Geochemical compatibility and discrimination elements of magnetite on the eastern and western beaches of Taiwan

Abstract

Our primary purposes are to determine the genesis and essential source rocks that supply the magnetite on beaches and the compatible and discriminate chemical elements of the rocks and beach sands magnetite using the multivariate diagram and Principle component analysis (PCA) technique. The magnetite formation environments in this study are magmatic and hydrothermal genesis. Regularly, the concentration of magnetite on the western side is decreasing from north to south, where the higher concentration at Crescent Beach, which is considered as the river mouth of the Touqian river which is passing across through some of the andesite rocks, that is regarded as the source of the magnetite at this region. On the eastern side, the higher concentration of magnetite at Dagangkou, Chenggong (Sanxiantai), Donghe beaches and Taitung Creek Estuary in Taitung city, and Nan-an and Heping beaches in Yilan city. A higher concentration of the magnetite at Dagangkou, Chenggong (Sanxiantai), Donghe beaches and Taitung Creek Estuary may be due to these sites considered the river mouths of the Beinan, Wamuku and Xiuguluan rivers, these rivers passing across through Lichi mélange, which leads to the higher concentration due to the presence of these igneous and hydrothermal facies. Generally, the surrounding rocks are considered the main supplies of magnetite on the western and eastern beaches.