Classification of martian rocks and soils at Tianwen-1 landing site based on laser-induced breakdown spectroscopy...

Laser-Induced Breakdown Spectroscopy (LIBS) is an analytical technique used to determine the chemical compositions of Martian materials. The Mars Surface Composition Detector (MarSCoDe), carried by the Zhurong Rover, is a powerful instrument for analyzing the chemical compositions of rocks and soils at the Tianwen-1 landing site. The varied environment and diverse lithologies pose significant challenges for the quantitative analysis of chemical compositions. Therefore, we propose a rapid method based on Principal Component Analysis (PCA) to classify Martian rocks and soils using on-board calibration targets acquired with the same instrument and under identical environmental conditions as the in-situ rock/soil spectra-thus eliminating instrument and environmental discrepancies. This model demonstrates good performance when applied to LIBS spectra from ChemCam calibration targets and Martian materials, indicating its applicability to MarSCoDe data. Cluster analysis of MarSCoDe measurements indicates the presence of altered minerals (e.g., montmorillonite) near the landing site, although the degree of alteration appears minor. This indicates a weak aqueous alteration process, possibly resulting from interactions with atmospheric water or groundwater. This study presents a method for rapidly identifying mineral types on the Martian surface using LIBS spectroscopy. This method provides a framework for the quantitative interpretation of MarSCoDe data and offers important insights into the geological origin and hydrological evolution of the landing region.