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What was the Queenston Delta?

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Ordovician paleogeography — Ordovician Period The distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the Ordovician Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

The Queenston Delta was a massive wedge of sediments that accumulated across northeastern North America during the Late Ordovician Period (approximately 461 to 444 million years ago).1

This geological feature was formed as a direct result of the Taconic orogeny, a series of mountain-building events that occurred along the eastern edge of the North American continent (Laurentia). As the rising highlands of the ancestral Appalachian Mountains were eroded, streams transported the resulting debris westward, depositing it into deep basins created by the crustal flexure of the continent.231

The delta was thickest in the regions of present-day New York and Quebec, with sediments spreading as far west as Lake Huron. The name is derived from the reddish Queenston Shale, which formed on the landward front of the advancing delta, while underwater deposits remained gray due to a lack of oxidation.1