d18O (LS01HOCH): interpretation1_variable: 'E/P' has been replaced by 'effectivePrecipitation'
d18O (LS01HOCH): interpretation2_variable: 'P_E' has been replaced by 'effectivePrecipitation'
d18O (LS01HOCH): interpretation3_variable: 'T_water' has been replaced by 'temperature'

d18O (LS01HOCH): paleoData_longName: '' has been replaced by 'AD'
year (MATae2887b82a): paleoData_units: 'AD' has been replaced by 'yr AD'
year (MATae2887b82a): paleoData_longName: '' has been replaced by 'AD'
depth (MATc97475c57e): paleoData_longName: '' has been replaced by 'AD'

Hodell, D. A., Brenner, M., Curtis, J., Guilderson, T.

Hodell, D. A.: Solar Forcing of Drought Frequency in the Maya Lowlands, Science, 292(5520), 1367–1370, doi:10.1126/science.1057759, 2001.

Solar Forcing of Drought Frequency in the Maya Lowlands

Sieved and cleaned following Xia et al. 1997

Hypothesised that deep lake temperatures dont change, as recorded by benthic ostracods Thus difference between ostracods and authigenic carbonate relates to temperature

Although evaporation could potentially cause more 18O enrichment in surface water than in bottom water of a lake, this factor is likely negligible at Farewell Lake, because the lake has a large volume (maximum depth of the south basin: 55 m; surface area: 4 km2) and because no major moisture deficit exists in the region. This argument is supported by the fact that the 18O values (12.2?12.5?) of water samples taken weekly from the lake surface during July 19?September 25, 2000, show no time-dependent trend. 18Oac reflects changes in atmospheric temperature, as abiotic carbonate precipitation occurs in surface water, where the temperature fluctuates in response to atmospheric temperature changes (19). In contrast, because Farewell Lake is deep and has a large water volume, the bottom-water temperature likely remains constant at 4i¿½C, as it was in June 1990 and July 2000, based on field measurements. Therefore, the deviation of 18Oac from contemporaneous 18Obo results from oxygen-isotope frac- tionation induced by the temperature difference between sur- face and bottom waters after accounting for any vital effects.