Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cartwright, J. Articles by Bolton, A. Search for Related Content GeoRef GeoRef Citation

Recognition of an early Holocene polygonal fault system in Lake Superior: Implications for the compaction of fine-grained sediments

¹ 3D LAB, School of Earth Sciences, P.O. Box 914, Cardiff University, Cardiff CF10 3YE, UK
² Large Lakes Observatory, University of Minnesota, Duluth, Minnesota 55812, USA
³ 3D LAB, School of Earth Sciences, P.O. Box 914, Cardiff University, Cardiff CF10 3YE, UK

Extensive geophysical surveying of western Lake Superior has revealed the presence of a system of small extensional faults deforming a 10–15-m-thick interval of glacio-lacustrine clays of early Holocene age over an area of 5000 km². Mapping of these closely spaced faults shows that they have (1) a polygonal planform geometry with a large range of strikes and (2) oblique to orthogonal intersection geometries. The fault system is layer bound and restricted to fine-grained postglacial sediments. The fault system is overlain by an extensive field of 100–400-m-diameter, 1–7-m-deep pockmarks, directly implicating the faults in the process of pockmark formation. The fault system is the youngest and most accurately dated example of a polygonal fault system described to date and the first to be described from a freshwater setting. This example conclusively demonstrates that nontectonic faulting can occur in sediment buried only a few meters and can be accompanied by highly focused fluid flow, a result that has wide implications for compaction processes of fine-grained sediments.

Key Words: compaction • pockmarks • faults • clays • Holocene

This article has been cited by other articles:

				N. R. Goulty Geomechanics of polygonal fault systems: a review Petroleum Geoscience, November 1, 2008; 14(4): 389 - 397. [Abstract] [Full Text] [PDF]

				N.R. GOULTY and R.E. SWARBRICK Development of polygonal fault systems: a test of hypotheses Journal of the Geological Society, July 1, 2005; 162(4): 587 - 590. [Abstract] [Full Text] [PDF]