Abstract
We analyzed seafloor morphology and geophysical anomalies of the Southeast Indian Ridge (SEIR) to reveal the remarkable changes in magma supply along this intermediate fast-spreading ridge. We found systematic differences of the Australian-Antarctic Discordance (AAD) from adjacent ridge segments with the residual mantle Bouguer gravity anomaly (RMBA) being more positive, seafloor being deeper, morphology being more chaotic, M factors being smaller at the AAD. These systematic anomalies, as well as the observed Na8.0 being greater and Fe8.0 being smaller at AAD, suggest relatively starved magma supply and relatively thin crust within the AAD. Comparing to the adjacent ridges segments, the calculated average map-view M factors are relatively small for the AAD, where several Oceanic Core Complexes (OCCs) develop. Close to 30 OCCs were found to be distributed asymmetrically along the SEIR with 60% of OCCs at the northern flank. The OCCs are concentrated mainly in Segments B3 and B4 within the AAD at ≈124°–126°E, as well as at the eastern end of Zone C at ≈115°E. The relatively small map-view M factors within the AAD indicate stronger tectonism than the adjacent SEIR segments. The interaction between the westward migrating Pacific mantle and the relatively cold mantle beneath the AAD may have caused a reduction in magma supply, leading to the development of abundant OCCs.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Anderson R N, Spariosu D J, Weissel J K, et al. 1980. The interrelation between variations in magnetic anomaly amplitudes and basalt magnetization and chemistry along the Southeast Indian Ridge. Journal of Geophysical Research: Solid Earth, 185(B7): 3883–3898, doi: https://doi.org/10.1029/JB085iB07p03883
Behn M D, Ito G. 2008. Magmatic and tectonic extension at midocean ridges: 1. Controls on fault characteristics. Geochemistry, Geophysics, Geosystems, 9(8): Q08O10, doi: https://doi.org/10.1029/2008GC001965
Buck W R, Lavier L L, Poliakov A N B. 2005. Modes of faulting at midocean ridges. Nature, 434(7034): 719–723, doi: https://doi.org/10.1038/nature03358
Cann J R, Blackman D K, Smith D K, et al. 1997. Corrugated slip surfaces formed at ridge-transform intersections on the Mid-Atlantic Ridge. Nature, 385(6612): 329–332
Christie D M, West B P, Pyle D G, et al. 1998. Chaotic topography, mantle flow and mantle migration in the Australian-Antarctic discordance. Nature, 394(6694): 637–644, doi: https://doi.org/10.1038/29226
Ciazela J, Koepke J, Dick H J B, et al. 2015. Mantle rock exposures at oceanic core complexes along mid-ocean ridges. Geologos, 21(4): 207–231, doi: https://doi.org/10.1515/logos-2015-0017
Cundall P A. 1989. Numerical experiments on localization in frictional material. Ingenieur-Archiv, 58(2): 148–159, doi: https://doi.org/10.1007/bf00538368
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
Escartín J, Mével C, Macleod C J, et al. 2003. Constraints on deformation conditions and the origin of oceanic detachments: The Mid-Atlantic Ridge core complex at 15°45’N. Geochemistry, Geophysics, Geosystems, 4(8): 1067, doi: https://doi.org/10.1029/2002GC000472
Escartín J, Smith D K, Cann J R, et al. 2008. Central role of detachment faults in accretion of slow-spreading oceanic lithosphere. Nature, 455(7214): 790–794, doi: https://doi.org/10.1038/nature07333
Gurnis M, Müller R D, Moresi L. 1998. Cretaceous vertical motion of Australia and the Australian Antarctic discordance. Science, 279(5356): 1499–1504, doi: https://doi.org/10.1126/science.279.5356.1499
Gurnis M, Müeller R D. 2003. Origin of the Australian-Antarctic discordance from an ancient slab and mantle wedge. Geological Society of America Special Papers, 372: 417–429
Hayes D E. 1976. Nature and implications of asymmetric sea-floor spreading-“different rates for different plates”. GSA Bulletin, 87(7): 994–1002, doi: https://doi.org/10.1130/0016-7606(1976)87<994:NAIOAS>2.0.CO;2
Hayes D E. 1988. Age-depth relationships and depth anomalies in the Southeast Indian Ocean and south Atlantic Ocean. Journal of Geophysical Research: Solid Earth, 93(B4): 2937–2954, doi: https://doi.org/10.1029/JB093iB04p02937
