Stratigraphic framework of a late pleistocene shelf-edge delta, northeast Gulf of Mexico

Journal Article · Mon Aug 01 04:00:00 EDT 1994 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6721671

Sydow, J; Roberts, H H ^[1]

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1. Louisiana State Univ., Baton Rouge, LA (United States)

Lithologic, biostratrigraphic, and chronostratigraphic data from a 92-m continuous surface boring, in the Main Pass area of the outer Mississippi-Alabama shelf, were used to calibrate high-resolution seismic profiles in a study of a late Pleistocene shelf-edge delta. The boring is the first of its kind through a shelf-edge clinoform wedge and the first [open quotes]ground-truth[close quotes] confirmation that the clinoforms in the study area are deltaic in origin. Chronologic control for the late Pleistocene outer shelf stratigraphy is based on the identification of Ericson Zones X, Y, and Z (alternating warm and cold water planktonic foraminifera zones) in the boring, representing at least the last 130 k.y. During sea level lowering related to the previous glacial maximum, the delta system prograded onto a carbonate-rich outer shelf and upper slope starved of terrigenous sediments. The ancestral Mobile River, possibly joined by the Pascagoula River, was the fluvial feeder of the shelf-edge delta. The upper portion of the delta wedge is extensively eroded, primarily by a broad swath of significant fluvial scour centered along the northeast- to southwest-oriented dip axis of the delta, and to a lesser extent by subsequent transgressive truncation. Fluvial scour resulted in a broad erosional trough filled with fluvial and estuarine facies. Thin estuarine and overlying marine units reflect transgression of the Lagniappe delta during the late Pleistocene-early Holocene transgression. According to standard sequence stratigraphic definitions, the extent of the sequence boundary, identified as the erosional base of the fluvial facies, places the majority of the outer shelf delta in the highstand systems tract. The portion of the delta thus categorized as highstand was built during the falling to lowstand minimum part of the relative sea level curve. 64 refs., 18 figs.

• OSTI ID: 6721671
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 78:8; ISSN 0149-1423; ISSN AABUD2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CENOZOIC ERA
COASTAL REGIONS
CONTINENTAL MARGIN
CONTINENTAL SHELF
GEOLOGIC AGES
GEOLOGY
PLEISTOCENE EPOCH
QUATERNARY PERIOD
RIVER DELTAS
STRATIGRAPHY