太白山高山带距今5520年以来气候-环境变化--佛爷池沉积物的多指标记录及其结果的解译  

Climatic and Environmental Changes Occurring during the Last 5520 Years on Alpine Belt of Taibai Mountain: the Records of a Few Proxies of Sediments from Foye Chi and Their Interpretations

作　　者：张彩娜 王红亚[1] 刘鸿雁[1] 程颖 宋雅琼[1] 罗耀[1] 邓雷 

机构地区：[1]地表过程与模拟教育部重点实验室、北京大学城市与环境学院,北京100871

出　　处：《北京大学学报（自然科学版）》2015年第6期1091-1101,共11页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金(41171160)资助

摘　　要：佛爷池为秦岭主峰太白山南坡高山带的冰蚀湖。在其干涸的底床挖掘一条深70cm的探坑，自坑壁取得沉积物样品。对这一剖面的3个样品做加速器质谱（AMS）HC测年，56个样品做总有机碳含量（TOC）和碳／氮比值（C／N）分析、低频磁化率（χIf）和非滞后性剩磁（ARM）测试、粒度分析和孢粉分析，并计算ARM／χIf。利用这些测年结果建立这一剖面的年代框架，并对TOC和C／N，χIf，ARM和ARM／χIf，平均粒径及栎属孢粉（Qucercus）含量在剖面中的变化进行解译，由此初步推测佛爷池周边距今5520年以来的气候及环境变化。在5520～3800aBP,气候为冷干，在其中的5100-4300aBP冷干程度可能最强。在3800～2300aBP,气候渐转暖湿。在2300～1300aBP,气候更为湿润。在1300～700aBP,气候更为温暖，可能是过去5500多年中最温暖的时期。在700。500aBP,气候再度变冷、变干。由于共同受到东亚季风的影响，太白山高山带中、晚全新世这一气候-环境变化与中国东亚季风区一些地点的变化趋势颇为相似。Foye Chi is a small lake developing in a cirque in the alpine belt of southern slope of Taibai Mountain which is the peak of the Qinling Mountain Range. A 70 cm deep pit was excavated on the desiccated floor of this lake and sediments were sampled from the pit＇s wall. AMS 14C dating was performed for three samples from this sediment profile. For all the 56 samples, anal）,sis of total organic carbon content （TOC） and carbon-nitrogen ratio （C/N） and measurements of low-frequency magnetic susceptibility （χIf） and anhysteretic remanent magnetization （ARM） were undertaken. So were analyses of particle-size and pollen. ARM/χIf was further calculated as well. A chronological framework was developed based on the dating results. Variations in TOC, C/N, χIf, ARM, ARM/χIf, mean particle-size and percentage of Quercus pollen of this sequence were interpreted and climatic and environmental changes occurring around Foye Chi since 5520 aBP were so preliminarily inferred. The climate and environment were generally cold and arid during 5520-3800 aBP and the coldest and driest during 5100-4300 aBP. During 3800-2300 aBP, the climate and environment have turned to be warm and humid. The climate and environment were even wetter during 2300-1300 aBP and warmer during 1300-700 aBP which might be the warmest phase of the last -5500 years. During 700-500 aBP, the climate and environment tended to be cool and arid again. These climate-environment changes happening during the middle and late Holocene in alpine belt of Taibai Mountain are generally similar to the changes at some sites in the region influenced by the East Asian monsoon in China since these sites are all under the influence of East Asian monsoon.

关 键 词：佛爷池 湖泊沉积物 太白山 高山带 古气候-环境变化 

分 类 号：P467[天文地球—大气科学及气象学]