MORB trace element geochemistry in the eastern of southwest indian ridge and its indication for the composition of mantle source
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摘要:
西南印度洋中脊东段（E-SWIR）处于61°～70°E区域，具有相对匮乏的熔体供给。该区产出的大多数洋中脊玄武岩（MORB）具有富集不相容元素以及大离子亲石元素等特征，属典型E-MORB。基于玄武岩样品的微量元素地球化学资料，通过La/Sm、Zr/Nb和Lu/Tb等分析表明E-SWIR地幔具有明显的不均一性，这种不均一性可能与地幔中辉石岩含量的沿轴变化有关。利用稀土元素Ce、Sm、Lu和Yb含量结合部分熔融计算模拟结果，进一步阐明地幔源区中石榴石的作用与影响，并且认为其可能是以含金红石榴辉岩的形式赋存于地幔之中。对E-SWIR地幔源区榴辉岩性质和赋存形式的识别是探讨E-MORB成因、地幔不均一性与洋中脊构造演化等科学问题的关键。
Abstract:The eastern of the southwest Indian ridge (E-SWIR) is located between 61° and 70° E, with relatively low melt supply. Most of the mid-ocean ridge basalts (MORB) produced in this area is a typical E-MORB with the characteristics of enrichment of incompatible elements and large ion lithophile elements. Based on the trace element geochemical data of basalt samples, the analysis of La/Sm, Zr/Nb and Lu/Tb shows that the E-SWIR mantle has obvious heterogeneity, which may be related to the axial variation of pyroxenite content in the mantle. Using the contents of rare earth elements Ce, Sm, Lu and Yb in combination with the simulation results of partial melting calculation, the role and influence of garnet in the mantle source area are further clarified, and it is believed that it may exist in the mantle as auriferous garnet pyroxene. The identification of the nature and occurrence form of eclogites in the E-SWIR mantle source region is the key to discuss the origin of E-MORB, mantle heterogeneity and the tectonic evolution of mid ocean ridge.
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图 1 研究区及采样位置
a：西南印度洋中脊水深图， b：西南印度洋中脊东段水深图，c：西南印度洋中脊东段水深剖面图及岩浆构造单元（灰色代表斜向扩张段63°～64°E ，红色代表64°E Jourdanne海山，蓝色代表正向扩张段64°～65°E），d：64°E附近水深图及本文样品位置（改自文献[22]）。
Figure 1. Location of the study area and sampling
a: The geotectonic setting and topography of the Southwest Indian Ridge (SWIR), b: the area between the Melville Fracture Zone and Rodrigues Triple Junction, c: along-axis bathymetric profile between 61°E and 69°E, d: topography of the Tianzuo hydrothermal field and the adjacent Tiancheng and Mt. Jourdanne fields from multibeam sonar data (modified from reference [22]).
