Alberta Geological Survey

This study examines how prolonged snow cover and meltwater affect breeding behavior and success in Gentoo ( Pygoscelis papua ) and Adélie ( Pygoscelis adeliae ) penguins. We monitored nearly 7,000 nests at Lions Rump, King George Island, where both species breed sympatrically, across two seasons with contrasting snow cover: a relatively snow-free 2008/09 season and a snow-heavy 2009/10 season.While penguin population changes and trends have been widely studied, the effects of extreme snow conditions—such as abnormally thick cover during the onset and incubation periods—on the breeding success of Gentoo and Adélie penguins nesting in the same colonies remain poorly understood.These anomalous conditions strongly influenced breeding outcomes by delaying nest initiation and increasing habitat instability during incubation and chick-rearing. In response to extensive snow cover during the 2009/10 season, Gentoo penguins shifted their nest-site distribution, concentrating on elevated, snow-free bedrock and moraine exposures while abandoning snow-covered beach terraces and low-elevation valley sites. In contrast, Adélie penguins largely retained their traditional elevated bedrock nesting areas with minimal spatial adjustment. Despite these behavioral differences, both species experienced delayed breeding, increased nest attrition, and reduced clutch sizes under snow stress. Gentoo penguins exhibited greater sensitivity to these conditions, with more variable breeding success and lower chick survival. Adélie penguins, by comparison, maintained stable chick survival and stronger nest-site fidelity, indicating greater resilience to snow-induced environmental stress. Importantly, Gentoo penguins also demonstrate significant interannual variability in breeding chronology and flexible nest-site selection, which may buffer reproductive success under varying environmental conditions. The pronounced nest loss and spatial reorganization in Gentoo penguins reflect their heightened vulnerability to snow accumulation and meltwater exposure, whereas Adélie penguins, though affected, sustained more consistent nesting patterns and reproductive outcomes.These findings highlight the vulnerability of Antarctic seabirds to shifts in snow dynamics and emphasize the ecological importance of microhabitat resilience and species-specific behavioral strategies in coping with environmental variability.

Stable carbon isotope ratios (delta 13C values) of marine carbonates are widely used to infer the relative burial rates of organic carbon, a source of oxygen to the ocean-atmosphere system. This inference, however, is based on the assumption that ocean-atmospheric carbon is buried either as organic carbon or as marine carbonate minerals. The burial of authigenic carbonate minerals formed within sediments after deposition, with low delta 13C values (i.e., similar to organic carbon), has been proposed to explain high delta 13C values in marine carbonates without the need for high burial fluxes of organic carbon. To test this hypothesis, we focus on the Late Devonian, a time period with both pervasive ocean anoxia and a severe reduction in shallow-water carbonate deposition-conditions hypothesized to promote authigenic carbonate formation. We present sedimentological and geochemical data from limestones and black shales of the Wabamun Group, Besa River and Exshaw formations of the Western Canada Sedimentary Basin. These data are compared to inorganic and organic weight percent measurements of North American shales acquired from the USGS National Geochemical Database (N = 4,437). Results show that basinal shale lack authigenic carbonate with low delta 13C values and that the mean delta 13C value of carbonate in these shales (-0.3 parts per thousand) do not differ substantially from mean delta 13C of carbonates in platform carbonates of a similar age (0.4 parts per thousand). Furthermore, inorganic carbon content in Late Devonian shales (mean weight percent = 0.55%, N = 54) is lower than average Phanerozoic North American shale (mean of 1.95%, N = 4,055). Lastly, organic carbon-to-inorganic carbon ratios (OC:IC) of North American shales are well above 1 (mean = 3.72 for Late Devonian shales (N = 374), 2.25 for shales (N = 3,653) of all other ages). Therefore, even if the burial of fine-grained siliciclastic formations carrying authigenic carbonates were to increase, the concomitant increase in organic carbon burial would be even larger. Together, data from this study do not provide evidence that the burial of authigenic carbonate would have a significant effect on global carbon isotope mass balance. Stable carbon isotope ratios (delta 13C) of marine carbonate rocks are widely used as a proxy for estimating the relative amount of organic carbon buried throughout geological time. Certain instances in the geologic record indicate pronounced delta 13C excursions for which there is no corroborating evidence for enhanced organic carbon burial. It has been proposed that these excursions may be the result of high burial rates of authigenic carbonate-carbonate minerals formed in situ within marine sediments. We test this hypothesis by analyzing the stable carbon isotope composition of Late Devonian limestones and shales of the Western Canada Sedimentary Basin. We also compare the organic and inorganic carbon compositions of shales from this field study with those from the USGS Geochemical database, an archive of North American shale geochemistry data from across the Phanerozoic. Results show that carbonates found in Devonian shales do not have low average delta 13C values, and average organic carbon content was shown to be significantly higher than inorganic carbon in shale samples across the Phanerozoic. These results signify that authigenic carbonate burial had a negligible effect on the global carbon cycle, and furthermore, an increase in shale burial would result in a higher increase in organic carbon compared to authigenic carbonate. CaCO3 found in Late Devonian shales has average carbon isotope values similar to Late Devonian shallow marine carbonates Weight percent values of inorganic carbon content in Late Devonian shales are low compared to average North American shale The mass ratio of organic to inorganic carbon in Late Devonian shales is much higher than average North American shale

