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Timing of turbidite sedimentation on the Mississippi Fan

Journal Article · · AAPG Bulletin (American Association of Petroleum Geologists); (United States)
OSTI ID:6065855
 [1];  [2]
  1. Elf Aquitaine Production, Pau (France)
  2. Texaco EPTD, Houston, TX (United States)

Sandy turbidite sedimentation on the Mississippi Fan, initiated during the falling and maximum relative lowstand stages of sea level during the last glacio-eustatic cycle, was significant well into the mid to late sea level during the last glacio-eustatic cycle, was significant well into the mid to late sea level rise until the Holocene, 12,000-11,000 yr B.P. or slightly thereafter. Several factors suggest this late continuation of sandy turbidite sedimentation: (1) landward extension of the Mississippi Canyon into the mid-shelf water depths as sea level rose, (2) a major increase in glacial meltwater discharge and sediment loads (pebble to clay size) delivered directly to the head of the canyon by the Mississippi River during the rising sea level, (3) probable persistent interception of longshore drift by the canyon as it eroded landward, (4) steep gradients at the head of the canyon that favored slumping of depocenters and formation of turbidity currents, and (5) absence of expected coarse-grained lithologies and deltaic stratal patterns within the canyon, indicating sediment bypass through the canyon into deep water. The late sand-prone turbidite sedimentation inferred for the Mississippi Fan is compatible with the occurrence of sandy turbidites in the middle Amazon Fan subsequent to 13,285 [+-] 650 yr B.P. and significant deposition of turbidites and clastics until the Holocene elsewhere in the deep ocean. Sand-prone turbidite sedimentation into the middle/late rise of sea level is in contrast to the common perception of sequence-stratigraphic models. This perception assumes that turbidite and fan sedimentation occurs mainly during falling. Maximum lowstand, and early rise of sea level. Late continuation of significant sandy turbidite sedimentation will impact concepts of subsurface stratigraphic calibration, interferences of depositional systems, and reservoir predictions. 56 refs., 7 figs., 1 tab.

OSTI ID:
6065855
Journal Information:
AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:7; ISSN 0149-1423; ISSN AABUD2
Country of Publication:
United States
Language:
English