Various influences on three-dimensional mantle convection with phase transitions

Yuen, David A.; Reuteler, D.; Balachandar, S.; Steinbach, Volker; Malevsky, Andrei V.; Smedsmo, J.J.

doi:10.1016/0031-9201(94)05068-6

Cited by 67 publications

(30 citation statements)

References 38 publications

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“…Christensen and Yuen (1985) have found other important results, i.e., the flow becomes more layered as the Rayleigh number increases. This point was also confirmed by recent 2-D and 3-D studies (e.g., Steinbach et al, 1993;Yuen et al, 1994). Since the Earth was undoubtedly hot in the past, which implies a higher Rayleigh number, their finding has potentially important implications for the Earth's history (e.g., Maruyama, 1994).…”

Section: Introductionsupporting

confidence: 64%

Model for Convective Cooling of Mantle with Phase Changes: Effects of Aspect Ratios and Initial Conditions.

Honda¹,

Yuen²

1994

J,Phys,Earth

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The effects of the aspect ratios and initial conditions on a cooling mantle with phase changes are studied using a 2-D Cartesian convection model without internal heating. The aspect ratio is either 3 or 5 and the side-boundaries are periodic. The initial condition is either a quasi-equilibrium state of convective flow or linear temperature increase from the top to the bottom surface. Bottom or core temperature is changed to match the core cooling by the convective heat transfer. Considerable qualitative and quantitative differences exist among the models with different initial conditions and aspect ratios. For example, we cannot find the convenient criterion, such as critical Rayleigh number, for the massive overturn of the upper and lower mantle associated with the endothermic phase transition (flushing). The presence of the thermal boundary layer at the endothermic phase boundary plays an important role in cooling both the upper and lower mantles. A common feature is that the upper mantle becomes hottest during the flushing event. In some cases, we find qualitatively similar "events" in which the style of flow changes. These events reflect the physical properties of the upper and lower mantles. Geological information of the past may be necessary to constrain the different models.

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Section: Introductionsupporting

confidence: 64%

Model for Convective Cooling of Mantle with Phase Changes: Effects of Aspect Ratios and Initial Conditions.

Honda¹,

Yuen²

1994

J,Phys,Earth

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show abstract

“…One might argue that this situation is artificially forced by the initial conditions. There are, however, some suggestions that convection was much more layered in the early history of both Earth and Venus due to the higher ambient temperatures and the greater abundance of radiogenic heat sources and, in fact, higher convective vigor [13][14][15][16][17]. Thus it is interesting to investigate the evolution of such a possibly unstable scenario.…”

Section: Resultsmentioning

confidence: 99%

The influences of surface temperature on upwellings in planetary convection with phase transitions

Steinbach

Yuen

1998

Earth and Planetary Science Letters

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The importance of surface temperature for mantle convection appears with the presence of adiabatic heating and cooling and the release and consumption of latent heat in the presence of phase transitions. For some planetary bodies these effects cannot be neglected. The dimensionless surface temperature T 0 , which is the ratio between the temperature at the top of the convective region and the temperature drop across the mantle, is close to one for Mars and Venus. For the Earth, T 0 lies between 0.2 and 0.5. The dynamical influence of T 0 is especially poignant for internally heated convection with temperature-dependent viscosity. There is a tight coupling between the magnitude of the temperature field and the viscosity itself. We have studied temperature-dependent viscosity convection for both low-T 0 (0.2) and high-T 0 (1.2) situations and with internal heating in mantle convection with two upper-mantle phase transitions. Our results show that within this range of T 0 there exist two regimes for the evolution of upwellings in the mantle. In transient situations plume-plume collisions lead to the formation of megaplumes for high-T 0 regimes but are less likely to do so for low T 0 . In the long-term regime, plumes with low T 0 are prone to develop from the transition zone with a supply of hot material coming from the shallow lower mantle. In systems with high T 0 , however, long-lived plumes tend to have deeper mantle origins. In quasi-layered situations high T 0 may act as a positive feed-back mechanism in inducing powerful hot upwellings into the upper mantle.

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“…Whole mantle convection models indicate that propensity to layered convection increases with increasing Rayleigh number [Yuen et al, 1994]. Our model runs with R,a = 10 7 shoxv a quasi-periodical penetration of the slab through the 670 discontinuity even at high trench migration rates.…”

mentioning

confidence: 99%

Trench migration and subduction zone geometry

Olbertz

Wortel

Hansen

1997

Geophysical Research Letters

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Abstract. Seismic tomography results shoxv a large variety in upper mantle structure along convergent plate boundaries. \¾e numerically investigate the effect of trench migration on the evolution of a slab (with temperature dependent viscosity) encountering a viscosity interface. \¾e find that subduction zone geometry is sensitive to even small rates (1 cm/yr) of retrograde motion: increase in trench migration rate decreases the dip angle of the slab and its ability to penetrate the lower mantle. Upon including a background mantle flow it turns out that trench migration relative to the upper mantle flow is more decisive than the absolute plate velocities. Subduction zone geometry appears to be strongly time-dependent. \¾e conclude that individual tectonic setting and time-dependent slab behaviour can account for many different types of observable subduction zone anomalies. Our model temperature can adequately account for magnitudes and pattern s of seismic anomalies as obtained from seismic tomography.

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Various influences on three-dimensional mantle convection with phase transitions

Cited by 67 publications

References 38 publications

Model for Convective Cooling of Mantle with Phase Changes: Effects of Aspect Ratios and Initial Conditions.

Model for Convective Cooling of Mantle with Phase Changes: Effects of Aspect Ratios and Initial Conditions.

The influences of surface temperature on upwellings in planetary convection with phase transitions

Trench migration and subduction zone geometry

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