Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8907339 | Earth and Planetary Science Letters | 2018 | 12 Pages |
Abstract
Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (δ17O and δ18O) and hydrogen (δD) 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 â¼15 to 0.6 cal. kyrs BP). The isotopic record indicates the driest conditions occurred during the Younger Dryas (YD; â¼12-13 cal. kyrs BP). We estimate a RHn of â¼40-45% during the YD, which is â¼30-35% lower than today. Because of the southward displacement of the Polar Front to â¼42°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 (â¼11 to 8 cal. kyrs BP, 50-60%), reaching 70-75% RHn from â¼7.5 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.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth and Planetary Sciences (General)
Authors
Fernando Gázquez, Mario Morellón, Thomas Bauska, Daniel Herwartz, Jakub Surma, Ana Moreno, Michael Staubwasser, Blas Valero-Garcés, Antonio Delgado-Huertas, David A. Hodell,