Abstract
Electron microprobe analysis was conducted on plagioclase from the plagioclase ultraphyric basalts (PUBs) erupted on the Southwest Indian Ridge (SWIR) (51°E) to investigate the geochemical changes in order to better understand the magmatic processes occurring under ultraslow spreading ridges and to provide insights into the thermal and dynamic regimes of the magmatic reservoirs and conduit systems. The phenocryst cores are generally calcic (An74–82) and are depleted in FeO and MgO. Whereas the phenocryst rims (An67–71) and the plagioclase in the groundmass (An58–63) are more sodic and have higher FeO and MgO contents than the phenocryst cores. The crystallization temperatures of the phenocryst cores and the calculation of the equilibrium between the phenocrysts and the matrix suggest that the plagioclase cores are unlikely to have crystallized from the host basaltic melt, but are likely to have crystallized from a more calcic melt. The enrichment in incompatible elements (FeO and MgO), as well as the higher FeO/MgO ratios of the outermost phenocryst rims and the groundmass, are the result of plagioclase-melt disequilibrium diffusion during the short residence time in which the plagioclase crystallized. Our results indicate that an evolved melt replenishing under the SWIR (51°E) drives the eruption over a short period of time.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
Bennett E N, Lissenberg C J, Cashman K V. 2019. The significance of plagioclase textures in mid-ocean ridge basalt (Gakkel Ridge, Arctic Ocean). Contributions to Mineralogy and Petrology, 174(6): 49, doi: https://doi.org/10.1007/s00410-019-1587-1
Bézos A, Humler E. 2005. The Fe3+/ΣFe ratios of MORB glasses and their implications for mantle melting. Geochimica et Cosmochimica Acta, 69(3): 711–725, doi: https://doi.org/10.1016/j.gca.2004.07.026
Bindeman I N, Davis A M, Drake M J. 1998. Ion microprobe study of plagioclase-basalt partition experiments at natural concentration levels of trace elements. Geochimica et Cosmochimica Acta, 62(7): 1175–1193, doi: https://doi.org/10.1016/S0016-7037(98)00047-7
Cannat M, Sauter D, Bezos A, et al. 2008. Spreading rate, spreading obliquity, and melt supply at the ultraslow spreading Southwest Indian Ridge. Geochemistry, Geophysics, Geosystems, 9(4): Q04002, doi: https://doi.org/10.1029/2007GC001676
Chen Xiaoming, Tan Qingquan, Zhao Guangtao. 2002. Plagioclases from the basalt of Okinawa Trough and its petrogenesis significance. Acta Petrologica Sinica (in Chinese), 18(4): 482–488
Coogan L A, MacLeod C J, Dick H J B, et al. 2001. Whole-rock geochemistry of gabbros from the Southwest Indian Ridge: constraints on geochemical fractionations between the upper and lower oceanic crust and magma chamber processes at (very) slow-spreading ridges. Chemical Geology, 178(1–4): 1–22, doi: https://doi.org/10.1016/S0009-2541(00)00424-1
Coote A C, Shane P. 2016. Crystal origins and magmatic system beneath Ngauruhoe volcano (New Zealand) revealed by plagioclase textures and compositions. Lithos, 260: 107–119, doi: https://doi.org/10.1016/j.lithos.2016.05.017
Coote A, Shane P, Stirling C, et al. 2018. The origin of plagioclase phenocrysts in basalts from continental monogenetic volcanoes of the Kaikohe-Bay of Islands field, New Zealand: implications for magmatic assembly and ascent. Contributions to Mineralogy and Petrology, 173(2): 14, doi: https://doi.org/10.1007/s00410-018-1440-y
Costa F, Chakraborty S, Dohmen R. 2003. Diffusion coupling between trace and major elements and a model for calculation of magma residence times using plagioclase. Geochimica et Cosmochimica Acta, 67(12): 2189–2200, doi: https://doi.org/10.1016/S0016-7037(02)01345-5
Costa F, Coogan L A, Chakraborty S. 2010. The time scales of magma mixing and mingling involving primitive melts and melt-mush interaction at mid-ocean ridges. Contributions to Mineralogy and Petrology, 159(3): 371–387, doi: https://doi.org/10.1007/s00410-009-0432-3
Cullen A, Vicenzi E, McBirney A R. 1989. Plagioclase-ultraphyric basalts of the Galapagos Archipelago. Journal of Volcanology and Geothermal Research, 37(3–4): 325–337, doi: https://doi.org/10.1016/0377-0273(89)90087-5