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图 2 E-SWIR稀土元素比值关系图
a：Y/Nb与Zr/Nb关系图，b：Nb/Y与Zr/Y关系图， c：（La/Sm）N与Zr/Nb关系图， d：（Lu/Tb）PM与ThPM关系图。本文以外数据来自PetDB 数据库http://www.petdb.org
Figure 2. The relationship between rare-earth elements
a: Y/Nb and Zr/N, b: Nb/Y and Zr/Y, c:（La/Sm）N and Zr/Nb, d: (Lu/Tb)PM and ThPMData outside of this article are from PetDB, http://www.petdb.org
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图 3 63°～65°E区域Ce，Lu，Sm和Yb分别与La的关系图
图上显示尖晶石方辉橄榄岩与石榴石二辉橄榄岩部分熔融曲线，以及两者混合熔体（1%石榴石二辉橄榄岩+X%尖晶石二辉橄榄岩）。本文以外数据来自PetDB 数据库http://www.petdb.org
Figure 3. The relationship between Ce, Lu, Sm, Yb and La at 63°～65°E
Partial melting curves of spinel harzburgite and garnet lherzolite and their mixed melts (1% garnet lherzolite + X% spinel lherzolite). Data outside of this article are from PetDB, http://www.petdb.org
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图 4 63°～65°E区域Sm/Yb与Sm、Sc关系图
a：Sm/Yb与Sm关系图，b：Sm/Yb与Sc关系图。图上显示尖晶石二辉橄榄岩、石榴石二辉橄榄岩和榴辉岩部分熔融曲线。图例和数据来源同图3。
Figure 4. The relationship of Sm/Yb and Sm, Sm/Yb and Sc at 63°～65°E
a: Sm/Yb and Sm, b: Sm/Yb and Sc. Partial melting curves of spinel harzburgite and garnet lherzolite and their mixed melts are shown in the figure. The legends and data source same as Fig.3
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图 5 63°～65°E区域稀土元素关系图
a：Lu与La关系图，b：Yb与La关系图，c：（Hf/Sm）PM与（Nb/Ta）PM关系图。图上显示尖晶石二辉橄榄岩、石榴石二辉橄榄岩和榴辉岩部分熔融曲线。图例和数据来源同图3。
Figure 5. The relationship of Lu and La, Yb and La, (Hf/Sm)PM and (Nb/Ta)PM at 63°～65°E
a: Lu and La, b: Yb and La, c: (Hf/Sm)PM and (Nb/Ta)PM. Partial melting curves of spinel harzburgite and garnet lherzolite and their mixed melts are shown in the figure. The legends and data source same as Fig.3
1 64°E玄武岩样品微量和稀土元素（10−6）测试结果
样品 87-S01 87-S02 87-S03 87-S06 19III-TVG03 26VI-TVG02 26VI-TVG03-1 26VI-TVG03-2 30I-TVG2-1 30I-TVG2-2 49I-TVG01-1 Sc 35.2 34.2 32.5 34.3 43.3 42.5 43.3 43.4 26.3 22.1 32.8 V 199 192 185 197 240 236 244 240 147 125 181 Cr 202 205 192 182 152 207 174 174 223 205 263 Co 109.5 232 154.5 99.2 35.1 33.2 34.6 34.2 132 104 33.2 Ni 93 88.5 85.8 84.4 41.2 43.7 41.3 42 58.4 48.8 93.4 Cu 61.5 76.5 60.4 53.5 88.3 82.5 82.8 85 60.5 44.9 65.8 Zn 55 54 51 55 124 68.7 70.6 72.9 42.7 35.3 68.5 Rb 1 0.6 0.5 2.1 2.36 2.16 2.47 2.64 1.42 1.15 1.77 Sr 203 214 225 208 186 195 195 201 271 283 232 Y 24.3 22.6 21.9 24 35.4 33.5 35.1 35.5 18.7 15.7 23.4 Zr 117.5 107 106.5 114.5 144 141 145 149 79.4 66.7 101 Nb 3.6 4.4 3.3 3.8 4.75 4.52 4.72 4.91 3.41 2.7 3 Ba 19.9 20.4 20.1 19.8 26.1 26.9 27 26.5 17.9 16 22.1 Hf 2.4 2.2 2.2 2.4 3.21 2.96 3.11 2.93 1.93 1.51 2.28 Ta 0.65 2.66 0.83 1.19 0.31 0.28 0.3 0.32 0.87 0.49 0.22 Th 0.3 0.3 0.26 0.27 0.35 0.36 0.34 0.36 0.18 0.16 0.26 U 0.12 0.13 0.1 0.1 0.13 0.12 0.12 0.21 0.092 0.064 0.079 La 4.4 3.8 3.7 4.6 6.21 6.34 6.49 6.56 3.6 3.28 4.41 Ce 14 11.5 11.1 14.5 17.7 17.5 18 18.2 10.2 8.85 17.8 Pr 1.93 1.9 1.87 1.87 2.76 2.56 2.59 2.68 1.56 1.35 1.97 Nd 9.4 9.6 9.5 9.3 12.7 12.5 13.3 13.3 7.66 6.62 9.43 Sm 2.89 2.73 2.83 2.9 4.02 4 4.07 4.1 2.29 1.87 2.65 Eu 1.06 1.11 1.14 1.11 1.45 1.36 1.42 1.43 0.9 0.84 1.11 Gd 3.62 3.7 3.4 3.38 5.16 5.13 5.02 5.28 2.72 2.22 3.33 Tb 0.62 0.63 0.65 0.65 0.92 0.81 0.91 0.91 0.5 0.43 0.63 Dy 4.26 4.18 4.01 