Hayes D E, Conolly J R. 1972. Morphology of the Southeast Indian Ocean. In: Hayes D E, ed. Antarctic Oceanology II: The Australian-New Zealand Sector. Washington D C: Wiley, 125–145, doi: https://doi.org/10.1029/AR019p0125
Klein E M, Langmuir C H. 1987. Global correlations of ocean ridge basalt chemistry with axial depth and crustal thickness. Journal of Geophysical Research: Solid Earth, 92(B8): 8089–8115, doi: https://doi.org/10.1029/JB092iB08p08089
Klein E M, Langmuir C H, Staudigel H. 1991. Geochemistry of basalts from the Southeast Indian Ridge, 115°E-138°E. Journal of Geophysical Research: Solid Earth, 96(B2): 2089–2107, doi: https://doi.org/10.1029/90JB01384
Klein E M, Langmuir C H, Zindler A, et al. 1988. Isotope evidence of a mantle convection boundary at the Australian-Antarctic Discordance. Nature, 333(6174): 623–629, doi: https://doi.org/10.1038/333623a0
Kojima Y, Shinohara M, Mochizuki K, et al. 2003. Seismic velocity structure in the Australian-Antarctic Discordance, Segment B4 revealed by airgun-OBS experiment. In: American Geophysical Union, Fall Meeting 2003, S21F–0396
Kuo Baiyuan, Forsyth D W. 1988. Gravity anomalies of the ridgetransform system in the South Atlantic between 31 and 34.5°S: Upwelling centers and variations in crustal thickness. Marine Geophysical Researches, 10(3-4): 205–232, doi: https://doi.org/10.1007/BF00310065
Lavier L L, Buck W R. 2002. Half graben versus large-offset low-angle normal fault: Importance of keeping cool during normal faulting. Journal of Geophysical Research: Solid Earth, 107(B6): 2122, doi: https://doi.org/10.1029/2001JB000513
Lavier L L, Buck W R, Poliakov A N B. 2000. Factors controlling normal fault offset in an ideal brittle layer. Journal of Geophysical Research: Solid Earth, 105(B10): 23431–23442, doi: https://doi.org/10.1029/2000JB900108
Lin J, Purdy G M, Schouten H, et al. 1990. Evidence from gravity data for focused magmatic accretion along the Mid-Atlantic Ridge. Nature, 344(6267): 627–632, doi: https://doi.org/10.1038/344627a0
Müller R D, Sdrolias M, Gaina C, et al. 2008. Age, spreading rates, and spreading asymmetry of the world’s ocean crust. Geochemistry, Geophysics, Geosystems, 9(4): Q04006, doi: https://doi.org/10.1029/2007GC001743
Macdonald K C. 1990. A slow but restless ridge. Nature, 348(6297): 108–109, doi: https://doi.org/10.1038/348108a0
MacLeod C J, Searle R C, Murton B J, et al. 2009. Life cycle of oceanic core complexes. Earth and Planetary Science Letters, 287(3–4): 333–344, doi: https://doi.org/10.1016/j.epsl.2009.08.016
Mahoney J J, Graham D W, Christie D M, et al. 2002. Between a hotspot and a cold spot: Isotopic variation in the Southeast Indian Ridge asthenosphere, 86°E-118°E. Journal of Petrology, 43(7): 1155–1176, doi: https://doi.org/10.1093/petrology/43.7.1155
Marks K M, Vogt P R, Hall S A. 1990. Residual depth anomalies and the origin of the Australian-Antarctic Discordance zone. Journal of Geophysical Research: Solid Earth, 95(B11): 17325–17337, doi: https://doi.org/10.1029/JB095iB11p1732
Ohara Y, Yoshida T, Kato Y, et al. 2001. Giant megamullion in the Parece Vela backarc basin. Marine Geophysical Researches, 22(1): 47–61, doi: https://doi.org/10.1023/A:1004818225642
Okino K, Matsuda K, Christie D M, et al. 2004. Development of oceanic detachment and asymmetric spreading at the Australian-Antarctic Discordance. Geochemistry, Geophysics, Geosystems, 5(12): Q12012, doi: https://doi.org/10.1029/2004GC000793
Oldenburg D W. 1974. The inversion and interpretation of gravity anomalies. Geophysics, 39(4): 526–536, doi: https://doi.org/10.1190/1.1440444
Olive J A, Behn M D, Mittelstaedt E, et al. 2016. The role of elasticity in simulating long-term tectonic extension. Geophysical Journal International, 205(2): 728–743, doi: https://doi.org/10.1093/gji/ggw044
Olive J A, Behn M D, Tucholke B E. 2010. The structure of oceanic core complexes controlled by the depth distribution of magma emplacement. Nature Geoscience, 3(7): 491–495, doi: https://doi.org/10.1038/ngeo888
