Possible solutions to several enigmas of Cretaceous climate

Hay, William W.; DeConto, Robert M.; Boer, Poppe de; Flögel, Sascha; Song, Yu; Stepashko, A. A.

doi:10.1007/s00531-018-1670-2

Cited by 42 publications

(20 citation statements)

References 157 publications

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“…Other testable evidences not observed yet or purely speculative Hay et al (2018) and Hay & Floegel (2012) indicated that, during the Cretaceous, continental palaeoelevations were smaller than they are today ('Continental elevation problem') and speculated that there were more extensive terrestrial wetlands like lakes and meandering rivers with oxbow lakes and swamps. Coupled climate model sensitivity runs for the mid-Cretaceous by Hay et al (2018) used eight times the preindustrial CO 2 level and 50-75% water surfaces on land, providing water vapour as an additional greenhouse gas. Modelling results show reduced meridional temperature gradients and conditions compatible with the palaeontological and stratigraphic record.…”

Section: Other Phanerozoic Evidences For Aquifer-eustasymentioning

confidence: 99%

“…This is particularly important when considering various palaeogeographic settings in Earth history that are more or less different from today (especially different topographies, i.e. lower average elevations and, thus, considerably higher 'available' pore space and groundwater volumes, as has been suggested for the Cretaceous for example, see the 'Continental elevation problem' of Hay 2011Hay , 2017Hay et al 2018, and references therein) and an almost totally ice-free, warm greenhouse to 'hothouse' world (e.g. during the mid-Cretaceous).…”

Section: Earth's 'Surface' Water Resources and Their Distributionmentioning

confidence: 99%

“…In this case and including the minor component of thermo-eustasy, aquifer-eustasy would be the main and sole mechanism to be considered for changing sea-level on short timescales. Moreover, such settings would result in even higher aquifer volumes of 'available' groundwater because the widespread or total lack of continental ice sheets and permafrost areas would increase the aquiferaccessible land area (Hay 2011;Föllmi 2012;Hay et al 2018). Therefore, depending on the climate mode of the Earth as well as the climate state, that is the presence of predominantly arid or predominantly humid conditions, both the allocation of water volumes between glacial water and groundwater on the one hand, and the respective operative water volumes processed by the hydrological cycle on the other hand, can vary considerably (mainly regarding the transfer of water from the oceans to continents and in reverse, and enhanced water transfer from low to high latitudes, e.g.…”

Section: Earth's 'Surface' Water Resources and Their Distributionmentioning

confidence: 99%

“…'Nonavailable' groundwater refers groundwater partially at and below the respective actual sea-level which does not contribute to aquifer-eustatic sea-level fluctuations. It is also important to note that a significant flow of groundwater directly entering the ocean does not interact directly with the climate system and is, thus, not included in respective climate models (Hay et al 2018). may influence hothouse marginal-marine carbon isotope ratios as recently put forward by Laurin et al (2019) for the OAE 2 interval. In marginal marine settings such as the Western Interior Seaway, negative δ 13 C peaks show orbital control on obliquity and short eccentricity scales (80-120 kyr).…”

Section: Sea-levelmentioning

confidence: 99%

“…Aquifer-eustasy may have dominated times when no ice shields were present on the planet, i.e. the hothouse ('supergreenhouse') state of Earth's climate of Kidder & Worsley (2012) and Hay et al (2018). The mid-Cretaceous constitutes the main period for a hothouse Earth, with its distinct oceanwide anoxia that relate to extreme hot climates.…”

Section: Cretaceous Intervals Dominated By Aquifer-eustatic Short-termentioning

confidence: 99%

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Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

Sames

Wagreich

Conrad

et al. 2020

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A review of short-term (,3 myr: c. 100 kyr to 2.4 myr) Cretaceous sea-level fluctuations of several tens of metres indicates recent fundamental progress in understanding the underlying mechanisms for eustasy, both in timing and in correlation. Cretaceous third-and fourth-order hothouse sea-level changes, the sequencestratigraphic framework, are linked to Milankovitch-type climate cycles, especially the longer-period sequencebuilding bands of 405 kyr and 1.2 myr. In the absence of continental ice sheets during Cretaceous hothouse phases (e.g. Cenomanian-Turonian), growing evidence indicates groundwater-related sea-level cycles: (1) the existence of Milankovitch-type humid-arid climate oscillations, proven via intense humid weathering records during times of regression and sea-level lowstands; (2) missing or inverse relationships of sea-level and the marine δ 18 O archives, i.e. the lack of a pronounced positive excursion, cooling signal during sealevel lowstands; and (3) the anti-phase relationship of sea and lake levels, attesting to high groundwater levels and charged continental aquifers during sea-level lowstands. This substantiates the aquifer-eustasy hypothesis. Rates of aquifer-eustatic sea-level change remain hard to decipher; however, reconstructions range from a very conservative minimum estimate of 0.04 mm a −1 (longer time intervals) to 0.7 mm a −1 (shorter, probably asymmetric cycles). Remarkably, aquifer-eustasy is recognized as a significant component for the Anthropocene sealevel budget.

