A History Review On Problem For The Lower Boundary Of Quaternary Period

The lower boundary of the Quaternary / Neogene which was an important content of chronostratigraphic research also was the basic issue of Quaternary research. However, the problem had been discussed for a very long time, and it was difficult to get a consistent understanding. International Union of Geological Sciences(IUGS) approved the proposal from International Commission on Stratigraphy(ICS) that the Quaternary was a formal chronostratigraphic unit with its bottom defined as 2.588 Ma, in March 17, 2009, while the bottom boundary of the Pleistocene was from 1.8Ma down to 2.588 Ma. Since then, "Quaternary" used in geological sciences for nearly 250 years had been unified historically and obtained a legal status on the understanding for the first time. In fact, only a few people knew the rough path for the boundary establishment of Quaternary. This paper reviewed and analyzed the debate in detail in order to gain experience and lessons for China Quaternary research.Aiming at the history of Quaternary lower boundary research, based on a large number of documents and data, three main views were concluded as below:1. The establishment of geological age and its boundary was an important basic research for geology, especially for geology stratigraphy. The dispute on the boundary for Quaternary / Neogene was keen on the sign that divided the boundary, embodying in practice in geological field. This paper analyzed the origins and problems of the current signs determined for the lower boundary of the Quaternary, and the conclusions was not considered to be global synchronization, even some areas lost the possibility for a global comparison. Therefore, those signs were not be the unique sign for the boundary, and the application for "golden spike" that determined by continuous marine sedimentary section to continental sedimentary Quaternary would be some difficulties.2. Brief history of the Quaternary lower boundary in main countries and areas was summarized. Wherein(1) Quaternary lower boundary in the northwest former Green ladder glacial deposition;(2) most scholars of the Soviet / Russian accepted the suggestion of Italy Marine Calabria bottom boundary as the Quaternary lower boundary after1972, its age was 1.8Ma. If considering loess deposits lower boundary to be the Quaternary lower boundary, its age was 2.3Ma;(3) The boundary of Q / P in Japan was determined by the symbols of Metasequoia plants disappearing and temperate plants flourish. India Malaysia fauna transformed into China Nihewan fauna, the boundaries of which are located in Auburn dimensional positive subchron;(4) Quaternary strata of the Indian subcontinent was mainly for siwalik group, but where was Quaternary lower boundary of siwalik group exactly, further work should be done to determine.3. Current research status for Chinese Quaternary lower boundary were summarized. At present China Quaternary research tended to be the age for 2.4~2.6Ma, although there were several other views. At last, the establishment of Nihewan step indicated that the limits and solution s in the research of Chinese Quaternary lower boundary.