Browsing by Author "Lang, Zhongmin"

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    Geophysical study of deep-crustal structure: Mid-Atlantic passive continental margin
    (1997) Lang, Zhongmin; Talwani, Manik
    Migration results of two multi-channel vertical incidence reflection seismic dataset offshore Virginia are presented. A new velocity model derived from multi-channel and wide-angle reflection/refraction data is developed and fit into regional geology context. The validity and limitation of the new model is discussed by means of ray-tracing travel time forward modeling and 2-D acoustic wave-equation modeling methods. Our new results show that there is a sharp boundary separating normal continental crust from crust produced by the sea-floor spreading process in this region and that the Moho appears to be continuous across the boundary. The zone of so-called "magmatic underplating" proposed previously (Sheridan et al., 1993) may well be magmas produced during the initial stage of sea-floor spreading. There may be some fragments of continental crust entrained in the region immediately seaward of the boundary, but there is no evidence of the existence of large volume of continental crust and we believe the crust in this area is also primarily product of the Mesozoic sea-floor spreading. (Abstract shortened by UMI.)