Discussion of He et al. (2011, Geo-Marine Letters) Evidence of internal-wave and internal-tide deposits in the Middle Ordovician Xujiajuan Formation of the Xiangshan Group, Ningxia, China

Abstract

This discussion of He et al. (Geo-Mar Lett (2011). doi:10.1007/s00367-011-0253-z, 2011) Evidence of internal-wave and internal-tide deposits in the Middle Ordovician Xujiajuan Formation of the Xiangshan Group, Ningxia, China, in Geo-Marine Letters, is placed within the broader context of what is known and what is unknown about the oceanographic phenomenon of internal tides and their deposits.