- Title
- Three-dimensional reconstruction of meander-belt evolution, cretaceous McMurray Formation, Alberta Foreland Basin, Canada
- Creator
- Durkin, Paul R.; Boyd, Ron L.; Hubbard, Stephen M.; Shultz, Albert W.; Blum, Michael D.
- Relation
- Journal of Sedimentary Research Vol. 87, Issue 10, p. 1075-1099
- Publisher Link
- http://dx.doi.org/10.2110/jsr.2017.59
- Publisher
- Society for Sedimentary Geology (SEPM)
- Resource Type
- journal article
- Date
- 2017
- Description
- The three-dimensional reconstruction of meander-belt deposits from ancient strata provides insight into the formative processes of meander-bend evolution and paleogeographic interpretations. A significant challenge to such analyses is limited exposures in outcrop belts and widely spaced or sparse subsurface datasets. An unprecedented dataset consisting of 600 km2 of 3-D seismic data and over 1000 well penetrations from the Cretaceous McMurray Formation in northeastern Alberta, Canada, provides a unique opportunity to characterize an ancient continentalscale river system. Paleochannels ranged from 475 to 1180 m wide and from 35 to 50 m deep, with meander-belt width-to-thickness ratios between 107:1 and 401:1. The data reveal evidence for intra-point-bar erosion and punctuated rotation, counter-point-bar development, and protracted channel cut-off and meander-loop abandonment. Observations enable interpretation of morphodynamic processes that are commonly observed in modern systems, yet rarely described from the rock record. A 3-D geocellular model and reconstructed paleochannel migration patterns reveal the evolutionary history of seventeen individual meander belt-elements, including point bars, counter-point bars, and their associated abandoned channel fills, which have been mapped using core, FMI logs, and seismic data. Results of the study show that intrapoint- bar erosion surfaces bound accretion packages characterized by unique accretion directions, internal stratigraphic architecture, and lithologic properties. We provide evidence for channel-belt-edge confinement and development of a counter-point bar, as well as the deposition of side bars and preservation of a mid-channel bar during meander-bend abandonment. Analysis of changes in meander-belt morphology over time reveal a decrease in channel-belt width/thickness ratio and sinuosity, which we compare with observations from the lower Mississippi River and attribute to the landward migration of the paleo-backwater limit due to transgression of the Cretaceous Boreal Sea into the Alberta foreland basin.
- Subject
- Alberta Foreland Basin; Canada; 3D Reconstruction; meander-belt deposits
- Identifier
- http://hdl.handle.net/1959.13/1355579
- Identifier
- uon:31492
- Identifier
- ISSN:1527-1404
- Rights
- This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
- Language
- eng
- Full Text
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