Barrie Creeks, Lovers Creek, and Hewitt's Creek Subwatershed Plan

The Barrie Creeks, Lovers Creek and Hewitt’s Creek Subwatershed Plan
2.4 Geology and Physical Geography
The geology, topography and other physical features of a subwatershed provide the foundation
for the subwatershed’s hydrological and ecological processes, as they provide a strong
influence on factors such as local climate patterns, types of land cover, land use practices, and
surface water and groundwater flow paths.
2.4.1 Geology
There have been a number of studies that have lead to the geologic understanding in the Barrie
area. A generalized description of the bedrock geology, quaternary geology, and conceptual
stratigraphic units within the Barrie, Lovers, and Hewitt’s Creeks subwatersheds is provided. For
more detailed information the reader is referred to: Johnson et al., (1992), Barnett, (1992) and
Armstrong and Carter, (2006).
2.4.1.1. Bedrock Geology
The bedrock can be characterized as being from the Paleozoic Era, consisting primarily of
limestone of the Middle Ordovician Simcoe Group. The Simcoe Group overlies the Precambrian
‘basement’ rock units that comprise the Canadian Shield and outcrop (present at surface) north
of the Lake Simcoe watershed. The Simcoe Group has been overlain by a sequence of
sediments that have been deposited over the last 135, 000 years by glacial, fluvial and
lacustrine environments.
The Middle Ordovician-aged carbonates and shales of the Simcoe Group were deposited in a
gradually deepening shelf system in a shallow subtropical sea approximately 460 million years
ago (Brookfield and Brett, 1988). The Simcoe Group consists of four formations that dip gently
towards the southwest: Gull River Formation, Bobcaygeon Formation, Verulam Formation and
the Lindsay Formation from oldest to youngest. However, only the Verulam and Lindsay
Formations are found within these subwatersheds.
Verulam Formation
The oldest Paleozoic rocks underlying the subwatersheds are those of the Verulam Formation.
This formation occurs along the shoreline of Kempenfelt Bay and expands west of the City of
Barrie. A small portion also extends down to a small area south of Cook’s Bay. The formation is
a member of the Simcoe Group (which is represented as [blue] on Figure 2-16). Within the
subwatershed the formation ranges in thickness from 32 to 65 m and consists of fossiliferous
limestone with inter-beds of calcareous shale. The depositional environment of Verulam
Formation was open marine shelf (Thurston et al., 1992).
Lindsay Formation
The Lindsay Formation overlays the Verulam Formation and extends up from the south towards
Kempenfelt Bay, underlying most of the southern portions of the subwatersheds. The formation
is represented as (blue) on Figure 2-16. Within the subwatershed the Lindsay Formation tends
to be less than 67 m thick and is richly fossiliferous, indicating that the depositional environment
was a shallow to deep marine environment (Thurston et al., 1992).
Chapter 2: Study Area: The Barrie Creeks, Lovers Creek and Hewitt’s Creek Subwatersheds 39