A new local meteoric water line for Inuvik (NT, Canada)

The paper presents a new local meteoric water line (LMWL) of stable oxygen and hydrogen isotopes in precipitation from Inuvik in the western Canadian Arctic. Data were obtained over 37 months between August 2015 and August 2018 resulting in 134 measurements of the isotopic composition of both types of precipitation, snow and rain. For 33 months of the sampling period each month is represented at least two times from different years. The new LMWL from Inuvik is characterized by a slope of 7.39 and an intercept of −6.70 and fills a data gap in the western Arctic, where isotopic composition data of precipitation are scarce and stem predominantly from before the year 1990. Regional studies of meteorology, hydrology, environmental geochemistry and paleoclimate will likely benefit from the new Inuvik LMWL. Data are available on the PANGAEA repository under https://doi.org/10.1594/PANGAEA.935027 (Fritz et al., 2021).

A new local meteoric water line for Inuvik (NT, Canada)

The paper presents a new local meteoric water line (LMWL) of precipitation stable oxygen and hydrogen isotopes from Inuvik in the Western Canadian Arctic. Data were obtained over 37 months between August 2015 and August 2018 resulting in 134 measurements of the isotopic composition of both types of precipitation, snow and rain. For 33 months of the sampling period each month is represented at least two times from different years. The new LMWL from Inuvik is characterized by a slope of 7.39 and an intercept of –6.70, and fills a data gap in the Western Arctic where isotopic composition data of precipitation are scarce and stem predominantly from before the year 1990. Regional studies of meteorology, hydrology, environmental geochemistry and paleoclimate will likely benefit from the new Inuvik LMWL.

Controls of seasonality and altitude on generation of leaf water isotopes

Stable oxygen and hydrogen isotopes (δ18O and δ2H) of leaf water which bridges between hydrological processes and plant-derived organic materials that vary spatially and temporally. It is crucially critical to study what controls the δ18O and δ2H values of leaf water for a wide range of applications. Here, we repeatedly sampled soil water, stem water, and leaf water along an elevation transect across seasons on the Chinese Loess Plateau, and analyzed the variations of in the δ18O and δ2H values from precipitation, soil water, stem water, and ultimate leaf water. We found a consistency in the δ18O and δ2H values from in precipitation, soil water, stem water, and leaf water across seasons. , indicating that leaf water can record well the isotopic signals of precipitation well. Importantly, leaf water isotope lines are were generated by the first-order control of source water (soil water and precipitation) associated with seasonality and altitude, and as well as the secondary control of hydroclimate and biochemical factors resulting in weak correlations of the δ18O and δ2H values in leaf water. This study is helpful to better understandimproves our understanding of the generation of leaf water isotopes.

Impact of the Southern Ecuadorian Andes on Oxygen and Hydrogen Isotopes in Precipitation

Determining how the elevation of the Northern Andes has evolved over time is of paramount importance for understanding the response of the Northern Andes to deformational and geodynamic processes and its role as an orographic barrier for atmospheric vapor transport over geologic time. However, a fundamental requirement when using stable isotope data for paleoaltimetry reconstructions is knowledge about the present-day changes of δ18O and δD with elevation (isotopic lapse rate). This study defines the present-day river isotopic lapse rate near the Equator (∼3°S) based on analysis of δ18O and δD of surface waters collected from streams across the Western Cordillera and the Inter-Andean depression in Southern Ecuador. The results for the two domains show a decrease of δ18O with elevation which fits a linear regression with a slope of −0.18‰/100 m (R2 = 0.73, n = 83). However, we establish a present-day lapse rate of −0.15‰/100 m for δ18O (R2 = 0.88, n = 19) and -1.4‰/100 m for δD (R2 = 0.93, n = 19) from water samples collected along the west facing slopes of the Western Ecuadorian Cordillera which is mainly subject to moisture transport from the Pacific. We argue that this empirical relationship, consistent with those obtained in different tropical areas of the world, can inform stable isotope paleoaltimetry reconstructions in tropical latitudes.

FORMATION CONDITIONS OF GROUNDWATER OF THE UPPER JURASSIC OF THE CENTRAL REGIONS OF THE ZAURAL MEGAMONOCLYSIS

The article presents the first results of complex isotope-hydrogeochemical studies of reservoir waters of the Upper Jurassic deposits of the central regions of the Zaural megamonoclysis. It was shown that most waters have a narrow distribution of oxygen and hydrogen isotopes (δD from -103.2 to -85.6 ‰ and δO from -15.4 to -12.9 ‰). Some of them have pronounced excursions on the isotopic composition, which indicates a difference in their genesis: from condensate to mixed with ancient infiltrogenic. The isotopic composition of carbon of water-dissolved carbon dioxide (δС from -41.6 to -16.3 ‰) indicates its biogenic origin and the possibility of interstratal flows from overlying horizons.

Triple Oxygen Isotope Paleoaltimetry of Crystalline Rocks

Triple oxygen isotopes of hydrothermally altered minerals from crystalline rocks can be used to determine past elevations of mountain ranges. This method uses all three isotopes of oxygen (16O, 17O, and 18O) to create arrays that can be extrapolated back to the meteoric water line. One advantage of this technique is that it relies only on oxygen isotopes in contrast to previous studies that use oxygen and hydrogen isotopes to determine the isotopic composition of meteoric waters. Our analysis suggests that hydrogen isotopes may exchange with ambient fluids. Triple oxygen isotopes provide an independent check on the reliability of hydrogen isotope studies.