I basically agree with the viewpoints of Shanmugam (Journal of Palaeogeography 7(3):197-238, 2018) and Zavala (Journal of Palaeogeography 8(3), 2019) who cited, refined and interpreted the definitions of hypopycnal flow, homopycnal flow and hyperpycnal flow. I appreciate two typical case studies of hyperpycnal flows induced by the Yellow River and Yangtze River, and the Gaoping River. The former is a normal type while the latter is catastrophic. They make up a complete knowledge about hyperpycnal flows and hyperpycnites. According to the interpretation of the word “hyperpycnal” from Greek to English, the “hypopycnal flow” should be “less density flow” or “lower density flow” (“低密度流”), the “homopycnal flow” should be “equal density flow” (“等密度流”), and the “hyperpycnal flow” should be “higher density flow” or “over density flow” (“高密度流” or “超密度流”). Some geologists called the “hypopycnal flow” as “异轻流” (“abnormally light flow”) and called the “hyperpycnal flow” as “异重流” (“abnormally heavy flow”). There are at least more than 10 names or terms about the “density flows” and the “deposits of density flows”. It is a problem indeed. In addition, the density could be changed by salinity, temperature and pressure of water. Therefore, the term “density flow” may be problematic either. Another problem is that reliable and irrefutable identification markers of ancient heperpycnites are lacking. We should observe the policy of “A hundred flowers blossom and a hundred schools of thought contend” to discuss these problems and to promote progress and development of hyperpycnal flows and hyperpycnites.

中文翻译：

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主编的话——关于高密度流和高密度石的评论和讨论的一些想法

我基本同意 Shanmugam (Journal of Palaeogeography 7(3):197-238, 2018) 和 Zavala (Journal of Palaeogeography 8(3), 2019) 的观点，他们引用、细化和解释了低密度流、同密度流的定义和超重血流。我欣赏了黄河、长江和高平河引起的超重流的两个典型案例研究。前者是正常类型，而后者是灾难性的。它们构成了关于高密度流和高密度岩的完整知识。根据“hyperpycnal”一词从希腊语到英语的解释，“hypopycnal flow”应为“低密度流量”或“低密度流量”（“低密度流”），“同密度流量”应为“等密度流量”密度流”（“等密度流”），“高密度流”应为“高密度流”或“超密度流”（“高密度流”或“超密度流”）。有地质学家称这种“低密度流”为“异轻流”（“异常轻流”），将“高密度流”称为“异重流”（“异常重流”）。关于“密度流”和“密度流的沉积物”的名称或术语至少有10多个。这确实是个问题。此外，密度会因水的盐度、温度和压力而改变。因此，术语“密度流”也可能有问题。另一个问题是缺乏可靠的、无可辩驳的古代高铁矿识别标记。我们应该遵循“百花盛开，百家争鸣”的方针来讨论这些问题，促进高密度流和高密度流的进步和发展。