TY - JOUR T1 - Radiocarbon age anomalies in land snail shells from Texas: Ontogenetic, individual, and geographic patterns of variation JF - Radiocarbon Y1 - 1999 A1 - Goodfriend, G. A. A1 - Ellis, G. L. A1 - Toolin, L. J. KW - Carbonate AB - Accelerator mass spectrometric (AMS) radiocarbon analyses of live-collected, prebomb samples of shell carbonates of the land snails Rabdotus dealbatus and R. alternatus from Texas were carried out to quantify the characteristic age anomalies of land snails from limestone areas. Age anomalies are similar for the two species; they average +700 yr and vary by +/-180 yr (1 sigma) among samples. Serial analysis of I shell reveals a significant ontogenetic trend in C-14 age anomalies, with older apparent ages (up to 1200 yr) in the apical part of the shell and younger and uniform ages in the last whorl. No trend in age anomalies was found across a broad range of rainfall conditions (from 300 to 1000 mm mean annual rainfall). VL - 41 SN - 0033-8222 IS - 2 N1 - 228qgTimes Cited:28 Cited References Count:18 JO - Radiocarbon ER -