Evidence of internal-wave and internal-tide deposits in the Middle Ordovician Xujiajuan Formation of the Xiangshan Group, Ningxia, China

Modern internal waves and internal tides along oceanic pycnoclines: Challenges and implications for ancient deep-marine baroclinic sands: Discussion

“…We have presented large volumes of data in our articles so that other researchers can study the data and draw their own conclusions. Shanmugam references He et al (2008, 2011 as an example where massive or graded sands were formed by deep tidal currents and internal waves. He et al (2011) is an excellent article.…”

“…Shanmugam references He et al (2008, 2011 as an example where massive or graded sands were formed by deep tidal currents and internal waves. He et al (2011) is an excellent article. In Ordovician deep-water strata, He et al (2011) document sandstones with partial and complete Bouma sequences interbedded with cross-bedded sands and sands with other features indicative of tractive flow.…”

Reply to the 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

“…The upper part of the underlying Miboshan Formation comprises dark-gray shale and micritic limestone representing in situ suspension deposits, whereas slump structures are well developed in the micritic limestone (He et al 2011, their Fig. 7).…”

“…Inevitably, the application of these concepts to the interpretation of the rock record met with even greater reservations. We are thus very pleased to see that our paper (He et al 2011) has received international attention-constructive discussion of the issue at hand can only be beneficial to the identification and interpretation of ancient internal-wave and internal-tide deposits in various settings. Below, we address the main points raised by Shanmugam (2012, this volume).…”

“…The term "internal-tide deposit" was coined by Gao and Eriksson in the 1990s when they studied the Ordovician Bays Formation in the Appalachians, North America (Gao and Eriksson 1991). Since then, numerous investigations have been carried out on the topicfor example, in China (e.g., Gao et al 1997Gao et al , 2000He et al 1998He et al , 2003He et al , 2005He et al , 2007He et al , 2008He et al , 2010He et al , 2011He and Gao 1999;Jin et al 2002;Guo et al 2003Guo et al , 2004Li et al 2005aLi et al , 2005bWang et al 2005;Li et al 2009Li et al , 2010.…”