147:(2 Ma). Although there is agreement that the ridge is being subducted, there is little agreement on the effect that this has had on either the subducting or over-riding plates. Some models argue that the buoyancy associated with the thickened crust of the ridge has caused the downgoing Nazca Plate to tear, leaving a relatively flat section carrying the ridge, flanked by two sections with steeper dip. The presence of a flat section is not supported by a more recent study of
52:
107:. Wide-angle seismic reflection and refraction data acquired over the central and eastern part of the ridge give crustal thicknesses of 13 km and 19 km respectively for crust that has estimated ages of about 11 Ma and 20 Ma. Layer 2 thicknesses are similar to the neighbouring normal oceanic crust with thickening taking place in layer 3.
94:
The
Carnegie Ridge is seen to extend eastwards over 1,000 km from the Galapagos islands to the Colombia-Ecuador trench and is interpreted to continue beneath northern Ecuador for about a further 700 km. The subducted extent is disputed, with some workers arguing that there is no evidence of
130:
moved so that most of the hotspot magmatism affected the Nazca Plate, forming the combined
Carnegie and Malpelo Ridges. At about 14.5 Ma the spreading center jumped south, such that most of the magmatism affected the Cocos Plate and caused the Malpelo Ridge to rift away from the Carnegie Ridge. This
131:
stage caused the narrowing of the
Carnegie Ridge now seen between 85° W and 87° W. At about 9.5 Ma rifting between the Malpelo and Carnegie Ridges ceased. The Galapagos Rise moved north again at about 5 Ma, leaving the hotspot entirely within the Nazca Plate, which is the current situation.
384:
Spikings, R.A.; Winkler W.; Seward D.; Handler R. (2001). "Along-strike variations in the thermal and tectonic response of the continental
Ecuadorian Andes to the collision with heterogeneous oceanic crust".
55:
Outline of aseismic ridges and plate boundaries off northwestern South
America, suggested continuation of Carnegie Ridge beneath Ecuador from Gutcher et al. 1999, other models suggest that this area is much
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The formation of the
Carnegie Ridge and other aseismic ridges in this part of the Pacific started at about 20 Ma when the Galapagos hotspot formed, following the break-up of the
467:
267:
299:
228:
139:
The onset of subduction of the
Carnegie Ridge beneath the South American Plate has been dated variously from about mid-
345:"The Cocos and Carnegie Aseismic Ridges: a Trace Element Record of Long-term Plume– Spreading Center Interaction"
472:
422:"Seismological evidence on the geometry of the Orogenic System in central-northern Ecuador (South America)"
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256:"Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction"
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Backbone of the
Americas: shallow subduction, plateau uplift, and ridge and terrane collision
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316:
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180:"Tectonic segmentation of the North Andean margin: impact of the Carnegie Ridge collision"
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16:
Aseismic ridge on the Nazca Plate that is being subducted beneath the South
American Plate
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a subducted ridge beneath
Ecuador extending more than about 60 km from the trench.
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406:
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Guillier, B.; Chatelain J.-L; Jaillard É.; Yepes H.; Poupinet G.; Fels J.-F. (2001).
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292:"Seismic structure of the Carnegie ridge and the nature of the Galápagos hotspot"
76:. The ridge is thought to be a result of the passage of the Nazca Plate over the
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Sallarès, V.; Charvis P.; Flueh E.R.; Bialas; SALIERI Scientific Party (2005).
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262:. Memoir. Vol. 204. Geological Society of America. pp. 217–228.
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154:, which found a constant dip of about 25°–35° down to 200 km.
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Gutscher, M.-A.; Malavieille J.; Lallemand S.; Collot J.-Y. (1999).
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Harpp, K.S.; Wanless V.; Otto R.H.; Hoernle K.; Werner R. (2004).
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National Geospatial-intelligence Agency (4 June 2010).
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254:Michaud, F.; Witt, C.; Royer, J.-Y. (2009).
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103:The Carnegie Ridge consists of thickened
123:and Nazca Plates. At about 19.5 Ma, the
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468:Underwater ridges of the Pacific Ocean
80:. It is named for the research vessel
7:
387:Earth and Planetary Science Letters
187:Earth and Planetary Science Letters
119:and the formation of the separate
14:
300:Geophysical Journal International
322:10.1111/j.1365-246X.2005.02592.x
86:, which discovered it in 1929.
1:
407:10.1016/S0012-821X(01)00225-4
207:10.1016/S0012-821X(99)00060-6
426:Geophysical Research Letters
64:is an aseismic ridge on the
229:"Undersea Features History"
489:
370:10.1093/petrology/egh064
399:2001E&PSL.186...57S
199:1999E&PSL.168..255G
57:
54:
447:10.1029/2001GL013257
349:Journal of Petrology
74:South American Plate
438:2001GeoRL..28.3749G
361:2005JPet...46..109H
313:2005GeoJI.161..763S
33: /
58:
432:(19): 3749–3752.
269:978-0-8137-1204-8
143:(15 Ma) to about
78:Galapagos hotspot
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231:. Archived from
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193:(3–4): 255–270.
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128:spreading center
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355:(1): 109–133.
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235:on 9 July 2013
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125:Galapagos Rise
117:Farallon Plate
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68:that is being
62:Carnegie Ridge
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105:oceanic crust
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393:(1): 57–73.
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326:. Retrieved
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233:the original
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210:. Retrieved
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72:beneath the
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37:1.0°S 83.0°W
18:
152:hypocenters
145:Pleistocene
66:Nazca Plate
42:-1.0; -83.0
40: /
462:Categories
158:References
149:earthquake
135:Subduction
328:25 August
275:25 August
239:25 August
212:24 August
99:Structure
70:subducted
83:Carnegie
434:Bibcode
395:Bibcode
357:Bibcode
309:Bibcode
195:Bibcode
141:Miocene
111:History
56:smaller
28:83°00′W
266:
90:Extent
25:1°00′S
295:(PDF)
183:(PDF)
121:Cocos
330:2010
277:2010
264:ISBN
241:2010
214:2010
60:The
442:doi
403:doi
391:186
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317:doi
305:161
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191:168
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