Magnetic Fabric of Late Devonian Metasedimentary Rocks from Longyan,Southwestern Fujian,China

摘要

This study presents the results of magnetic fabric on Late Devonian metasedimentary rocks fromLongyan,Southwestern Fujian,China.Measurements of low—field anisotropy of magnetic susceptibili-ty(AMS)were made on 59 specimens(sites 48—53)using a Sapphire SI—2 induction coil instru-ment.Our data show that the magnetic fabric at sites 48—51 and 53 is mainly carried by paramagneticminerals(muscovite,chlorite and biotite),while at site 52 both paramagnetic minerals and hematite con-tribute to the total AMS.Separation of the two components of anisotropy indicates that they areapproximately coaxial.The magnetic foliation is either parallel to an Indosinian(Late Triassic)metamorphic schistosity(sites 48—52)or to a Yanshanian(Late Mesozoic)microscopicmylonitic foliation(site53).The magnetic lineation corresponds either to the regional structural trend(sites48—52)or to the line of intersection between the schistosity and the mylonitic surface(site 53 ).Our re-sults suggest that Indosinian metamorphism and