Continental breakup and the onset of ultra-slow seafloor spreading off Flemish Cap on the Newfoundland Rifted Margin


Hopper, J.R., Funck, T., Tucholke, B.E., Larsen, H.C., Holbrook, W.S., Louden, K.E., Shillington, D. and Lau, H. (2004) Continental breakup and the onset of ultra-slow seafloor spreading off Flemish Cap on the Newfoundland Rifted Margin. Geology, 32, 93-96. (doi:10.1130/G19694.1).

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Description/Abstract

Prestack depth-migrated seismic reflection data collected off Flemish Cap on the Newfoundland margin show a structure of abruptly thinning continental crust that leads into an oceanic accretion system. Within continental crust, there is no clear evidence for detachment surfaces analogous to the S reflection off the conjugate Galicia Bank margin, demonstrating a first-order asymmetry in final rift development. Anomalously thin (3–4 km), magmatically produced oceanic crust abuts very thin continental crust and is highly tectonized. This indicates that initial accretion of the oceanic crust was in a magma-limited setting similar to present-day ultraslow spreading environments. Seaward, oceanic crust thins to <1.3 km and exhibits an unusual, highly reflective layering. We propose that a period of magma starvation led to exhumation of mantle in an oceanic core complex that was subsequently buried by deep-marine sheet flows to form this layering. Subsequent seafloor spreading formed normal, 6-km-thick oceanic crust. This interpretation implies large fluctuations in the available melt supply during the early stages of seafloor spreading before a more typical slow-spreading system was established.

Item Type: Article
ISSNs: 0091-7613 (print)
Keywords: continental margin, seafloor spreading, extension tectonics, continental breakup
Subjects: Q Science > QE Geology
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
ePrint ID: 43707
Date Deposited: 29 Jan 2007
Last Modified: 27 Mar 2014 18:28
Contact Email Address: hopper@geo.tamu.edu
URI: http://eprints.soton.ac.uk/id/eprint/43707

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