica, 2011, 27(12): 3666−3674. [15] Ginibre C, Wörner G, Kronz A. Crystal zoning as an archive for magma evolution[J]. Elements, 2007, 3(4): 261−266. doi: 10.2113/gselements.3.4.261 [16] Wei Xun, Xu Yigang, Luo Zhenyu, et al. Composition of the Tarim mantle plume: constraints from clinopyroxene antecrysts in the early Permian Xiaohaizi dykes, NW China[J]. Lithos, 2015, 230: 69−81. doi: 10.1016/j.lithos.2015.05.010 [17] 谢元惠, 单伟, 于学峰, 等. 胶东白垩纪煌斑岩中单斜辉石再循环晶的识别及其地质意义[J]. 岩石学报, 2021, 37(7): 2203−2233. doi: 10.18654/1000-0569/2021.07.14Xie Yuanhui, Shan Wei, Yu Xuefeng, et al. Identification of clinopyroxene antecrysts in Cretaceous lamprophyre dykes from the Jiaodong Peninsula and their geological significance[J]. Acta Petrologica Sinica, 2021, 37(7): 2203−2233. doi: 10.18654/1000-0569/2021.07.14 [18] Lallemand S. Philippine Sea Plate inception, evolution, and consumption with special emphasis on the early stages of Izu-Bonin-Mariana subduction[J]. Progress in Earth and Planetary Science, 2016, 3(1): 15. doi: 10.1186/s40645-016-0085-6 [19] Wu J, Suppe J, Lu Renqi, et al. Philippine Sea and East Asian plate tectonics since 52 Ma constrained by new subducted slab reconstruction methods[J]. Journal of Geophysical Research: Solid Earth, 2016, 121(6): 4670−4741. doi: 10.1002/2016JB012923 [20] Hall R. Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: computer-based reconstructions, model and animations[J]. Journal of Asian Earth Sciences, 2002, 20(4): 353−431. doi: 10.1016/S1367-9120(01)00069-4 [21] Deschamps A, Lallemand S. The West Philippine Basin: an Eocene to early Oligocene back arc basin opened between two opposed subduction zones[J]. Journal of Geophysical Research: Solid Earth, 2002, 107(B12): 2322. [22] Tang Yong, Li Mingbi, Li Jiabiao, et al. The geomorphological features and continuity of the Kyushu-Palau Ridge (KPR)[J]. Acta Oceanologica Sinica, 2011, 30(5): 114−124. doi: 10.1007/s13131-011-0136-1 [23] 张洁, 李家彪, 丁巍伟. 九州−帕劳海脊地壳结构及其形成演化的研究综述[J]. 海洋科学进展, 2012, 30(4): 595−607.Zhang Jie, Li Jiabiao, Ding Weiwei. Reviews of the study on crustal structure and evolution of the Kyushu-Palau Ridge[J]. Advances in Marine Science, 2012, 30(4): 595−607. [24] Nishizawa A, Kaneda K, Oikawa M. Crust and uppermost mantle structure of the Kyushu-Palau Ridge, remnant arc on the Philippine Sea plate[J]. Earth, Planets and Space, 2016, 68(1): 30. doi: 10.1186/s40623-016-0407-3 [25] Niu Xiongwei, Tan Pingchuan, Ding Weiwei, et al. Oceanic crustal structure and tectonic origin of the southern Kyushu-Palau Ridge in the Philippine Sea[J]. Acta Oceanologica Sinica, 2022, 41(1): 39−49. doi: 10.1007/s13131-021-1978-9 [26] Wei Xiaodong, Ding Weiwei, Ruan Aiguo, et al. Crustal structure and variation along the southern part of the Kyushu-Palau Ridge[J]. Acta Oceanologica Sinica, 2022, 41(1): 50−57. doi: 10.1007/s13131-021-1979-8 [27] Ding Hanghang, Ding Weiwei, Zhao Yanghui, et al. Spatiotemporal distribution of seamount volume along the Kyushu-Palau Ridge: implications