Two-phased collapse of the shallow-water carbonate factory during the late Pliensbachian–Toarcian driven by changing climate and enhanced continental weathering in the Northwestern Gondwana Margin

Krencker, François-Nicolas; Fantasia, Alicia; Danisch, Jan; Martindale, Rowan C.; Kabiri, Lahcen; Ouali, Mohamed El; Bodin, Stéphane

doi:10.1016/j.earscirev.2020.103254

Cited by 34 publications

(32 citation statements)

References 148 publications

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“…This study adds to the growing body of literature confirming that eutrophication and deoxygenation plagued Western Tethyan carbonate platforms in the early Toarcian (eutrophication: Blomeier & Reijmer, 1999;Graziano et al, 2006;Woodfine et al, 2008;Léonide et al, 2012;Trecalli et al, 2012;Krencker et al, 2020;anoxia: Léonide et al, 2012;Sabatino et al, 2013;Lu et al, 2010). Perhaps more damaging to carbonate systems, however, were the effects of ocean acidification.…”

Section: Oceanographic Changes Associated With the Toarcian Oceanic Amentioning

confidence: 58%

“…The skeletal assemblage of the T-OAE interval is dominated by epifaunal, sessile, filter feeders (crinoids and brachiopods), which have predominantly opportunistic competitor forms (Graziano et al, 2006); these taxa likely had high growth rates and produced numerous offspring, allowing them to take advantage of vacated niche spaces through rapid proliferation. The composition of these communities, along with the anomalous appearance of clotted microbial accretions and microbially coated grains throughout the T-OAE interval ( Figs 5, 6D and 6H), is suggestive of mesotrophic to eutrophic palaeoceanographic conditions (Hallock & Schlager, 1986;Brasier, 1995), which have previously been established as an important factor in the demise of oligotrophic communities in the early Toarcian (Zempolich, 1993;Blomeier & Reijmer, 1999;Krencker et al, 2020). Monospecific trace fossil assemblages, specifically narrow Chondrites galleries within the lower hardground interval, indicate depleted oxygen levels within the shallow sediment (Bromley & Ekdale, 1984).…”

Section: Depositional Environmentsmentioning

confidence: 75%

“…Incipient platform drowning was thus influenced, and possibly triggered by, an influx of nutrient-rich waters and the subsequent development of photic-zone anoxia which likely forced non-resilient benthos to either migrate or perish. This initial phase of perturbation likely corresponds to the first phase of collapse of the shallow-water carbonate factory during the late Pliensbachian-Toarcian, as defined by Krencker et al (2020).…”

Section: Evolution Of the Adriatic Carbonate Platform Across The Toarmentioning

confidence: 99%

“…, 2012; Krencker et al. , 2020). The emplacement of the Karoo–Ferrar–Chon Aike Large Igneous Province (LIP) was coincident with black shale deposition and elevated p CO 2 during the late Pliensbachian and early Toarcian (Burgess et al.…”

Section: Introductionmentioning

confidence: 99%

“…The Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE) was a geologically brief episode associated with globally enhanced organic carbon burial (Jenkyns, 1988) and carbonate platform crises (Woodfine et al, 2008;Léonide et al, 2012;Trecalli et al, 2012;Krencker et al, 2020). The emplacement of the Karoo-Ferrar-Chon Aike Large Igneous Province (LIP) was coincident with black shale deposition and elevated pCO 2 during the late Pliensbachian and early Toarcian (Burgess et al, 2015) and as such has been implicated as the trigger for both the T-OAE and the preceding late Pliensbachian-early Toarcian mass extinction (Caruthers et al, 2013(Caruthers et al, , 2014Danise et al, 2013;Bodin et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform

et al. 2020

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Severe global climate change led to the deterioration of environmental conditions in the oceans during the Toarcian Stage of the Jurassic. Carbonate platforms of the Western Tethys Ocean exposed in Alpine Tethyan mountain ranges today offer insight into this period of environmental upheaval. In addition to informing understanding of climate change in deep time, the effect of ancient carbon cycle perturbations on carbonate platforms has important implications for anthropogenic climate change; the patterns of early Toarcian environmental deterioration are similar to those occurring in modern oceans. This study focuses on the record of the early Toarcian Oceanic Anoxic Event (ca 183.1 Ma) in outcrops of the northwest Adriatic Carbonate Platform in Slovenia. Amidst environmental deterioration, the northwest Adriatic Platform abruptly transitioned from a healthy, shallow-water environment with diverse metazoan ecosystems to a partially drowned setting with low diversity biota and diminished sedimentation. An organic carbon-isotope excursion of −2.2‰ reflects the massive injection of CO 2 into the ocean-atmosphere system and marks the stratigraphic position of the Toarcian Oceanic Anoxic Event. A prominent dissolution horizon and suppressed carbonate deposition on the platform are interpreted to reflect transient shoaling of the carbonate compensation depth to unprecedentedly shallow levels as the dramatic influx of CO 2 overwhelmed the ocean's buffering capacity, causing ocean acidification. Trace metal geochemistry and palaeoecology highlight water column deoxygenation, including the development of photic-zone anoxia, preceding and during the Toarcian Oceanic Anoxic Event. Ocean acidification and reduced oxygen levels likely had a profoundly negative effect on carbonate-producing biota and growth of the Adriatic Platform. These effects are consistent with the approximate doubling of the concentration of CO 2 in the ocean-atmosphere system from pre-event levels, which has previously been linked to a volcanic triggering mechanism. Mercury enrichments discovered in this study support a temporal and genetic link between volcanism, the Toarcian Oceanic Anoxic Event and the carbonate crisis.

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Section: Oceanographic Changes Associated With the Toarcian Oceanic Amentioning

confidence: 58%

Section: Depositional Environmentsmentioning

confidence: 75%

Section: Evolution Of the Adriatic Carbonate Platform Across The Toarmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform

et al. 2020

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Glendonite-bearing concretions from the upper Pliensbachian (Lower Jurassic) of South Germany: indicators for a massive cooling in the European epicontinental sea

Merkel

Munnecke

2023

Facies

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The Pliensbachian–Toarcian transition was characterised by a drastic turnover from a cool climate to a period of rapid global warming. While the warming associated with the Early Toarcian Oceanic Anoxic Event is rather well-studied, the cause, intensity and extent of the preceding cooling in the late Pliensbachian are still discussed. Occurrences of glendonite play an important role in this debate, since glendonite is a pseudomorph after the cryophilic carbonate mineral ikaite. This study describes the first glendonite-bearing carbonate concretions from South Germany (Buttenheim clay pit, northern Franconian Alb), which represent the southernmost glendonite occurrence in the late Pliensbachian documented so far. Based on petrographical and sedimentological investigations as well as stable isotope analyses it is concluded that a low temperature was the main factor for ikaite formation in the studied section, suggesting that the late Pliensbachian cooling had a more far-reaching impact on the temperature of the European epicontinental sea than previously assumed. To explain the low temperatures required for ikaite precipitation, a model for the sea-ice driven formation of cold bottom-water masses on the continental shelf is proposed. The occurrence of several layers containing reworked hiatus concretions in the studied outcrop is interpreted as the result of recurrent sea-level falls caused by multiple glacial pulses characterising the overall cool climate in the late Pliensbachian.

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Brachiopodes toarciens de la coupe d’Aït Athmane, Haut Atlas centro-oriental (Maroc)

Benzaggagh

Salamon

Khaffou

et al. 2022

Annales de Paléontologie

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Two-phased collapse of the shallow-water carbonate factory during the late Pliensbachian–Toarcian driven by changing climate and enhanced continental weathering in the Northwestern Gondwana Margin

Cited by 34 publications

References 148 publications

Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform

Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform

Glendonite-bearing concretions from the upper Pliensbachian (Lower Jurassic) of South Germany: indicators for a massive cooling in the European epicontinental sea

Brachiopodes toarciens de la coupe d’Aït Athmane, Haut Atlas centro-oriental (Maroc)

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