LASER-INDUCED BREAKDOWN SPECTROSCOPY OF SILICATE, VANADATE AND SULFIDE ROCKS

Laser-induced breakdown spectroscopy (LIBS) in air at atmospheric pres sure has been used to study four logical samples belonging to differen t structural families. Atomic emission spectra of vanadinite, pyrite, garnet and a type of quartz (compostela's quartz) are shown. The 532 n m line of a Nd:YAG laser at an irradiance of 18 x 10(11) W cm(-2) was used. The precise focus of the beam allowed microanalysis of a 0.02 mm (2) surface area working in single-laser shot mode. The use of an inte nsified gateable charge-coupled-device (CCD) detector permitted time-r esolved studies. The spectral lines have been assigned to transitions in the neutral charge state of the corresponding atom of the material under investigation. The behavior of different transitions with time d elay are shown. In experiments, minor components contained in several minerals have been detected. This fact has been used to demonstrate th e applicability of the technique to characterize and identify similar minerals.