for rejuvenated volcanism[J]. Journal of Asian Earth Sciences, 2022, 240: 105391. doi: 10.1016/j.jseaes.2022.105391 [28] Hawkins J W, Castillo P R. Early history of the Izu-Bonin-Mariana arc system: evidence from Belau and the Palau Trench[J]. Island Arc, 1998, 7(3): 559−578. doi: 10.1111/j.1440-1738.1998.00210.x [29] Arculus R J, Ishizuka O, Bogus K A, et al. A record of spontaneous subduction initiation in the Izu-Bonin-Mariana arc[J]. Nature Geoscience, 2015, 8(9): 728−733. doi: 10.1038/ngeo2515 [30] Arculus R, Ishizuka O, Bogus K A. Izu-Bonin-Mariana arc origins: continental crust formation at intraoceanic arc: foundations, inceptions, and early evolution[J]. International Ocean Discovery Program Scientific Prospectus, 2013, 351. [31] Mizuno A. Granodiorite from the Minami-koho Seamount on the Kyushu-Palau Ridge, and its K-Ar age[J]. Bulletin of Geological Survey of Japan, 1977, 28(8): 507−511. [32] Taylor B, Goodliffe A M. The West Philippine Basin and the initiation of subduction, revisited[J]. Geophysical Research Letters, 2004, 31(12): L12602. [33] Okino K, Ohara Y, Fujiwara T, et al. Tectonics of the southern tip of the Parece Vela Basin, Philippine Sea Plate[J]. Tectonophysics, 2009, 466(3/4): 213−228. [34] Fang Yinxia, Li Jiabiao, Li Mingbi, et al. The formation and tectonic evolution of Philippine Sea Plate and KPR[J]. Acta Oceanologica Sinica, 2011, 30(4): 75−88. doi: 10.1007/s13131-011-0135-2 [35] Morimoto N. Nomenclature of pyroxenes[J]. Mineralogical Journal, 1989, 14(5): 198−221. doi: 10.2465/minerj.14.198 [36] 鄢全树, 石学法, 王昆山, 等. 南海新生代玄武岩中单斜辉石矿物化学及成因意义[J]. 岩石学报, 2007, 23(11): 2981−2989.Yan Quanshu, Shi Xuefa, Wang Kunshan, et al. Mineral chemistry and its genetic significance of olivine in Cenozoic basalts from the South China Sea[J]. Acta Petrologica Sinica, 2007, 23(11): 2981−2989. [37] Sun S S, McDonough W F. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes[J]. Geological Society, London, Special Publications, 1989, 42(1): 313−345. doi: 10.1144/GSL.SP.1989.042.01.19 [38] Leterrier J, Maury R C, Thonon P, et al. Clinopyroxene composition as a method of identification of the magmatic affinities of paleo-volcanic series[J]. Earth and Planetary Science Letters, 1982, 59(1): 139−154. doi: 10.1016/0012-821X(82)90122-4 [39] 邱家骧, 曾广策. 中国东部新生代玄武岩中低压单斜辉石的矿物化学及岩石学意义[J]. 岩石学报, 1987(4): 1−9.Qiu Jiaxiang, Zeng Guangce. The main characteristics and petrological significance of low pressure clinopyroxenes in the Cenozoic basalts from eastern China[J]. Acta Petrologica Sinica, 1987(4): 1−9. [40] Nisbet E G, Pearce J A. Clinopyroxene composition in mafic lavas from different tectonic settings[J]. Contributions to Mineralogy and Petrology, 1977, 63(2): 149−160. doi: 10.1007/BF00398776 [41] Le Bas M J. The role of aluminum in igneous clinopyroxenes with relation to their parentage[J]. American Journal of Science, 1962, 260(4): 267−288. doi: 10.2475/ajs.260.4.267 [42] Kushiro I. Si-Al relation in clinopyroxenes from igneous rocks[J]. American Journal of Science, 1960, 258(8): 548−554. doi: 10.2475/ajs.258.8.548 [43] Ubide T, Galé C, Arranz E, et al. Clinopyroxene and amphibole crystal populations in a lamprophyre sill from the Catalonian Coastal Ranges (NE Spain): a record of magma history and a window to mineral-melt partitioning[J]. Lithos, 2014, 184−187: 225−242. doi: 10.1016/j.lithos.2013.10.029 [44] 黄小龙, 徐义刚, 杨启军, 等. 