Multi-Technique Analysis of Geochemical Elements in Kesongo Volcanic Mud Using Advanced Calibration-Free LIBS and X-ray Fluorescence Spectroscopy (XRF)

The determination and quantification of geochemical constituents in Kesongo volcanic mud are highly essential for identifying valuable elemental compositions. In this study, two spectroscopic methods were employed to identify and quantify the elemental content of mud samples collected from eight sites near the eruption center in Indonesia: calibration-free laser-induced breakdown spectroscopy (CF-LIBS) by a pulsed Nd:YAG laser and X-ray fluorescence (XRF) spectroscopy. Both CF-LIBS and XRF spectroscopy were successfully applied for qualitative and quantitative analysis. The results confirmed the presence of major elements such as silicon (Si), calcium (Ca), iron (Fe), and potassium (K), as well as trace elements including copper (Cu), lead (Pb), manganese (Mn), and titanium (Ti). Elemental concentrations varied across samples, with ranges as follows: Si (26.50–42.21%), Ca (5.46–8.77%), Fe (17.97–26.14%), K (9.54–14.99%), Mn (0.01–0.11%), Ti (0.15–0.88%), Pb (0.99–2.43%), Sr (0.58–1.09%), Cu (0.02–0.20%), along with other minor constituents (0.45–0.61% and 0.01–0.05%). Notably, rare earth elements such as yttrium (Y) and europium (Eu), which are very important to advanced technologies, were also detected. The CF-LIBS results showed strong agreement with XRF measurements. Furthermore, LIBS demonstrated its advantage by detecting light elements, including hydrogen (H) and oxygen (O), that are typically challenging to observe with XRF.