干旱区生态环境知识资源中心

A pollen record from Haiyuan section in the southern part of Ningxia revealed a detailed history of vegetation variation and associated climate changes during the period from similar to 13.0 to similar to 7.0 C-14 ka BP. A steppe landscape under a moderately dry (and probably cool) condition (-12.7-similar to 12.1 C-14 ka BP) was replaced by a coniferous forest dominating the landscape under a generally wet climate from similar to 12.1 to -11.0 C-14 ka BP. This generally wet period, corresponding to the European Bolling/Allerod period, can be divided into three stages: a cool and wet stage between similar to 12.1 and similar to 11.4 C-14 ka BP, a mild and relatively dry stage between similar to 11.4 and similar to 11.2 (14) C ka BP, and a mild and wet stage between similar to 11.2 and similar to 11.0 (14) C ka BR The coniferous forest-dominated landscape was then deteriorated into steppe landscape (similar to 11.0-similar to 10.6 (14) C ka BP) and further into a desert steppe landscape from similar to 10.6 to similar to 9.8 (14) C ka BP, being correspondent to the European Younger Dryas period. After a brief episode of a cool and wet climate (similar to 9.8-similar to 9.6 C-14 ka BP), a relatively mild and dry condition prevailed during the early Holocene (similar to 9.6-7.6 (14) C ka BP) and then a warm and humid climate started the mid-Holocene (similar to 7.6-similar to 7.2 (14) C ka BP).