Deep magmatic process of new volcano ridge in Segment 27, Southwest Indian Ridge: Constraints from plagioclase phenocrysts

WANG Conghao; LIU Jia; TAO Chunhui; LI Wei

doi:10.16562/j.cnki.0256-1492.2022040101

2022 Vol. 42, No. 6

Article Contents

Article navigation > Marine Geology & Quaternary Geology > 2022 > 42(6): 11-20

Next Article Previous Article

WANG Conghao, LIU Jia, TAO Chunhui, LI Wei. Deep magmatic process of new volcano ridge in Segment 27, Southwest Indian Ridge: Constraints from plagioclase phenocrysts[J]. Marine Geology & Quaternary Geology, 2022, 42(6): 11-20. doi: 10.16562/j.cnki.0256-1492.2022040101

Citation:

WANG Conghao, LIU Jia, TAO Chunhui, LI Wei. Deep magmatic process of new volcano ridge in Segment 27, Southwest Indian Ridge: Constraints from plagioclase phenocrysts[J]. Marine Geology & Quaternary Geology, 2022, 42(6): 11-20. doi: 10.16562/j.cnki.0256-1492.2022040101

Deep magmatic process of new volcano ridge in Segment 27, Southwest Indian Ridge: Constraints from plagioclase phenocrysts

1.
Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China
2.
Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
3.
School of Earth Sciences, Zhejiang University, Hangzhou 310027, China

Received Date: 01 April 2022

Revised Date: 27 April 2022

Publish Date: 28 December 2022

Abstract

Abstract

Most previous geochemical studies on basalts from the Southwest Indian Ridge (SWIR) were based on the analysis of bulk rocks, and those on phenocrysts are rare. We conducted bulk rock and mineral analyses of two rock samples of plagioclase-rich basalts from Segment 27, SWIR, where the Duanqiao hydrothermal field is located. The SiO₂ and MgO contents of the two samples (34IV-TVG07 and 30III-TVG14) are 49.16% and 6.76%, and 49.50 and 6.52%, respectively. Their trace elemental patterns are similar to typical N-MORB (normal mid-ocean ridge basalts). The EPMA analysis show that the An (% of anorthite) of the plagioclase phenocrysts vary in the range of 76.2 to 87.9, and most are above 80, which is significantly greater than those of plagioclase in the Mount Jordanne basalts, indicating that the An-rich plagioclase phenocrysts at 50.4°E are not derived from the lower oceanic crust of the Mount Jordanne. In addition, the Petrolog3 modeling shows that they could not crystallize directly from the mother magma. By combining the experimental constrains and previous evidence for ancient mantle wedge-like component entrained beneath this ridge, we believe that the An-rich plagioclase in Segment 27 basalts were most likely crystallized from magma due to partial melting of an ancient depleted sub-arc mantle.
- basalts /
- plagioclase phenocryst /
- sub-arc mantle /
- southwest Indian Ridge

FullText(HTML)

