Carolina Lithgow-Bertelloni

• Ph.D, UC Berkeley
• Chair at University of California, Los Angeles

Mineral phase transitions can either hinder or accelerate mantle flow. In the present day, the formation of the bridgmanite + ferropericlase assemblage from ringwoodite at 660 km depth has been found to cause weak and intermittent layering of mantle convection. However, for the higher temperatures in Earth's past, different phase transitions could...

Optical distortion caused by changes in the refractive index of fluid flow is a common issue in flow visualization using techniques, such as particle image velocimetry (PIV). In thermally driven convection, this distortion can severely interfere with PIV results due to the ubiquitous density and, therefore, refractive index heterogeneity in the flu...

The shape of the ocean floor (bathymetry) and the overlaying sediments provide the largest carbon sink throughout Earth’s history, supporting ~one to two orders of magnitude more carbon storage than the oceans and atmosphere combined. While accumulation and erosion of these sediments are bathymetry dependent (e.g., due to pressure, temperature, sal...

Mineral phase transitions can either hinder or accelerate mantle flow. In the present day, the formation of the bridgmanite + ferropericlase assemblage from ringwoodite at 660 km depth has been found to cause weak and intermittent layering of mantle convection. However, for the higher temperatures in Earth’s past, different phase transitions could...

We expand the scope of HeFESTo by encompassing the rich physics of iron in the mantle, including the existence of multiple valence and spin states. In our previous papers, we considered iron only in its most common state in the mantle: the high-spin divalent (ferrous) cation. We now add ferric iron end-members to six phases, as well as the three ph...

Using 2D numerical subduction models, we compare deep slab behaviour with oceanic and continental overriding plates and a mantle viscosity structure where the lower mantle viscosity jump occurs either at 660 km or at 1000 km depth as suggested by the latest geoid inversions. We demonstrate that a strong, thick, and buoyant continental plate, combin...

Mantle water content estimates range from 0.5 to 15 oceans of water. Its evolution is even more unclear. Rapid degassing during mantle solidification likely released much of the water to the surface, initially flooding Earth. However, evidence for subaerial land from at least 3.5 Ga means that much of this water must have been rapidly cycled back i...

Key Points The editors thank the 2022 peer reviewers

Subduction of bathymetric anomalies (e.g., an active ridge) can alter the morphology of subducted slabs and their coupling to surface processes. A natural laboratory to study these effects is the subduction of the Oceanic Chilean Ridge beneath the South American plate, which led to the formation of the Patagonian slab window. Its formation and subs...

In this study, we examine the influence of the mantle and large-scale tectonics on the global mid-ocean ridge (MOR) system. Using solely seismically-inferred upper mantle temperatures below the melting zone (260-600 km) and an interpretable machine learning model (Random Forest and Principal Component Analysis), we predict, with up to 90\% accuracy...

Stochastic tomography, made possible by dense deployments of seismic sensors, is used to identify phase changes in Earth's mantle that occur over depth intervals. This technique inverts spatial coherences of amplitudes and travel times of body waves to determine the depth and dependence of the spatial spectrum of seismic velocity. This spectrum is...

Mantle viscosity controls a variety of geodynamic processes such as glacial isostatic adjustment (GIA), but it is poorly constrained because it cannot be measured directly from geophysical measurements. Here we develop a method that calculates viscosity using empirical viscosity flow laws coupled with mantle parameters (temperature and water conten...

Phase transitions play an important role for the style of mantle convection. While observations and theory agree that a substantial fraction of subducted slabs and rising plumes can move through the whole mantle at present day conditions, this behavior may have been different throughout Earth’s history. Higher temperatures, such as in the early Ear...

Water has been stored in the Martian mantle since its formation, primarily in nominally anhydrous minerals. The short-lived early hydrosphere and intermittently flowing water on the Martian surface may have been supplied and replenished by magmatic degassing of water from the mantle. Estimating the water storage capacity of the solid Martian mantle...

