Updated: Oct 1, 2020
Based on 'Rock glazes of NZ' Minna Bondy
Sample 80. Lewis Pass Gravel
Mainly Quartz and Feldspar. Also a good deal of very fine probably clayey material, probably derived from shist.
I was puzzled with the description of this sample and wondered if gravel from Lewis Pass in the 1950s was still there in 2020? As I drove, the pass opened into a vast valley with high cliffs on either side that were exposed and crumbling.
These cliffs are referred to as moraine, a glacier-formed material ground by a river of ice during the last ice age. Definitely been there for a while!
There are many road cuttings in the Lewis Pass where the moraine is exposed. This photo doesn't do justice to the scale, this was a mountain of gravel, note the car for scale in the landscape.