滇西莴中晚始新世高镁富钾火山岩中单斜辉石斑晶环带结构的成因: 岩浆补给−混合过程[J]. 高校地质学报, 2007, 13(2): 250−260.Huang Xiaolong, Xu Yigang, Yang Qijun, et al. Genesis of compositional zoning of clinopyroxene phenocrysts in the Wozhong Late Eocene high-Mg ultrapotassic lavas, western Yunnan, China: magma replenishment-mixing process[J]. Geological Journal of China Universities, 2007, 13(2): 250−260. [45] Debari S, Kay S M, Kay R W. Ultramafic xenoliths from Adagdak volcano, Adak, Aleutian Islands, Alaska: deformed igneous cumulates from the Moho of an island arc[J]. The Journal of Geology, 1987, 95(3): 329−341. doi: 10.1086/629133 [46] Samajpati E, Hickey-Vargas R. Early magmatic history of the IBM arc inferred from volcanic minerals and melt inclusions from early-late Oligocene DSDP Site 296: a mineral-melt partition approach[J]. Contributions to Mineralogy and Petrology, 2022, 177(3): 41. doi: 10.1007/s00410-022-01909-6 [47] Dobosi G, Fodor R V. Magma fractionation, replenishment, and mixing as inferred from green-core clinopyroxenes in Pliocene basanite, southern Slovakia[J]. Lithos, 1992, 28(2): 133−150. doi: 10.1016/0024-4937(92)90028-W [48] 葛振敏, 鄢全树, 赵仁杰, 等. 科科斯脊玄武岩斜长石矿物化学及地质意义[J]. 海洋学报, 2020, 42(7): 93−107.Ge Zhenmin, Yan Quanshu, Zhao Renjie, et al. Mineral chemistry and geological significance of plagioclases hosted by basalts from the Cocos Ridge[J]. Haiyang Xuebao, 2020, 42(7): 93−107. [49] Streck M J. Mineral textures and zoning as evidence for open system processes[J]. Reviews in Mineralogy and Geochemistry, 2008, 69(1): 595−622. doi: 10.2138/rmg.2008.69.15 [50] Wei Xun, Zhang Yan, Shi Xuefa, et al. Concurrent magma mixing and crystallization processes revealed by clinopyroxene macrocrysts from Lamont guyot lavas in NW Pacific[J]. Lithos, 2022, 428−429: 106833. doi: 10.1016/j.lithos.2022.106833 [51] Putirka K D, Mikaelian H, Ryerson F, et al. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho[J]. American Mineralogist, 2003, 88(10): 1542−1554. doi: 10.2138/am-2003-1017 [52] Putirka K D. Thermometers and barometers for volcanic systems[J]. Reviews in Mineralogy and Geochemistry, 2008, 69(1): 61−120. doi: 10.2138/rmg.2008.69.3 [53] Neave D A, Putirka K D. A new clinopyroxene-liquid barometer, and implications for magma storage pressures under Icelandic rift zones[J]. American Mineralogist, 2017, 102(4): 777−794. doi: 10.2138/am-2017-5968 [54] Putirka K. Clinopyroxene + liquid equilibria to 100 kbar and 2450 K[J]. Contributions to Mineralogy and Petrology, 1999, 135(2/3): 151−163. [55] Mollo S, Putirka K, Misiti V, et al. A new test for equilibrium based on clinopyroxene-melt