...John E. Damuth; Robert W. Emebley ABSTRACT Three large mass-transport deposits occur on the upper to middle Amazon Cone. These slump/debris-flow complexes have been mapped from 3.5-kHz echograms and cover approximately 75,000 sq km or about 10% of the cone. The debris flows traveled down slopes...

...JOHN E. DAMUTH; NARESH KUMAR Abstract The morphology, sediment distribution, and growth pattern of the Amazon cone are similar to those of other deep-sea fans; its sediment, at least during the late Quaternary Period, was deposited in response to glacial-interglacial cycles, and its age...

...Naresh Kumar Abstract A sediment-isopach map of the western equatorial Atlantic off northern Brazil reveals major structural trends and significant sediment accumulations. The main features of the region beyond the continental slope are: the Amazon Cone, the aseismic Ceará Rise, the Demerara...

...FIG. 9 —Seismic reflection profiles across Amazon cone (47), and on shelf (46), taken during Chain 115, using paired 40-in. air guns. Deep strata on middle shelf may represent top of lower Miocene Amapá limestone (profile 46); reefal feature, R, is on right and possible channels, C , suggest...

...J. E. Damuth; V. Kolla; R. D. Flood; R. O. Kowsmann; M. A. Gorini; J. J. C. Palma; R. H. Belderson The Amazon Cone is a large deep-sea fan off northeast Brazil. Previous studies utilizing 3.5-kHz echograms, seismic profiles, and piston cores show that the modern fan is characterized by a complex...

... an oceanic structure, probably formed by local tectonic activity. Sediments of the upper Amazon Cone are more than 11 km thick, but they thin both landward and seaward. Owing to the great sedimentary thickness, refraction arrival times from oceanic basement could not be identified, but basement is assumed...

.... The Ceará Rise has continuously subsided since its formation and has been covered by calcareous and siliceous pelagic sediments. However, a large influx of terrigenous sediments from the Brazilian margin, which coincided with the growth of the Amazon Cone since early Miocene time, has buried the western...

... for each region can now be used to compute thickness from vertical reflection data. The velocity characteristics of the Pelotas Basin and Pelotas Rise are similar to those of the Amazon Cone and some other large deltaic deposits, which suggests that the discharge of the Rio de la Plata may have formerly...

... by bottom photographs. Similar deposits are observed on the Amazon cone and the North American continental rise and in the Gulf of Mexico and the Mediterranean Sea. Debris flows are probably a much more important depositional process on the sea floor than was previously suspected. Geological Society...

... evidence together suggest that large fracture zones serve as the site of intrusion of ultrabasic rocks from depth. The deformation of the lithosphere due to the sediment load of the Amazon cone and the resulting gravity anomalies were computed for various flexural rigidities, using two-dimensional elastic...

...Dennis E. Hayes; Maurice Ewing ABSTRACT A geologic and geophysical reconnaissance of the continental margin of the north coast of Brazil led to the discovery of a narrow basement ridge, herein called the North Brazilian Ridge. The ridge closely parallels the coast of Brazil between the Amazon cone...

... is available today on some of the important cones from different parts of the world, some of which have been studied in great detail, e.g. Amazon cone (Damuth and Komar, 1975), Astoria fan (Nelson, 1976), Mississipi (Huang and Goodell, 1970),Nile cone (Maldonado and Stanley, 1976). The GangesBrahmaputra cone...

... published by Hollister for the western North Atlantic. Cores from the Amazon cone have been excluded from these measurements because (1) the cone is a large deep-sea fan which apparently has been formed exclusively by turbidity-current deposition ( Damuth and Kumar, 1975 ), and (2) because the continental...