- 责任者：Dong Jinguo (College of Geography Science ; Nantong University ; Nantong 226007 ; China)
- 刊名：Quaternary Sciences
- 出版年：2013
- 卷期：33(1)
- 关键词：石笋 ; stalagmites ; 古气候 ; paleoclimate ; 湖北 ; Hubei Province
- 页码：p.146-154
- 图表：illus., 1 table, 45 refs.
- 分类号：1400
- issnNo：ISSN1001-7410
- isbnNo：CN11-2708/P
The Sanbao Cave （31°40＇N, 110°26＇E） is located at an elevation of 1900m on the northern slope of Mt. Shennongjia,near the southern edge of Chinese Loess Plateau. Precipitation in the region is highly seasonal because of its position within the modern subtropical front. The mean annual rainfall and temperature at Sanbao Cave are typically around 2000ram and 8 ～9℃. During the boreal summer seasons（ June through to September） , the inflow of warm/humid air from equatorial Pacific penetrates into the northern slope of Mt. Shennongjia, delivering more than 60% of total annual precipitation. Sanbao Cave is 〉 1200m long with chambers up to 300m below the surface. Dense forested vegetation, consisting primarily of temperature deciduous broad-leaved plants, covers above the cave and surrounding areas. The soil above the cave is several meters thick. Relative humidity in the cave is 95% and cave temperature （9℃） approximates mean annual value. Seventeen stalagmites （ No ： SB3, SB10, SB11, SB22, SB23, SB24, SB25 - 1, SB25-2, SB26, SB27, SB34, SB41, SB42, SB43, SB44, SB46 and SB49 ） were collected in different position of Sanbao Cave. The longest stalagmite（SB41 ）is 925mm and the shortest（ SB3 ）is 135mm. Aeumulative length of all stalagmites is 6469mm. Diameters vary from 200ram to 150mm on the bottom and from 20mm to 80mm on the top. All of the samples were cut into two halves along the growth axis and the surface was polished. Every stalagmite is pure and slightly porous on the polished surface. Samples for dating were drilled using carbide dental burrs following stratigraphic horizons. A total of 190 sub-samples were measured by an inductively coupled plasma mass spectrometry（ICP-MS） on a Finnigan-MAT Element at the department of Geology and Geophysics, University of Minnesota,USA. The uncertainty of reported age is ±2σ,usually better than 0.8% in relative error. The timing of growth period in 17 stalagmites from Sanbao Cave has been precisely dated for the period of 220kaB. P. Here,the result shows the variability of the stalagmite growth rate changed in glacial-interglacial cycles That is, during the interglacial period, the average growth rate was more than 70μm/a, while it was less than 25μm/a in the glacial period. So the growth rate of stalagmites was 200% higher during the wet warm marine isotope stage 1 and 5 （ MIS land MIS 5 ） than during the dry cold marine isotope stage 2,4 and 6 （ MIS 2, MIS 4 and MIS 6）. In progressively,we analyse growth frequency of 17 stalagmites with 5000 year-step in the same cave. The results show the highest accumulative growth frequency during the Holocene and the last interglacial period, being 60% of the whole growth quantity and the lower accumulative growth frequency during the last glacial period and the penultimate glacial period,which takes up only 28% of the whole growth quantity. So,the growth rate and quantity of the Cave stalagmite could reflect the shift of the outer cave climate in the orbital scale. We suggest that high sea level and strong summer insolation for 33°N during the interglacial period strengthen the East Asian summer monsoon and developed well in vegetation above the cave, which increase the calcite super-saturation of drip water, and finally result in abundance stalagmites.