Climatic fluctuations modeled for carbon and sulfur emissions from end-Triassic volcanism

Landwehrs, Jan; Feulner, Georg; Hofmann, Matthias; Petri, Stefan

doi:10.1016/j.epsl.2020.116174

Cited by 33 publications

(26 citation statements)

References 49 publications

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“…Potentially, the concentrations of plant matter below the oldest CAMP flows in North America record widespread plant mortality in response to the initial phase of the eruptions. As noted earlier, some studies have suggested that the initiation of the CAMP eruptions was earlier in Morocco than in North America 12,13 ; this may have caused heightened plant mortality through acid deposition and heavy metal toxicity 16,18,19 , as well as providing an initial source of Ir through outgassing. Subsequent releases of Ir and associated PGEs may have been subject to pH-enhanced mobilization in the sedimentary column, with sequestration focused by formation of organometallic complexes at specific organic-rich horizons, including those recording eruption-related plant mortality.…”

Section: Discussionmentioning

confidence: 95%

“…The ETE is now generally acknowledged as the consequence of outgassing during CAMP activity that caused multiple environmental disturbances through episodes of SO 2 -aerosol driven cooling and reduced primary productivity, CO 2 -forced radiative warming, volcanogenic heavy-metal toxicity and acidification of environments 4,5,11,[15][16][17][18][19] . Estimation of the mass of outgassed CO 2 and SO 2 has proved a contentious issue given the uncertainties in the erupted volume, but most calculations have suggested the release of both CO 2 and SO 2 at the scale of 10 3 -10 4 Gt 5,11 .…”

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confidence: 99%

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Widespread elevated iridium in Upper Triassic–Lower Jurassic strata of the Newark Supergroup: implications for use as an extinction marker

Tanner

Kyte

Puffer

2020

Sci Rep

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Anomalous levels of iridium in sedimentary strata are associated with mass extinction events caused by impact events. In the case of the end-Triassic extinction event, the anomalies as well as the extinctions are linked to the eruption of the Central Atlantic Magmatic Province (CAMP) flood basalts. We report new data on concentrations of iridium in continental strata of the Fundy, Deerfield, Hartford and Newark basins, both above and below the oldest CAMP flows in these basins, that demonstrate that these anomalies are more common than previously known. We conclude that the enrichments were at least in some instances likely derived locally by concentration due to leaching directly from the lavas into sediments proximal to the CAMP flows due to post-eruptive hydrothermal activity. In other instances, the enrichments likely record the global fallout of aerosols and/or ash particles during the eruptions of the CAMP basalts. The common association of the highest levels of enrichment with organic matter suggests either redox control or stabilization by formation of organometallic complexes following post-eruptive redistribution. These findings demonstrate the importance of considering the distribution and magnitude of iridium anomalies in considering the source of the iridium and possible extinction mechanisms.

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Section: Discussionmentioning

confidence: 95%

mentioning

confidence: 99%

Widespread elevated iridium in Upper Triassic–Lower Jurassic strata of the Newark Supergroup: implications for use as an extinction marker

Tanner

Kyte

Puffer

2020

Sci Rep

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“…Thus, analysis of lava flow morphology can help examine the spatial and temporal variations in the emplacement rate of a CFB province. These spatiotemporal eruptive rate variations are critical for understanding the magmatic plumbing systems of CFBs (Sheth and Cañón-Tapia, 2015;Ernst et al, 2019) as well as the environmental impacts (e.g., Schmidt et al, 2016;Clapham and Renne 2019;Hull et al, 2020;Landwehrs et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Thickness Characteristics of Pāhoehoe Lavas in the Deccan Province, Western Ghats, India, and in Continental Flood Basalt Provinces Elsewhere

