Will try to clarify a few things I have been pondering.
One good picture of Voyager Mountains and I predict we will 'grok' the ridge system on Iapetus. (Cassini Regio, I am not so sure)
The Voyager Mountains will be obvious non volcanic forms. I suspect their manner of formation to be a stream of materials on ballistic trajectories from the west, accumulating at the upper elevations, and sliding/slumping as the materials accumulate. This is a new way of making a mountain, something we have not seen before.
The intermittency of the ridge west of the (<-) point common to the trifurcated portion is expected from the manner of formation. While the Voyager Mountains may be crater damaged, they will not be sections of a once continuous ridge subsequently sundered by craters.
We need to consider the 'start up' sequence of an emplacing ring system. Start with orbiting materials about Iapetus, inside the Roche limit, collapsing towards the Lapacian plane. Until the planar form is reached, the dynamical ring spreading process is not operative. The main interaction occuring in the still organizing ring system is collisions over the equator. (refer to the great diagram in TNSS, Planetary Rings chapter) The result of the collisions is to primarily reduce the inclinations of the orbiting materials. The collisions take place in a sphere around Iapetus due to the Iapetan oblateness spreading the originally 'mono' inclined ( a word I just banged up) materials 'all the way' about Iapetus. The collisions continue until all the material is planar. Once that state is achieved, angular momentum can be redistributed throughout the ring system via objects in adjacent orbits bumping. The angular momentum is redistributed such that the lower edge of the ring descends, and the higher edge ascends.
The process proceeds slowly. While the particles on the low edge are spiralling downwards, the amount of drop, per orbit is small compared to the particles individual radii.
As the lower edge of the ring descends, it inevitably comes in contact with the highest point along the equatorial ground track. This point remains fixed (NSE and W, but not in elevation) during emplacement of the ring materials onto the surface. Materials that come into physical contact with the surface are immediately condemned to 'pulverizing and sliding' out into the famous wedge ramp structure we see today.
Additionally, materials still in the ring, that have not yet contacted the high point, but that do interact with the pulverized materials that have contacted the surface just ahead and just below them, ascribe a different path than the non affected particles immediately around them in the ring do. They have suffered a small velocity decrease, but are not in contact with the surface, so they get a final elliptical orbit about Iapetus.
In the early stages of emplacement, before the highest spot along the equatorial ground track gets very high, this 'doomed' population of ring materials probably doesn't make it very far. But as the high spot gets higher, this elliptical orbiting population of ring particles can do something rather amazing. By being able to get back around Iapetus one last time, they have the opprotunity to impact other randomly located spots nearly as high as the original highest spot.
And they accumulate in these places simultaneously as the wedge ramp continues to grow. The amount of materials deposited in these secondary 'piles' depends on their height and spacing. A longer gap along the ground track will allow more materials to accrue.
The heights of all these peaks along the equator will correlate, and the emplaced volumes in these peaks will be proportional to their spacing (assuming a smooth distribution of velocities in the elliptical subset of emplacing ring particles)
Now, let the process run to an exhaustion of ring particles.
Then, after the passage of sufficient time another sub-moon crosses into the Iapetan Roche limit, or another impactor lofts another debris pile, and the ring process starts again. This time, the sub-moon is in a slightly inclined orbit and generates a ring with a similar slight inclination. Or (if that isn't feasible from Laplace's perspective) in the intervening interval, Iapetus has had a few degrees of axial tilt occur, this ring emplaces a bit differently. The highest point along the equator still penetrates the ring plane, but not continuously. It passes through the ring plane twice per rotation. Once from north to south, and 180 degrees later, from south to north. This makes (alternatingly) the perfectly matched, symmetrical, identically diverging, attendant ramps.
But now, the conditions are even more different. We are starting 20 kms up. Not at an existing random highspot along the groundtrack which might have been only slightly higher than some other high-ish spots, but something much, much higher. All the materials emplace on the (short) attendant wedge ramps. The slopes are steeper than an apparent critical angle, so now the high spot doesn't get any higher, and all the emplacement is evenly divided on the 2 attendants.
Also, materials interacting at the high spot with materials in contact with the surface, are not deceled enough to contact anything other than the highest spot along their ground track, the highest spot of the wedge ramp.
There are no 'Voyager Mountains' along the great circle paths you trace out from the attendant ridges.
[Moderator's note: Thread split. A new thread containing actual images from the flyby as well as discussion of the them is here]
. Just to clarify one of the mapping details, the break in the bellyband that shows up at about 140W is an artifact (that I haven't yet time to fix) and should likely in actuality be more continuous.