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Central role of detachment faults in accretion of slow-spreading oceanic lithosphere

Abstract

The formation of oceanic detachment faults is well established from inactive, corrugated fault planes exposed on sea floor formed along ridges spreading at less than 80 km Myr–1 (refs 1–4). These faults can accommodate extension for up to 1–3 Myr (ref. 5), and are associated with one of the two contrasting modes of accretion operating along the northern Mid-Atlantic Ridge. The first mode is asymmetrical accretion involving an active detachment fault6 along one ridge flank. The second mode is the well-known symmetrical accretion, dominated by magmatic processes with subsidiary high-angle faulting and the formation of abyssal hills on both flanks. Here we present an examination of 2,500 km of the Mid-Atlantic Ridge between 12.5 and 35° N, which reveals asymmetrical accretion along almost half of the ridge. Hydrothermal activity identified so far in the study region is closely associated with asymmetrical accretion, which also shows high levels of near-continuous hydroacoustically and teleseismically recorded seismicity. Increased seismicity is probably generated along detachment faults that accommodate a sizeable proportion of the total plate separation. In contrast, symmetrical segments have lower levels of seismicity, which occurs primarily at segment ends. Basalts erupted along asymmetrical segments have compositions that are consistent with crystallization at higher pressures than basalts from symmetrical segments, and with lower extents of partial melting of the mantle. Both seismic evidence and geochemical evidence indicate that the axial lithosphere is thicker and colder at asymmetrical sections of the ridge, either because associated hydrothermal circulation efficiently penetrates to greater depths or because the rising mantle is cooler. We suggest that much of the variability in sea-floor morphology, seismicity and basalt chemistry found along slow-spreading ridges can be thus attributed to the frequent involvement of detachment faults in oceanic lithospheric accretion.

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Figure 1: Bathymetry of the study area and examples of symmetrical and asymmetrical segments with associated seismicity.
Figure 2: Along-axis distribution of asymmetrical and symmetrical ridge sections and correlation with hydrothermal and seismic activity.
Figure 3: Systematic differences in basalt chemistry from symmetrical and asymmetrical ridge sections.
Figure 4: Across-axis sections corresponding to symmetrical and asymmetrical accretion and associated processes.

References

  1. Tucholke, B. E. et al. Role of melt supply in oceanic detachment faulting and formation of megamullions. Geology 36, 455–458 (2008)

    ADS  Article  Google Scholar 

  2. Cann, J. R. et al. Corrugated slip surfaces formed at North Atlantic ridge-transform intersections. Nature 385, 329–332 (1997)

    ADS  Article  Google Scholar 

  3. Cannat, M. et al. Modes of seafloor generation at a melt-poor ultraslow-spreading ridge. Geology 34, 605–608 (2006)

    ADS  Article  Google Scholar 

  4. Okino, K. et al. Development of oceanic detachment and asymmetric spreading at the Australian-Antarctic Discordance. Geochem. Geophys. Geosyst. 5 10.1029/2004GC000793 (2004)

    Article  Google Scholar 

  5. Tucholke, B. E., Lin, J. & Kleinrock, M. C. Megamullions and mullion structure defining oceanic metamorphic core complexes on the Mid-Atlantic Ridge. J. Geophys. Res. 103 (B5). 9857–9866 (1998)

    ADS  Article  Google Scholar 

  6. Smith, D. K., Cann, J. R. & Escartín, J. Widespread active detachment faulting and core complex formation near 13° N on the Mid-Atlantic Ridge. Nature 443, 440–444 (2006)

    ADS  Article  Google Scholar 

  7. Smith, D. K. et al. Fault rotation and core complex formation: Significant processes in seafloor formation at slow spreading mid-ocean ridges (Mid-Atlantic Ridge, 13–15° N). Geochem. Geophys. Geosyst. 9 10.1029/2007GC001699 (2008)

    Article  Google Scholar 

  8. Buck, W. R., Lavier, L. L. & Poliakov, A. N. B. Modes of faulting at mid-ocean ridges. Nature 434, 719–723 (2005)

    ADS  CAS  Article  Google Scholar 

  9. Fujiwara, T. et al. Crustal evolution of the Mid-Atlantic Ridge near the Fifteen-Twenty Fracture Zone in the last 5 Ma. Geochem. Geophys. Geosyst. 4 10.1029/2002GC000364 (2003)

