Turquoise Sources (IMAGE) Geological Society of America Caption Figure 1 from Thibodeau et al., GSA Bulletin, June 3, 2015: Turquoise sources in the southwestern United States and northern Mexico for which lead and strontium isotopic ratios are reported or discussed in Thibodeau et al. Credit Thibodeau et al., <i>GSA Bulletin</i>, 2015. Usage Restrictions Credit: Thibodeau et al., <i>GSA Bulletin</i>, 2015. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.