References

[1]	Sauter D, Cannat M. The ultraslow spreading Southwest Indian ridge[M]//Rona P A, DeveyC W, Dyment J, et al. Diversity of Hydrothermal Systems on Slow Spreading Ocean Ridges. Washington, D. C.: American Geophysical Union, 2010, 88: 153-173. Google Scholar
[2]	孙国洪, 田丽艳, 李小虎, 等. 西南印度洋中脊岩石地球化学特征及其岩浆作用研究[J]. 海洋地质与第四纪地质, 2021, 41(5):126-138 Google Scholar SUN Guohong, TIAN Liyan, LI Xiaohu, et al. A review of studies on the magmatism at Southwest Indian Ridge from petrological and geochemical perspectives [J]. Marine Geology & Quaternary Geology, 2021, 41(5): 126-138. Google Scholar
[3]	Dick H J B, Lin J, Schouten H. An ultraslow-spreading class of ocean ridge [J]. Nature, 2003, 426(6965): 405-412. doi: 10.1038/nature02128 CrossRef Google Scholar
[4]	Li J B, Jian H C, Chen Y J, et al. Seismic observation of an extremely magmatic accretion at the ultraslow spreading Southwest Indian Ridge [J]. Geophysical Research Letters, 2015, 42(8): 2656-2663. doi: 10.1002/2014GL062521 CrossRef Google Scholar
[5]	Jian H C, Singh S C, Chen Y J, et al. Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge [J]. Geology, 2017, 45(2): 143-146. doi: 10.1130/G38356.1 CrossRef Google Scholar
[6]	Chen J, Cannat M, Tao C H, et al. 780 thousand years of upper - crustal construction at a melt-rich segment of the ultraslow spreading southwest Indian Ridge 50°28′E [J]. Journal of Geophysical Research:Solid Earth, 2021, 126(10): e2021JB022152. Google Scholar
[7]	Yang A Y, Zhao T P, Zhou M F, et al. Isotopically enriched N-MORB: A new geochemical signature of off - axis plume - ridge interaction–A case study at 50°28′E, Southwest Indian Ridge [J]. Journal of Geophysical Research:Solid Earth, 2017, 122(1): 191-213. doi: 10.1002/2016JB013284 CrossRef Google Scholar
[8]	Yu X, Dick H J B. Plate-driven micro-hotspots and the evolution of the Dragon Flag melting anomaly, Southwest Indian Ridge [J]. Earth and Planetary Science Letters, 2020, 531: 116002. doi: 10.1016/j.jpgl.2019.116002 CrossRef Google Scholar
[9]	李伟. 西南印度洋中脊玄武岩岩石地球化学特征: 对超慢速扩张的启示[D]. 中国地质大学博士学位论文, 2017 Google Scholar LI Wei. Petrogeochemical characteristics of basalts from Southwest Indian Ridge: Implications for magmatic processes at ultra-slow spreading ridge[D]. Doctor Dissertation of China University of Geosciences (Beijing), 2017. Google Scholar
[10]	初凤友, 陈建林, 马维林, 等. 中太平洋海山玄武岩的岩石学特征与年代[J]. 海洋地质与第四纪地质, 2005, 25(4):55-59 Google Scholar CHU Fengyou, CHEN Jianlin, MA Weilin, et al. Petrologic characteristics and ages of basalt in Middle Pacific mountains [J]. Marine Geology & Quaternary Geology, 2005, 25(4): 55-59. Google Scholar
[11]	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 CrossRef Google Scholar
[12]	McDonough W F, Sun S S. The composition of the Earth [J]. Chemical Geology, 1995, 120(3-4): 223-253. doi: 10.1016/0009-2541(94)00140-4 CrossRef Google Scholar
[13]	Li W, Tao C H, Zhang W, et al. Melt inclusions in plagioclase macrocrysts at mount Jourdanne, southwest Indian ridge (~64ºE): implications for an enriched mantle source and shallow magmatic processes [J]. Minerals, 2019, 9(8): 493. doi: 10.3390/min9080493 CrossRef Google Scholar
[14]	Beard J S, Borgia A. Temporal variation of mineralogy and petrology in cognate gabbroic enclaves at Arenal volcano, Costa Rica [J]. Contributions to Mineralogy and Petrology, 1989, 103(1): 110-122. doi: 10.1007/BF00371368 CrossRef Google Scholar
[15]	Crawford A J, Falloon T J, Eggins S. The origin of island arc high-alumina basalts [J]. Contributions to Mineralogy and Petrology, 1987, 97(3): 417-430. doi: 10.1007/BF00372004 CrossRef Google Scholar
[16]	Sinton C W, Christie D M, Coombs V L, et al. Near-primary melt inclusions in anorthite phenocrysts from the Galapagos Platfrom [J]. Earth and Planetary Science Letters, 1993, 119(4): 527-537. doi: 10.1016/0012-821X(93)90060-M CrossRef Google Scholar
[17]	Stolz A J, Varne R, Wheller G E, et al. The geochemistry and petrogenesis of K-rich alkaline volcanics from the Batu Tara volcano, eastern Sunda arc [J]. Contributions to Mineralogy and Petrology, 1988, 98(3): 374-389. doi: 10.1007/BF00375187 CrossRef Google Scholar
[18]	Kudo A M, Weill D F. An igneous plagioclase thermometer [J]. Contributions to Mineralogy and Petrology, 1970, 25(1): 52-65. doi: 10.1007/BF00383062 CrossRef Google Scholar
[19]	Duncan R A, Green D H. The genesis of refractory melts in the formation of oceanic crust [J]. Contributions to Mineralogy and Petrology, 1987, 96(3): 326-342. doi: 10.1007/BF00371252 CrossRef Google Scholar
[20]	Hirschmann M M. Water, melting, and the deep Earth H₂O cycle [J]. Annual Review of Earth and Planetary Sciences, 2006, 34: 629-653. doi: 10.1146/annurev.earth.34.031405.125211 CrossRef Google Scholar
[21]	Wang W, Kelley K A, Li Z G, et al. Volatile element evidence of local MORB mantle heterogeneity beneath the southwest Indian ridge, 48º-51ºE [J]. Geochemistry, Geophysics, Geosystems, 2021, 22(7): e2021GC009647. Google Scholar
[22]	Liu J, Tao C H, Zhou J P, et al. Water enrichment in the mid-ocean ridge by recycling of mantle wedge residue [J]. Earth and Planetary Science Letters, 2022, 584: 117455. doi: 10.1016/j.jpgl.2022.117455 CrossRef Google Scholar
[23]	Panjasawatwong Y, Danyushevsky L V, Crawford A J, et al. An experimental study of the effects of melt composition on plagioclase-melt equilibria at 5 and 10 kbar: implications for the origin of magmatic high-An plagioclase [J]. Contributions to Mineralogy and Petrology, 1995, 118(4): 420-432. doi: 10.1007/s004100050024 CrossRef Google Scholar
[24]	Danyushevsky L V. The effect of small amounts of H₂O on crystallisation of mid-ocean ridge and backarc basin magmas [J]. Journal of Volcanology and Geothermal Research, 2001, 110(3-4): 265-280. doi: 10.1016/S0377-0273(01)00213-X CrossRef Google Scholar
[25]	Gao C G, Dick H J B, Liu Y, et al. Melt extraction and mantle source at a Southwest Indian Ridge Dragon Bone amagmatic segment on the Marion Rise [J]. Lithos, 2016, 246-247: 48-60. doi: 10.1016/j.lithos.2015.12.007 CrossRef Google Scholar
[26]	Michael P. Regionally distinctive sources of depleted MORB: Evidence from trace elements and H₂O [J]. Earth and Planetary Science Letters, 1995, 131(3-4): 301-320. doi: 10.1016/0012-821X(95)00023-6 CrossRef Google Scholar