Water has been stored in the Martian mantle since its formation, primarily in nominally anhydrous minerals. The short-lived early hydrosphere and intermittently flowing water on the Martian surface may have been supplied and replenished by magmatic degassing of water from the mantle. Estimating the water storage capacity of the solid Martian mantle...

Key Point The editors thank the 2021 peer reviewers

Hotspot cool down Deep-seated mantle plumes are responsible for volcanic island chains such as Hawai’i. Upwelling from the deep interior requires that the plumes are hotter than the surrounding mantle to make it all the way up to the surface. However, Bao et al . found that some of these “hotspots” are surprisingly cool. The temperature is actually...

We derive exact expressions for the thermal expansivity, heat capacity, and bulk modulus for assemblages with arbitrarily large numbers of components and phases, including the influence of phase transformations and chemical exchange. We illustrate results in simple two-component, two-phase systems, including Mg-Fe olivine-wadsleyite and Ca-Mg clino...

Key Points The editors thank the 2020 peer reviewers

The water content in Earth's mantle today remains poorly constrained, but the bulk water storage capacity in the solid mantle can be quantified based on experimental data and may amount to a few times the modern surface ocean mass (OM). An appreciation of the mantle water storage capacity is indispensable to our understanding of how water may have...

Finding the Emperor's head Volcanic island and seamount chains form from deep-seated plumes of hot material upwelling through the mantle. The most famous of these is the Hawaiian-Emperor seamount chain. However, a large volcanic structure associated with a plume head that should precede the chain has long been missing. Wei et al. finally identified...

Slab orphaning is a newly discovered phenomenological behavior, where the slab tip breaks off at the top of the lower mantle (~660 km depth) and is abandoned by its parent slab. Upon orphaning, subduction continues uninterrupted through the lateral motion of the parent slab above 660 km depth. In this work, we present a regime diagram for the range...

The publishing process relies on the work of volunteer reviewers, and evaluating the interdisciplinary papers published in G‐Cubed can be challenging. As Editors and Associate Editors, we would like to give our appreciation to all reviewers and would like to acknowledge them in this editorial. G‐Cubed published 326 manuscripts out of 650 submission...

Water content plays a vital role in determining mantle rheology and thus mantle convection and plate tectonics. Most parameterised convection models predict that Earth initially underwent a period of rapid degassing and heating, followed by a slow and sustained period of regassing and cooling. However, these models assume water is instantaneously m...

Several theoretical studies indicate that a substantial fraction of the measured seismic anisotropy could be interpreted as extrinsic anisotropy associated with compositional layering in rocks, reducing the significance of strain‐induced intrinsic anisotropy. Here we quantify the potential contribution of grain‐scale and rock‐scale compositional an...

Supporting Information S1

Mantle convection can drive long-wavelength and low-amplitude topography, which can occur synchronously and superimposed to tectonics. The discrimination between these two topographic components, however, is difficult to assert. This is because there are still several uncertainties and debates in the geodynamic community, for example, the scales an...

As the Earth's primary mode of planetary cooling, the oceanic plate is created at mid-ocean ridges, transported across the planet's surface, and destroyed at subduction zones. The evolution of its buoyancy and rheology during its lifespan maintains the coherence of the plate as a distinct geological entity and controls the localised deformation and...

The sinking remnant of a surface plate crosses and interacts with multiple boundaries in Earth's interior. Here, we specifically investigate the prominent dynamic interaction of the sinking plate portion with the upper-mantle transition zone and its corresponding surface elevation signal. We unravel, for the first time, that the collision of the si...

The long-wavelength surface deflection of Earth's outermost rocky shell is mainly controlled by large-scale dynamic processes like isostasy or mantle flow. The largest topographic amplitudes are therefore observed at plate boundaries due to the presence of large thermal heterogeneities and strong tectonic forces. Distinct vertical surface deflectio...

Continental rifting has a fundamental role in the tectonic behaviour of the Earth, shaping the surface we live on. Although there is not yet a consensus about the dominant mechanism for rifting, there is a general agreement that the stresses required to rift the continental lithosphere are not readily available. Here we use a global finite element...

