A revised depositional setting for Halton sediments in the Oak Ridges Moraine Area, Ontario

• Main Authors: Sharpe, David R., Russell, Hazen A.J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2016
• Subjects: Ice Shelf
• Online Access: http://hdl.handle.net/1807/71475; http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2015-0150

Outcrop and continuous core descriptions, high-resolution seismic profiling and downhole geophysical data, are integrated with detailed mapping to update sedimentary and stratigraphic frameworks for Halton sediment, a complex mud-rich lithofacies succession. Halton sediment has a gradational transition from underlying Oak Ridges Moraine (ORM) sediment and can abruptly overlie Newmarket Till. Halton strata thin and fine upwards from Oak Ridges Moraine sand and gravel to graded sand, silt, and clay rhythmites, with muddy diamicton and sand and gravel inter-beds. These strata fill basin lows and drape ORM sediment lobes and Newmarket Till drumlins. These distinct sedimentary units are here informally referred to as Halton formation. Formal Halton Till is a proposed sub-unit of Halton formation, a clay-rich diamicton mapped from Niagara Peninsula to ORM and eastward. Halton Till has traditionally been inferred to represent a late, climatically-induced re-advance of grounded ice from Lake Ontario basin, which deposited drumlinized till. Halton sedimentary architecture and facies are interpreted as deposition in an ice-marginal /subglacial lake bounded by Niagara Escarpment, ORM and grounding line oscillation of a semi-buoyant ice shelf /lid over Lake Ontario. Large volumes of transported mud are distal equivalents of ORM high-energy gravelly sand deposits to the east. Glaciolacustrine sedimentation is indicated by mud-rich texture and laminations. Clay-silt rhythmites, diamicton inter-beds, and intra-clasts indicate ponding, debris flow and periodic ice loading. Halton depositional model may apply to other muddy diamictons in Great Lakes basins. Halton formation facies are not compatible with proposed grounded ice stream events in Lake Ontario basin. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.