  10. Canales, J. P. et al. Seismic structure across the rift valley of the Mid-Atlantic ridge at 23° 20' N (MARK area): Implications for crustal accretion processes at slow-spreading ridges. J. Geophys. Res. 105 (B12). 28411–28425 (2000)

    ADS  Article  Google Scholar 

  11. Smith, D. K. et al. Hydroacoustic monitoring of seismicity at the slow-spreading Mid-Atlantic Ridge. Geophys. Res. Lett. 29 10.1029/2001GL013912 (2002)

  12. Bohnenstiehl, D. et al. Aftershock sequences in the mid-ocean ridge environment: an analysis using hydroacoustic data. Tectonophysics 354, 49–70 (2002)

    ADS  Article  Google Scholar 

  13. deMartin, B. J. et al. Kinematics and geometry of active detachment faulting beneath the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge. Geology 35, 711–714 (2007)

    ADS  Article  Google Scholar 

  14. Smith, D. K. et al. Spatial and temporal distribution of seismicity along the northern Mid-Atlantic Ridge (15°–35° N). J. Geophys. Res. 108 (B3). 10.1029/2002JB001964 (2003)

  15. Kong, L. S., Solomon, S. C. & Purdy, G. M. Microearthquake characteristics of a mid-ocean ridge along-axis high. J. Geophys. Res. 97, 1659–1685 (1992)

    ADS  Article  Google Scholar 

  16. Toomey, D. R. et al. Microearthquakes beneath the median valley of the Mid-Atlantic ridge near 23° N: hypocenters and focal mechanisms. J. Geophys. Res. 90, 5443–5458 (1985)

    ADS  Article  Google Scholar 

  17. Barclay, A. H., Toomey, D. R. & Solomon, S. C. Microearthquake characteristics and crustal Vp/Vs structure at the Mid-Atlantic Ridge, 35° N. J. Geophys. Res. 106 (B2). 2017–2034 (2001)

    ADS  Article  Google Scholar 

  18. Wolfe, C. et al. Microearthquake characteristics and crustal velocity structure at 29° N of the Mid-Atlantic Ridge: The architecture of a slow-spreading segment. J. Geophys. Res. 100 (B12). 24449–24472 (1995)

    ADS  Article  Google Scholar 

  19. Klinkhammer, G. et al. Hydrothermal manganese plumes in the Mid-Atlantic Ridge rift valley. Nature 314, 727–731 (1985)

    ADS  CAS  Article  Google Scholar 

  20. McCaig, A. et al. Oceanic deachment faults focus very large volumes of black smoker fluids. Geology 35, 935–938 (2007)

    ADS  CAS  Article  Google Scholar 

  21. Boschi, C. et al. Mass transfer and fluid flow during detachment faulting and development of an oceanic core complex, Atlantic Massif (MAR 30° N). Geochem. Geophys. Geosyst. 7 10.1029/2005GC001074 (2006)

    Article  Google Scholar 

  22. Bougault, H. et al. Mantle heterogeneity from trace elements: MAR triple junction near 14° N. Earth Planet. Sci. Lett. 88, 27–36 (1988)

    ADS  CAS  Article  Google Scholar 

  23. Klein, E. & Langmuir, C. H. Local versus global variations in ocean ridge basalt composition: a reply. J. Geophys. Res. 94 (B4). 4241–4252 (1989)

    ADS  CAS  Article  Google Scholar 

  24. Lissenberg, C. J. & Dick, H. J. B. Melt–rock reaction in the lower oceanic crust and its implications for the genesis of mid-ocean ridge basalt. Earth Planet. Sci. Lett. 271, 311–325 (2008)

    ADS  CAS  Article  Google Scholar 

  25. Escartín, J. et al. Quantifying tectonic strain and magmatic accretion at a slow spreading ridge segment, Mid-Atlantic Ridge, 29° N. J. Geophys. Res. 104 (B5). 10421–10437 (1999)

    ADS  Article  Google Scholar 

  26. Macdonald, K. C. & Luyendyk, B. P. Deep-Tow studies of the structure of the Mid-Atlantic Ridge crest near lat 37° N. Geol. Soc. Am. Bull. 88, 621–636 (1977)

    ADS  Article  Google Scholar 

  27. McAllister, E. & Cann, J. R. in Tectonic, Magmatic, Hydrothermal and Biological Segmentation of Mid-Ocean Ridges Vol. 118 (eds MacLeod, C. J., Tyler, P. A. & Walker, C. L.). 29–48 (1996)