Dick H J B. 1989. Abyssal peridotites, very slow spreading ridges and ocean ridge magmatism. In: Saunders A D, Norry M J, eds. Magmatism in the Ocean Basins. Geological Society, London, Special Publications, 42: 71–105, doi: https://doi.org/10.1144/GSL.SP.1989.042.01.06
Dick H J B, Lin Jian, Schouten H. 2003. An ultraslow-spreading class of ocean ridge. Nature, 426(6965): 405–412, doi: https://doi.org/10.1038/nature02128
Drignon M J, Nielsen R L, Tepley III F J, et al. 2019. Upper mantle origin of plagioclase megacrysts from plagioclase-ultraphyric mid-oceanic ridge basalt. Geology, 47(1): 43–46, doi: https://doi.org/10.1130/G45542.1
Georgen J E, Lin Jian, Dick H J B. 2001. Evidence from gravity anomalies for interactions of the Marion and Bouvet hotspots with the Southwest Indian Ridge: effects of transform offsets. Earth and Planetary Science Letters, 187(3–4): 283–300, doi: https://doi.org/10.1016/S0012-821X(01)00293-X
Ginibre C, Wörner G, Kronz A. 2002. Minor-and trace-element zoning in plagioclase: implications for magma chamber processes at Parinacota volcano, northern Chile. Contributions to Mineralogy and Petrology, 143(3): 300–315, doi: https://doi.org/10.1007/s00410-002-0351-z
Ginibre C, Wörner G, Kronz A. 2004. Structure and dynamics of the laacher see magma chamber (Eifel, Germany) from major and trace element zoning in sanidine: a cathodoluminescence and electron microprobe study. Journal of Petrology, 45(11): 2197–2223, doi: https://doi.org/10.1093/petrology/egh053
Grove T L, Baker M B, Kinzler R J. 1984. Coupled CaAl-NaSi diffusion in plagioclase feldspar: experiments and applications to cooling rate speedometry. Geochimica et Cosmochimica Acta, 48(10): 2113–2121, doi: https://doi.org/10.1016/0016-7037(84)90391-0
Hellevang B, Pedersen R B. 2008. Magma ascent and crustal accretion at ultraslow-spreading ridges: constraints from plagioclase ultraphyric basalts from the arctic mid-ocean ridge. Journal of Petrology, 49(2): 267–294
Jian Hanchao, Singh S C, Chen Y J, et al. 2017. Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge. Geology, 45(2): 143–146, doi: https://doi.org/10.1130/G38356.1
Kamenetsky V S, Everard J L, Crawford A J, et al. 2000. Enriched end-member of primitive MORB melts: petrology and geochemistry of glasses from Macquarie Island (SW Pacific). Journal of Petrology, 41(3): 411–430, doi: https://doi.org/10.1093/petrology/41.3.411
Kudo A M, Weill D F. 1970. An igneous plagioclase thermometer. Contributions to Mineralogy and Petrology, 25(1): 52–65, doi: https://doi.org/10.1007/BF00383062
Landi P, Métrich N, Bertagnini A, et al. 2004. Dynamics of magma mixing and degassing recorded in plagioclase at Stromboli (Aeolian Archipelago, Italy). Contributions to Mineralogy and Petrology, 147(2): 213–227, doi: https://doi.org/10.1007/s00410-004-0555-5
Lange A E, Nielsen R L, Tepley III F J, et al. 2013. The petrogenesis of plagioclase-phyric basalts at mid-ocean ridges. Geochemistry, Geophysics, Geosystems, 14(8): 3282–3296, doi: https://doi.org/10.1002/ggge.20207
Martel C, Radadi Ali A, Poussineau S, et al. 2006. Basalt-inherited microlites in silicic magmas: evidence from Mount Pelée (Martinique, French West Indies). Geology, 34(11): 905–908, doi: https://doi.org/10.1130/G22672A.1
Martel C, Schmidt B C. 2003. Decompression experiments as an insight into ascent rates of silicic magmas. Contributions to Mineralogy and Petrology, 144(4): 397–415, doi: https://doi.org/10.1007/s00410-002-0404-3
Mollo S, Putirka K, Iezzi G, et al. 2011. Plagioclase-melt (dis)equilibrium due to cooling dynamics: implications for thermometry, barometry and hygrometry. Lithos, 125(1–2): 221–235, doi: https://doi.org/10.1016/j.lithos.2011.02.008
Moore A, Coogan L A, Costa F, et al. 2014. Primitive melt replenishment and crystal-mush disaggregation in the weeks preceding the 2005–2006 eruption 9°50′N, EPR. Earth and Planetary Science Letters, 403: 15–26, doi: https://doi.org/10.1016/j.epsl.2014.06.015
Mutch E J F, Maclennan J, Holland T J B, et al. 2019. Millennial storage of near—Moho magma. Science, 365(6450): 260–264, doi: https://doi.org/10.1126/science.aax4092
