Abstract
This paper presents new field observations that assist in further defining the extent of Last Permafrost Maximum (LPM)permafrost and frozen ground in north China. In that respect, this region is specific by its arid environment and continental position. Bedrock exposures and sand and gravel pits were examined along a south-north transect from southern Ordos as far as the vicinity of Dongsheng District, Ordos City on the Ordos Plateau (North China). Attention focussed upon the recognition of sand-wedge remains and possible cryoturbations. Two types of wedge structures were recognized: type A wedges extend to depths in excess of 3.0 m and are thought to have formed under conditions of continuous permafrost. Type B wedges are restricted to the upper 1.5 m and are thought to reflect discontinuous permafrost and/or deep seasonal frost. OSL dating of wedge infills indicates that type A wedges formed between 23–19 ka and younger type B wedges formed until the early Holocene. It is now possible to delineate a more exact position of the boundary between continuous permafrost and discontinuous permafrost and/or deep seasonal frost on the Ordos Plateau during the LPM. This boundaries occur between Dongsheng and Jinbian at 37°-39°N.
| Original language | English |
|---|---|
| Pages (from-to) | 87-97 |
| Number of pages | 11 |
| Journal | Quaternary Science Reviews |
| Volume | 214 |
| Early online date | 14 May 2019 |
| DOIs | |
| Publication status | Published - 15 Jun 2019 |
Funding
Research was jointly supported by the National Natural Science Foundation of China and Russian Federation Bureau of Research on Formation, modern state of Pleistocene cryogenic deposits in Eastern Asia, and forecast of their dynamics in relation to the ongoing climatic variations (Grant No. 41811530093 ), a subproject of Chinese Academy of Sciences Strategic Pilot Science and Technology Project Permafrost in China during the Holocene Megathermal Period and Last Glaciation Maximum (Grant No. XDA05120302 ). Fieldwork undertaken by H.M. French was supported by the CAS, when he was a visiting professor at the State Key Laboratory of Frozen Soils Engineering (SKLFSE, CAS), Lanzhou in 2015. Fieldwork by J. Vandenberghe was also supported by the SKLFSE, CAS, in June 2015 and June 2018. The authors thank the reviewers for their helpful suggestions and Xiaoying Li and Ansley Charbonneau for their help with Fig. 1 . Appendix A
| Funders | Funder number |
|---|---|
| Holocene Megathermal Period and Last Glaciation Maximum | |
| Russian Federation Bureau of Research on Formation | |
| National Natural Science Foundation of China | 41811530093 |
| Chinese Academy of Sciences | XDA05120302 |
| State Key Laboratory of Frozen Soil Engineering |
Keywords
- China
- Dongsheng
- Last permafrost maximum
- Ordos
- Permafrost
- Permafrost extent
- Sand wedge
- Sand-wedge cast
