Image of the Moho across the continent-ocean transition, U.S. east coast

• Published in: Geology (Boulder) 1992-03, Vol.20 (3), p.203-206
• Main Authors: Holbrook, W. Steven, Reiter, Edmund C, Purdy, G. M, Toksoz, M. Nafi
• Format: Article
• Language: English
• Subjects: applied (geophysical surveys & methods); Atlantic Ocean; Carolina Trough; continental margin; crust; Eastern U.S; Geology; geophysical methods; geophysical surveys; Geophysics; imagery; intrusions; Jurassic; Mesozoic; Mohorovicic discontinuity; multichannel methods; North American Atlantic; ocean bottom seismographs; oceanography; Pangaea; Plate tectonics; rifting; seismic methods; seismographs; seismology; solid Earth (tectonophysics); surveys; thickness; transition zones; troughs; United States
• ISSN: 0091-7613; 1943-2682
• DOI: 10.1130/0091-7613(1992)020<0203:IOTMAT>2.3.CO;2

Strong wide-angle reflections from the Moho were recorded by ocean-bottom seismic instruments during the 1988 Carolina Trough multichannel seismic experiment, in an area where the Moho is difficult to detect with vertical-incidence seismic data. Prestack depth migration of these reflections has enabled the construction of a seismic image of the Moho across the continent-ocean transition of a sedimented passive margin. The Moho rises across the margin at a slope of 10°-12°, from a depth of about 33 km beneath the continental shelf to 20 km beneath the outer rise. This zone of crustal thinning defines a distinct, 60-70-km-wide continent-ocean transition zone. We interpret the Moho in the Carolina Trough as a Jurassic feature, formed by magmatic intrusion and underplating during the rifting of Pangea.