Anna J. P. Gülcher

California Institute of Technology | Jet Propulsion Laboratory · Division of Geological and Planetary Sciences | Division ofPlanetary Interiors and Geophysics

The evolution of the system Earth is critically influenced by the long-term dynamics, composition and structure of the mantle. While cosmochemical and geochemical constraints indicate that the lower mantle hosts an ancient primordial reservoir that may be enriched in SiO2 with respect to the upper mantle, geophysical observations and models point t...

In the absence of global plate tectonics, mantle convection and plume-lithosphere interaction are the main drivers of surface deformation on Venus. Among documented tectonic structures, circular volcano-tectonic features known as coronae may be the clearest surface manifestations of mantle plumes and hold clues to the global Venusian tectonic regim...

The nature of compositional heterogeneity in Earth's lower mantle remains a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. Here, we use global-scale 2D models of thermochemical mantle convection to investigate the coupled evolution and mixing of (intrinsically dense) recycled and (intri...

The rheological properties of Earth's lower mantle are key for mantle dynamics and planetary evolution. The main rock-forming minerals in the lower mantle are bridgmanite (Br) and smaller amounts of ferropericlase (Fp). Previous work has suggested that the large differences in viscosity between these minerals greatly affect the bulk rock rheology....

Venus is the planet in the Solar System most similar to Earth in terms of size and (probably) bulk composition. Until the mid-20th century, scientists thought that Venus was a verdant world—inspiring science-fictional stories of heroes battling megafauna in sprawling jungles. At the start of the Space Age, people learned that Venus actually has a h...

The dynamics and evolution of Venus’ mantle are of first-order relevance for the origin and modification of the tectonic and volcanic structures we observe on Venus today. Solid-state convection in the mantle induces stresses into the lithosphere and crust that drive deformation leading to tectonic signatures. Thermal coupling of the mantle with th...

The nature of compositional heterogeneity in Earth’s lower mantle remains a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. Here, we use global-scale 2D models of thermochemical mantle convection to investigate the coupled evolution and mixing of (intrinsically-dense) recycled and (intri...

The nature of compositional heterogeneity in Earth’s lower mantle remains a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. Here, we use global-scale 2D models of thermo- chemical mantle convection to investigate the coupled evolution and mixing of (intrinsically-dense) recycled and (int...

Venus Corona and Tessera Explorer (VeCaTEx) would use an aerobot to descend repeatedly beneath the dense clouds for imaging targeted area of the surface in the near infrared to address six of the prime investigations prioritized by VEXAG. The technologies needed could be matured during the next decade.

{lay summary} The surface of Venus is littered with ring-shaped structures called “coronae”, whose formation is often linked to tectonic and volcanic activity in the past. Yet, using computer simulations that mimic their formation, we show how these structures provide unique insights into the present-day dynamics of Venus’ interior. We identify do...

The nature of compositional heterogeneity in Earth's lower mantle is a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. On relatively small scales (<1km), the concept of a "marble cake" mantle has gained wide acceptance, emphasizing that streaks of recycled oceanic crust (ROC) and lithosp...

Rocks in the Earth's interior consist of different mineralogical phases with different rheological properties. In Earth's lower mantle, the main rock constituents are bridgmanite (Br) and smaller amounts of ferropericlase (Fp). Bridgmanite is substantially stronger than ferropericlase, and lower mantle rheology may be highly dependent on the relati...

Despite stirring by vigorous convection over billions of years, the Earth’s lower mantle appears to be heterogeneous on various length scales. On scales <1km, the concept of a “marble cake” mantle has gained wide acceptance, emphasizing that streaks of recycled oceanic crust (ROC) and lithosphere make up much of the mantle. On larger scales (10s-10...

Rocks in the Earth's interior are not homogeneous but consist of different mineralogical phases with different rheological properties. Deformation of heterogeneous rocks is thus also heterogeneous, and strongly depends on the rheological contrasts and spatial distribution of the mineral phases. In Earth's lower mantle, the main rock constituents ar...

The evolution of the system Earth is critically influenced by the long-term dynamics, composition and structure of the mantle. While cosmochemical and geochemical constraints indicate that the lower mantle hosts an ancient primordial reservoir that may be enriched in SiO2 with respect to the upper mantle, geophysical observations and models point t...

Extensional detachment faults, which have been widely documented in slow-spreading and ultraslow-spreading ridges on Earth, can effectively localize deformation due to their weakness. After the onset of oceanic closure, these weak oceanic detachments may directly control the nucleation of a subduction zone parallel to the former mid-ocean ridge, as...

Extensional detachment faults, which have been widely documented in slow-spreading and ultraslow-spreading ridges on Earth, can effectively localize deformation due to their weakness. After the onset of oceanic closure, these weak oceanic detachments may directly control the nucleation of a subduction zone parallel to the former mid-ocean ridge, as...

With the absence of global plate tectonics, mantle plumes and related gravitational potential variations are generally thought to be driving Venusian tectonics. The ~circular volcano-tectonic corona structures are perhaps the most profound surface manifestations of these mantle plume upwellings, yet their origin remains enigmatic and possibly non-u...