We review currently available Canadian and international lithostratigraphic and lithodemic schemes and find most of them inadequate for classifying intrusive and strongly metamorphosed rocks of Canada and beyond. A new system is proposed, one that unifies, complements, and extends components of the revised North American Stratigraphic Code, the British Geological Survey Rock Unit Classification System of 2021, and the International Stratigraphic Guide of 1999. This new Cooperative Lithodemic and Stratigraphic System (CLASS) is intended to serve as a practical guide to geoscientists who need to classify and report on lithodemic units in North America and has broad applicability to other jurisdictions. It is built with database management practices in mind and employs the concept of inheritance of root characteristics between seven formal rock unit ranks, which will allow incorporation of the scheme into compact object-oriented and relational databases designed for purpose. Broad application of CLASS, especially to historically problematic lithodemic units, should help to foster jurisdictional interoperability, data sharing, global compilations, and thematic studies. At the heart of this proposed system is a subdivision and accompanying nomenclature that allows classification of rocks into seven formal ranks. Following the well-established lithostratigraphic supergroup, group, subgroup, formation, member, submember, and bed approach, CLASS proposes three classes of lithodemic subdivisions for formally naming lithodemic rock units.

We generate earthquake iso-nuisance and iso-damage maps for Alberta. These maps show the spatial distribution of earthquake magnitude required to reach a specific level of nuisance and damage, considering human exposure and surficial geological conditions. We rely on population distribution for the human exposure factor while utilizing Vs30 derived from surficial geological modeling to approximate site amplification effects. By including the trailing seismicity factor, the iso-nuisance and iso-damage maps provide the base for the Magnitude Threshold for Acceptable Seismicity maps, which can set a guideline for the upper magnitude boundary, or largest magnitude event permissible, related to industrial activities causing seismicity. The trailing seismicity factor refers to the subsequent seismicity after a substantial change or end of the seismogenic operations; for instance, the cessation of seismogenic hydraulic fracturing activities under a traffic light protocol after a magnitude threshold event (red-light event). Considering variations in the trailing seismicity factor, we derive different Magnitude Threshold for Acceptable Seismicity maps for various injection-induced activities, including hydraulic fracturing and fluid disposal activities. Extended versions of the Magnitude Threshold for Acceptable Seismicity maps could allow for safety factors pertinent to critical infrastructure in a particular area, incorporating other factors beyond the population distribution and warranting a different tolerance level. These maps help to define the magnitude threshold from induced seismicity, maintaining the same tolerance levels throughout a region. Thus, they can be highly beneficial in managing current and future cases of induced seismicity related to the energy sector.