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Section: Other Phanerozoic Evidences For Aquifer-eustasymentioning

confidence: 99%

Section: Earth's 'Surface' Water Resources and Their Distributionmentioning

confidence: 99%

Section: Earth's 'Surface' Water Resources and Their Distributionmentioning

confidence: 99%

Section: Sea-levelmentioning

confidence: 99%

Section: Cretaceous Intervals Dominated By Aquifer-eustatic Short-termentioning

confidence: 99%

See 3 more Smart Citations

Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

Sames

Wagreich

Conrad

et al. 2020

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Connecting the Deep Earth and the Atmosphere

Torsvik

Svensen

Steinberger

et al. 2021

Geophysical Monograph Series

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Most hotspots, kimberlites, and large igneous provinces (LIPs) are sourced by plumes that rise from the margins of two large low shear-wave velocity provinces in the lowermost mantle. These thermochemical provinces have likely been quasi-stable for hundreds of millions, perhaps billions of years, and plume heads rise through the mantle in about 30 Myr or less. LIPs provide a direct link between the deep Earth and the atmosphere but environmental consequences depend on both their volumes and the composition of the crustal rocks they are emplaced through. LIP activity can alter the plate tectonic setting by creating and modifying plate boundaries and hence changing the paleogeography and its long-term forcing on climate.Extensive blankets of LIP-lava on the Earth's surface can also enhance silicate weathering and potentially lead to CO2 drawdown (cooling), but we find no clear relationship between LIPs and post-emplacement variation in atmospheric CO2 proxies on very long (>10 Myrs) timescales.Subduction is a key driving force behind plate tectonics but also a key driver for the long-term climate evolution through arc volcanism and degassing of CO2. Subduction fluxes derived from full-plate models provide a powerful way of estimating plate tectonic CO2 degassing (sourcing) and correlate well with zircon age frequency distributions through time. This suggest that continental arc activity may have played an important role in regulating long-term climate change (greenhouse vs. icehouse conditions) but only the Permo-Carboniferous icehouse (~330-275 Ma) show a clear correlation with the zircon record.

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High‐frequency sequences within a retrogradational deltaic succession: Upper Cenomanian Dunvegan Formation, Western Canada Foreland Basin

Hay

Plint

2020

The Depositional Record

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After prograding for several hundred kilometres during Middle Cenomanian time, the Dunvegan delta complex in north‐west Alberta and adjacent British Columbia experienced stepwise transgression, commencing at about the Middle to Late Cenomanian boundary. Progressive drowning of the delta complex is recorded by Dunvegan allomembers B and A, each comprised of three simple depositional sequences, bounded by composite subaerial unconformity/flooding surfaces. Each sequence represents an array of deltaic depositional environments. Delta‐front sandstones preserve little evidence, such as hummocky cross‐stratification, for powerful storm wave action, although wave and combined‐flow ripples are common. Delta‐front sandstone bodies tend to be smaller and lobate in the lower part of the studied interval, and larger and more linear near the top. This suggests increasingly effective wave‐driven redistribution of sand as more open‐marine conditions were gradually established. The top surfaces of allomembers B and A are locally incised by sandstone‐filled palaeovalleys up to 19 m deep; river incision may have been a response to relative sea‐level fall and/or a change in the ratio of discharge to sediment load. Overall, the shoreline described a broad arc, open to the south east, with the sense of shoreline migration north‐west to south‐east. For each sequence, the shoreline migrated an average of 80 km between transgressive and regressive limits. The transgressive limit shows a progressive landward offset of about 15 km per sequence, culminating in complete drowning of the delta system above sequence A3. Isopach maps show that syn‐depositional tectonic subsidence rotated the basin down to the south‐west; palaeogeographic maps show, however, that the sea floor sloped to the south‐east, implying that sediment redistribution effectively filled all tectonically generated accommodation and maintained a south‐east inclined depositional surface. Transgressions and regressions across this surface were therefore driven primarily by eustasy rather than pulses of tectonic subsidence. Simple calculations based on inferred alluvial gradients of 10–20 cm/km suggest that eustatic excursions of ca 8–16 m would have been sufficient to generate sequence thicknesses on the order of 10 m. Limited geochronologic and biostratigraphic control suggests that the six simple sequences that form Dunvegan allomembers B and A each represent an average of about 41 kyr, suggesting that the orbital obliquity cycle was the primary control on high‐frequency sea‐level cycles.

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Possible solutions to several enigmas of Cretaceous climate

Cited by 42 publications

References 157 publications

Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

Connecting the Deep Earth and the Atmosphere

High‐frequency sequences within a retrogradational deltaic succession: Upper Cenomanian Dunvegan Formation, Western Canada Foreland Basin

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