Continental break-up and the onset of ultraslow seafloor spreading off Flemish Cap on the Newfoundland rifted margin
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Continental break-up and the onset of ultraslow seafloor spreading off Flemish Cap on the Newfoundland rifted margin. / Hopper, John R.; Funck, Thomas; Tucholke, Brian E.; Larsen, Hans Christian; Holbrook, W. Steven; Louden, Keith E.; Shillington, Donna; Lau, Helen.
I: Geology, Bind 32, Nr. 1, 01.2004, s. 93-96.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Continental break-up and the onset of ultraslow seafloor spreading off Flemish Cap on the Newfoundland rifted margin
AU - Hopper, John R.
AU - Funck, Thomas
AU - Tucholke, Brian E.
AU - Larsen, Hans Christian
AU - Holbrook, W. Steven
AU - Louden, Keith E.
AU - Shillington, Donna
AU - Lau, Helen
PY - 2004/1
Y1 - 2004/1
N2 - 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.
AB - 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.
KW - Continental breakup
KW - Continental margin
KW - Extension tectonics
KW - Seafloor spreading
UR - http://www.scopus.com/inward/record.url?scp=1142269818&partnerID=8YFLogxK
U2 - 10.1130/G19694.1
DO - 10.1130/G19694.1
M3 - Journal article
AN - SCOPUS:1142269818
VL - 32
SP - 93
EP - 96
JO - Geology
JF - Geology
SN - 0091-7613
IS - 1
ER -
ID: 355633864