Greenhouse World and the Mesozoic Ocean

Takashima, Reishi; Nishi, Hiroshi; Huber, Brian T.; Leckie, R. Mark

doi:10.5670/oceanog.2006.07

Cited by 124 publications

(52 citation statements)

References 13 publications

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“…Global preservational biases caused by changing oxygen levels may not be unique to the Ediacaran-Ordovician interval. The prevalence of exceptional assemblages within marine/transitional facies associated with the Toarcian (Ansorge, 2003;Martindale et al, 2017) and Cenomanian/Turonian (Martill et al, 2011) global oceanic anoxic events (Takashima et al, 2006;Figs. 12a-d and 14a, b) indicates such events favored exceptional preservation.…”

Section: Exceptional Preservation Through Time In Marine Settingsmentioning

confidence: 99%

Exceptionally Preserved Fossil Assemblages Through Geologic Time and Space

Muscente¹,

Laflamme²,

Schiffbauer³

et al. 2016

Geological Society of America Abstracts With Programs

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Geologic deposits containing fossils with remains of non-biomineralized tissues (i.e. Konservat-Lagerstätten) provide key insights into ancient organisms and ecosystems. Such deposits are not evenly distributed through geologic time or space, suggesting that global phenomena play a key role in exceptional fossil preservation. Nonetheless, establishing the influence of global phenomena requires documenting temporal and spatial trends in occurrences of exceptionally preserved fossil assemblages. To this end, we compiled and analyzed a dataset of 694 globally distributed exceptional fossil assemblages spanning the history of complex eukaryotic life (~610 to 3 Ma). Our analyses demonstrate that assemblages with similar ages and depositional settings commonly occur in clusters, each signifying an ancient geographic region (up to hundreds of kilometers in scale), which repeatedly developed conditions conducive to soft tissue preservation. Using a novel hierarchical clustering approach, we show that these clusters decrease in number and shift from open marine to transitional and nonmarine settings across the Cambrian-Ordovician interval. Conditions conducive to exceptional preservation declined worldwide during the early Paleozoic in response to transformations of near-surface environments that promoted degradation of tissues and curbed authigenic mineralization potential. We propose a holistic explanation relating these environmental transitions to ocean oxygenation and bioturbation, which affected virtually all taphonomic pathways, in addition to changes in seawater chemistry that disproportionately affected processes of soft tissue conservation. After these transitions, exceptional preservation rarely occurred in open marine settings, excepting times of widespread oceanic anoxia, when low oxygen levels set the stage. With these patterns, nonmarine cluster count is correlated with non-marine rock quantity, and generally decreases with age. This result suggests that geologic processes, which progressively destroy terrestrial rocks over time, limit sampling of non-marine deposits on a global scale. Future efforts should aim to assess the impacts of such phenomena on evolutionary and ecological patterns in the fossil record.

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Section: Exceptional Preservation Through Time In Marine Settingsmentioning

confidence: 99%

Exceptionally Preserved Fossil Assemblages Through Geologic Time and Space

Muscente¹,

Laflamme²,

Schiffbauer³

et al. 2016

Geological Society of America Abstracts With Programs

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“…Remnants of these anoxic events are black shale sediments (Takashima et al, 2006). During such THC collapses, the uptake of CO 2 into the oceanic crust stayed restricted to organic carbon sediments.…”

Section: Introductionmentioning

confidence: 99%

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

et al. 2017

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Abstract. Power stations, ships and air traffic are among the most potent greenhouse gas emitters and are primarily responsible for global warming. Iron salt aerosols (ISAs), composed partly of iron and chloride, exert a cooling effect on climate in several ways. This article aims firstly to examine all direct and indirect natural climate cooling mechanisms driven by ISA tropospheric aerosol particles, showing their cooperation and interaction within the different environmental compartments. Secondly, it looks at a proposal to enhance the cooling effects of ISA in order to reach the optimistic target of the Paris climate agreement to limit the global temperature increase between 1.5 and 2 • C.Mineral dust played an important role during the glacial periods; by using mineral dust as a natural analogue tool and by mimicking the same method used in nature, the proposed ISA method might be able to reduce and stop climate warming. The first estimations made in this article show that by doubling the current natural iron emissions by ISA into the troposphere, i.e., by about 0.3 Tg Fe yr −1 , artificial ISA would enable the prevention or even reversal of global warming. The ISA method proposed integrates technical and economically feasible tools.

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“…the Upper Cretaceous), when OMZs were widely expanded and black shales deposited (e.g. Takashima et al, 2006;Schön-feld et al, 2015). Our study contributes to the unsolved question of production vs. preservation of organic debris when trying to explain the origin of black shales and oil source rocks in the Earth's history (e.g.…”

Section: Discussionmentioning

confidence: 99%

Bathypelagic particle flux signatures from a suboxic eddy in the oligotrophic tropical North Atlantic: production, sedimentation and preservation

et al. 2016

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The lithogenic ballasting obviously resulted in high particle settling rates and, thus, a fast transfer of epi-/mesopelagic signatures to the bathypelagic traps. We suspect that the two-to three-fold increase in particle fluxes with depth as well as the tight coupling of mineral dust and organic carbon in the deep trap samples might be explained by particle focusing processes within the deeper part of the eddy. Molar C : N ratios of organic matter during the ACME passage were around 18 and 25 for the upper and lower trap samples, respectively. This suggests that some productivity under nutrient (nitrate) limitation occurred in the euphotic zone of the eddy in the beginning of 2010 or that a local nitrogen recycling took place. The δ 15 N record showed a decrease from 5

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Greenhouse World and the Mesozoic Ocean

Cited by 124 publications

References 13 publications

Exceptionally Preserved Fossil Assemblages Through Geologic Time and Space

Exceptionally Preserved Fossil Assemblages Through Geologic Time and Space

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

Bathypelagic particle flux signatures from a suboxic eddy in the oligotrophic tropical North Atlantic: production, sedimentation and preservation

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