Metzger, John M. and Flemings, Peter B. (1998): Comparison of middle Miocene and late Miocene/Pliocene sequence architecture, offshore New Jersey

Leg/Site/Hole:
Identifier:
1999-036434
georefid

Creator:
Metzger, John M.
Pennsylvania State University, Department of Geosciences, University Park, PA, United States
author

Flemings, Peter B.
author

Identification:
Comparison of middle Miocene and late Miocene/Pliocene sequence architecture, offshore New Jersey
1998
In: Anonymous, Geological Society of America, 1998 annual meeting
Geological Society of America (GSA), Boulder, CO, United States
30
7
268
We compare a middle Miocene sequence (Light Blue, approximately 14.7-14.3 Ma, Poulsen et al., in press) and a late Miocene/Pliocene sequence (pp4(s), approximately 10.0-1.7 Ma) using ODP Leg 174A log/core data, local industry wells, and closely spaced ( approximately 300-500 m) 1995 2-D seismic data. The Light Blue sequence is dominated by a thick ( approximately 400 m) lowstand wedge that onlaps the underlying breakpoint, downlaps successively seaward, and has a shale-prone, coarsening-upward log signature. It is overlain by a thin highstand deposit ( approximately 40 m) that also has a coarsening-upward log signature. The highstand deposit constitutes the entire sequence landward of the breakpoint. In contrast, the pp4(s) sequence has no evidence of onlap onto the underlying shelf. A landward-thickening ( approximately 50-150 m) sand-prone facies comprises the entire sequence 10 km landward of the breakpoint. Seaward of the breakpoint, a thick ( approximately 200 m), shale-prone, deepening-upward deposit migrates and pinches landward. It overlies the sand-prone facies on the shelf. The pp5(s) reflector separates these facies and records the transition from inner to middle neritic paleodepths. This facies succession represents a deepening-upward transgressive deposit. This is overlain by a seaward-thickening, progradational highstand deposit. On the shelf, this highstand deposit is thin ( approximately 20 m), shale-prone, and coarsens upward. It thickens 10 km seaward to approximately 150 m and is sand-dominated. During the middle Miocene, high regional sedimentation rates (Poag and Sevon, 1989) and a falling, fluctuating, eustatic sea level (Haq et al., 1987) preserved a highly progradational, relatively short duration sequence. During the late Miocene/Pliocene, high regional sedimentation rates and a large amplitude, rising eustatic sea level preserved a transgressive-dominated sequence. These differences show that sea level falls superimposed on an overall falling sea level and sea level falls superimposed on an overall rising sea level create sequences with fundamentally different internal stacking patterns.
English
Coverage:Geographic coordinates:
North:75.0000
West:-80.0000East: 20.0000
South:0.0000

Stratigraphy; Atlantic Ocean; Cenozoic; eustacy; geophysical methods; geophysical surveys; Leg 174; lithofacies; middle Miocene; Miocene; Neogene; New Jersey; North Atlantic; Ocean Drilling Program; patterns; Pliocene; regression; sea-level changes; seismic methods; sequence stratigraphy; stacking; surveys; Tertiary; thickness; transgression; two-dimensional models; United States; upper Miocene;

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