As the glacier melts or retreats, the debris is deposited and a ridge down the middle of the valley floor is created. J B Transmission Products. This erosion can also be caused by moving water. Interlocking spurs. It occurs when ridge spurs, which were formed in a mountainous area by river action, have been truncated by the action of ice or active faulting. Most DDS systems are designed so that the phase truncation spurs are less than the DAC spurs. A ribbon lake is a large, narrow lake occupying a U-shaped valley. Synonyms for TRUNCATED: shortened, abbreviated, reduced, abridged, curtailed, syncopated, trimmed, compressed; Antonyms of TRUNCATED: extended, elongated, lengthened . add to list. Melting at a glacier margin causes the ice to thin, and ground-up rock debris carried in the base of the ice or dragged along beneath the glacier is deposited. Truncated spurs can be found within mountains, along the walls of river valleys, or along coastlines. Visitors have the right to withdraw their consent. As the valley glacier moves, abrasion and plucking erode the protruding tips of the spurs, leaving steep cliff-like truncated spurs. How are interlocking spurs turn into truncated spurs? //