Introduction

Overview of the
Humber River

Global and Continental Glaciation

Land Form Development in North America

Geological History
of the Great Lakes

Development of the
Oak Ridges Moraine

Geology of the
Humber River Watershed

Ecology & Recreation

Early Inhabitants

Maps of the
Humber River Watershed

Photo Gallery Humber River Watershed

Humber Marshlands looking north to the Old Mill, Toronto

Overview of Geology of the Humber River

River systems in North America generally are subject to the physical forces of nature including erosion. The Humber River of Southern Ontario is no exception. In addition, the origin of most river systems owes homage to historical geological events including plate tectonics, oceanic depositional events and glaciation.

The geology of the watershed generally consists of Quaternary sediments infilling an ancient fluvial valley system incised into the bedrock surface. This bedrock valley system drained the Upper Great Lakes basin into what is now the St. Lawrence River.

There are four main geologic features present, including:

* A bedrock valley system that contains thick sand and gravel deposits (Georgian Bay Formation-Ordivician)

* The Niagara Escarpment that forms the western boundary of the Humber River watershed (Silurian Cuesta)

* The Oak Ridges Moraine (ORM) that forms the headwater of the Humber Watershed (Wisconsonian Glaciation Period)

* Areas where Quaternary sediments have eroded and largely in-filled with sequences of sand and silt. This erosive action is attributed to tunnel channel formation beneath glacial ice

(abst: Humber River State of the Watershed Reports, TRCA 2008).

Introduction to => | Geology of the Humber |