Use of environmental magnetic measurements to characterize and correlate tephra-A case study in Iceland  

作　　者：XIADunsheng J.Bloemendal R.C.Chiverrell J.A.Dearing JINMing 

机构地区：[1]KeyLaboratoryofDesertandDesertification,ColdandAridRegionsEnvironmentalandEngineeringResearchInstitute,ChineseAcademyofSciences,Lanzhou730000,China [2]EnvironmentalMagnetismLaboratory,DepartmentofGeography,TheUniversityofLiverpool,Liverpool,L693BX,UK

出　　处：《Chinese Science Bulletin》2004年第3期286-294,共9页

摘　　要：A set of environmental magnetic parameters(i.e. magnetic susceptibility, xARM, IRMs, hysteresis loops and thermomagnetic curves) has been applied to two soil sections from SE Iceland. Results demonstrate that the main magnetic minerals in the tephras are ferrimagnetic minerals (e.g.magnetite) and canted antiferromagnetic minerals (e.g.haematite), with abundant paramagnetic material also present. Cross plots of Mrs/Ms vs. (B0)cr/(B0)c and xfd% vs.xARM/SIRM indicate that the main magnetic grain sizes in tephras are pseudo single domain (PSD) and multidomain(MD). Initial correlation of tephra layers was achieved, usingall the measured magnetic parameters, by use of the multi-variate statistical measures of Similarity Coefficient (SC) andEuclidean Distance (ED). This demonstrates that magnetictechniques can potentially assist in the identification andcorrelation of distal tephra.A set of environmental magnetic parameters (i.e. magnetic susceptibility, XARM IRMs, hysteresis loops and thermomagnetic curves) has been applied to two soil sections from SE Iceland. Results demonstrate that the main magnetic minerals in the tephras are ferrimagnetic minerals (e.g. magnetite) and canted antiferromagnetic minerals (e.g. haematite), with abundant paramagnetic material also present. Cross plots of Mrs/Ms vs. (B0)cr/(B0)c and Xfd% vs. XARM/SIRM indicate that the main magnetic grain sizes in tephras are pseudo single domain (PSD) and multidomain (MD). Initial correlation of tephra layers was achieved, using all the measured magnetic parameters, by use of the multi-variate statistical measures of Similarity Coefficient (SC) and Euclidean Distance (ED). This demonstrates that magnetic techniques can potentially assist in the identification and correlation of distal tephra.

关 键 词：火山灰 冰岛 磁性参数 相似系数 欧几里德距离 

分 类 号：P619.264[天文地球—矿床学]