pairs: clues on the solidification temperatures of Etnean alkaline melts at post-eruptive conditions[J]. Chemical Geology, 2013, 352: 92−100. doi: 10.1016/j.chemgeo.2013.05.026 [56] Ishii T. Pyroxene geothermometry of basalts and an andesite from the Palau-Kyushu and West Mariana Ridges, Deep Sea Drilling Project Leg 59[J]. Initial Reports of the Deep Sea Drilling Project, 1981, 59: 693−718. [57] D’Antonio M, Savov I, Spadea P, et al. Petrogenesis of Eocene oceanic basalts from the West Philippine Basin and Oligocene arc volcanics from the Palau-Kyushu Ridge drilled at 20°N, 135°E (western Pacific Ocean)[J]. Ofioliti, 2006, 31(2): 157−171. [58] Wass S Y. Multiple origins of clinopyroxenes in alkali basaltic rocks[J]. Lithos, 1979, 12(2): 115−132. doi: 10.1016/0024-4937(79)90043-4 [59] Soesoo A. A multivariate statistical analysis of clinopyroxene composition: empirical coordinates for the crystallisation PT-estimations[J]. GFF, 1997, 119(1): 55−60. doi: 10.1080/11035899709546454 [60] Jayasuriya K D, O’Neill H S C, Berry A J, et al. A Mössbauer study of the oxidation state of Fe in silicate melts[J]. American Mineralogist, 2004, 89(11/12): 1597−1609. [61] 王锦团, 熊小林, 陈伊翔, 等. 俯冲带氧逸度研究: 进展和展望[J]. 中国科学: 地球科学, 2020, 63(12): 1952−1968. doi: 10.1007/s11430-019-9662-2Wang Jintuan, Xiong Xiaolin, Chen Yixiang, et al. Redox processes in subduction zones: progress and prospect[J]. Science China Earth Sciences, 2020, 63(12): 1952−1968. doi: 10.1007/s11430-019-9662-2 [62] Cameron M, Papike J J. Structural and chemical variations in pyroxenes[J]. American Mineralogist, 1981, 66(1/2): 1−50. [63] Schweitzer E L, Papike J J, Bence A E. Statistical analysis of clinopyroxenes from deep-sea basalts[J]. American Mineralogist, 1979, 64(5/6): 501−513. [64] Andersen D J, Lindsley D H, Davidson P M. QUILF: a pascal program to assess equilibria among Fe-Mg-Mn-Ti oxides, pyroxenes, olivine, and quartz[J]. Computers & Geosciences, 1993, 19(9): 1333−1350. [65] Aoki K I. Clinopyroxenes from alkaline rocks of Japan[J]. American Mineralogist, 1964, 49(9/10): 1199−1223. [66] Kuritani T, Yoshida T, Kimura J I, et al. Water content of primitive low-K tholeiitic basalt magma from Iwate Volcano, NE Japan arc: implications for differentiation mechanism of frontal-arc basalt magmas[J]. Mineralogy and Petrology, 2014, 108(1): 1−11. doi: 10.1007/s00710-013-0278-2 [67] Perinelli C, Mollo S, Gaeta M, et al. An improved clinopyroxene-based hygrometer for Etnean magmas and implications for eruption triggering mechanisms[J]. American Mineralogist, 2016, 101(12): 2774−2777. doi: 10.2138/am-2016-5916 [68] Armienti P, Perinelli C, Putirka K D. A new model to estimate deep-level magma ascent rates, with applications to Mt. Etna (Sicily, Italy)[J]. Journal of Petrology, 2013, 54(4): 795−813. doi: 10.1093/petrology/egs085 [69] Aparicio A. Relationship between clinopyroxene composition and the formation environment of volcanic host rocks[J]. The IUP Journal of Earth Sciences, 2010, 4(3): 34−44.