Variability in the marine radiocarbon reservoir effect in Muscat (Sultanate of Oman) during the 4th millennium BC: reflection of taphonomy or environment?

► We determine the marine reservoir effect (MRE) in coastal Oman during the 4th millenium BC. ► Terrestrial and marine remains are 14C dated in three graves from the site of RH5. ► Large differences in 14C ages are found within each grave. ► Likely causes of variability are the old-wood effect and diagenesis. ► Environment and taphonomic processes may also play a role.