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Tight Entrance Cave stable-isotope record. Trends in stable carbon and oxygen isotopes from land-snail shells reveal declining relative humidities or temperatures following the accumulation of unit D (119–89 ka). δ13C, δ18O values are expressed as mean ± SE; horizontal bars denote errors on mean ages for units. Data have been corrected for ice volume contributions to δ18O, and changes in δ13C of atmospheric CO2 from fossil fuel burning (SI Appendix).
