Demagnetization of igneous rocks by alternating magnetic fields

摘要: Abstract The presence of secondary components magnetization in basalts often limits the usefulness their directions natural remanent megnetization for palaeomagnetic work. Them may be removed by alternating magnetic fields. procedures doing this are described end tests based on internal consistency results re devised to judge reliability. supplied successfully a series from specimens collected Tertiary New South Wales. Australia. and determination geomegnetic field S.E. Australia during Lower is obtained. A study behaviour these high fields suggests that most iron mineral grains have multi-domain character, contain hard soft component ratio about 1:10.