Measurements of the velocity field associated with plumes rising through a viscous fluid are performed using stereoscopic Particle-Image Velocimetry in the Rayleigh number range 4.4 × 105 − 6.4 × 105. The experimental model is analogous to a mantle plume rising from the core-mantle boundary to the base of the lithosphere. The behaviour of the plume...

In order to link the geochemical signature of hot spot basalts to Earth's deep interior, it is first necessary to understand how plumes sample different regions of the mantle. Here, we investigate the relative amounts of deep and shallow mantle material that are entrained by an ascending plume and constrain its source region. The plumes are generat...

The viscosity structure of Earth’s deep mantle affects the thermal evolution of Earth, the ascent of mantle plumes, settling of subducted oceanic lithosphere, and the mixing of compositional heterogeneities in the mantle. Based on a reanalysis of the long-wavelength nonhydrostatic geoid, we infer viscous layering of the mantle using a method that a...

Subduction exerts a strong control on surface topography and is the main cause of large vertical motions in continents, including past events of large-scale marine flooding and tilting. The mechanism is dynamic deflection: the sinking of dense subducted lithosphere gives rise to stresses that directly pull down the surface. Here we show that subduc...

The three-dimensional velocity and temperature fields surrounding an isolated thermal plume in a fluid with temperature-dependent viscosity are measured using Particle-Image Velocimetry and thermochromatic liquid-crystals, respectively. The experimental conditions are relevant to a plume rising through the mantle. It is shown that while the velocit...

The process of subduction provides continuous chemical and thermal heterogeneity to Earth’s mantle. How heterogeneity is stirred, stretched and distributed depends on the detail of mantle convection as well as chemical and physical properties of mantle materials. Seismic observations have revealed heterogeneities in Earth’s mantle at varying scales...

Convection in the Earth's mantle is mainly driven by cold, dense subducting slabs, but relatively little is known about how 3D variations in slab morphology and buoyancy affect mantle flow or how the surface above deforms in response (i.e. dynamic topography). We investigate this problem by studying the dynamics of an active region of flat-slab sub...

The Mohorovičić seismic discontinuity, known today as the Moho, was discovered in 1909 by Andrija Mohorovičić. It is defined by a jump in seismic velocities from 5.6 to ~7.8 km/s. It represents the boundary between the more felsic crust and the mafic mantle. Combining seismic, gravity, and other data to map the Moho has led to global compilations (...

Convection from an isolated heat source in a chamber has been previously studied numerically, experimentally and analytically. These have not covered long time spans for wide ranges of Rayleigh number Ra and Prandtl number Pr. Numerical calculations of constant viscosity convection partially fill the gap in the ranges Ra D 103-106 and Pr D 1; 10; 1...

Seismic refraction studies of deep-crustal and upper mantle structure beneath some oceanic hotspot provinces reveal the presence of ultramafic bodies with P-wave velocities of Vp ~ 7.4-8.0 km/s lying at or above the Moho, e.g., Hawaii, the Marquesas, and La Reunion. However, at other hotspot provinces such as the Galapagos, Nazca Ridge, and Louisvi...

1] The new aluminous (NAL) phase and aluminous phase with calcium ferrite (CF) structure constitutes more than 25 volume % of the deeply subducted crust at lower mantle depths. Using first principle simulations, we calculate the energetics, equation of state, and elasticity of NAL phase with a widely varying composition including CaMg 2 Al 6 O 12 ,...

Chemical heterogeneity, produced by the near-surface rock cycle and dominated volumetrically by subducted oceanic crust and its depleted residue, is continuously subducted into the mantle. This lithologic-scale chemical heterogeneity may survive in the mantle for as long as the age of Earth because chemical diffusion is inefficient. Estimates of ra...

Earth's subducting plates move 3-4 times faster than its overriding plates, but it remains unclear whether these contrasting plate speeds are caused by additional pull from subducting slabs or by increased viscous drag on the lithosphere-asthenosphere boundary beneath deeply-protruding continental roots. To investigate the relative importance of pl...