2021

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Constraining the eruption rates of flood basalt lava flows remains a significant challenge despite decades of work. One potential observable proxy for eruption rates is flood basalt lava-flow lobe thicknesses, a topic that we tackle here quantitatively. In this study, we provide the first global compilation of pāhoehoe lava-lobe thicknesses from various continental flood basalt provinces (∼ 3,800 measurements) to compare characteristic thicknesses within and between provinces. We refer to thin lobes (∼ ≤5 m), characteristic of “compound” lavas, as hummocky pāhoehoe lava flows or flow-fields. Conversely, we term thicker lobes, characteristic of “simple” flows, as coming from sheet-lobe-dominated flows. Data from the Deccan Traps and Columbia River flood-basalt provinces are archetypal since they have the most consistent datasets as well as established chemo- and litho-stratigraphies. Examining Deccan lobe thicknesses, we find that previously suggested (and disputed) distinct temporal and regional distributions of hummocky pāhoehoe and sheet-lobe-dominated flow fields are not strongly supported by the data and that each geochemically defined formation displays both lobe types in varying amounts. Thin flow-lobes do not appear to indicate proximity to source. The modal lobe thickness of Deccan formations with abundant “thin” lava-lobes is 8 m, while the mode for sheet-lobe-dominated formations is only 17 m. Sheet-lobes up to 75–80 m are rare in the Deccan and Columbia River Provinces, and ones >100 m are exceptional globally. For other flood basalt provinces, modal thickness plots show a prevalence toward similar lobe thicknesses to Deccan, with many provinces having some or most lobes in the 5–8 m modal range. However, median values are generally thicker, in the 8–12 m range, suggesting that sheet-lobes dominate. By contrast, lobes from non-flood basalt flow-fields (e.g., Hawai’i, Snake River Plain) show distinctly thinner modes, sub-5 m. Our results provide a quantitative basis to ascertain variations in gross lava morphology and, perhaps, this will in future be related to emplacement dynamics of different flood basalt provinces, or parts thereof. We can also systematically distinguish outlier lobes (or regions) from typical lobes in a province, e.g., North American Central Atlantic Magmatic Province lava-lobes are anomalously thick and are closely related to feeder-intrusions, thus enabling a better understanding of conditions required to produce large-volume, thick, flood basalt lava-lobes and flows.

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“…Energy balance models and simple climate models (e.g., Haustein et al, 2019; Smith, Forster, et al, 2018), which continue to underpin IPCC calculations of radiative forcing and are used in studies that assess the 1.5°C target of the Paris Agreement (e.g., Smith et al, 2019), remain dependent on such conversions. Furthermore, studies that estimate forcing from volcanism on geological timescales (e.g., Landwehrs et al, 2020) rely on using scaling factors to convert SAOD to volcanic forcing.…”

Section: Introductionmentioning

confidence: 99%

Large Variations in Volcanic Aerosol Forcing Efficiency Due to Eruption Source Parameters and Rapid Adjustments

Marshall

Smith

Forster

et al. 2020

Geophysical Research Letters

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The relationship between volcanic stratospheric aerosol optical depth (SAOD) and volcanic radiative forcing is key for quantifying volcanic climate impacts. In their Fifth Assessment Report, the Intergovernmental Panel on Climate Change used one scaling factor between volcanic SAOD and volcanic forcing based on climate model simulations of the 1991 Mt. Pinatubo eruption, which may not be appropriate for all eruptions. Using a large ensemble of aerosol-chemistry-climate simulations of eruptions with different sulfur dioxide emissions, latitudes, emission altitudes, and seasons, we find that the effective radiative forcing (ERF) is on average 20% less than the instantaneous radiative forcing, predominantly due to a positive shortwave cloud adjustment. In our model, the volcanic SAOD-ERF relationship is non-unique and varies widely depending on time since an eruption, eruption latitude, and season due to differences in aerosol dispersion and incoming solar radiation. Our revised SAOD-ERF relationships suggest that volcanic forcing has been previously overestimated. Plain Language Summary Powerful explosive volcanic eruptions inject sulfur gases high into the atmosphere where they form a layer of sulfate aerosol particles that scatter sunlight back into space, decrease the transparency of the atmosphere, and cause surface cooling. The amount of sunlight that is scattered depends on the location of the layer of particles and particle size. We have used a complex climate model to quantify how eruptions of different magnitudes and occurring in different seasons and locations may affect the climate. We find that the relationship between the transparency of the atmosphere and the resulting climatic impact caused by volcanic sulfate aerosol particles depends on the amount of sunlight and the spread of the aerosol and therefore the time since the eruption, the eruption location, and the season. Our simulations also show that the eruptions reduce the cooling effect of clouds, which reduces the overall effectiveness of volcanoes at cooling the Earth's surface.

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Climatic fluctuations modeled for carbon and sulfur emissions from end-Triassic volcanism

Cited by 33 publications

References 49 publications

Widespread elevated iridium in Upper Triassic–Lower Jurassic strata of the Newark Supergroup: implications for use as an extinction marker

Widespread elevated iridium in Upper Triassic–Lower Jurassic strata of the Newark Supergroup: implications for use as an extinction marker

Thickness Characteristics of Pāhoehoe Lavas in the Deccan Province, Western Ghats, India, and in Continental Flood Basalt Provinces Elsewhere

Large Variations in Volcanic Aerosol Forcing Efficiency Due to Eruption Source Parameters and Rapid Adjustments

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