Geology of the Primary Selenium Deposits in Mainland China

Selenium deposits in mainland China are distributed across various tectonic units, including the North China Platform, Yangtze Platform, South China Geosyncline, Qinghai-Tibet Plateau, Tarim Terrane, and Tianshan and Qilianshan tectonic belts. These deposits exhibit a diverse geological background, with varying genetic types and geochemical properties. China's selenium deposits include both independent and associated/symbiotic deposits. They are classified into sedimentary, magmatic, skarn, hydrothermal, and volcanic types. Selenium deposits in the Yangtze Platform are mostly sedimentary, while those in the North China Platform are primarily hydrothermal and sedimentary. In the South China Geosyncline, selenium deposits are closely linked to igneous rocks, with hydrothermal and volcanic types dominating. The Qinghai-Tibet Plateau contains mainly hydrothermal and sedimentary selenium deposits. Other regions, such as the Tianshan tectonic belt, Tarim terrane, and Qilian Mountain tectonic belt, feature hydrothermal and sedimentary deposits. Selenium deposits have formed at varying rates throughout geological history, with the highest output occurring during the Mesozoic era. These deposits contain diverse metallogenic series, and selenium is often found alongside organic matter, sulfides, and various metal elements. Selenium content varies significantly across deposits.