A group of vertical clastic dikes has recently been found in the volcanic blocks at Chichi in the Coastal Range, easter Taiwan. These dikes pinch out upwards and show a thickness variation from 10 to 30 centimeters. The dike rocks consist essentially of quartz, feldspar and lithic fragments, all being similar to those constituents of the sandstones in the Paliwan Formation. The volcanic blocks are considered slide blocks, produced through the block glide of the Tuluanshan volcanics. the clastic dikes are accordingly interpreted as the products of the upward injection of unconsolidated sediments into the volcanic blocks due to liquefaction caused by an abrupt increase in pore-fluid pressure in the sediments induced by the block glide of the volcanics during the deposition of the Paliwan Formation. The slide volcanic blocks ranging from several centimeters to hundreds of meters in size are widely distributed in the Coastal Range. It is believed that the block glide of the volcanic rocks and the slumping of sediments were very common in the Coastal Range during the arc-continent collision.
