Abstract
Several mechanisms have been proposed to account for the rotation of the nearly north-south abyssal hill fabric formed on the East Pacific Rise north of the Easter Microplate to the nearly east-west trends in the northern microplate interior. Proposed mechanisms include rigid microplate rotation, transform fault – parallel shear, and bookshelf faulting during the transfer of lithosphere from the Nazca Plate to the microplate. We used a submersible magnetometer on a NAUTILE dive program to measure the magnetic vector rotation of a pillow basalt and dike spur near Pito Deep, the present location of the tip of the propagating rift system that created the microplate. Our results, although too limited to draw strong conclusions from, suggest clockwise rotations of the seafloor magnetic vectors inconsistent with the transform-parallel shear model, and larger than can be explained solely by rigid microplate rotation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Acton, G., Stein, S. and Engeln, J. F. 1988, Formation of curved seafloor fabric by changes in rift propagation velocity and spreading rate: Application to the 95.5°W Galapagos propagator, J. Geophys. Res., 93, 11845–11861.
Cogné, J. P., Francheteau, J., Courtillot, V. and Pito93 Scientific Team, 1995, Large rotation of the Easter microplate as evidenced by oriented paleomagnetic samples from the ocean floor, Earth and Planet. Sci. Lett., 136, 213–222.
Engeln, J. F. and Stein, S., 1984, Tectonics of the Easter plate, Earth Planet. Sci. Lett., 68, 259–270.
Engeln, J. F., Stein, S., Werner, J. and Gordon, R. G., 1988, Microplate and shear zone models for oceanic spreading center reorganizations, J. Geophys. Res., 93, 2839–2856.
Francheteau, J., Patriat, P., Segoufin, J., Armijo, R., Doucoure, M., Yelles-Chaouche, A., Zukin, J., Calmant, S., Naar, D. F. and Searle, R. C., 1988, Pito and Orongo Fracture Zones: the Northern and Southern boundaries of the Easter microplate (southeast Pacific), Earth Planet. Sci. Lett., 89, 363–374.
Hekinian, R., Francheteau, J., Armijo, R., Cogne, J. P., Constantin, M., Girardeau, J., Hey, R., Naar, D. F., Searle, R., 1986, Petrology of the Easter microplate region in the South Pacific, J. of Volcanology and Geothermal Research, 72, 259–289.
Hey, R. N., Naar, D. F., Kleinrock, M. C., Phipps Morgan, W. J., Morales, E. and Schilling, J. G., 1985, Microplate tectonics along a superfast seafloor spreading system near Easter Island, Nature, 317, 325–331.
Hey, R. N., Kleinrock, M. C., Miller, S. P., Atwater, T. M. and Searle, R. C., 1986, Sea Beam/Deep-Tow investigation of an active oceanic propagating rift system, J. Geophys. Res., 91, 3369–3393.
Hey, R. N., Sinton, J. M., Kleinrock, M. C., Yonover, R. N., Macdonald, K. C., Miller, S. P., Searle, R. C., Christie, D. M., Atwater, T. M., Sleep, N. H., Johnson, H. P. and Neal, C. A., 1992, ALVIN investigation of an active propagating rift system, Galapagos 95.5W, Mar. Geophys. Res., 14, 207–226.
Hey, R. N., Johnson, P. D., Martinez, F., Korenaga, J., Somers, M. L., Huggett, Q. J., LeBas, T. P., Rusby, R. I. and Naar, D. F., 1995, Plate boundary reorganization at a large-offset, rapidly propagating rift, Nature, 378, 167–170.
Kleinrock, M. C. and Hey, R. N., 1989, Migrating transform zone and lithospheric transfer at the Galapagos 95.5º W propagator, J. Geophys. Res., 94, 13859–13878.
Macdonald, K. C., Miller, S. P., Luyendyk, B. P., Atwater, T. M. and Shure, L., 1983, Investigation of a Vine Matthews magnetic lineation from a submersible: The source and character of marine magnetic anomalies, J. Geophys. Res., 8, 3403–3418.