    Google Scholar 

  28. Carbotte, S. M. et al. New integrated data management system for Ridge2000 and MARGINS research. EOS Trans. Am. Geophys. Un. 85, 553–559 (2004)

    ADS  Article  Google Scholar 

  29. Müller, R. D. et al. Digital isochrons of the world's ocean floor. J. Geophys. Res. 102 (B2). 3211–3214 (1997)

    ADS  Article  Google Scholar 

  30. Lehnert, K. et al. A global geochemical database structure for rocks. Geochem. Geophys. Geosyst. 1, 1999GC000026 (2000)

    Article  Google Scholar 

  31. Su, Y. J. Mid-Ocean Ridge Basalt Trace Element Systematics: Constraints from Database Management, ICPMS Analyses, Data Compilation and Petrological Modeling (Univ. Columbia, 2002)

    Google Scholar 

  32. Davydov, M. P. et al. Ferromanganese deposits in the Ashadze-1 hydrothermal field (Mid-Atlantic Ridge, 12° 58′ N). Dokl. Earth Sci. 415A, 954–960 (2007)

    ADS  CAS  Article  Google Scholar 

  33. Beltenev, V. et al. New hydrothermal sites at 13° N, Mid Atlantic Ridge. InterRidge News 14, 14–16 (2005)

    Google Scholar 

  34. Beltenev, V. et al. A new hydrothermal field at 13° 30′ N on the Mid-Atlantic Ridge. InterRidge News 16, 10–11 (2007)

    Google Scholar 

  35. Batuyev, B. N. et al. Massive sulphide deposits discovered and sampled at 14° 45′ N, Mid-Atlantic Ridge. Bridge Newslett. 6, 6–10 (1994)

    Google Scholar 

  36. Beltenev, V. et al. A new hydrothermal field at 16° 38.4′ N, 46° 28.5′ W on the Mid-Atlantic Ridge. InterRidge News 13, 5–6 (2004)

    Google Scholar 

  37. Ocean Drilling Program Leg 106 Scientific Party Drilling the Snake Pit hydrothermal sulfite deposit on the Mid-Atlantic ridge, lat 23° 22′ N. Geology 14, 1004–1007 (1986)

  38. Rona, P. A. et al. Black smokers, massive sulphides and vent biota at the Mid-Atlantic Ridge. Nature 321, 33–37 (1986)

    ADS  CAS  Article  Google Scholar 

  39. James, R. H., Elderfield, H. & Palmer, M. R. The chemistry of hydrothermal fluids from the Broken Spur site, 29° N Mid-Atlantic Ridge. Geochim. Cosmochim. Acta 59, 651–659 (1995)

    ADS  CAS  Article  Google Scholar 

  40. Kelley, D. S. et al. An off-axis hydrothermal vent field near the Mid-Atlantic Ridge at 30° N. Nature 411, 145–149 (2001)

    ADS  Article  Google Scholar 

  41. Cann, J. & Smith, D. K. Evolution of volcanism and faulting in a segment of the Mid-Atlantic Ridge at 25° N. Geochem. Geophys. Geosyst. 6, Q09008 (2005)

    ADS  Article  Google Scholar 

  42. Langmuir, C. H. et al. in Back-arc Spreading Systems: Geological, Biological, Chemical and Physical Interactions (eds Christie, D. M. et al.) 87 (AGU Geophys. Monogr. Series, 2006)

    Book  Google Scholar 

Download references

Acknowledgements

This work was carried out during a during a 16-month visit to Harvard University and MIT by J.E., and was supported by CNRS (J.E.), NSF (D.K.S., H.S., C.L. and S.E.), WHOI (J.E., D.K.S., H.S. and J.C.), Harvard University (J.E., C.L. and S.E.), University of Leeds (J.C.) and MIT (J.E.). We thank M. Cannat and J. P. Canales for discussions, and W. R. Buck and B. Ildefonse for reviews. This is IPGP contribution 2404.

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Correspondence to J. Escartín.

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Author Contributions All authors contributed to the interpretation and analysis of the data. J.E. led the data analysis and writing of the manuscript, with contributions from all the co-authors.

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Escartín, J., Smith, D., Cann, J. et al. Central role of detachment faults in accretion of slow-spreading oceanic lithosphere. Nature 455, 790–794 (2008). https://doi.org/10.1038/nature07333

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