A while back, I posted some fault photos from a large exposure of Eureka Quartzite. Today's fault photos are from that same large outcrop, this time, from a part of the outcrop that exposes two sets of overlapping slickensides.Here, above, is the overall dual-slick exposure, with AA batteries for scale. You can easily see the slightly oblique dip-slip slickenlines (nearly vertical) in the dark brown surface against which the batteries are leaning, along with strike-slip slickenlines (horizontal) in the golden yellow area above the batteries.A close-up of the lower part of the exposure shows both sets of slickenlines more closely. Now, my finger is running parallel to the slightly oblique, mostly dip-slip slickenlines, and the horizontal strike-slip slicks can be seen right above in the golden yellow area.
The next two photos are close-ups of the upper part of the exposure.
My finger points to and runs somewhat parallel to the mostly horizontal strike-slip slickenlines. Now my finger is running parallel to the mostly dip-slip, darker brown slickenlines, from the same area as the previous photo.
This fault plane has had at least two directions of movement, dip-slip and strike-slip, with the slickensides somewhat overlapping each other on the rock surface. I wasn't really able to tell which set of slickensides was older than the other, and I'm not sure I would be able to tell from this one exposure, though maybe carefully made thin-sections would help.