Machine learning reveals the influence of the Changbaishan mantle plume sourced from the mantle transition zone on Cenozoic intraplate magmatism in NE China

This study investigates the influence of the Changbaishan mantle plume, formed by dehydration of stagnant slab, on Cenozoic intraplate magmatism in Northeast China, focusing on the plume's dominant influence zone. Compared to prior research, this paper includes a more extensive published dataset of major and trace element compositions of basalts and adopts machine learning algorithms with better generalization capabilities for the data being analyzed. This approach measures the geochemical similarity of basalts in Northeast China to training data from different geological backgrounds, determining their degree of influence by subduction-derived fluids. Global ocean island basalts (OIBs) and East African continental rift basalts (CRBs) serve as training data for subduction-distal basalts, while global island arc basalts (IABs) represent subduction-proximal basalts. A binary classification model is constructed through ridge logistic regression and support vector machine to establish a hyperplane in high-dimensional space. The greater the positive distance of the basalt data from the hyperplane, the closer it is to subduction-proximal basalts, and vice versa. Model feature importances correlate with their enrichment capacity in fluids, and the application of well-trained models to basalts with known water content shows a positive correlation between model results and H2O/Ce ratios, collectively demonstrating the models' ability to capture fluid signals. Model results of all Cenozoic basalts in Northeast China reveal that within a 600km range centered on Changbaishan, fluid signals attenuate radially outward, rather than a continuous decrease along the subduction direction of the Pacific plate. This indicates a fluid-rich upwelling centered around Changbaishan, with fluid distribution decreasing from the center to the periphery. This upwelling plays a primary role in controlling the generation of Cenozoic basalts within a specific geographic range.