中文摘要：

Ky1石笋采自山东半岛西部的开元洞,沿生长轴方向长度75mm。在高精度U-230 Th测年基础上,通过年纹层连续计数和平均沉积速率内插/外推相结合的定年方法,确定Ky1石笋生长于892—1894AD的1 000年间。在沿石笋生长轴采集的583个样品中,选择303个进行了δ18 O、δ13 C测试,平均分辨率约为3年。结果显示,最近1000年来Ky1石笋的δ18 O比值变化呈现明显阶段性,显示与小冰期（LIA）和中世纪暖期（MWP）对应的数百年尺度波动。根据δ18 O记录,山东半岛在1482AD前后发生与MWP/LIA转换对应的气候突变,1 482AD前相当于夏季风强烈、降水较多的中世纪暖期,1482AD后则为夏季风微弱、降水较少的小冰期,以1609AD夏季风最弱。Ky1石笋的δ13 C比值变化,也由与MWP、LIA相当的两个阶段构成,其间也存在突变关系。比较而言,δ13 C变化要比δ18 O显著平缓,而且LIA后期以来二者变化明显不同步。最近1 000年来,与MWP/LIA对应的气候突变相当于明朝中期;就各个朝代内部的气候变化趋势而言,不同朝代之间不尽相同;不同朝代之间的更替期均大致与MWP、LIA内部的次级气候突变时期对应。因此,中世纪暖期和小冰期内部的次级气候波动对中国社会发展的影响,可能比千年尺度上最剧烈的MWP/LIA突变本身更显著。另一方面,洞穴所在山地的土地利用程度不断提高,其与气候变化共同影响着洞穴所在山地的植被的C3/C4植物构成及土壤性质,从而影响到石笋δ13 C比值。从892—1318AD,土地利用对山地植被构成、土壤特征的影响程度尚不及气候变化;1318—1479AD,已达到或超过小幅度的气候变化;1483—1779AD,达到或超过大幅度的气候变化;1779—1894AD,土地利用程度趋于稳定,气候变化对环境的影响程度则又相对凸显。

英文摘要：

The Stalagmite Ky1,a 75 mm long stalagmite,was collected from the Kaiyuan Cave on western Shandong Peninsula.Upon the basis of high precision U-230 Th dating,further dated with annual lamination counting and interpolation/extrapolation of the average deposition rate,the stalagmite is about 1 000 years in age from 892 AD to 1894 AD.583samples are collected along the growth axis of the Ky1 stalagmite,and theδ18 O andδ13C values for 303 samples are measured.The average temporal resolution is about3 years.Theδ18 O values of the stalagmite Ky1 are obviously phased in the recent 1000 years.There are a series of centennial to multicentennial climatic fluctuations in the Little Ice Age（LIA）and Medieval Warm Period（MWP）.Theδ18 O records also indicates a climate mutation occurred at about 1482 AD on Shandong Peninsula corresponding to the MWP/LIA transformation,relatively wet and strong summer monsoon climate was prevailing over the Medieval Warm Period before 1482 AD,and relatively dry and weak summer monsoon climates dominated the Little Ice Age after 1482 AD.The weakest summer monsoon occurs in1609 AD.Theδ13C curve of the stalagmite Ky1 is also composed of the two stages corresponding to MWP and LIA respectively with a mutation in between.Relatively,the curve ofδ13C is smoother than the curve ofδ18 O and the variation inδ13C values andδ18 O values are obvious out of sync in late LIA.The climate mutation corresponding to the MWP/LIA transformation was happened roughly in the middle Ming Dynasty in China.The climate variation tendency is different in different dynasties.The changing stages of different dynasties are usually corresponding to the secondary climate period within MWP and LIA.So the impact of the fluctuation of the secondary climate variation on human society development in MWP and in LIA looked more prominent than the most violent climate transition between MWP and LIA in a millennium scale.On the other hand,the degree of the land use showed unceasing enhancement in the study area together wi