Global patterns of plate motions provide a constraint on plate tectonic forces and mantle structure, but the relative importance of plausible driving and resisting forces has not yet been determined. To help disentangle the various controls of Earth's plate motions, we constructed numerical models that combine (i) lateral viscosity variations assoc...

Since the first studies on dynamic topography and basin evolution, low-dipping subduction has been related to intracontinental, long-wavelength and high-amplitude subsidence, whereas retreating to normal subduction systems to uplift. This was proposed to explain the Cretaceous-early Cenozoic topographic evolution of the western US. However, modern...

Iceland has produced magma in a series of episodic events. From lava chemistry it has been inferred that the plume temperature decreased over the first 5 Myr by ~50°C and for the next 3 Myr following continental break up it continued to oscillate by ~25°C. Such data has been used to infer possible episodic collapse of the Iceland plume. Collapsing...

Since 2004 we have known that perovskite, the dominant lower mantle mineral, undergoes a phase change to post-perovskite at high pressures. However, it has been unclear if or where this transition occurs within the Earth's mantle, due to uncertainties in both the thermochemical state of the lowermost mantle, and the pressure-temperature conditions...

Lithospheric density and thickness variations are important contributors to the state of stress of the plates. The relationship between the lithosphere's isostatic state, subcrustal structure and stress field, however, remains unresolved due to the uncertainties on its thickness, composition and rheology. To study the influence of lithospheric stru...

We complete the development and description of a thermodynamic method for the computation of phase equilibria and physical properties of multiphase mantle assemblages. Our previous paper focused on the computation of physical properties. In this paper, our focus shifts to the phase equilibria. We further develop our theory to specify the ideal and...

The concept of mantle plumes has had a significant impact on our ideas about mantle geochemical heterogeneity and evolution. And yet many aspects remain controversial from their geochemical signature, excess temperature and seismic detectability to their very existence. We take an experimental approach not to tackle the question of plume survival i...

We analyze the Pampean foreland (the Pampas) along the modern flat-slab segment of the south-central Andes between 31° and 33° South latitude and to the east of the Argentine “flat-slab” province, using flexural and gravity studies and computations of dynamic topography. Bouguer anomalies and flexural analysis predict a foredeep of ∼ 250 km width a...

Central to the goals of mineral physics is an elucidation of how material behavior governs planetary processes. Planetary accretion, differentiation into crust, mantle, and core, ongoing processing by magmatism, dynamics and thermal evolution, and the generation of magnetic fields, are all processes controlled by the physical properties and phase e...

Mechanical coupling between the convecting mantle and Earth's lithospheric plates determines how buoyancy forces within the deep mantle are expressed at the surface as plate motions and lithospheric stresses. Strong viscosity variations associated with deeply-penetrating continental roots have been shown to significantly modify this plate-mantle co...

Contributions to Earth's surface topography range from short-wavelength uncompensated features due to tectonic activity, to variations in crustal structure and long-wavelength deflections of the lithosphere caused by mantle dynamics. The latter we call dynamic topography. Dynamic topography elevates or depresses the surface even if the density anom...

Some of the most powerful evidence for the nature of mantle heterogeneity has come from the study in mantle products of variations in trace element and isotopic concentrations, variations to which geophysical probes are insensitive. Major element heterogeneity, to which seismology and dynamical processes are sensitive, is expected to exist on indep...

Significant differences exist between isotopic signatures of typical mid-ocean ridge basalts (MORB) and those associated with many ocean islands, with ocean island basalts (OIB) generally exhibiting more variability in trace element concentrations and a bias towards enrichment in more primitive isotopes as well in some cases. Such observations coup...

The presence of deeply penetrating continental roots may locally increase the magnitude of basal shear tractions by up to a factor of 4 compared to a layered viscosity structure. Here we examine how these increases in mantle-lithosphere coupling influence stress patterns in the overlying elastic lithosphere. By coupling a mantle flow model to a mod...

