Terahertz transmission spectroscopy of soil minerals for geoarchaeological evaluation of sediments excavated from Pinagbayanan Batangas Philippines

Abstract Sediments consisting of different soil minerals were collected from an archaeological site located in Pingabayanan Batangas Philippines. Each of the soil samples from selected layers or sampling depth was examined and profiled. Standard characterization techniques such as XRF, XRD, and FTIR spectroscopy were then performed for elemental and crystal analysis. All three aforementioned characterization techniques are in good agreement with the archaeological descriptions of sediments profile. Moreover, terahertz (THz) transmission spectroscopy was also performed to explore the feasibility of utilizing this novel spectroscopy for characterizing soil minerals. Terahertz time-domain spectroscopy (THz-TDS) results show good agreement to the standard characterization results in terms of detection of trace metals and minerals. Hence, the THz transmission spectra can provide necessary information related to the sedimentation profile and archaeological recordings that were conducted. Results suggest that THz-TDS may prove as a quick and non-destructive method to study soil samples, complementary to standard techniques for geoarchaeological surveys.