Geology and Tectonics
Geologic & tectonic research at UCLA follows a tradition of excellence in the study of the growth and demise of mountain belts, basin analysis, remote sensing, and surficial processes. Our faculty and researchers combine field research with computer modeling, geochemical analysis, geochronology, petrology, and satellite image analysis to understand Earth evolution and the geologic record of plate interactions.
Planetary Science
UCLA faculty study the dynamics and physical properties of the interiors, surfaces, and atmospheres of Earth, planets, moons, and other solar system objects. We investigate the convective motions in planetary mantles and cores, the links between the microscopic-scale structure of minerals and planetary scale processes, models of plate dynamics at a range of scales, and the atmospheric, surface, and interior processes in the solar system as revealed by spacecraft missions and ground-based telescopes.
Geochemistry and Cosmochemistry
UCLA geochemists and cosmochemists explore chemical processes at scales ranging from atoms, molecules and unit cells to plate boundaries, mountain belts, whole planets, and the solar system. We seek to understand the origin of our solar system, including its connection with the interstellar medium, the processes that transformed the cloud of dust and gas surrounding the nascent sun into the building blocks of planets, the geologic processes on those early planetesimals, and their accretion to form Earth and planets.
Space Physics
UCLA is recognized internationally as a leader in the plasma physics of space. Research done by the space physics group includes data analysis, simulation, modeling, and theoretical plasma physics. Topics of interest include the dynamics of the solar wind, the magnetospheres of the Earth and planets, and the interaction of the solar wind with bodies in the solar system including asteroids, planetary satellites, unmagnetized planets, and planetary magnetospheres.
Geophysics
Our faculty are internationally recognized as some of the foremost authorities on fault mechanics, earthquake forecasting, seismic imaging, and deep earth structure. Field areas range from downtown Los Angeles to remote Siberia. Within UCLA, we work closely with specialists in tectonics, geodesy, geocomplexity, and applied mathematics to solve recalcitrant problems. We also take advantage of our special geographical location. California is a famous hotbed of earthquake research, with major collaboratories such as the Southern California Earthquake Center (SCEC) and the Jet Propulsion Laboratory (JPL). Here we need only to step outside our doors to see the objects of our research.
Geobiology
UCLA paleontologists are involved in projects spanning the entire fossil record, from the original of life to recent speciation events. Faculty and students are documenting extraordinarily slow rates of evolution among cyanobacteria; establishing and revising the classification, taxonomy and biostratigraphy of Neogene foraminifera; calculating where the iridium anomaly should be in K-T boundary sections; interpreting the evolutionary dynamics and the mechanisms of species flock formation among freshwater African gastropods; producing 3-D computer images of blastoid hydrospires; using molecular techniques to establish the relationships of the chordates and their sister groups; investigating the relationship between sea-level changes and mass extinction; reconstructing the nature and dynamics of proteins and the evolution of complexity; collecting and compiling morphometric data on North American carnivores with aims at interpreting their ecology; studying the paleobiology and paleoecology of late Cambrian molluscs of the western US; documenting the global stratigraphy and taphonomy of the Ediacaran faunas; investigating the origin of molluscs and
Department of Earth, Planetary, and Space Sciences
Open Access Policy Publications and other Recent Works (529)
End-member models of boundary-modulated convective dynamos
Convective planetary dynamos depend upon secular cooling and internal radioactive decay for generating fluid motions within the core. Some planetary dynamo models also include heat flux variations along the core-mantle boundary (CMB) that modify the dynamo process. Here we study the effects of CMB heat flux variations in two sets of numerical dynamo models. In the first set, the possibility of dynamo action in a stably-stratified, Boussinesq, rotating spherical fluid shell is investigated. In these cases, lateral variations in CMB heat flux can drive significant zonal flows, but no dynamo action develops. In the second set of models, the fluid shell is neutrally-stratified. Dynamo action in these models is controlled by the pattern of CMB heat flux.Our neutrally-stratified models are relevant for studying the limiting effects of strong boundary forcing acting atop a convectively well-mixed state. We study four neutrally-stratified dynamo cases with different spherical harmonic heat flux patterns imposed on the CMB: Y10, Y11, Y20 and Y22. These cases demonstrate that the fundamental symmetries of the dynamo field follow the spatial symmetries of the CMB heat flux pattern. Our results show that convective dynamos are not necessarily killed by boundary-driven thermal winds, a result of interest if Earth's core top is close to adiabatic. A strong Y10 forcing is likely to produce a dynamo with hemispherical magnetic field structure reminiscent of Mars surface magnetization. However, as boundary-modulated convective dynamos produce magnetic fields generally one order of magnitude weaker than homogeneous convective dynamos with an equivalent forcing amplitude, it seems unlikely that this process is at the origin of Mars' regions of strong crustal magnetization. © 2011 Elsevier B.V.
Constraints on the martian crust away from the InSight landing site.
The most distant marsquake recorded so far by the InSight seismometer occurred at an epicentral distance of 146.3 ± 6.9o, close to the western end of Valles Marineris. On the seismogram of this event, we have identified seismic wave precursors, i.e., underside reflections off a subsurface discontinuity halfway between the marsquake and the instrument, which directly constrain the crustal structure away (about 4100-4500 km) from the InSight landing site. Here we show that the Martian crust at the bounce point between the lander and the marsquake is characterized by a discontinuity at about 20 km depth, similar to the second (deeper) intra-crustal interface seen beneath the InSight landing site. We propose that this 20-km interface, first discovered beneath the lander, is not a local geological structure but likely a regional or global feature, and is consistent with a transition from porous to non-porous Martian crustal materials.