zhè / zhǒng / fěn / shā / shí / kē / lì / xì / cháng / yòng / yú / yán / jiū / chén / jī / huán / jìng这种粉砂石颗粒细,常用于研究沉积环境。This type of siltstone has fine grains and is often used to study depositional environments.