3.95 6.01 5.45 5.93 5.9 3.34 2.81 4.19 Ho 0.93 0.84 0.89 0.88 1.28 1.17 1.19 1.19 0.68 0.59 0.86 Er 2.37 2.41 2.46 2.41 3.63 3.48 3.6 3.61 1.9 1.7 2.47 Tm 0.36 0.36 0.36 0.37 0.56 0.5 0.54 0.56 0.29 0.24 0.37 Yb 2.46 2.37 2.37 2.18 3.52 3.25 3.45 3.23 1.8 1.54 2.31 Lu 0.33 0.31 0.33 0.33 0.53 0.48 0.5 0.52 0.27 0.23 0.35 Pb − − − − 1.17 1.2 0.99 0.95 2.33 5.48 0.76 ΣREE 48.63 45.44 44.61 48.43 66.45 51.64 59.4 67.47 37.71 32.57 51.88 (La/Sm)N 0.95 0.84 0.81 1.00 0.99 1.02 0.79 1.03 1.01 1.13 1.07 (La/Yb)N 1.32 1.14 1.11 1.34 1.27 1.24 0.97 1.46 1.436 1.53 1.37 (Ce/Yb)N 1.58 1.35 1.30 1.85 1.40 1.50 1.45 1.57 1.57 1.60 2.14 (Sm/Yb)N 1.31 1.28 1.33 1.48 1.27 1.37 1.31 1.41 1.41 1.35 1.27 
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[1] Le Roux P J, Le Roex A P, Schilling J G, et al. Mantle heterogeneity beneath the southern Mid-Atlantic Ridge: trace element evidence for contamination of ambient asthenospheric mantle[J]. Earth and Planetary Science Letters, 2002, 203(1):479-498. doi: 10.1016/S0012-821X(02)00832-4
[2] Sobolev A V, Hofmann A W, Kuzmin D V, et al. The amount of recycled crust in sources of mantle-derived melts[J]. Science, 2007, 316(5823):412-417. doi: 10.1126/science.1138113
[3] Zhang G L, Zong C L, Yin X B, et al. Geochemical constraints on a mixed pyroxenite-peridotite source for east Pacific Rise basalts[J]. Chemical Geology, 2012, 330-331:176-187. doi: 10.1016/j.chemgeo.2012.08.033
[4] Lambart S, Laporte D, Schiano P. Markers of the pyroxenite contribution in the major-element compositions of oceanic basalts: review of the experimental constraints[J]. Lithos, 2013, 160-161:14-36. doi: 10.1016/j.lithos.2012.11.018
[5] Paquet M, Hamelin C, Moreira M, et al. The isotopic (He, Ne, Sr, Nd, Hf, Pb) signature in the Indian mantle over 8.8 Ma[J]. Chemical Geology, 2020, 550:119741. doi: 10.1016/j.chemgeo.2020.119741
[6] Brunelli D, Paganelli E, Seyler M. Percolation of enriched melts during incremental open-system melting in the spinel field: a REE approach to abyssal peridotites from the southwest Indian Ridge[J]. Geochimica et Cosmochimica Acta, 2014, 127:190-203. doi: 10.1016/j.gca.2013.11.040
[7] Brunelli D, Cipriani A, Bonatti E. Thermal effects of pyroxenites on mantle melting below mid-ocean ridges[J]. Nature Geoscience, 2018, 11(7):520-525. doi: 10.1038/s41561-018-0139-z
[8] Paquet M, Cannat M, Brunelli D, et al. Effect of melt/mantle interactions on MORB chemistry at the easternmost southwest Indian Ridge (61◦–67◦ E)[J]. Geochemistry, Geophysics, Geosystems, 2016, 17(11):4605-4640. doi: 10.1002/2016GC006385
[9] Muller M R, Minshull T A, White R S. Segmentation and melt supply at the southwest Indian Ridge[J]. Geology, 1999, 27(10):867-870. doi: 10.1130/0091-7613(1999)027<0867:SAMSAT>2.3.CO;2
[10] Cannat M, Rommevaux-Jestin C, Sauter D, et al. Formation of the axial relief at the very slow spreading southwest Indian Ridge (49° to 69°E)[J]. Journal of Geophysical Research:Solid Earth, 1999, 104(B10):22825-22843. doi: 10.1029/1999JB900195
[11] Cannat M, Rommevaux-Jestin C, Fujimoto H. Melt supply variations to a magma-poor ultra-slow spreading ridge (southwest Indian Ridge 61° to 69°E)[J]. Geochemistry, Geophysics, Geosystems, 2003, 4(8):9104.
