sentences:  At present, the CCD reaches a maximum depth of about 5000 meters near the equator.The characteristing banding and ribbon-like layering often observed in radiolarites is primarily due to changing sediment influx, which is secondarily enhanced by diagenetic effects.In the simple two component system clay/silica with constant clay supply the rhythmically changing radiolarian blooms are responsible for creating a clay-chert interlayering.