Mantle involvement in lithospheric collision: Seismic evidence from the Trans-Hudson Orogen, western Canada

Z. Hajnal, B. Nemeth, R. M. Clowes, R. M. Ellis, G. D. Spence, M. J.A. Burianyk, I. Asudeh, D. J. White, D. A. Forsyth

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Abstract

Three seismic refraction/wide-angle reflection profiles were recorded over the Trans-Hudson Orogen. The profiles display high quality coherent seismic signals associated with the Moho and lithospheric mantle to depths in excess of 160 km. As outlined by wide-angle reflections, depth to Moho varies between 40-54 km with a number of well-defined structural reliefs. Immediately beneath the Moho, in the central part of the orogen, an anomalous high-velocity zone (∼8.45 km/s) with lateral dimensions of 100 km (north-south) by 130 km (east-west) and maximum thickness of 50 km was delineated by mantle refraction arrivals. This zone may represent a locally preserved remnant of older mantle from micro-continental collisions. Mantle discontinuities with some structural relief are interpreted at average depths of 75 and 158 km. Based on wide-angle reflections at offsets beyond 400 km, they bound a layered zone with variable velocities, probably representing imbricated sequences of peridotite and eclogite. We postulate that these unusual features of the upper mantle are the result of lithospheric convergence of bounding Archean cratons and closure of the intervening ocean basin.

Original languageEnglish
Article number97GL01958
Pages (from-to)2079-2082
Number of pages4
JournalGeophysical Research Letters
Volume24
Issue number16
DOIs
Publication statusPublished - Jan 1 1997

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ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Hajnal, Z., Nemeth, B., Clowes, R. M., Ellis, R. M., Spence, G. D., Burianyk, M. J. A., Asudeh, I., White, D. J., & Forsyth, D. A. (1997). Mantle involvement in lithospheric collision: Seismic evidence from the Trans-Hudson Orogen, western Canada. Geophysical Research Letters, 24(16), 2079-2082. [97GL01958]. https://doi.org/10.1029/97GL01958