[12] Pertermann M, Hirschmann M M. Partial melting experiments on a MORB-like pyroxenite between 2 and 3 GPa: constraints on the presence of pyroxenite in basalt source regions from solidus location and melting rate[J]. Journal of Geophysical Research:Solid Earth, 2003, 108(B2):2125.
[13] Pertermann M, Hirschmann M M. Anhydrous partial melting experiments on MORB-like eclogite: phase relations, phase compositions and mineral–melt partitioning of major elements at 2-3 GPa[J]. Journal of Petrology, 2003, 44(12):2173-2201. doi: 10.1093/petrology/egg074
[14] Ito G, Mahoney J J. Flow and melting of a heterogeneous mantle: 1. Method and importance to the geochemistry of ocean island and mid-ocean ridge basalts[J]. Earth and Planetary Science Letters, 2005, 230(1-2):29-46. doi: 10.1016/j.jpgl.2004.10.035
[15] Georgen J E, Kurz M D, Dick H J B, et al. Low 3He/4He ratios in basalt glasses from the western southwest Indian Ridge (10°-24°E)[J]. Earth and Planetary Science Letters, 2003, 206(3-4):509-528. doi: 10.1016/S0012-821X(02)01106-8
[16] Graham D W, Jenkins W J, Schilling J G, et al. Helium isotope geochemistry of mid-ocean ridge basalts from the south Atlantic[J]. Earth and Planetary Science Letters, 1992, 110(1-4):133-147. doi: 10.1016/0012-821X(92)90044-V
[17] Yang Z F, Li J, Liang W F, et al. On the chemical markers of pyroxenite contributions in continental basalts in Eastern China: implications for source lithology and the origin of basalts[J]. Earth-Science Reviews, 2016, 157:18-31. doi: 10.1016/j.earscirev.2016.04.001
[18] Yang Z F, Li J, Jiang Q B, et al. Using major element logratios to recognize compositional patterns of basalt: implications for source lithological and compositional heterogeneities[J]. Journal of Geophysical Research:Solid Earth, 2019, 124(4):3458-3490. doi: 10.1029/2018JB016145
[19] Le Roux V, Lee C T A, Turner S J. Zn/Fe systematics in mafic and ultramafic systems: implications for detecting major element heterogeneities in the earth’s mantle[J]. Geochimica et Cosmochimica Acta, 2010, 74(9):2779-2796. doi: 10.1016/j.gca.2010.02.004
[20] Le Roux V, Dasgupta R, Lee C T A. Mineralogical heterogeneities in the Earth’s mantle: constraints from Mn, Co, Ni and Zn partitioning during partial melting[J]. Earth and Planetary Science Letters, 2011, 307(3-4):395-408. doi: 10.1016/j.jpgl.2011.05.014
[21] Sauter D, Cannat M, Rouméjon S, et al. Continuous exhumation of mantle-derived rocks at the southwest Indian Ridge for 11 million years[J]. Nature Geoscience, 2013, 6(4):314-320. doi: 10.1038/ngeo1771
