Mechanistic insights into a hydrate contribution to the Paleocene‐Eocene carbon cycle perturbation from coupled thermohydraulic simulations

Minshull, T. A.; Marín‐Moreno, Héctor; McKay, David I. Armstrong; Wilson, Paul A.

doi:10.1002/2016gl069676

Cited by 12 publications

(12 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, methane hydrate dissociation was hypothesized to play an important role in the Paleocene-Eocene thermal maximum (PETM) at~55.5 Ma (Dickens, Castillo, et al, 1997;Dickens et al, 1995) and in warming episodes during Late Quaternary climate oscillations (Kennett et al, 2000;Kennett et al, 2003). However, the role of methane hydrate during the PETM has been questioned due to an insufficient amount of carbon stored in methane hydrate (Higgins & Schrag, 2006;Zachos et al, 2003), the delayed and incomplete release of such carbon to the seabed from methane hydrate (Minshull et al, 2016), and the persistent low ocean surface pH during the PETM (Gutjahr et al, 2017). The proposed contribution of hydrate dissociation during Quaternary climate oscillations has been questioned on the basis of hydrogen isotope analyses (Sowers, 2006) and ice core analyses (Chappellaz et al, 2013;Melton et al, 2012;Petrenko et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Methane Hydrate Formation in Geological Systems

You

Flemings

Malinverno

et al. 2019

Reviews of Geophysics

145

110

View full text Add to dashboard Cite

Natural gas hydrate is ice‐like mixture of gas (mostly methane) and water that is widely found in sediments along the world's continental margins and within and beneath permafrost and glaciers in a near‐surface depth interval where the pressure is sufficiently high and temperature sufficiently low for gas hydrate to be stable. We categorize the myriad of geological gas hydrate deposits into five characteristic types. We then review the multiple quantitative models that have proposed to describe the genesis of these deposits and describe how each may have formed. We emphasize the importance of coupling multiphase flow (free gas and liquid water) and multicomponent reactive transport with geological history to describe the dynamical processes of gas hydrate formation and evolution in geological systems. A better insight into the kinetics of methane formation from microbial biogenesis and the processes of multiphase flow at the pore scale will advance our knowledge of how these systems form. By understanding the generation and evolution of gas hydrate through time, we will better decipher the role of gas hydrate in the carbon cycle, its potential to contribute to climate change and geohazards, and how to design optimal strategies for gas production from hydrate reservoirs.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanisms of Methane Hydrate Formation in Geological Systems

You

Flemings

Malinverno

et al. 2019

Reviews of Geophysics

145

110

View full text Add to dashboard Cite

show abstract

“…Methane hydrates have drawn international interest as an alternative energy resource to conventional fossil fuels, and as a major hazard for offshore drilling and gas production operations, global climate change, and seafloor instability . Quantitative evaluation of the resource potential of gas hydrate reservoirs and of their response to natural and/or human‐induced changes in pressure and temperature (P‐T) conditions requires precise knowledge of the hydrate phase change phenomenon and of its effect on the mechanical stability of the reservoir.…”

Section: Introductionmentioning

confidence: 99%

A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments

Fuente

Vaunat

Marín‐Moreno

2020

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

SUMMARY Recent pore‐scale observations and geomechanical investigations suggest the lack of true cohesion in methane hydrate‐bearing sediments (MHBSs) and propose that their mechanical behavior is governed by kinematic constrictions at pore‐scale. This paper presents a constitutive model for MHBS, which does not rely on physical bonding between hydrate crystals and sediment grains but on the densification effect that pore invasion with hydrate has on the sediment mechanical properties. The Hydrate‐CASM extends the critical state model Clay and Sand Model (CASM) by implementing the subloading surface model and introducing the densification mechanism. The model suggests that the decrease of the sediment available void volume during hydrate formation stiffens its structure and has a similar mechanical effect as the increase of sediment density. In particular, the model attributes stress‐strain changes observed in MHBS to the variations in sediment available void volume with hydrate saturation and its consequent effect on isotropic yield stress and swelling line slope. The model performance is examined against published experimental data from drained triaxial tests performed at different confining stress and with distinct hydrate saturation and morphology. Overall, the simulations capture the influence of hydrate saturation in both the magnitude and trend of the stiffness, shear strength, and volumetric response of synthetic MHBS. The results are validated against those obtained from previous mechanical models for MHBS that examine the same experimental data. The Hydrate‐CASM performs similarly to previous models, but its formulation only requires one hydrate‐related empirical parameter to express changes in the sediment elastic stiffness with hydrate saturation.

show abstract

“…Results for skewness, kurtosis, and sensitivity analyses for all metrics can be found in the Supplement. Rahmstorf, 2002;Stocker and Wright, 1991;Stommel, 1961) and the growth or collapse of large ice sheets (although no substantial ice sheets existed at this time) (DeConto et al, 2008;DeConto and Pollard, 2003;Pagani et al, 2011;Pollard and DeConto, 2009). Any shorter-term drivers of instability closer to the event, for example changes in ocean and atmospheric dynamics or precursor warming on millennial timescales (Secord et al, 2010;Sluijs et al, 2007a), will be missed and could thus constitute "missed alarms".…”

Section: Introductionmentioning

confidence: 99%

Reduced carbon cycle resilience across the Palaeocene–Eocene Thermal Maximum

McKay

Lenton

2018

Clim. Past

View full text Add to dashboard Cite

Abstract. Several past episodes of rapid carbon cycle and climate change are hypothesised to be the result of the Earth system reaching a tipping point beyond which an abrupt transition to a new state occurs. At the Palaeocene–Eocene Thermal Maximum (PETM) at ∼56 Ma and at subsequent hyperthermal events, hypothesised tipping points involve the abrupt transfer of carbon from surface reservoirs to the atmosphere. Theory suggests that tipping points in complex dynamical systems should be preceded by critical slowing down of their dynamics, including increasing temporal autocorrelation and variability. However, reliably detecting these indicators in palaeorecords is challenging, with issues of data quality, false positives, and parameter selection potentially affecting reliability. Here we show that in a sufficiently long, high-resolution palaeorecord there is consistent evidence of destabilisation of the carbon cycle in the ∼1.5 Myr prior to the PETM, elevated carbon cycle and climate instability following both the PETM and Eocene Thermal Maximum 2 (ETM2), and different drivers of carbon cycle dynamics preceding the PETM and ETM2 events. Our results indicate a loss of “resilience” (weakened stabilising negative feedbacks and greater sensitivity to small shocks) in the carbon cycle before the PETM and in the carbon–climate system following it. This pre-PETM carbon cycle destabilisation may reflect gradual forcing by the contemporaneous North Atlantic Volcanic Province eruptions, with volcanism-driven warming potentially weakening the organic carbon burial feedback. Our results are consistent with but cannot prove the existence of a tipping point for abrupt carbon release, e.g. from methane hydrate or terrestrial organic carbon reservoirs, whereas we find no support for a tipping point in deep ocean temperature.

show abstract

Mechanistic insights into a hydrate contribution to the Paleocene‐Eocene carbon cycle perturbation from coupled thermohydraulic simulations

Cited by 12 publications

References 56 publications

Mechanisms of Methane Hydrate Formation in Geological Systems

Mechanisms of Methane Hydrate Formation in Geological Systems

A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments

Reduced carbon cycle resilience across the Palaeocene–Eocene Thermal Maximum

Contact Info

Product

Resources

About