Martinez, F., Naar, D. F., Reed(IV), T. B. and Hey, R. N., 1991, Three-dimensional SeaMARC II, gravity, and magnetics study of large-offset rift propagation at the Pito rift, Easter microplate, Marine Geophys. Res., 13, 255–285.
McElhinny, M. W. and McFadden, P. L., 1997, Paleosecular variation over the past 5 Myr based on a new generalized database, Geophys. J. Int., 131, 240–252.
McKenzie, D. P., 1986, The geometry of propagating rifts, Earth Planet. Sci. Lett., 77, 176–186.
McKenzie, D. P. and Jackson, J., 1983, The relationship between strain rates, crustal thickening, paleomagnetism, finite strain and fault movements within a deforming zone, Earth Planet. Sci. Lett., 65, 182–202.
McKenzie, D. P. and Jackson, J., 1986, A block model of distributed deformation by faulting, J. Geol. Soc. Lond., 143, 349–353.
Miller, S. P. and Hey, R. N. Three-dimensional magnetic modeling of a propagating rift, Galapagos 95 30´ W, J. Geophys. Res., 91, B3, 3395–3406.
Naar, D. F. and Hey, R. N., 1989, Recent Pacific-Easter-Nazca plate motions, in Evolution of Mid-Oceanic Ridges, Geophysical Monograph Series, AGU, 9-30.
Naar, D. F. and Hey, R. N., 1991, Tectonic evolution of the Easter microplate, J. Geophys. Res., 96, 7961–7993.
Naar, D. F., Martinez, F., Hey, R. N., Reed(IV), T. B. and Stein, S., 1991, Pito rift: How a large-offset rift propagates, Marine Geophys. Res., 13, 287–309.
Rusby, R. I., and Searle, R. C., 1995, A history of the Easter microplate, 5.25 Ma to present, J. Geophys. Res., 100, 12617–12640.
Schouten, H., Klitgord, K. D. and Gallo, D. G., 1993, Edge-driven microplate kinematics, J. Geophys. Res., 98, 6689–6701.
Searle, R. C. and Hey, R. N., 1983, GLORIA observations of the propagating rift at 95.5°W on the Cocos-Nazca spreading center, J. Geophys. Res., 88, 6433–6447.
Searle, R. C., Rusby, R. I., Engeln, J., Hey, R. N., Zukin, J., Hunter, P. M., LeBas, T. P., Hoffman, H. J. and Livermore, R., 1989, Comprehensive sonar imaging of the Easter microplate, Nature, 341, 701–705.
Talwani, M., 1965, Computation with the help of a digital computer of magnetic anomalies caused by bodies of arbitrary shape, Geophysics, 30, 797–817.
Tivey, M. A., 1996, Vertical magnetic structure of ocean crust determined from near-bottom magnetic field measurements, J. Geophys. Res., 101, 20275–20296.
Tivey, M. A. and Johnson, H. P., 1993, Variations in oceanic crustal structure and the implications for the fine-scale magnetic anomaly signal, Geophys. Res. Lett., 20, 1879–1882.
Tivey, M. A., Rona, P. A. and Schouten, H., 1993, Reduced crustal magnetization beneath the active sulfide mound, TAG hydrothermal field, Mid-Atlantic Ridge at 26ºN, Earth Planet. Sci. Lett., 115, 101–115.
Wessel, P., and Smith, W. H. F., 1991, Free software helps map and display data, Eos Trans. AGU, 72, 441, 445-446.
Wetzel, L. R., Weins, D. A. and Kleinrock, M. C., 1993, Evidence from earthquakes for bookshelf faulting at large non-transform ridge offsets, Nature, 362, 235–237.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hey, R., Martinez, F., Diniega, S. et al. Preliminary attempt to characterize the rotation of seafloor in the Pito Deep area of the Easter Microplate using a submersible magnetometer. Marine Geophysical Researches 23, 1–12 (2002). https://doi.org/10.1023/A:1021257915420
Issue Date:
DOI: https://doi.org/10.1023/A:1021257915420