Decelerating Nazca-South America and Nazca-Pacific Plate Motions

Balancing the force budget of plate tectonics along the Nazca/South America plate margin

Mountain belt growth inferred from histories of past plate convergence: A new tectonic inverse problem

Past plate motions display a range of variability, including speedups and slowdowns that cannot easily be attributed to changes in mantle related driving forces. One key controlling factor for these variations is the surface topography at convergent margins, as previous modeling shows that the topographic load of large mountain belts consumes a significant amount of the driving forces available...

Plate motions, Andean orogeny, and volcanism above the South Atlantic convection cell

The geometric and kinematic evolution of the Andes provides insight onto the nature of the force balance beneath the South American plate. While the Andean load is opposed on its western edge by the force induced by subduction of the Nazca plate, its more elusive eastern counterpart, which we explore herein, requires some contribution from the mantle beneath the South Atlantic. Using a mantle f...

Space geodetic observations of nazca-south america convergence across the central andes

Space geodetic data recorded rates and directions of motion across the convergent boundary zone between the oceanic Nazca and continental South American plates in Peru and Bolivia. Roughly half of the overall convergence, about 30 to 40 millimeters per year, accumulated on the locked plate interface and can be released in future earthquakes. About 10 to 15 millimeters per year of crustal shorte...

The deforming Nazca slab in the mantle transition zone and lower mantle: Constraints from teleseismic tomography on the deeply subducted slab between 6°S and 32°S

We present new tomographic models of the Nazca slab under South America from 6°S to 32°S, and from 95 km to lower mantle (895 km) depths. By combining data from 14 separate networks in the central Andes, we use finite-frequency teleseismic P-wave tomography to image the Nazca slab from the upper mantle into the mantle transition zone (MTZ) and the uppermost lower mantle on a regional scale. Our...