Van Houten cycle. Lacustrine strata in the Newark basin, such as this part of the Towaco Formation from the ACE cores, show cyclical changes in color, sediment fabrics, fossil types, and total organic carbon content. Shallow-water lacustrine and playa (dry-lake bed) deposits tend to be red and massive (from repeated bioturbation and mudcracking) and contains reptile footprints and roots; very deep-water lacustrine deposits tend to be black, and laminated or microlaminated, have high total organic carbon content, and contain fish fossils. Depth rank is a relative index of water level, with 0 being very shallow and 5 being deep. A Van Houten cycle, as defined by Olsen (1986), records a complete cycle of the lake-level rise (increasing depth rank), lake high-stand (maximum depth rank), and lake-level fall (decreasing depth rank). Modified from Olsen et al. (1989) based on Olsen (1986).

Van Houten cycle