Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor, NW China Since the Last Interglacial  

作　　者：YANGTaibao YUYongtao LIJijun ANCongrong LIUJinfeng ZHANGJunyan 

机构地区：[1]KeyLaboratoryofWesternEnvironmentalChanges,ChineseMinistryofEducation,LanzhouUniversity,Lanzhou730000China [2]DepartmentofGeography,SchoolofGeosciences,NanjingNormalUniversity,Nanjing210097,China [3]InstituteofGeologyandGeophysics,ChineseAcademyofSciences,Beo＇ing100029,China

出　　处：《Journal of Mountain Science》2004年第2期128-142,共15页山地科学学报（英文）

基　　金：This work is funded by the National Natural Science Foundation of China(NSFC Grant No.94731010).

摘　　要：Paleomagnetic determinations on lithological profiles of two paralleled[( )-275(long )]drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event ([(28.4)( )]kyr~[(25.8)( )]kyr), Laschamp Event ([(43.3)( )]kyr^40.5 kyr), Gaotai Event (82.8 kyr~[(72.4)25( )]kyr) and the Blake Event (127.4 kyr^113.3 kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1-H6)[(. )-250( )]Here,[( )-250( )]we tentatively[( )-250( )]propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earths magnetic field shifted between a temporal normal and a negative period, the earths magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earths incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions.

关 键 词：PALEOMAGNETISM geomagnetic excursion the Late Pleistocene arid Northwestern China 

分 类 号：P318.44[天文地球—固体地球物理学] P534.631[天文地球—地球物理学]