The first right upper premolar discovered in 1994 has been dated using laser ablation ICP-MS. Dating procedures followed those applied to the Banyoles mandible (Grün et al. 2006). Combining the ESR and U-series data for the modelling of the U-uptake (Grün et al. 1988), an US/ESR age of 501 +94 -76 ka is obtained (with associated p-values of 1.43 ± 0.59 and 0.75 ± 0.45 for enamel and dentine, respectively). Sediment samples were used for OSL dating. The OSL measurement followed the procedures applied in previous studies of the Pleistocene successions of Casablanca (Rhodes et al. 2006). The sample above the tooth yielded an age of 420 ± 34 ka and the one below 391 ± 32 ka. These results are in agreement with an earlier OSL study, which bracketed the age between 360 and 470 ka. Nevertheless, lithostratigraphy and biochronology suggest that this is a minimum age.
It would seem that approximately 500,000 years old for the Thomas Quarry I fossils is the most appropriate geographical age.
Three quarries near Casablanca (Morocco) which have produced Middle Pleistocene faunal material, Acheulean tools, and hominid specimens. The Thomas 1 quarry yielded a mandible in 1969; the Thomas 3 quarry, cranial fragments in 1972. The sites are of approximately the same age, close to that of the nearby finds from Salé and Sidi Abderrahman, ca. 400-300 Ka.
The Thomas 1 mandible is similar to those from Tighenif (formerly Ternifine) in Algeria, especially mandible 3, but is robust with large teeth, although the third molar is reduced in size. The Thomas 3 cranial fragments have not yet been studied in detail, but they include frontal, facial, and dental parts of a small individual, probably comparable with the Salé specimen in size. The associated teeth, like those of Salé, are large and heavily worn, yet the associated face is delicately built. A 1992 study using CT (computed tomography) scans has permitted reconstruction of a nearly complete skull from the combined Salé and Thomas 3 remains, suggesting membership in “archaic Homo sapiens.”