∑REE abundances are lower in the Surma
mudrocks (216–253 ppm), but range to higher values in the Tipam
Group (186–327 ppm). Abundances are also high in the two Dupitila
mudrocks analyzed (303 and 470 ppm).∑REE contents of the
sandstones are generallyb200 ppm, reflecting quartz dilution. Values
are lowest in Dupitila sandstones (88–98 ppm), in association with the
highest SiO2contents (83–96 wt.%).