We test a mineral physics model of the upper mantle against seismic observations. The model is based on current knowledge of material properties at high temperatures and pressures. In particular, elastic properties are computed with a recent self-consistent thermodynamic model, based on a six oxides (NCFMAS) system. We focus on average structure be...

The 25 March 1990 (Mw = 7.0) subduction megathrust earthquake that occurred offshore the Nicoya Peninsula, Costa Rica, produced a large number of aftershocks on the subduction plate interface as expected and preceded an unusual sequence of earthquakes 75 km inland that had two periods of significant increase, one at 60–90 days and one near 270 days...

We employ a new thermodynamic method for self-consistent computation of compositional and thermal effects on phase transition depths, density, and seismic velocities. Using these profi les, we compare theoretical and observed differential traveltimes between P410s and P (T410) and between P600s and P410s (T660-410) that are affected only by seismic...

Partial melting of mantle peridotite generates a physically and chemically layered oceanic lithosphere that is cycled back into the mantle in subduction zones. Stirring times of the mantle are too long to allow for complete re-homogenization of subducted basalt and harzburgite, given the low chemical diffusivity of the solid mantle. This suggests t...

The relationship between surface deformation and mantle-lithosphere coupling depends strongly on the viscosity structure of both the lithosphere and convecting mantle. Lateral variations in the thickness and viscosity of the lithosphere affect both the flow pattern and shear stress magnitude at the base of deeply penetrating continental roots. We e...

Deformation of both subducting and overriding at convergent plate boundaries tends to dissipate energy that would otherwise be used to drive plate motions. For subducting plates, the magnitude of the bending deformation is not known because of poor constraints on slab strength. For overriding plates, back-arc orogeny results from upper plate shorte...

Radial and lateral variations in major element chemistry have been a prominent feature of mantle models for some time, motivated, among other factors by the apparent difference in the Mg/Si ratio between C1 carbanaceous chondrites and the MORB source, the presence of multiple mantle reservoirs with distinctive trace element chemistry, and features...

We use a self-consistent thermodynamic formalism to compute the phase equilibria and physical properties of model mantle compositions, demonstrating that the seismological properties of a mantle comprised of (1) an equilibrium assemblage (EA) of pyrolitic composition and (2) a mechanical mixture (MM) of basalt and harzburgite with identical bulk co...

Although subducting slabs undergo a bending deformation that resists tectonic plate motions, the magnitude of this resistance is not known because of poor constraints on slab strength. However, because slab bending slows the relatively rapid motions of oceanic plates, observed plate motions constrain the importance of bending. We estimated the slab...

Although many have studied the chemistry and dynamics of mantle plumes, fundamental questions remain. These can be grouped into two general issues: a) Plume structure and dynamical interaction with the surrounding mantle, b) The degree of entrainment and mixing in mantle plumes of chemically distinct material from the deep mantle. Heat is used as t...

A fundamental question regarding the dynamics of mantle convection is whether some intraplate volcanic centers, known as “hotspots,” are the surface manifestations of hot, narrow, thermally driven upwellings, or plumes, rising from the lower mantle. Shown here is a global negative correlation between the thickness of the mantle transition zone (nea...

In an attempt to understand the global temperature distribution in the mantle and its consequences for Earth structure we construct a model for the instantaneous temperature field of the mantle, assuming downwellings slabs to be the most important source of density heterogeneity and temperature variations. We neglect the contributions due to active...

We further explore the properties of a mantle model consisting of a mechanical mixture of basalt and harzburgite with varying basalt fraction. We have found that such a mechanical mixture is faster and better explains 1-D seismic profiles than an equilibrated pyrolite of the same bulk composition, particularly in the transition zone [Xu et al., 200...

Variations in lithospheric thickness and density contribute to the Earth's surface stress field. The relationship between the continental lithosphere's isostatic state, sub-crustal structure and the surface stress field, however, remains unresolved due to the poor constraints on its thickness, composition and rheology. Here, we present calculations...

