Channel-mouth lobe complex of the recent Amazon Fan: The missing piece

Jégou, Isabelle; Savoye, Bruno; Pirmez, Carlos; Droz, Laurence

doi:10.1016/j.margeo.2008.03.004

Cited by 98 publications

(88 citation statements)

References 51 publications

(92 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This evidence, combined with observations in other megafan environments, (e.g., Fontana et al, 2008;Assine and Silva, 2009; suggests that the processes of construction and subsequent abandonment of depositional lobes are the primary mechanisms of megafan construction. An analog can also be drawn with deep-sea fans, as some processes (e.g., avulsion and aggradation) and forms (e.g., levees, lobes, and crevasses) reported in the literature for submarine systems (Curray et al, 2002;Jegou et al, 2008) are very similar to what is observed in the Taquari. Observations at several scales reveal that there is a continuum interface between small gradational features (~20 km 2 ) forming lobate landforms (~1500 km 2 ), which in turn make up the depositional lobes (~3000 km 2 ).…”

Section: Enhanced Landforms and Underlying Processesmentioning

confidence: 79%

Remote sensing analysis of depositional landforms in alluvial settings: Method development and application to the Taquari megafan, Pantanal (Brazil)

2012

View full text Add to dashboard Cite

Section: Enhanced Landforms and Underlying Processesmentioning

confidence: 79%

Remote sensing analysis of depositional landforms in alluvial settings: Method development and application to the Taquari megafan, Pantanal (Brazil)

2012

View full text Add to dashboard Cite

“…Sediment gravity flows, predominantly turbidity currents, sculpt the seafloor by erosion and deposition into dramatic seascapes, including deeply incised submarine canyons (Paull et al, 2011), sinuous submarine channels with numerous meander cutoffs (Antobreh and Krastel, 2006;Kolla et al, 2012), and submarine fans consisting of lobes and distributary channels (Deptuck et al, 2008;Jegou et al, 2008). The architecture of these depositional systems is strongly influenced by the input grain-size distribution (e.g., sand-rich vs. mud-rich systems of Reading and Richards, 1994).…”

Section: Introductionmentioning

confidence: 99%

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Jobe¹,

Sylvester²,

Parker³

et al. 2015

Journal of Sedimentary Research

View full text Add to dashboard Cite

Changes in sediment supply and caliber during the last ~130 ka have resulted in a complex architectural evolution of the Y channel system on the western Niger Delta slope. This evolution consists of four phases, each with documented or inferred changes in sediment supply. Phase 1 flows created wide (1,000 m), low-sinuosity (1.1) channel forms with lateral migration and little to no aggradation. During Phase 2, the Y channel system began to aggrade, creating more narrow (300 m) and sinuous (1.4) channel forms with many meander cutoffs. This system was abandoned at ~ 130 ka, perhaps related to rapid relative sea-level rise during MIS (Marine Isotope Stage) 5. Phase 3 flows were mud-rich and deposited sediment on the outer bends of the channel form, resulting in the narrowing (to 250 m), straightening (to a sinuosity of 1.22), and aggradation of the Y channel system. Renewed influx of sand into the Y channel system occurred with Phase 4 at ~ 50 ka, during MIS 3 sea-level fall. The onset of Phase 4 is marked by the initiation of the Y′ tributary channel, which re-established sand deposition in the Y channel system. Flows entering the Y channel from the Y′ channel were underfit, resulting in inner levee deposition that is most prevalent on outer banks, acting to further straighten (1.21) and narrow (to 200 m wide) the Y channel. The inner levees accumulated quickly as the flows sought equilibrium, with deposition rates > 200 cm/ky. Marked by the presence of the last sand bed, abandonment occurred at ~19 ka in the Y channel and ~15 ka in the Y′ channel and is likely related to progressive abandonment due to shelf-edge delta avulsion and/or progressive sea level rise associated with Melt Water Pulse 1-A. The muddy, 5-meter-thick Holocene layer has thickness variations that mimic those seen in the sandy part of Phase 4, suggesting that dilute, muddy flows continue to affect the modern Y channel system. This unique dataset allows us to unequivocally link changes in submarine channel architecture to variations in sediment supply and caliber. Changes in the updip sediment routing system (i.e. the channel "plumbing") are shown to have profound implications for submarine channel architecture and reservoir connectivity.

show abstract

“…Lobe deposits have been mainly investigated in sand-prone turbidite systems that are thought to be modern reservoir analogues (Piper et al, 1999;Piper and Normark, 2001;Kenyon et al, 2002;Deptuck et al, 2008). Few studies have concentrated on the lobes of silt/mud-rich turbidite systems (Wynn et al, 2002;Bonnel et al, 2005;Jegou et al, 2008). The lack of sedimentological and stratigraphical data has hindered understanding of these systems.…”

Section: Introductionmentioning

confidence: 99%

Lobe construction and sand/mud segregation by turbidity currents and debris flows on the western Nile deep-sea fan (Eastern Mediterranean)

Migeon

Ducassou

Gonidec

et al. 2010

Sedimentary Geology

View full text Add to dashboard Cite

Channel-mouth lobe complex of the recent Amazon Fan: The missing piece

Cited by 98 publications

References 51 publications

Remote sensing analysis of depositional landforms in alluvial settings: Method development and application to the Taquari megafan, Pantanal (Brazil)

Remote sensing analysis of depositional landforms in alluvial settings: Method development and application to the Taquari megafan, Pantanal (Brazil)

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Lobe construction and sand/mud segregation by turbidity currents and debris flows on the western Nile deep-sea fan (Eastern Mediterranean)

Contact Info

Product

Resources

About