Ways to determine age of rockfall scars?

Howzit guys

I’m posting this mainly out of curiosity on the subject, hoping there may be some knowledge on the VE forum about this.

I've noticed what looks like a relatively fresh rock fall scar on a peak we climbed over the weekend. I call it ‘relatively fresh’ as I do not recall it being there since June 2012 when I last climbed this route up the peak. In addition, I have climbed this peak probably close to 10 times in the last 5-6 years, as it has lovely vistas, is relatively easy to climb with quick access. I think I would’ve noticed this had it been there on previous occasions: it is right next to the main scramble route up the peak’s final rock bands which I use most of the times.

Herewith a photo of what it looks like from afar, i.e. in the process of ascending it. It is the obvious bright looking scar on the highest of the two rock layers on top (just right of the center of photo).



As mentioned, this is right next to the scramble up (which is just left of this white scar up the lower rock layer, followed by an easy traverse right past this scar on the way to the left hand side of the picture where one easily scrambles up the second rock layer). The following photo therefore shows the scar up close:



Also notice the clearly older rock fall scar on the third photo, reddish in colour under the rock overhang, about 7-8 meters from this bright looking scar.



Based on the above information, I have the following questions:
• Assuming I may still be incorrect about noticing/not noticing this scar in recent years: Is there any way the colour of such a scar can highlight whether it is new or old?
• Will this scar start to look like the older scar as pointed out 7-8 meters from it in years to come, or are there potential reasons for looking different?

The curiosity comes from the fact that we may start looking at different things as one gets more and more familiar with a certain areas. That may explain why I haven’t noticed it before, or then again, it may really be new. It would be great if there are some easy ways of determining relative age of rock falls.

Even if just for fun.

PS. I do not have any older photos with me currently to prove/disprove age of this scar.

Thanks for the photos and for the details.

My day job is more in weather and climate than geomorph and geology, but here are some pointers to your questions.
Is there any way the colour of such a scar can highlight whether it is new or old?
Relatively speaking, yes. Two key things change the colour of the rock: weathering (breakdown of the newly exposed rock surface physically and chemically) and plants. The older rocks tend to have lichen growing on them - the new ones won't. Lichens have been used extensively to date rock surface exposure. The larger the lichen diameter, the longer the rock has been exposed. Lichen growth on gravestones have provided the control for the rate of growth though there won't be those sort of controls in the Berg.

Will this scar start to look like the older scar as pointed out 7-8 meters from it in years to come, or are there potential reasons for looking different?
Yes - both weathering and lichen growth will change the rock colour.

Another way of dating the rock failure would be on the basis of the scar in the vegetation that the debris left down slope. Again, one would have to know something about the vege regrowth rates for the area to date the failure.