Terahertz Dating of Sedimentary Rocks

Abstract

The depositional products of sedimentary rocks provide vital references for investigating the paleoenvironment, paleogeography, and tectonic evolution history. However, the detection methods of geological evolution are still relatively complicated, and how to combine geological age and geological evolution is confusing. Based on the sensitivity of terahertz waves to organic matter, a THz dating method was introduced for characterizing the geological age of sedimentary rocks. In this study, the geological evolution of Liujiang Basin was analyzed by using terahertz time domain spectroscopy (THz-TDS). According to the close relation between organic matter content and sedimentary environment, it can be inferred that the geological deposition in this area is affected by Marine cover. In addition, the refractive index of Ordovician sedimentary rocks is significantly higher than that of other sedimentary rocks. Based on these results, it is inferred that the sedimentary environment of the Liujiang Basin gradually changed from continental deposition to deep-water marine deposition from the Neoproterozoic to the Ordovician, and the sea water gradually retreated due to the crustal movement, resulting in a transition from deep-water deposition to continental inshore ocean facies deposition. These findings are highly consistent with the geological history of the study area. Combined with principal component analysis (PCA) technology, the relative geological age of sedimentary rocks can be divided. Our study con-firmed the reliability of this THz dating technique, which provides an effective way to study the geological evolution history of sedimentary rocks.

The high-performance linear scan imaging system of terahertz Si-based blocked-impurity-band detector

“…The blocked-impurity-band (BIB) detector is a new type of THz detector, which uses low-frequency breakthrough technology from infrared to achieve THz detection. With its high sensitivity, large array scale, and wide detection spectrum advantages (Iglesias et al, 2008;Woods et al, 2011), the BIB detector stands out among the THz detectors and has been widely used in space target detection (Reynolds et al, 1989;Werner, 2005), atmospheric monitoring (Hogue et al, 2008), astronomical observation (Hanaoka et al, 2016;Xiao et al, 2022) and other fields (Kaplan et al, 2021;Meng et al, 2022).…”

Terahertz Dielectric Permittivity Anisotropy and Fabric of Oil Shales: Comparison to Acoustic, Magnetic Susceptibility, and X-ray Microtomography Results

“…Although the results obtained more than 30 years ago indicated encouraging results, − it has not been widely developed mainly due to experimental difficulties, such as the use of electrodes. However, recently, thanks to advanced technologies, a better way to measure dielectric permittivity using high-frequency electromagnetic (EM) waves (>0.8 THz) has been proposed. ,− In particular, in refs and − , the authors link the measured terahertz (THz) signal to the organic matter of the shales, and in refs − , to its change as a result of temperature-maturation. Specially, in three papers, ,, the authors have worked on the anisotropy of the dielectric permittivity in the THz band.…”