摘要
本文对青藏高原东北部全新世风成沉积剖面的年代数据应用概率密度方法结合年代数据分布情况重建了该区全新世风沙活动历史.结果表明:青藏高原东北部早全新世风沙活动强烈,但也存在不同尺度的空间差异,表现在共和盆地、柴达木盆地及青海湖盆地风成砂都广泛发育,但青海湖盆地同期还有古土壤发育,冬给措纳湖流域在这一时期也有少量的风成砂层出现;中全新世古土壤广泛发育,风沙活动较弱,整个东北部具有较好的一致性;晚全新世以来,柴达木盆地和冬给措纳湖流域风成砂发育较好,而共和盆地古土壤广泛发育,同时青海湖盆地风成砂和古土壤均有出现,说明风沙活动强度的区域差异较大,这可能是由于局部地区受到了人为活动强烈干扰的影响.风沙活动强度与区域有效湿度密切相关,区域有效湿度较高时,风沙活动较弱;反之,风沙活动较强.另外,大面积湖泊的存在使得青海湖盆地和冬给措纳湖流域全新世风沙活动的特点与柴达木盆地和共和盆地不尽相同,湖泊水位与湖泊增湿降温效应的相互关系以及物源供给特点可能是造成这一现象的原因.年代数据的概率密度方法相对于频率统计直方图具有一定的优势,充分利用了单个年代数据符合正态分布的特点,能够反映年代数据的范围和精度.
Aeolian deposits are widely distributed in the Northeastern Tibetan Plateau.Dating of the Holocene eolian sedimentary section in Northeastern Plateau was done.Probability density method was used to reconstruct Holocene aeolian activity history.It was found that Early Holocene aeolian activity was strong in the Northeastern Tibetan Plateau,but differences between different spatial scales were also found,mainly between different basins and in internal parts of the Qinghai Lake Basin.Aeolian sand was found to be welldeveloped in Gonghe Basin,Qaidam Basin and Qinghai Lake area,but Qinghai Lake area also had simultaneous paleosol.Eolian sand layer almost does not appear during this period in the Donggi Cona catchment.Middle Holocene,paleosol is widely developed,aeolian activity is weak,the whole northeast of the Tibetan Plateau has good consistency.Since the late Holocene,aeolian sand has been well-developed in the Qaidam Basin and the Donggi Cona catchment,but paleosol is well-developed in the Gonghe Basin,aeolian sand and paleosol both appear during this period in the Qinghai Lake area.Regional differences in strength of aeolian activity are large,possibly due to local human activities.Aeolian activity intensity is closely related to effective moisture,the higher the effective moisture,the weaker the aeolian activity.Further,Holocene aeolian activity in the Qinghai Lake area and the Donggi Cona catchment is different from aeolian activity in the Qaidam Basin and Gonghe Basin because they have large lakes,interrelation of lake level and humidifying cooling effect of the lake,also and the correlation between lake level and detrital materials mainly originate from lake may be the cause of this phenomenon.Compared to frequency histogram,probability density method of dating has some advantages.This makes full use of the characteristic that dating is subordinate to normal distribution law,reflecting error ranges and accuracies of dating data.
出处
《北京师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2016年第1期97-104,共8页
Journal of Beijing Normal University(Natural Science)
基金
国家重点基础研究发展计划基金资助项目(2013CB956001)
国家自然科学基金资助项目(41071129)
地表过程模型与模拟创新研究群体科学基金资助项目(41321001)
关键词
青藏高原
东北部
全新世
风沙活动
年代数据
Qinghai-Tibetan
northeastern
Holocene
aeolian activity
dating data
