Abstract The measurement of stable water isotopes (i.e. δ 18 O and δ 2 H) in precipitation is a powerful tool for detecting changes in climate patterns, assessing groundwater movements and studying the hydrological budget. In this study, daily precipitation was collected and δ 18 O and δ 2 H were analysed in Corner Brook, western Newfoundland, and Labrador, for 2015. The study provides the first background data of any kind related to liquid water isotopes in western Newfoundland. More than 130 samples were analysed using a state-of-the-art cavity ring-down spectrometer, the Picarro Liquid Water Isotope Analyzer L2130-i, with a minimal instrumental error. The data suggest seasonal variations in which the δ 18 O varies from −33.4 to −0.03‰ (±0.023‰) and δ 2 H ranges from −253.4 to 15.1‰ (±0.148‰). Our data are compared with modern meteorological data and publicly available δ 18 O and δ 2 H data from greater Atlantic Canada, which suggests that the atmospheric circulation patterns, spatial features and other climate factors are distinct in Corner Brook. Isotopes in meteorological precipitation data referenced and collected in this study reflect the cool, wet climate and air-mass fluctuations unique to the geographical region and thus, this baseline is fundamental to understanding the modern isotope hydrological/climatic studies for this region.

Abstract Three major problems in cave micrometeorology are analysed: the concept of the temperature of a cave and its phenomenology; the internal energy flows and consequent local entropy production; and a non-hydrostatic physical model of the underground convective air circulation. A cave’s temperature is rich in information, but it is often difficult to obtain because it requires experimental accuracies to be pushed beyond the reach of common external meteorological instruments to detect a variety of factors, such as thermal sedimentation, seasonal variations and the effects of external morphology. Energy flow has an essential role in estimating the sensitivity of a cave to external inputs. A model for evaluating the local entropy production is developed. Entropy seems to be the most basic parameter, explaining both the sensitivity of the environment and its tendency to form complex structures. Analysis of the second-order terms of convective air circulation is more complex than expected; nevertheless, only such an analysis is able to explain the behaviours (e.g. continuity in the airflow) that cannot be predicted by the first-order models.

Environmental changes linked to Deccan volcanism are still poorly known. A major limitation resides in the paucity of direct Deccan volcanism markers and in the geologically short interval where both impact and volcanism occurred, making it hard to evaluate their contributions to the mass extinction. We investigated the low-magnetic-susceptibility interval just below the iridium-rich layer of the Bidart (France) section, which was recently hypothesized to be the result of paleoenvironmental perturbations linked to paroxysmal Deccan phase 2. Results show a drastic decrease of detrital magnetite and presence of scarce akaganeite, a hypothesized reaction product formed in the aerosols derived from reaction of a volcanic plume with water and oxygen in the high atmosphere. A weathering model of the consequences of acidic rains on a continental regolith reveals nearly complete magnetite dissolution after ~31,000 yr, which is consistent with our magnetic data and falls within the duration of the Deccan phase 2. These results highlight the nature and importance of the Deccan-related environmental changes leading up to the end- Cretaceous mass extinction.