Understanding the first-order dynamical and compositional structure of Earth's mantle is a fundamental goal in solid-earth geophysics. Rudimentary knowledge of mantle structure relies on observations from geochemistry and seismic tomography and on inferences from theoretical convection models. Seismic tomography has shown the lower mantle to be dom...

The opposite signs of the Clapeyron slopes render temperature dependent depths of the olivine to wadsleyite (at ~410 km) and ringwoodite to perovskite and ferropericlase transitions (at ~660 km). Seismological analysis of phase conversions and reflections demonstrate thicker and thinner transition zones in 'downwelling' and 'upwelling' regions, res...

Our goal is the construction of a model of lateral variations in temperature and composition in the upper mantle obtained directly from the inversion of a global collection of long period three component multimode seismic waveforms. We start from a reference 1D model corresponding to a known pyrolite composition and a 60My geotherm connected with a...

At mid-ocean ridges, partial melting of a presumably homogeneous and equilibrated pyrolitic source generates a basaltic crust and leaves behind its depleted complement, harzburgite. The oceanic lithosphere that subducts into the mantle is thus physically and chemically layered. During subduction we expect basalt to separate from harzburgite and the...

Using a self-consistent computation of phase equilibria and physical properties, we determine isobaric velocity–temperature and velocity–density scalings as a function of depth, focusing on the upper 800 km. The scalings contain an isomorphic part due to the influence of temperature on the physical properties of individual phases, and a metamorphic...

The thermal evolution of Earth is governed by the rate of secular cooling and the amount of radiogenic heating. If mantle heat sources are known, surface heat flow at different times may be used to deduce the efficiency of convective cooling and ultimately the temporal character of plate tectonics. We estimate global heat flow from 65 Ma to the pre...

Our present picture of Earth's chemical and dynamical evolution points to an uncertain knowledge of the composition of the mantle, which is important for us to understand the thermal and dynamical evolution of Earth. Dynamical models suggest a mantle made of a mechanical mixture of basalt and harzburgite, especially perhaps a basaltic gradient and...

The internal deformation of plates is controlled by the state of stress of the lithosphere. The sources of stress include variations in density and thickness of the lithosphere as well as basal and edge tractions that arise from plate driving forces. The coupling between mantle stresses and the lithosphere is determined by the rheology of the plate...

Offshore of the Nicoya Gulf at the Middle America Trench, the Cocos Plate is subducting beneath the Caribbean plate at about 84 mm per year. A line of seamounts are entering the trench in this region, causing dramatic deformation of the seafloor landward of the thrust. It has been suggested that these seamounts are being subducted, causing coastal...

We predict the phase diagram of CaSiO3 perovskite, finding the tetragonal I4∕mcm structure transforming to cubic Pm3̅ m with increasing temperature. The transition temperature is 1150 K at 0 GPa, and 2450 K at 140 GPa. The c∕a ratio of the tetragonal structure is 1.018 at 100 GPa and increases on compression, as does the static enthalpy difference...

Concurrent changes in seawater chemistry, sea level, and climate since the mid-Cretaceous are thought to result from an ongoing decrease in the global rate of lithosphere production at ridges. The present-day area distribution of seafloor ages, however, is most easily explained if lithosphere production rates were nearly constant during the past 18...

Our present picture of Earth's chemical and dynamical evolution points to an uncertain knowledge of the composition of the mantle, which is important for us to understand the thermal and dynamical evolution of Earth. Dynamical models suggest a mantle made of a mechanical mixture of basalt and harzburgite, while petrological studies suggest a chemic...

Earth's lithospheric plates are driven partly by shear tractions exerted on their base by viscous coupling to convective mantle flow. While downwelling flow associated with descent of subducted lithosphere has been well established as a driver of plate motions, the plate-driving role of upwelling flow is more controversial. We used a numerical mant...

Understanding the lithospheric stress field on Mars is essential in interpreting patterns of surface faulting and geomorphologic features, as well as assessing the accuracy of different lithospheric models. We compute the portion of the lithospheric stress field on Mars produced by variations in crustal density and thickness using data described in...