No abstract

The Central Andes is a key global location to study the enigmatic relation between volcanism and plutonism because it has been the site of large ignim briteforming eruptions during the past several million years and currently hosts the world's largest zone of silicic partial melt in the form of the Alti plano Puna Magma (or Mush) Body (APMB) and the Southern Puna Magma Body (SPMB). In this themed issue, results from the recently completed PLUTONS project are synthesized. This project focused an interdisciplinary study on two regions of largescale surface uplift that have been found to represent ongoing movement of magmatic fluids in the middle to upper crust. The loca tions are Uturuncu in Bolivia near the center of the APMB and Lazufre on the Chile Argentina border, on the edge of the SPMB. These studies use a suite of geological, geochemical, geophysical (seismology, gravity, surface defor ma tion, and electromagnetic methods), petrological, and geomorphological techniques with numerical modeling to infer the subsurface distribution, quantity, and movements of magmatic fluids, as well as the past history of eruptions. Both Uturuncu and Lazufre show separate geophysical anomalies in the upper, middle, and lower crust (e.g., low seismic velocity, low resistiv ity, etc.) indicating multiple distinct reservoirs of magma and/or hydrothermal fluids with different physical properties. The characteristics of the geophysical anomalies differ somewhat depending on the technique used-reflecting the different sensitivity of each method to subsurface melt (or fluid) of different compositions, connectivity, and volatile content and highlight the need for integrated, multidisciplinary studies. While the PLUTONS project has led to significant progress, many unresolved issues remain and new questions have been raised.

Lazufre volcanic center, located in the central Andes, is recently undergoing an episode of uplift, conforming one of the most extensive deforming volcanic systems worldwide, but its magmatic system and its connection with the observed uplift are still poorly studied. Here we image the electrical resistivity structure using the magnetotelluric method in the surroundings of the Lastarria volcano, one of the most important features in the Lazufre area, to understand the nature of the magmatic plumbing, the associated fumarolic activity, and the large‐scale surface deformation. Results from 3‐D modeling show a conductive zone at 6 km depth south of the Lastarria volcano interpreted as the magmatic heat source which is connected to a shallower conductor beneath the volcano, showing the pathways of volcanic gasses and heated fluid. A large‐scale conductive area coinciding with the area of uplift points at a magma intrusion at midcrustal depth.