DYNAMIC STRATIGRAPHY WORKGROUP

Publications and presentations: 

Publications:

Petter, A.L., and Steel, R.J., 2006, Hyperpycnal flow variability and slope organization on an Eocene shelf margin, Central Basin, Spitsbergen: American Association of Petroleum Geologists Bulletin, v. 90, p. 1451-1472.

 

Conference/meeting presentations:

Petter, A. L., P. Plink-Björklund, and R. J. Steel, 2007, Hyperpycnal-flow evolution from the shelf edge to the lower slope as evidenced by slope-channel deposits in the Tertiary Central Basin of Spitsbergen: AAPG/SEPM Annual Meeting, Long Beach, California.

Petter, A. L., and R. J. Steel, 2006, High- versus low-density hyperpycnal flow: deposits and relative timing within  4^th-order genetic sequence, Central Tertiary Basin, Spitsbergen: GSA Annual Meeting, Philadelphia, Pennsylvania, v. 38, no. 7, p. 541.

Petter, A. L., and R. J. Steel, 2006, High-latitude recipe for sand delivery to the deepwater via hyperpycnal flow: a Greenhouse example from the early Eocene, Central Spitsbergen Basin: AAPG/SEPM Annual Meeting, Houston, Texas.

Petter, A. L., and R. J. Steel, 2005, Deepwater-slope channels and hyperpycnal flows from the Eocene of the Central Spitsbergen Basin: predicting basin-floor sands from a shelf edge/upper slope perspective: AAPG/SEPM Annual Meeting, Calgary, Alberta, Canada.

Petter, A. L., 2004, Eocene falling-stage deltas and associated upper slope channels; an outcrop study of a deepwater feeder system (central Spitsbergen Basin): Geological Society of America South-Central Section Meeting, College Station, Texas, Abstracts with Programs – Geological Society of America, v. 36, p. 23.

People:

Andrew Petter, Ron Steel

 

Research question(s):

Identification of sediment bypass (particularly sand) at the shelf edge is critical to deepwater exploration. Hyperpycnal flow from rivers at the shelf edge provides a potential mechanism for sand to be transported across the slope to the basin floor. How can sediment delivery to deepwater by hyperpycnal flow be identified in the rock record?

Hyperpycnal flow variability and slope organization on an Eocene shelf margin, Central Basin, Spitsbergen

Summary of work:

The shelf margin of an early Eocene fourth-order sequence with an attached basin-floor fan in the Central Spitsbergen Basin was examined in outcrop. Turbidity currents were fed mainly by hyperpycnal flow emerging from shelf-edge deltas. The lifespan of any turbidity current was determined primarily by the sediment concentration of the flow and the duration of the river flood. High-density hyperpycnal flows created sand-filled slope-channel complexes 10-15 meters (33-49 feet) thick and 100-200 meters (328-656 feet) wide that served as conduits for bypass to the basin floor. Low-density hyperpycnal flows were unconfined and deposited heterolithic lobes on the slope. Shelf-margin accretion of ~1.5 kilometers (0.9 miles) during the falling stage gave way abruptly to bypass in the early lowstand. Most of the basin-floor fan growth was achieved after shelf-edge incision and before relative sea level rise. Coastal-plain aggradation in the late lowstand sequestered sediment from the shelf-edge distributaries, effectively diminishing high-density hyperpycnal flow output. The late lowstand was therefore marked by a second phase of shelf-margin accretion with only limited bypass to the basin floor, and a heterolithic, prograding complex downlapped the early lowstand channels. Transgression ultimately led to abandonment of the shelf-edge delta complex and accumulation of mainly mudstone on the margin. The shelf-margin architecture exhibited by this sequence should serve as a type example of a deepwater feeder system in which hyperpycnal flow is the primary initiator of turbidity currents for sand accumulation on the slope and basin floor.

Upper-stage, plane-parallel lamination within slope channel, Spitsbergen. Such sedimentary features are considered characteristic of sediments deposited from sustained turbidity currents such as hyperpycnal flow.

~10 m