Details
| Original language | English |
|---|---|
| Pages (from-to) | B02101 1-19 |
| Journal | Journal of Geophysical Research: Solid Earth |
| Volume | 109 |
| Issue number | 2 |
| Publication status | Published - 10 Feb 2004 |
| Externally published | Yes |
Abstract
The 1.5-km-high, obliquely subducting Nazca Ridge and its collision zone with the Peruvian margin have been imaged by wide-angle and reflection seismic profiles, swath bathymetry; and gravity surveying. These data reveal that the crust of the ridge at its northeastern tip is 17 km thick and exhibits seismic velocities and densities similar to layers 2 and 3 of typical oceanic crust. The lowermost layer contributes 10-12 km to the total crustal thickness of the ridge. The sedimentary cover is 300-400 m thick on most parts of the ridge but less than 100 m thick on seamounts and small volcanic ridges. At the collision zone of ridge and margin, the following observations indicate intense tectonic erosion related to the passage of the ridge. The thin sediment layer on the ridge is completely subducted. The lower continental slope is steep, dipping at ~9°, and the continental wedge has a high taper of 18°. Tentative correlation of model layers with stratigraphy derived from Ocean Drilling Program Leg 112 cores suggests the presence of Eocene shelf deposits near the trench. Continental basement is located <15 km landward of the trench. Normal faults on the upper slope and shelf indicate extension. A comparison with the Peruvian and northern Chilean forearc systems, currently not affected by ridge subduction, suggests that the passage of the Nazca Ridge along the continental margin induces a temporarily limited phase of enhanced tectonic erosion superposed on a long-term erosive regime.
Keywords
- Active Peruvian margin, Forearc structure, Reflection seismics, Ridge subduction, Tectonic erosion, Wide-angle seismics
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
- Earth and Planetary Sciences(all)
- Earth and Planetary Sciences (miscellaneous)
- Earth and Planetary Sciences(all)
- Space and Planetary Science
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In: Journal of Geophysical Research: Solid Earth, Vol. 109, No. 2, 10.02.2004, p. B02101 1-19.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Ridge subduction at an erosive margin
T2 - The collision zone of the Nazca Ridge in southern Peru
AU - Hampel, Andrea
AU - Kukowski, Nina
AU - Bialas, Joerg
AU - Huebscher, Christian
AU - Heinbockel, Raffaela
PY - 2004/2/10
Y1 - 2004/2/10
N2 - The 1.5-km-high, obliquely subducting Nazca Ridge and its collision zone with the Peruvian margin have been imaged by wide-angle and reflection seismic profiles, swath bathymetry; and gravity surveying. These data reveal that the crust of the ridge at its northeastern tip is 17 km thick and exhibits seismic velocities and densities similar to layers 2 and 3 of typical oceanic crust. The lowermost layer contributes 10-12 km to the total crustal thickness of the ridge. The sedimentary cover is 300-400 m thick on most parts of the ridge but less than 100 m thick on seamounts and small volcanic ridges. At the collision zone of ridge and margin, the following observations indicate intense tectonic erosion related to the passage of the ridge. The thin sediment layer on the ridge is completely subducted. The lower continental slope is steep, dipping at ~9°, and the continental wedge has a high taper of 18°. Tentative correlation of model layers with stratigraphy derived from Ocean Drilling Program Leg 112 cores suggests the presence of Eocene shelf deposits near the trench. Continental basement is located <15 km landward of the trench. Normal faults on the upper slope and shelf indicate extension. A comparison with the Peruvian and northern Chilean forearc systems, currently not affected by ridge subduction, suggests that the passage of the Nazca Ridge along the continental margin induces a temporarily limited phase of enhanced tectonic erosion superposed on a long-term erosive regime.
AB - The 1.5-km-high, obliquely subducting Nazca Ridge and its collision zone with the Peruvian margin have been imaged by wide-angle and reflection seismic profiles, swath bathymetry; and gravity surveying. These data reveal that the crust of the ridge at its northeastern tip is 17 km thick and exhibits seismic velocities and densities similar to layers 2 and 3 of typical oceanic crust. The lowermost layer contributes 10-12 km to the total crustal thickness of the ridge. The sedimentary cover is 300-400 m thick on most parts of the ridge but less than 100 m thick on seamounts and small volcanic ridges. At the collision zone of ridge and margin, the following observations indicate intense tectonic erosion related to the passage of the ridge. The thin sediment layer on the ridge is completely subducted. The lower continental slope is steep, dipping at ~9°, and the continental wedge has a high taper of 18°. Tentative correlation of model layers with stratigraphy derived from Ocean Drilling Program Leg 112 cores suggests the presence of Eocene shelf deposits near the trench. Continental basement is located <15 km landward of the trench. Normal faults on the upper slope and shelf indicate extension. A comparison with the Peruvian and northern Chilean forearc systems, currently not affected by ridge subduction, suggests that the passage of the Nazca Ridge along the continental margin induces a temporarily limited phase of enhanced tectonic erosion superposed on a long-term erosive regime.
KW - Active Peruvian margin
KW - Forearc structure
KW - Reflection seismics
KW - Ridge subduction
KW - Tectonic erosion
KW - Wide-angle seismics
UR - http://www.scopus.com/inward/record.url?scp=2542477165&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:2542477165
VL - 109
SP - B02101 1-19
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
SN - 2169-9313
IS - 2
ER -