What are silicification and argillization？
Silicification: When rock has contact with groundwater, any extra dissolved silicon dioxide in the groundwater will deposit in rock pores and result in an increase in the rock’s silicon amount. This geological process is known as silicification. Biological remains in the rocks are often replaced by silicon dioxide and become solid silisficated fossil.
Argillization: Rock minerals can transform into clay when the rock has contact with water and air above the ground (weathering); or hot underground water below the ground. This process also largely increases the percentage of clay minerals in the rock.
For more information, please go to the “Taiwan Geoscience Portal” website.