Status report of the new carbonate clumped laboratory of Isotope Climatology and Environmental Research Center (ICER), Debrecen, Hungary

L

Sulfur and oxygen isotopes in the gypsum deposits of the Provalata sulfuric acid cave (Macedonia)

K

Rainwater Isotopic Composition in the Ecuadorian Andes and Amazon Reflects Cross-Equatorial Flow Seasonality

The variability of the rainfall stable isotopic values (δ2Hp, δ18Op) in the Ecuadorian Amazon to the Andes presents a marked local “altitude” effect. At the same time, this complex orography creates diverse precipitation regimes (unimodal, bimodal, and three-modal) that make it difficult to establish a relationship with the local amount. Nevertheless, stations along these regions show a similar intra-annual isotopic variability, with lower values during MAM and ON. In contrast, higher values are found during DJF and JAS in a w-shaped pattern, suggesting a common regional controller. A monthly δ2Hp and δ18Op collection campaign was established in Central Ecuador (n = 30) to complement stations biased towards the northern and southern parts. Based on back trajectory analysis, the results demonstrated that moisture arrives from two primary sources: the Tropical North Atlantic (DJFM) and the Amazon Basin (JAS). Nevertheless, their convergence (AMJ and ON) is the crucial factor modulating the lowest isotopic values. Precisely, this convergence is stronger at the V-Index region (5° S–5° N, 65°–75° W), where the wind seasonality and reversal at low levels are enhanced, allowing the inter-hemispheric moisture flux transport (cross-equatorial flow). We propose that the amount of rainfall located at the V-Index region is a more robust approach for explaining the δ2Hp and δ18Op variability rather than the local amount

A potential groundwater aquifer for palaeoclimate reconstruction: Turonian aquifer, Tadla basin, Morocco

K

Record of ³H and ³⁶Cl from the Fukushima nuclear accident recovered from soil water in the unsaturated zone at Koriyama

The opportunity to measure the concentrations of ³H and ³⁶Cl released by the Fukushima nuclear accident in 2011 directly in rain was lost in the early stage of the accident. We have, however, been able to reconstruct the deposition record of atmospheric ³H and ³⁶Cl following the accident using a bore hole that was drilled in 2014 at Koriyama at a distance of 60 km from the accident. The contributions of ³H and ³⁶Cl from the accident are 1.4 × 10¹³ and 2.0 × 10¹² atoms m⁻² respectively at this site. Very high concentrations of both ³H (46 Bq L⁻¹) and ³⁶Cl (3.36 × 10¹¹ atoms L⁻¹) were found in the unsaturated soil at depths between 300 and 350 cm. From these, conservative estimates for the ³H and ³⁶Cl concentrations in the precipitation in the ～ 6 weeks following the accident were 607 Bq L⁻¹ and 4.74 × 10¹⁰ atoms L⁻¹, respectively. A second hole drilled in 2016 showed that ³H concentrations in the unsaturated soil and shallow groundwater had returned to close to natural levels, although the ³⁶Cl concentrations were still significantly elevated above natural levels