Quick Search:    advanced search

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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 Pratt, B. R. Articles by Miall, A. D. Search for Related Content GeoRef GeoRef Citation

Anatomy of a bioclastic grainstone megashoal (Middle Silurian, southern Ontario) revealed by ground-penetrating radar

¹ Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N OWO, Canada
² Department of Geology, University of Toronto, 22 Russell Street, Toronto, Ontario M5S 3B1, Canada

Porous grainstones deposited as offshore carbonate sand shoals are important hydrocarbon reservoirs, but little is known about their internal architecture and its effect on reservoir heterogeneity. The Middle Silurian Amabel Formation, exposed along the Niagara Escarpment of southern Ontario, provides an unparalleled opportunity to examine such a deposit in three dimensions with photomosaics and ground-penetrating radar. The Amabel is a dolomitized bioclastic grainstone unit up to 25 m thick, composed mainly of crinoid ossicles. It thins and grades westward to thin-bedded argillaceous dolostones. Although previously assumed to be reefal, the undulating and oblique bedding that dominates the internal geometry was caused by vertical and lateral accretion on hummocky topography and scour surfaces. Some scours are huge—as much as 15 m deep—and attest to the dramatic nature of sediment movement by storms and hurricanes. Ground-penetrating radar successfully detects the large-scale bedding pattern and, in conjunction with outcrop observations, has potential for mapping the three-dimensional architecture of ancient lithified deposits.

This article has been cited by other articles:

				C. S. Bristow and H. M. Jol An introduction to ground penetrating radar (GPR) in sediments Geological Society, London, Special Publications, January 1, 2003; 211(1): 1 - 7. [Abstract] [PDF]

				J. K. Russell and M. V. Stasiuk Ground-penetrating radar mapping of Minoan volcanic deposits and the Late Bronze Age palaeotopography, Thera, Greece Geological Society, London, Special Publications, January 1, 2000; 171(1): 105 - 121. [Abstract] [PDF]