Nielsen R L, Crum J, Bourgeois R, et al. 1995. Melt inclusions in high-An plagioclase from the Gorda Ridge: an example of the local diversity of MORB parent magmas. Contributions to Mineralogy and Petrology, 122(1–2): 34–50, doi: https://doi.org/10.1007/s004100050111
Niu Xiongwei, Ruan Aiguo, Li Jiabiao, et al. 2015. Along-axis variation in crustal thickness at the ultraslow spreading Southwest Indian Ridge (50°E) from a wide-angle seismic experiment. Geochemistry, Geophysics, Geosystems, 16(2): 468–485, doi: https://doi.org/10.1002/2014GC005645
Robinson C J, Bickle M J, Minshull T A, et al. 2001. Low degree melting under the Southwest Indian Ridge: the roles of mantle temperature, conductive cooling and wet melting. Earth and Planetary Science Letters, 188(3–4): 383–398, doi: https://doi.org/10.1016/S0012-821X(01)00329-6
Sauter D, Cannat M, Meyzen C, et al. 2009. Propagation of a melting anomaly along the ultraslow Southwest Indian Ridge between 46°E and 52°20′E: interaction with the Crozet hotspot?. Geophysical Journal International, 179(2): 687–699, doi: https://doi.org/10.1111/j.1365-246X.2009.04308.x
Shcherbakov V D, Plechov P Y, Izbekov P E, Shipman J S. 2011. Plagioclase zoning as an indicator of magma processes at Bezymianny Volcano, Kamchatka. Contributions to Mineralogy and Petrology, 162(1): 83–99, doi: https://doi.org/10.1007/s00410-010-0584-1
Sisson T W, Grove T L. 1993. Experimental investigations of the role of H2O in calc-alkaline differentiation and subduction zone magmatism. Contributions to Mineralogy and Petrology, 113(2): 143–166, doi: https://doi.org/10.1007/BF00283225
Stolper E. 1980. A phase diagram for mid-ocean ridge basalts: preliminary results and implications for petrogenesis. Contributions to Mineralogy and Petrology, 74(1): 13–27, doi: https://doi.org/10.1007/BF00375485
Tao Chunhui, Lin Jian, Guo Shiqin, et al. 2012. First active hydrothermal vents on an ultraslow-spreading center: Southwest Indian Ridge. Geology, 40(1): 47–50, doi: https://doi.org/10.1130/G32389.1
Yang Fan, Huang Xiaolong, Xu Yigang, et al. 2019. Plume-ridge interaction in the South China Sea: thermometric evidence from Hole U1431E of IODP Expedition 349. Lithos, 324–325: 466–478, doi: https://doi.org/10.1016/j.lithos.2018.11.031
Yang A Y, Zhao Taiping, Zhou Meifu, et al. 2013. Os isotopic compositions of MORBs from the ultra-slow spreading Southwest Indian Ridge: Constraints on the assimilation and fractional crystallization (AFC) processes. Lithos, 179: 28–35, doi: https://doi.org/10.1016/j.lithos.2013.07.020
Yang A Y, Zhou Meifu, Zhao Taiping, et al. 2014. Chalcophile elemental compositions of morbs from the ultraslow-spreading southwest Indian ridge and controls of lithospheric structure on S-saturated differentiation. Chemical Geology, 382: 1–13, doi: https://doi.org/10.1016/j.chemgeo.2014.05.019
Yang A Y, Zhao T P, Zhou M F, et al. 2017. Isotopically enriched N-MORB: a new geochemical signature of off-axis plume-ridge interaction-a case study at 50°28′E, Southwest Indian Ridge. Journal of Geophysical Research: Solid Earth, 122(1): 191–213, doi: https://doi.org/10.1002/2016JB013284
Zhang Tao, Lin Jian, Gao Jinyao. 2013. Magmatism and tectonic processes in Area A hydrothermal vent on the Southwest Indian Ridge. Science China Earth Sciences, 56(12): 2186–2197, doi: https://doi.org/10.1007/s11430-013-4630-5
Acknowledgements
We are grateful to Yin-Jia Jin and two anonymous reviewers for their careful editing and constructive comments, which improved the manuscript. We also thank the crew and scientists involved in the R/V Dayang Yihao Cruise DY115-21.
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation item: The National Natural Science Foundation of China under contract Nos 41606041 and 41903046; the Scientific Research Fund of the Second Institute of Oceanography, MNR under contract Nos JG1604 and JT1504; China Ocean Mineral R&D Association (COMRA) Project under contract Nos DY135-G2-1-03 and DY135-N2-1-04.
Rights and permissions
About this article
Cite this article
Li, J., Zhu, J., Chu, F. et al. Chemical composition and petrogenesis of plagioclases in plagioclase-phyric basalts from the Southwest Indian Ridge (51°E). Acta Oceanol. Sin. 39, 42–49 (2020). https://doi.org/10.1007/s13131-020-1613-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13131-020-1613-1