TY - JOUR
T1 - Triple oxygen and hydrogen isotopes of gypsum hydration water for quantitative paleo-humidity reconstruction
AU - Gazquez, Fernando
AU - Morellon, Mario
AU - Bauska, Thomas
AU - Herwartz, Daniel
AU - Surma, Jakub
AU - Moreno, Ana
AU - Staubwasser, Michael
AU - Valero-Garces, Bias
AU - Delgado-Huertas, Antonio
AU - Hodell, David A.
N1 - This research was supported by the ERC WIHM Project (#339694) to DAH.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (σ17O and σ18O) and hydrogen (σD) isotopes of structurally -bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humidity. An evaporation isotope-mass-balance model is used together with Monte Carlo simulations to determine the range of climatological conditions that simultaneously satisfy the stable isotope results of GHW, and with statistically robust estimates of uncertainty. We apply this method to reconstruct the isotopic composition of paleo-waters of Lake Estanya (NE Spain) and changes in normalized atmospheric relative humidity (RHn) over the last glacial termination and Holocene (from ∼15 to 0.6 cal. kyrs BP). The isotopic record indicates the driest conditions occurred during the Younger Dryas (YD; ∼12-13 cal. kyrs BP). We estimate a RHn of ∼40-45% during the YD, which is ∼30-35% lower than today. Because of the southward displacement of the Polar Front to ∼42°N, it was both windier and drier during the YD than the Bølling-Allerød period and Holocene. Mean atmospheric moisture gradually increased from the Preboreal to Early Holocene (∼11 to 8 cal. kyrs BP, 50-60%), reaching 70-75% RHn from ∼7.5 cal. kyrs BP until present-day. We demonstrate that combining hydrogen and triple oxygen isotopes in GHW provides a powerful tool for quantitative estimates of past changes in relative humidity.
AB - Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (σ17O and σ18O) and hydrogen (σD) isotopes of structurally -bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humidity. An evaporation isotope-mass-balance model is used together with Monte Carlo simulations to determine the range of climatological conditions that simultaneously satisfy the stable isotope results of GHW, and with statistically robust estimates of uncertainty. We apply this method to reconstruct the isotopic composition of paleo-waters of Lake Estanya (NE Spain) and changes in normalized atmospheric relative humidity (RHn) over the last glacial termination and Holocene (from ∼15 to 0.6 cal. kyrs BP). The isotopic record indicates the driest conditions occurred during the Younger Dryas (YD; ∼12-13 cal. kyrs BP). We estimate a RHn of ∼40-45% during the YD, which is ∼30-35% lower than today. Because of the southward displacement of the Polar Front to ∼42°N, it was both windier and drier during the YD than the Bølling-Allerød period and Holocene. Mean atmospheric moisture gradually increased from the Preboreal to Early Holocene (∼11 to 8 cal. kyrs BP, 50-60%), reaching 70-75% RHn from ∼7.5 cal. kyrs BP until present-day. We demonstrate that combining hydrogen and triple oxygen isotopes in GHW provides a powerful tool for quantitative estimates of past changes in relative humidity.
KW - Triple oxygen isotopes
KW - Gypsum hydration water
KW - Relative humidity
KW - Lake sediments
KW - Younger Dryas
KW - Late Glacial-Holocene transition
U2 - 10.1016/j.epsl.2017.10.020
DO - 10.1016/j.epsl.2017.10.020
M3 - Article
SN - 0012-821X
VL - 481
SP - 177
EP - 188
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -