The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred ...in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont apatite indicate a double-pulse warming event. The CHE coincided with an initial warming of 4 °C. This was followed by a transient cooling period and then a prolonged ∼7 °C warming in the later Carnian (Tuvalian 2). Carbon isotope perturbations associated with the CHE of western Tethys occurred contemporaneously in South China, and mark the start of a prolonged period of carbon cycle instability that persisted until the late Carnian. The dry-wet transition during the CHE coincides with the negative carbon isotope excursion and the temperature rise, pointing to an intensification of hydrologic cycle activities due to climatic warming. While carbonate platform shutdown in western Tethys is associated with an influx of siliciclastic sediment, the eastern Tethyan carbonate platforms are overlain by deep-water anoxic facies. The transition from oxygenated to euxinic facies was via a condensed, manganiferous carbonate (MnO content up to 15.1 wt%), that records an intense Mn shuttle operating in the basin. Significant siliciclastic influx in South China only occurred after the CHE climatic changes and was probably due to foreland basin development at the onset of the Indosinian Orogeny. The mid-Carnian biotic crisis thus coincided with several phenomena associated with major extinction events: a carbonate production crisis, climate warming, δ13C oscillations, marine anoxia, biotic turnover and flood basalt eruptions (of the Wrangellia Large Igneous Province).
•Carnian Pluvial Event manifested in South China, confirming a true global change.•The Carnian environmental perturbations were much longer than previously known.•Warming, δ13C oscillations, and intense euxinia are seen in the eastern Tethys.•Carbonate production crisis in South China predates Indosinian Orogeny activities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We conducted a genome-wide meta-analysis of cognitive empathy using the 'Reading the Mind in the Eyes' Test (Eyes Test) in 88,056 research volunteers of European Ancestry (44,574 females and 43,482 ...males) from 23andMe Inc., and an additional 1497 research volunteers of European Ancestry (891 females and 606 males) from the Brisbane Longitudinal Twin Study. We confirmed a female advantage on the Eyes Test (Cohen's d=0.21, P<2.2 × 10
), and identified a locus in 3p26.1 that is associated with scores on the Eyes Test in females (rs7641347, P
=1.58 × 10
). Common single nucleotide polymorphisms explained 5.8% (95% CI: 4.5%-7.2%; P=1.00 × 10
) of the total trait variance in both sexes, and we identified a twin heritability of 28% (95% CI: 13%-42%). Finally, we identified significant genetic correlation between the Eyes Test and anorexia nervosa, openness (NEO-Five Factor Inventory), and different measures of educational attainment and cognitive aptitude.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Defining the spatial distribution of geological structures and rock properties is important for understanding how fluid flow is controlled in a geothermal reservoir. Here, we present a procedure to ...examine the potential fluid pathways. By combining 3‐D resistivity models derived from audio‐magnetotelluric (AMT) data with available rock properties (porosity and permeability) and fluid sample data (fluid resistivity, salinity, and temperature), we investigated the relationship between electrical resistivity and fluid flow in an active volcanic system. Different petrophysical models and empirical relations are evaluated to determine the relationship between the fluid flow system at Mount Meager, British Columbia, and the resistivity model. In addition, we utilized porosity and permeability measured in the laboratory to define the porosity‐permeability relationship. The porosity of the volcanic core samples showed a range of 2.6%–23.2% and the permeability was in a range of 0.001–5,186.57 mD. The results showed the potential of 3‐D inversion of AMT data to map the fluid pathways at Mount Meager. These pathways are correlated with loss circulation zones in boreholes and can account for porosity up to 8.5%, which using the porosity‐permeability relationship translates to permeability of the order 0.249 mD. Not only are the fault and fracture zones important for reservoir exploitation, but they also provide permeability for the circulation of meteoric water. Our studies suggest that a set of fractures with 0.1 m spacing and 20 mm aperture can keep 40% fluid in pores and transmit fluid with possible permeability of 666 mD.
Plain Language Summary
Geothermal is the natural heat within the Earth. Heat passes to the near‐surface by the magma intrusion into the crust and circulation of groundwater through fluid flow pathways. This paper evaluates the fluid flow pathways, structure, and physical properties beneath the Mount Meager Volcanic Complex (MMVC; Canada). The audio‐magnetotelluric (AMT) method (natural‐source electromagnetic geophysical technique) was used to produce the 3‐D resistivity model. Moreover, utilizing laboratory experiments, we modified rock‐physical and fluid chemistry relationships to focus on the MMVC rather than using relations adapted to other volcanic settings. The AMT model shows correlations between the locations of conductors and faults and suggests that faults act as flow pathways. A porosity of up to 8.5% is expected in the potential reservoir zone. By combining the resistivity model with rock and fluid properties, we mapped potential flow pathways and rock properties. Results showed that in rocks with low porosity and permeability, fractures provide the primary way of flow with porosity and permeability up to 40% and 666 mD, respectively. This project contributes to the development of conceptual models of the hydrothermal flow, which could be used to reduce the risk of future exploitation of geothermal resources.
Key Points
Audio‐magnetotelluric data have been used to model the conductivity distribution beneath an active volcanic system in southwestern Canada
Utilizing 3‐D Inversion, we provide details on the structure, physical properties, and flow pathways of a volcano‐hosted geothermal system
Permeability can increase up to five orders of magnitude in fractured rocks beneath Mount Meager
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Modeled trends of key climate variables in the Winnipeg area show that the annual mean temperature has increased by about 1 °C over the past 105 years. Potential impacts of climate change on ...groundwater levels are investigated by analyzing the relationship between historical climate records and water levels in monitoring wells completed in the upper carbonate aquifer. Both precipitation and annual mean temperature display a strong correlation with annual groundwater levels in this aquifer. The correlation with temperature becomes stronger in the periods of higher annual mean temperatures. In areas where the aquifer is found at shallow depth, temperature has a greater influence than precipitation on groundwater levels. Results suggest that a trend of increasing temperatures, predicted by global climate models for this region, may reduce net recharge and affect groundwater levels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Early Triassic was a time of remarkably high temperatures, large carbon cycle perturbations and episodes of widespread ocean anoxia. The sediments in the Nanpanjiang Basin of South China provide ...superb opportunities to examine the sedimentary response to these extreme conditions especially during the crisis interval at the Smithian–Spathian (S-S) boundary. We have investigated a deep water section at Jiarong and a shallower water section at Mingtang. These contain a range of facies including black shales, micritic limestone units and rudaceous carbonate event beds that include flat pebble conglomerates and breccia debrites that bear similarities to the hybrid event beds seen in clastic turbidite successions.
Redox proxies (pyrite framboids and trace metals) reveal that widespread anoxia in the late Smithian persisted into the Novispathodus pingdingshanensis Zone of the early Spathian before a sharp transition to highly oxygenated “griotte facies” (red marine strata) in the Icriospathodus collinsoni Zone that records an “oxic rebound”. Benthic faunas are locally common but of low diversity and dominated by thin-shelled bivalves and ostracodes with small foraminifers and exceptionally rare fish remains. Bioturbation was intense only in the early–middle Spathian (I. collinsoni conodont zone) Griotte facies. Anoxia and extremely high temperatures probably played a role in severely restricting the abundance of fish and the small sizes of marine invertebrates at this time. The presence of ooids and seafloor fan cements in our study sections indicates highly saturated conditions rather than acidification at the end of the Smithian.
•Smithian–Spathian sections in the Nanpanjiang Basin saw swift redox changes.•The Spathian red beds show a form of oxic rebound from the anoxic–euxinic waters.•Late Smithian positive δ13C shift is best explained by enhanced organic carbon burial.•Anoxia, together with high temperatures, has played a key role in the S-S crisis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study evaluates the utility of sedimentary mercury (Hg) contents as a proxy for fingerprinting ancient massive volcanism, which is often associated with biogeochemical perturbations. Herein we ...present new Hg geochemical data from anoxic marine basins across the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) as a test of the complex Hg cycle. The T-OAE was likely initiated by the main eruptive phase of the Karoo–Ferrar large igneous province, which caused a subsequent cascade of environmental perturbations and resulting mass extinction. At present the leading interpretation of sedimentary Hg anomalies has been volcanogenic outgassing as the primary source. Our study and compilation results suggest, however, that Hg/TOC anomalies were restricted to shallow-water, and/or proximal environments, while deep-water, more distal depositional settings document no significant Hg-related anomalies. Furthermore, asynchronous stratigraphic deviations in Hg enrichments favor terrestrially sourced materials and local redox variability, rather than direct volcanogenic emissions, as a primary control mechanism. Additionally, Hg isotope signatures from our only study site documenting an Hg anomaly are also consistent with a terrestrial Hg origin during the T-OAE. Therefore, our results suggest that Hg anomalies in the geological record need to be re-evaluated as a “smoking gun” proxy that only infers volcanogenic inputs.
•Mercury concentration and isotopes from anoxic basins across the Toarcian OAE.•Compilation shows mercury anomalies are observed near landmasses.•Compilation suggests that Hg is dominantly delivered via terrestrial sources.•Mercury isotopes from one section agree with terrestrial source delivering Hg.•Sedimentary Hg anomalies are not a direct proxy for past volcanism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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