detected in the TMQ by XRF (Table 2),
may substitute Si4 in the tetrahedra,
producing charge imbalance compensated by interstitial cations in the SiO2 framework .
When the crystal lattice is subjected to stress, Garcia-Guinea etal.(2007) correspond the 340 nm TL band emission of many silicate minerals , including quartz , to silicon–oxygen bonding defects produced.
Al and Ti substitute Si in [SiO4] tetrahedron giving rise to the Al - center and Ti centers.
Pailão and Watanabe(2008) showed that the Al has astrong effect on the
TL intensity compared to Fe ,Ca ,Ti and Mg.
Especially , Al 2O3 enhances low temperature peaks.