Something warped the inner D rings and also outer C rings into a ridged spiral like pattern like the grooves in a vinyl record. The amplitudes of grooves are about 1 km for D rings with width of about 8.000 km and about 100 m for the C rings with width of about 17.000 km. Recall that Saturn's ring span an annulus with width of order 60.000 km and with distance from planet of the same order of magnitude. Their thickness is only about 20 m so that a warping for a very thin sheet of paper is an excellent analogy. Warping in a precise mathematical sense means bending of plane without tearing it (so that the Riemann geometry of the sheet remains flat) and occurs almost spontaneously as the experimentation with a sheet of paper shows. Locally the process would look like an ideal warping of plane along parallel lines but in long scales -thanks to the gravitational pull of Saturn- these lines could become curved and form spirals.
The guess of Matthew Hedman of Cornell University was that some perturbation - perhaps a comet or asteroid- should have caused this warping by tilting the rings with respect to the plane of Saturn's equator so that the gravitation of Saturn (Saturn is not a perfect sphere) would have caused tidal forces putting the rings into a wobbling motion and created the spiral grooving pattern. By running equations of motion backwards in time Hedman and colleagues showed that the event should have occurred around 1984. The pattern is however so widespread that the explanation in terms of a comet or asteroid must be given up.
TGD inspired model for the sheets would be as condensations of visible matter around dark matter forming similar structures. Could it be that a quantum counterpart of Earth quake but at the level of dark matter rings with large Planck constant and therefore in large length scales took place? Could this explain why the event was missed by telescopes and space-crafts?