4 CMB 4 – Highway 28 North of Apsley

Heidi Daxberger and Phillip Ruscica

GPS Coordinates (44°46’39.09″N, 78° 5’56.77″W)

Parking: At the shoulder of the road next to the outcrop.

The CMB 4 site is located 2 km North of the town of Apsley along HW 28. The roadside outcrop features highly altered and deformed metavolcanics with intercalations of metasedimentary rocks that are of Neo- to Mesoproterozoic of age and belong to the Flinton Group of the Grenville Supergroup (Geologic Map of Southern Ontario, Ontario Geological Survey OGS).


Click here to open the Bedrock Geology legend on the OGS website


The Digital Outcrops

The following 3D model shows how intensely deformed, altered and weathered the rocks at this site are.

The following model is the centre section of the outcrop.



The following model is the northern section of the outcrop.



The following model is the southern section of the outcrop.



Site Images


Thin Sections

In the following section you can take a look at thin section imagery of Samples take at CMB 4 which correlate to the samples shown above where available. The slide show below features the whole section scans of the provided thin sections. Further below you will find videos of full 360 degree rotations at specific close up locations of each thin section.


The following videos show full 360 close up rotations at higher magnification of the VLS_21_502 thin section in PPL and XPL.




Scanning Electron Microscope

Sample VLS-21-502



Go to the next chapter: CMB 5 – Highway 504!