Science. 1988 Nov 25;242(4882):1152-5. doi: 10.1126/science.242.4882.1152.
Laser-selective demagnetization (LSD) enables the determination of the magnetic moment associated with individual mineral grains in thin sections of rock. Small volumes can be demagnetize with laser pulses directed through the optics of a microscope, permitting resolution of remanence components in individual mineral grains. LSD of mafic granulite samples revealed two paleomagnetic directional components of opposite polarity: one resided in coarse magnetite, the other in ilmenohematite-hemoilmenite exsolution intergrowths and fine magnetite indusions in clinopyroxene. These directions are consistent with those inferred from bulk demagnetization techniques, but LSD permits direct identification of the remanence carriers. The ability to discriminate magnetization components in different generations of a single mineral and to define intergrain magnetic moment distributions are significant advantages of LSD.
激光选择去磁（LSD）可用于确定岩石薄片中单个矿物颗粒的磁矩。通过显微镜的光学器件引导激光脉冲，可以对小体积进行去磁，从而在单个矿物颗粒中解析剩余磁化强度分量。对镁铁质麻粒岩样品的 LSD 揭示了两个极性相反的古地磁方向分量：一个位于粗磁铁矿中，另一个位于钛铁矿-铁钛矿析离体和细磁铁矿包裹体中。这些方向与从整体退磁技术推断的方向一致，但 LSD 可直接识别剩余磁化强度载体。在单个矿物的不同世代中区分磁化分量并定义晶粒间磁矩分布的能力是 LSD 的重要优势。