[22] Dong Z, Tao C H, Liang J, et al. Geochemistry of basalts from southwest Indian Ridge 64°E: implications for the mantle heterogeneity east of the Melville transform[J]. Minerals, 2021, 11(2):175. doi: 10.3390/min11020175
[23] Zhou H Y, Dick H J B. Thin crust as evidence for depleted mantle supporting the Marion Rise[J]. Nature, 2013, 494(7436):195-200. doi: 10.1038/nature11842
[24] Seyler M, Brunelli D, Toplis M J, et al. Multiscale chemical heterogeneities beneath the eastern southwest Indian Ridge (52°E-68°E): trace element compositions of along-axis dredged peridotites[J]. Geochemistry, Geophysics, Geosystems, 2011, 12(9):Q0AC15. doi: 10.1029/2011GC003585
[25] 李献华, 刘颖, 涂湘林, 等. 硅酸盐岩石化学组成的ICP-AES和ICP-MS准确测定: 酸溶与碱熔分解样品方法的对比[J]. 地球化学, 2002, 31(3):289-294 LI Xianhua, LIU Ying, TU Xianglin, et al. Precise determination of chemical compositions in silicate rocks using ICP-AES and ICP-MS: a comparative study of sample digestion techniques of alkali fusion and acid dissolution[J]. Geochimica, 2002, 31(3):289-294.]
[26] Meyzen C M, Toplis M J, Humler E, et al. A discontinuity in mantle composition beneath the southwest Indian Ridge[J]. Nature, 2003, 421(6924):731-733. doi: 10.1038/nature01424
[27] Frey F A, Silva I G N, Huang S C, et al. Depleted components in the source of hotspot magmas: evidence from the Ninetyeast Ridge (Kerguelen)[J]. Earth and Planetary Science Letters, 2015, 426:293-304. doi: 10.1016/j.jpgl.2015.06.005
[28] Kelemen P B, Yogodzinski G M, Scholl D W. Along-strike variation in the Aleutian island arc: genesis of high Mg# andesite and implications for continental crust[M]//Eiler J. Inside the Subduction Factory. Washington: AGU, 2003: 223-276.
[29] Donnelly K E, Goldstein S L, Langmuir C H, et al. Origin of enriched ocean ridge basalts and implications for mantle dynamics[J]. Earth and Planetary Science Letters, 2004, 226(3-4):347-366. doi: 10.1016/j.jpgl.2004.07.019
[30] Cushman B, Sinton J, Ito G, et al. Glass compositions, plume-ridge interaction, and hydrous melting along the Galapagos spreading center, 90.5°W to 98°W[J]. Geochemistry, Geophysics, Geosystems, 2013, 5(8):Q08E17.
[31] 高山, 章军锋, 许文良, 等. 拆沉作用与华北克拉通破坏[J]. 科学通报, 2009, 54(14): 1962-1973 GAO Shan, ZHANG Junfeng, XU Wenliang, et al. Delamination and destruction of the North China Craton[J]. Chinese Science Bulletin, 2009, 54(19): 3367-3378.]
[32] 魏春景, 郑永飞. 大洋俯冲带变质作用、流体行为与岩浆作用[J]. 中国科学: 地球科学, 2020, 50(1): 1-27 WEI Chunjing, ZHENG Yongfei. Metamorphism, fluid behavior and magmatism in oceanic subduction zones[J]. Science China Earth Sciences, 2020, 63(1): 52-77.]
[33] 刘帅奇, 张贵宾. 榴辉岩部分熔融过程中的同位素分馏[J]. 岩石学报, 2021, 37(1): 95-112 LIU Shuaiqi, ZHANG Guibin. Isotope fractionation during partial melting of eclogite[J]. Acta Petrologica Sinica, 37(1): 95-112.]