Parker R L. 1973. The rapid calculation of potential anomalies. Geophysical Journal International, 31(4): 447–455, doi: https://doi.org/10.1111/j.1365-246X.1973.tb06513.x
Pyle D G, Christie D M, Mahoney J J. 1992. Resolving an isotopic boundary within the Australian-Antarctic Discordance. Earth and Planetary Science Letters, 112(1-4): 161–178, doi: https://doi.org/10.1016/0012-821X(92)90014-M
Sandwell D T, Müller R D, Smith W H F, et al. 2014. New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure. Science, 346(6205): 65–67, doi: https://doi.org/10.1126/science.1258213
Shaw W J, Lin Jian. 1996. Models of ocean ridge lithospheric deformation: Dependence on crustal thickness, spreading rate, and segmentation. Journal of Geophysical Research: Solid Earth, 101(B8): 17977–17993, doi: https://doi.org/10.1029/96JB00949
Smith D. 2013. Mantle spread across the sea floor. Nature Geoscience, 6(4): 247–248, doi: https://doi.org/10.1038/ngeo1786
Tucholke B E, Behn M D, Buck W R, et al. 2008. Role of melt supply in oceanic detachment faulting and formation of megamullions. Geology, 36(6): 455–458, doi: https://doi.org/10.1130/G24639A.1
Tucholke B E, Lin Jian. 1994. A geological model for the structure of ridge segments in slow spreading ocean crust. Journal of Geophysical Research: Solid Earth, 99(B6): 11937–11958, doi: https://doi.org/10.1029/94JB00338
Tucholke B E, Lin Jian, Kleinrock M C. 1998. Megamullions and mullion structure defining oceanic metamorphic core complexes on the Mid-Atlantic Ridge. Journal of Geophysical Research: Solid Earth, 103(B5): 9857–9866, doi: https://doi.org/10.1029/98JB00167
Vogt P R, Cherkis N Z, Morgan G A. 1983. Project Investigator-I: Evolution of the Australian-Antarctic Discordance deduced from a detailed aeromagnetic study. In: Oliver R L, James P R, Jago J B, eds. Antarctic Earth Science: 4th International Symposium. Camberra: Cambridge University Press, 608–613
Wang Tingting, Lin Jian, Tucholke B E, et al. 2011. Crustal thickness anomalies in the North Atlantic Ocean basin from gravity analysis. Geochemistry, Geophysics, Geosystems, 12(3): Q0AE02, doi: https://doi.org/10.1029/2010GC003402
Weissel J K, Hayes D E. 1971. Asymmetric seafloor spreading south of Australia. Nature, 231(5304): 518–522, doi: https://doi.org/10.1038/231518a0
Zhou Zhiyuan, Lin Jian, Behn M, Olive J A. 2015. Mechanism for normal faulting in the subducting plate at the Mariana Trench. Geophysical Research Letters, 42(11): 4309–4317, doi: https://doi.org/10.1002/2015GL063917
Zhou Zhiyuan, Lin Jian. 2018. Elasto-plastic deformation and plate weakening due to normal faulting in the subducting plate along the Mariana Trench. Tectonophysics, 734-735: 59–68, doi: https://doi.org/10.1016/j.tecto.2018.04.008
Zhou Zhiyuan, Lin Jian, Zhang Fan. 2018. Modeling of normal faulting in the subducting plates of the Tonga, Japan, Izu-Bonin and Mariana Trenches: implications for near-trench plate weakening. Acta Oceanologica Sinica, 37(11): 53–60, doi: https://doi.org/10.1007/s13131-0181146-z
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation item: The National Key R&D Program of China under contract Nos 2018YFC0310105 and 2018YFC0309800; the China Ocean Mineral Resources R&D Association under contract No. DY135-S2-1-04; the National Natural Science Foundation of China under contract Nos 41890813, 91628301, 41976066, 41706056, 41976064, 91858207 and U1606401; the Chinese Academy of Sciences under contract Nos Y4SL021001, QYZDY-SSW-DQC005 and 133244KYSB20180029; the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract No. GML2019ZD0205.
Rights and permissions
About this article
Cite this article
Liu, S., Lin, J., Zhou, Z. et al. Large along-axis variations in magma supply and tectonism of the Southeast Indian Ridge near the Australian-Antarctic Discordance. Acta Oceanol. Sin. 39, 118–129 (2020). https://doi.org/10.1007/s13131-019-1518-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13131-019-1518-z