Lake Chichancanab Terminal Classic Droughts Gypsum Hydration Water Isotopes Evans, N.P.; Bauska, T.K.; Gázquez-Sánchez, F.; Brenner, M.; Curtis, J.H.; Hodell, D.A. Evans, N.P. Bauska, T.K. Gázquez-Sánchez, F. Brenner, M. Curtis, J.H. Hodell, D.A. earth science/paleoclimate/climate reconstructions|paleolimnology (sample identification,null,null,null,null,climate reconstructions|paleolimnology,null,null,C,null) earth science/paleoclimate/paleolimnology (delta 18O,gypsum,null,per mil VSMOW,null,paleolimnology,null,cavity ring-down spectroscopy,N,d18O of Gypsum Hydration Water) earth science/paleoclimate/climate reconstructions|paleolimnology (delta 17O,lake water,null,per mil VSMOW,null,climate reconstructions|paleolimnology,null,null,N,d17O of calculated mother water) earth science/paleoclimate/instrumental (delta 2H,lake water,one standard deviation,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/instrumental (deuterium excess,lake water,null,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/paleolimnology (age,null,95% confidence interval upper bound,year Common Era,null,paleolimnology,null,null,N,max age 95% confidence interval) earth science/paleoclimate/paleolimnology (age,null,null,year Common Era,null,paleolimnology,null,null,N,mean age) earth science/paleoclimate/climate reconstructions|paleolimnology (age,null,null,year Common Era,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/instrumental (delta 17O,lake water,null,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/paleolimnology (depth,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,95% confidence interval lower bound,year Common Era,null,paleolimnology,null,null,N,min age 95% confidence interval) earth science/paleoclimate/paleolimnology (delta 17O,gypsum,null,per mil VSMOW,null,paleolimnology,null,cavity ring-down spectroscopy,N,d17O of Gypsum Hydration Water) earth science/paleoclimate/paleolimnology (delta 2H,gypsum,null,per mil VSMOW,null,paleolimnology,null,cavity ring-down spectroscopy,N,dD of Gypsum Hydration Water) earth science/paleoclimate/climate reconstructions|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/instrumental (delta 17O excess,lake water,null,per meg VSMOW/SLAP,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/instrumental (longitude,null,null,degree west,null,instrumental,null,null,C,null) earth science/paleoclimate/climate reconstructions|paleolimnology (delta 17O excess,lake water,null,per meg VSMOW/SLAP,null,climate reconstructions|paleolimnology,null,null,N,O17-excess of calculated mother water; 17O-excess = ln (δ17O + 1) – 0.528 ln (δ18O + 1)) earth science/paleoclimate/climate reconstructions|paleolimnology (moisture index,null,null,dimensionless,null,climate reconstructions|paleolimnology,null,null,N,probability of drought) earth science/paleoclimate/instrumental (delta 17O,lake water,one standard deviation,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/instrumental (delta 18O,lake water,null,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/instrumental (notes,null,null,null,null,instrumental,null,null,C,Lake name or groundwater or rainwater) earth science/paleoclimate/instrumental (delta 2H,lake water,null,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/instrumental (sample identification,null,null,null,null,instrumental,null,null,C,null) earth science/paleoclimate/instrumental (latitude,null,null,degree north,null,instrumental,null,null,C,null) earth science/paleoclimate/climate reconstructions|paleolimnology (depth,null,null,centimeter,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleolimnology (deuterium excess,lake water,null,per mil VSMOW,null,climate reconstructions|paleolimnology,null,null,N,d-excess of calculated mother water) earth science/paleoclimate/climate reconstructions|paleolimnology (delta 18O,lake water,null,per mil VSMOW,null,climate reconstructions|paleolimnology,null,null,N,d18O of calculated mother water) earth science/paleoclimate/climate reconstructions|paleolimnology (delta 2H,lake water,null,per mil VSMOW,null,climate reconstructions|paleolimnology,null,null,N,dD of calculated mother water) earth science/paleoclimate/instrumental (delta 18O,lake water,one standard deviation,per mil VSMOW,null,instrumental,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Lake Chichancanab>LATITUDE 19.855>LONGITUDE -88.763) The demise of Lowland Classic Maya civilization during the Terminal Classic Period (~800 to 1000 CE) is a well-cited example of how past climate may have affected ancient societies. Attempts to estimate the magnitude of hydrologic change, however, have met with equivocal success because of the qualitative and indirect nature of available climate proxy data. We reconstructed the past isotopic composition (d18O, dD, 17O-excess, and d-excess) of water in Lake Chichancanab, Mexico, using a technique that involves isotopic analysis of the structurally bound water in sedimentary gypsum, which was deposited under drought conditions. The triple oxygen and hydrogen isotope data provide a direct measure of past changes in lake hydrology. We modeled the data and conclude that annual precipitation decreased between 41 and 54% (with intervals of up to 70% rainfall reduction during peak drought conditions) and that relative humidity declined by 2 to 7% compared to present-day conditions. STUDY NOTES: Gypsum hydration water oxygen (d17O, d18O) and hydrogen (dD) isotopes from Lake Chichancanab, Yucatan, Mexico, for 602-1092 CE. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Evans, N.P. Investigator : Bauska, T.K. Investigator : Gázquez-Sánchez, F. Investigator : Brenner, M. Investigator : Curtis, J.H. Investigator : Hodell, D.A. 2018-08-02 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/24476 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018drought.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018gypsum.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018water.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018age.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018drought.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018gypsum.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018water.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018age.txt English https://www.ncdc.noaa.gov/paleo/study/24476 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018drought.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018gypsum.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018water.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/yucatan/chichancanab2018age.txt Nicholas P. Evans, Thomas K. Bauska, Fernando Gázquez-Sánchez, Mark Brenner, Jason H. Curtis, David A. Hodell2018Quantification of drought during the collapse of the classic Maya civilizationScience3616401498-50110.1126/science.aas9871http://science.sciencemag.org/content/361/6401/498 START YEAR: -545 AD * END YEAR: 2015 AD -88.763 19.855 -88.763 19.855