Causation of the Quaternary catastrophic sediment failures of the Amazon Fan

Author(s): Vilela, C. G.; Maslin, M. A.
Author Affiliation(s): Primary:
Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Other:
UCL, United Kingdom
Volume Title: Brazil 2000; 31st international geological congress; abstracts volume
Source: International Geological Congress [International Geological Congress, Abstracts = Congrès Géologique International, Résumés, Vol.31; Brazil 2000; 31st international geological congress, Rio de Janeiro, Brazil, Aug. 6-17, 2000. Publisher:], [location varies], International CODEN: IGABBY
Note: In English. File G2005012.PDF
Summary: The architecture and Quaternary history of the massive and highly structured Amazon Fan has been reconstructed using sediment recovered by ODP Leg 155. Huge regional mass-transport deposits make up a significant component of the Amazon Fan. Analysis of both benthic foraminiferal fauna and the sediments indicate that the mass-transport deposits originated on the continental slope, which is at least 200 km laterally and 1500 m above their present position. Each mass failure-event was formed by the catastrophic failure of the continental slope and has been dated and correlated with climate- induced changes in sea level. Studies of the benthic foraminiferal assemblages in the Amazon Fan mass transport deposits has been essential to our reconstruction of the origin and cause of these failures. The glacial mass transport deposits referred to as Bottom MTD and Unit R MTD contained rare shelf species and dominant upper-middle bathyal species (cassidulinids and buliminids). We conclude that originated between 200 and 600 m water depth, approximately the same zone in which gas hydrates occur. We suggest that rapid drops in sea level destabilized continental slope gas hydrate reservoirs causing slope failure and the glacial mass-transport deposits. However an alternative explaination is required for the MTDs which occur as sea level is rising during Termination I. We suggest from sedimentaion rates and carbon isotopes that the deglatiation of the Andes and the consequent flushing of Amazon River sediment on to the continental slope caused over-burdening and thus the deglacial mass-transport deposits.
Year of Publication: 2000
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Amazon Fan; Atlantic Ocean; Benthic taxa; Brazil; Carbon; Catastrophes; Cenozoic; Climate change; Deglaciation; Failures; Foraminifera; Glacial environment; Glaciomarine environment; Invertebrata; Isotopes; Leg 155; Marine environment; Marine sediments; Mass movements; Microfossils; North Atlantic; Ocean Drilling Program; Paleo-oceanography; Paleoecology; Protista; Provenance; Quaternary; Sea-level changes; Sedimentation rates; Sediments; Slope environment; Slumping; South America; Stream transport; Submarine fans
Coordinates: N043544 N065701 W0463759 W0490528
Record ID: 2004004260
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by International Geological Congress Organizational Committee
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100 1 |a Vilela, C. G.  |u Universidade Federal do Rio de Janeiro, Rio de Janeiro 
245 1 0 |a Causation of the Quaternary catastrophic sediment failures of the Amazon Fan 
300 |a unpaginated 
340 |a compact disc 
500 |a In English. File G2005012.PDF 
500 |a Research program: ODP Ocean Drilling Program 
500 |a Affiliation: Universidade Federal do Rio de Janeiro; Rio de Janeiro; BRA; Brazil 
500 |a Affiliation: UCL; ; GBR; United Kingdom 
500 |a Source note: International Geological Congress [International Geological Congress, Abstracts = Congrès Géologique International, Résumés, Vol.31; Brazil 2000; 31st international geological congress, Rio de Janeiro, Brazil, Aug. 6-17, 2000. Publisher:], [location varies], International 
500 |a Publication type: conference paper or compendium article 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by International Geological Congress Organizational Committee 
520 |a The architecture and Quaternary history of the massive and highly structured Amazon Fan has been reconstructed using sediment recovered by ODP Leg 155. Huge regional mass-transport deposits make up a significant component of the Amazon Fan. Analysis of both benthic foraminiferal fauna and the sediments indicate that the mass-transport deposits originated on the continental slope, which is at least 200 km laterally and 1500 m above their present position. Each mass failure-event was formed by the catastrophic failure of the continental slope and has been dated and correlated with climate- induced changes in sea level. Studies of the benthic foraminiferal assemblages in the Amazon Fan mass transport deposits has been essential to our reconstruction of the origin and cause of these failures. The glacial mass transport deposits referred to as Bottom MTD and Unit R MTD contained rare shelf species and dominant upper-middle bathyal species (cassidulinids and buliminids). We conclude that originated between 200 and 600 m water depth, approximately the same zone in which gas hydrates occur. We suggest that rapid drops in sea level destabilized continental slope gas hydrate reservoirs causing slope failure and the glacial mass-transport deposits. However an alternative explaination is required for the MTDs which occur as sea level is rising during Termination I. We suggest from sedimentaion rates and carbon isotopes that the deglatiation of the Andes and the consequent flushing of Amazon River sediment on to the continental slope caused over-burdening and thus the deglacial mass-transport deposits. 
650 7 |a Benthic taxa  |2 georeft 
650 7 |a Carbon  |2 georeft 
650 7 |a Catastrophes  |2 georeft 
650 7 |a Cenozoic  |2 georeft 
650 7 |a Climate change  |2 georeft 
650 7 |a Deglaciation  |2 georeft 
650 7 |a Failures  |2 georeft 
650 7 |a Foraminifera  |2 georeft 
650 7 |a Glacial environment  |2 georeft 
650 7 |a Glaciomarine environment  |2 georeft 
650 7 |a Isotopes  |2 georeft 
650 7 |a Marine environment  |2 georeft 
650 7 |a Marine sediments  |2 georeft 
650 7 |a Mass movements  |2 georeft 
650 7 |a Microfossils  |2 georeft 
650 7 |a Ocean Drilling Program  |2 georeft 
650 7 |a Paleo-oceanography  |2 georeft 
650 7 |a Paleoecology  |2 georeft 
650 7 |a Provenance  |2 georeft 
650 7 |a Quaternary  |2 georeft 
650 7 |a Sea-level changes  |2 georeft 
650 7 |a Sedimentation rates  |2 georeft 
650 7 |a Sediments  |2 georeft 
650 7 |a Slope environment  |2 georeft 
650 7 |a Slumping  |2 georeft 
650 7 |a Stream transport  |2 georeft 
650 7 |a Submarine fans  |2 georeft 
651 7 |a Amazon Fan  |2 georeft 
651 7 |a Atlantic Ocean  |2 georeft 
651 7 |a Brazil  |2 georeft 
651 7 |a Leg 155  |2 georeft 
651 7 |a North Atlantic  |2 georeft 
651 7 |a South America  |2 georeft 
653 |a Invertebrata 
653 |a Protista 
700 1 |a Maslin, M. A., 
711 2 |a Brazil 2000; 31st international geological congress  |d (2000 :  |c Rio de Janeiro, Brazil)  
773 0 |t Brazil 2000; 31st international geological congress; abstracts volume  |d [location varies] : [International Geological Congress], Aug. 2000  |k International Geological Congress, Abstracts Congrès Géologique International, Résumés  |y IGABBY  |n International Geological Congress [International Geological Congress, Abstracts = Congrès Géologique International, Résumés, Vol.31; Brazil 2000; 31st international geological congress, Rio de Janeiro, Brazil, Aug. 6-17, 2000. Publisher:], [location varies], International Publication type: conference paper or compendium article  |g Vol. 31