[34] 王超, 金振民, 高山, 等. 华北克拉通岩石圈破坏的榴辉岩熔体-橄榄岩反应机制: 实验约束[J]. 中国科学: 地球科学, 2010, 40(5): 541-555 WANG Chao, JIN Zhenmin, GAO Shan, et al. Eclogite-melt/peridotite reaction: experimental constrains on the destruction mechanism of the North China Craton[J]. Science China Earth Sciences, 2010, 53(6): 797-809.]
[35] Hofmann A W. Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust[J]. Earth and Planetary Science Letters, 1988, 90(3):297-314. doi: 10.1016/0012-821X(88)90132-X
[36] Shen Y, Forsyth D W. Geochemical constraints on initial and final depths of melting beneath mid-ocean ridges[J]. Journal of Geophysical Research:Solid Earth, 1995, 100(B2):2211-2237. doi: 10.1029/94JB02768
[37] White R S, McKenzie D, O'Nions R K. Oceanic crustal thickness from seismic measurements and rare earth element inversions[J]. Journal of Geophysical Research:Solid Earth, 1992, 97(B13):19683-19715. doi: 10.1029/92JB01749
[38] Bender J F, Langmuir C H, Hanson G N. Petrogenesis of basalt glasses from the Tamayo Region, east Pacific Rise[J]. Journal of Petrology, 1984, 25(1):213-254. doi: 10.1093/petrology/25.1.213
[39] Frey F A, Walker N, Stakes D, et al. Geochemical characteristics of basaltic glasses from the AMAR and FAMOUS axial valleys, Mid-Atlantic Ridge (36°-37°N): petrogenetic implications[J]. Earth and Planetary Science Letters, 1993, 115(1-4):117-136. doi: 10.1016/0012-821X(93)90217-W
[40] Blundy J D, Robinson J A C, Wood B J. Heavy REE are compatible in clinopyroxene on the spinel lherzolite solidus[J]. Earth and Planetary Science Letters, 1998, 160(3-4):493-504. doi: 10.1016/S0012-821X(98)00106-X
[41] Hirschmann M M, Stolper E M. A possible role for garnet pyroxenite in the origin of the "garnet signature" in MORB[J]. Contributions to Mineralogy and Petrology, 1996, 124(2):185-208. doi: 10.1007/s004100050184
[42] Hirschmann M M, Kogiso T, Baker M B, et al. Alkalic magmas generated by partial melting of garnet pyroxenite[J]. Geology, 2003, 31(6):481-484. doi: 10.1130/0091-7613(2003)031<0481:AMGBPM>2.0.CO;2
[43] Stracke A, Salters V J M, Sims K W W. Assessing the presence of garnet-pyroxenite in the mantle sources of basalts through combined hafnium-neodymium-thorium isotope systematics[J]. Geochemistry, Geophysics, Geosystems, 2013, 1(12):1006.
[44] Gaffney A M, Nelson B K, Blichert-Toft J. Melting in the Hawaiian plume at 1-2 Ma as recorded at Maui Nui: the role of eclogite, peridotite, and source mixing[J]. Geochemistry, Geophysics, Geosystems, 2005, 6(10):Q10L11.
[45] 陈振宇, 王登红, 陈毓川, 等. 榴辉岩中金红石的矿物地球化学研究及其意义[J]. 地球科学:中国地质大学学报, 2006, 31(4):533-538,550 CHEN Zhenyu, WANG Denghong, CHEN Yuchuan, et al. Mineral geochemistry of rutile in eclogite and its implications[J]. Earth Science:Journal of China University of Geosciences, 2006, 31(4):533-538,550.]
[46] 梁金龙, 施泽明, 徐进勇, 等. 金红石榴辉岩: 一个可能的超球粒陨石Nb/Ta储库[J]. 地球科学进展, 2012, 27(10):1094-1099 LIANG Jinlong, SHI Zeming, XU Jinyong, et al. Rutile-bearing eclogite: one of the possible reservoirs balancing the Nb-depleted silicate Earth[J]. Advances in Earth Science, 2012, 27(10):1094-1099.]
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