Stratigraphic And Structural Framework Of The FOZ D0 Amazonas Basin

Castro, Joel Carneiro de; Miura, Kazumi; Braga, Jose A.E.

doi:10.4043/3265-ms

Cited by 20 publications

(17 citation statements)

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“…3), forming valleys in the continental shelf. In the continental slope, a large submarine canyon directed sediments to abyssal regions of the Foz do Amazonas Basin (Castro et al 1978). This is made clear by the presence of coarser clastics in the Foz do Amazonas Basin in the continuation of the Mexiana Sub-basin.…”

Section: Amazonia Structural Arches Genesis and Paleogeography Gurupámentioning

confidence: 88%

“…Castro et al (1978 andShephard et al (2010) suggested it to have taken place in the Middle Miocene time; Hoorn et al (1995) and Figueiredo et al (2009) in the Late Miocene; Espurt et al (2007) and Roddaz et al (2005) not before the Pliocene; Latrubesse et al (2010), Campbell et al (2006) and Campbell (2010) in the Late Pliocene; and Almeida (1974) in the PlioceneEarly Pleistocene. Bezerra (2003), Rossetti et al (2005) and Bezerra and Ribeiro (2015) inferred the Amazon River to have flowed through the Tacutu Rift, the Essequibo River and the coast of Guyana Republic to the Atlantic Ocean in the Plio-Pleistocene and at the end of the Pleistocene and in the Holocene, being guided to its present valley site, by following neotectonic faults.…”

Section: Purus Arch and Amazon Basinmentioning

confidence: 99%

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Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

Caputo

Soares

2016

Braz. J. Geol.

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The development of the transcontinental Amazon River System involved geological events in the Andes Chain; Vaupés, Purus and Gurupá arches; sedimentary basins of the region and sea level changes. The origin and age of this river have been discussed for decades, and many ideas have been proposed, including those pertaining to it having originated in the Holocene, Pleistocene, Pliocene, Late Miocene, or even earlier times. Under this context, the geology of the sedimentary basins of northern Brazil has been analyzed from the Mesozoic time on, and some clarifications are placed on its stratigraphy. Vaupés Arch, in Colombia, was uplifted together with the Andean Mountains in the Middle Miocene time. In the Cenozoic Era, the Purus Arch has not blocked this drainage system westward to marine basins of Western South America or eastward to the Atlantic Ocean. Also the Gurupá Arch remained high up to the end of Middle Miocene, directing this drainage system westward. With the late subsidence and breaching of the Gurupá Arch and a major fall in sea level, at the beginning of the Late Miocene, the Amazon River quickly opened its pathway to the west, from the Marajó Basin, through deep headward erosion, capturing a vast drainage network from cratonic and Andean areas, which had previously been diverted towards the Caribbean Sea. During this time, the large siliciclastic influx to the Amazon Mouth (Foz do Amazonas) Basin and its fan increased, due to erosion of large tracts of South America, linking the Amazon drainage network to that of the Marajó Basin. This extensive exposure originated the Late Miocene (Tortonian) unconformity, which marks the onset of the transcontinental Amazon River flowing into the Atlantic Ocean.

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Section: Amazonia Structural Arches Genesis and Paleogeography Gurupámentioning

confidence: 88%

Section: Purus Arch and Amazon Basinmentioning

confidence: 99%

Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

Caputo

Soares

2016

Braz. J. Geol.

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“…Amazon River has been the major source of terrigenous sediments to the Equatorial Atlantic since Andean uplift in early Miocene (Castro et al, 1978). During the present sea-level high, sediments discharged by Amazon River are of mixed size grades (silt and clay dominate; Gibbs, 1967) and deposit on the shelf in a large subaqueous delta (Kuehl et aI., 1982;Nittrouer et aI., 1983Nittrouer et aI., , 1986.…”

Section: Introductionmentioning

confidence: 99%

Seismic Facies and Late Quaternary Growth of Amazon Submarine Fan

Flood¹,

Manley²,

Kowsmann³

et al. 1991

Frontiers in Sedimentary Geology

104

138

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The Amazon Fan contains sedimentary/acoustic sequences characteristic of many large and small modem mud-rich fans. Analyses of high-resolution single-channel seismic-reflection profiles and 3.5-kHz profiles suggest that fan growth is in part related to sea-level fluctuations and in part related to events such as channel bifurcations and large debris flows that appear unrelated to sea-level position. Sinuous fan channels are perched on top of lens-shaped overbank deposits to form channel-levee systems in the upper and middle fan. Individual channel-levee systems overlap and coalesce to build levee complexes that also stack and overlap, but that are bounded by large debris-flow deposits. Because both channel-levee systems and debris flows can be active at the same time, this depositional pattern does not necessarily develop as a result of sea-level change. The sinuous fan channels appear to be nearly at grade because channel sinuosity varies downfan to keep the along-channel gradient uniformly decreasing downfan. Flat-lying, high-amplitude reflection packets that underlie a channel-levee system and extend downfan to form part of the lower fan may develop when new, oversteepened channels are created as a result of avulsion on the middle fan. This suggests that portions of the lower fan are formed concurrently with channellevee systems. Piston cores from near the most recently active channel suggest that the locus of sedimentation shifted landward as sea level rose at the end of the last glaciation.

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“…The Amazon Fan has developed since the early Miocene, due to the massive increase in the sediment transport of the Amazon River following the Andean uplift (Castro et aL 1978;Curry et al 1995). At present, and during other interglacial periods, Amazon River terrigenous sediments are deposited predominantly on the inner continental shelf .…”

mentioning

confidence: 98%

Timing of the late Quaternary Amazon Fan Complex masstransport deposits

Maslin

Mikkelsen

1998

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The Amazon Fan at the mouth of the Amazon River is a large, highly structured muddy deep-sea fan. Sediment recovered by Ocean Drilling Program Leg 155 has allowed us to reconstruct the structure of the late Quaternary Amazon Fan Complex. A significant sedimentary component of the complex are the mass-transport deposits (MTDs) formed by catastrophic failure of the continental slope. There are two sets of MTDs: the near-surface MTDs and the deep MTDs. The near-surface MTDs are divided into the Eastern and Western Debris Flows which are capped by Holocene sediments. The deep debris flows are divided into the Unit R MTD in the western Amazon Fan complex, and the Deep Eastern MTD in the eastern Amazon Fan Complex. The MTDs each cover an area of up to 25 000 km 2, reach a maximum thickness of 200 m, and consist of approximately 50 000 gigatonnes of sediment. A characteristic of the MTDs is the inclusion of reworked glacial and interglacial material from both the continental slope and the surrounding fan. The relatively thin interglacial deposits below the MTDs are from the nanofossil zones CN14b and CN15a and thus younger than 460 ka. Bio-, seismic-and magnetostratigraphy and sedimentation rate constraints have been used to date the top of both the near-surface and the deep MTDs. It seems that the near-surface Western and Eastern Debris Flows were last active during Termination I. The Deep Eastern MTD was last active at about 33 ka, while the Unit R MTD was last active at about 45 ka. It is inferred that the interglacial deposits beneath these MTDs were formed during Oxygen Isotope Stages 7, 9 and 11. We speculate that the MTDs were triggered by climatically induced changes in sea level, and that the interglacial deposits may have acted as slip planes for the MTDs.

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Stratigraphic And Structural Framework Of The FOZ D0 Amazonas Basin

Cited by 20 publications

References 0 publications

Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

Seismic Facies and Late Quaternary Growth of Amazon Submarine Fan

Timing of the late Quaternary Amazon Fan Complex masstransport deposits

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