Records of paleoseismic events in the red-silk stone bed in Linqu, Shandong

Abstract：Red-silk stone is a kind of microcrystalline carbonate rocks with red silk thread-like curled laminations used for carving stone handicrafts (ink slabs, brush pots etc.), which occurs in the lower part of the Middle Ordovician in Linqu, Shandong. The portion of strata containing red-silk stone, about 60 m thick, is named “red silk stone bed”. Based on field observation, lab examination correlation of seismic structures, seismite layers with seismogenetic structures such as curl deformation (including plastic and semi-plastic deformations), circular laminations, microfractures (including ladder and conjugated ones), vibration fissures and shattered breccia are recognized in the red-silk stone bed. These seismites are records of Middle Ordovician paleseismic events. Red-silk stone is only one of common seismites formed by paleoseismism. As seismites also formed in the Middle Ordovician Tanlu zone, it is considered that these seismic records are evidence of the intense tectonic activity of the Paleo-Tanlu fault at that time.