High resolution stalagmite records of climate change since 800a A.D. in Libo,Guizhou
Year: 2008
Type: article
Abstract: Stalagmite L1 and stalagmite L2 from Longquan cave(N25°29′,E107°52′,550m altitude) at Libo,Guizhou are 50cm and 192cm high respectively.On the basis of 19 ICPMS 230 Th ages and 459 stable oxygen-carbon isotope samples analysis,it proves that the stalagmite L1's time range is from 918a A.D.to 1910a A.D.and the stalagmite L2 is from 724a A.D.to 1888a A.D..The stable isotope average resolution of the stalagmite L1 and stalagmite L2 are 6.6a and 3.6a respectively.The records of δ18O from the two stalagmite are coherent,which can be divided into three climatic periods:(1) Medieval cold period(724-995 a A.D.).During this period,δ18O of the stalagmite becomes heavier but the change scope is small,and the lightest value of oxygen isotope is-8.84‰,the heaviest value is-6.72‰ and the average is-7.76‰ which is 0.16‰ heavier than the average value of the two stalagmite(-7.92‰);(2)Medieval warm period(995-1340 a A.D.).It is recorded by stable oxygen isotope in the shape of two wave crest and one trough which form half a 200-year gyration,corresponding to two strong monsoon periods and one relative weak monsoon period.And the lightest value of oxygen stable isotope is-9.47‰,the heaviest-6.58‰ and the average-7.94‰;(3) Small ice age(1340-1880 a A.D.).This climatic period is recorded by stalagmite in the form of three wave crests and four troughs alternately that indicates 3 and half a 200-year monsoon gyration.In this climatic period,the lightest value of stable oxygen isotope is-9.50‰,the heaviest-6.07‰ and the average-7.92‰ which is larger than that of the medieval warm period and furthermore,fluctuating range of stable oxygen isotope is bigger than that of medieval warm period,especially in weak monsoon period.The stable oxygen isotope records from stalagmite L1 and stalagmite L2 parallels phonological records in east China well. As a whole,the change pattern of stalagmites can parallel records in the Greenland ice core.The stalagmite records can also parallel the production of cosmic nuclide and solar flare records.During small ice age,four troughs of stable oxygen isotope in stalagmite records(weak monsoon period) just correspond to low productive rate of cosmic nuclide and troughs of solar flare curve,and furthermore,four trough of stalagmite records coincided with sunspot activities: Dalton Minimum(1810),Maunder Minimum(1645-1715),Spreal Minimum((1420-1530) and Wolf Minimum(1280-1440) respectively.The change of sunspot leads to the change of solar radiant energy received by the earth directly.It shows that short scale monsoon climate at low latitude zone immediately respond to change of solar radiant energy.
Source: Zhongguo yanrong
Author: Jingcheng Ran
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: diamond
OpenAlex ID: W2390171768