Skip Nav Destination RESEARCH ARTICLE| MARCH 16, 2022 Assessing the effect of melt extraction from mushy reservoirs on compositions of granitoids: From a global database to a single batholith

Mafic and ultramafic plutonic rocks are often considered to be crystal cumulates (i.e., they are melt-depleted), but such a classification is much more contentious for intermediate to silicic granitoids (e.g., tonalite, granodiorite, granite, and syenite). Whether or not a given plutonic rock has lost melt to feed shallower subvolcanic intrusive bodies or volcanic edifices has key implications for understanding igneous processes occurring within the crust throughout the evolution of the Earth. We use statistical analyses of a global volcanic and plutonic rock database to show that most mafic to felsic plutonic rock compositions can be interpreted as melt-depleted (i.e., most of the minerals analyzed are more evolved than their bulk-rock compositions would allow). To illustrate the application of the method to natural samples (from the Tertiary Adamello Batholith in the southern Alps), we estimate the degree of melt depletion using a combination of magmatic textures, bulk-rock chemistry, modal mineralogy, distributions of plagioclase composition (using scanning electron microscope phase mapping/electron microprobe analyses), and thermodynamic modeling. We find that melt depletion correlates with the magmatic foliation and is accompanied by bulk depletion in incompatible elements, low amounts of near-solidus minerals, and mineral compositions that are too evolved (i.e., depleted in Ca or Mg, depending on the mineral) to be in equilibrium with their bulk-rock chemistry. The analytical and modeling workflow proposed in this study provides a path to quantifying melt depletion in any plutonic samples

Spatial interactions in agent-based modeling

Agent Based Modeling (ABM) has become a widespread approach to model complex interactions. In this chapter after briefly summarizing some features of ABM the different approaches in modeling spatial interactions are discussed. It is stressed that agents can interact either indirectly through a shared environment and/or directly with each other. In such an approach, higher-order variables such as commodity prices, population dynamics or even institutions, are not exogenously specified but instead are seen as the results of interactions. It is highlighted in the chapter that the understanding of patterns emerging from such spatial interaction between agents is a key problem as much as their description through analytical or simulation means. The chapter reviews different approaches for modeling agents' behavior, taking into account either explicit spatial (lattice based) structures or networks. Some emphasis is placed on recent ABM as applied to the description of the dynamics of the geographical distribution of economic activities, - out of equilibrium. The Eurace@Unibi Model, an agent-based macroeconomic model with spatial structure, is used to illustrate the potential of such an approach for spatial policy analysis.Comment: 26 pages, 5 figures, 105 references; a chapter prepared for the book "Complexity and Geographical Economics - Topics and Tools", P. Commendatore, S.S. Kayam and I. Kubin, Eds. (Springer, in press, 2014

A lexicographical dynamic flow model for relief operations

Emergency management is a highly relevant area of interest in operations research. Currently the area is undergoing widespread development. Furthermore, recent disasters have highlighted the importance of disaster management, in order to alleviate the suffering of vulnerable people and save lives. In this context, the problem of designing plans for the distribution of humanitarian aid according to the preferences of the decision maker is crucial. In this paper, a lexicographical dynamic flow model to solve this problem is presented, extending a previously introduced static flow model. The new model is validated in a realistic case study and a computational study is performed to compare both models, showing how they can be coordinated to improve their overall performance

Emergency logistics for wildfire suppression based on forecasted disaster evolution

This paper aims to develop a two-layer emergency logistics system with a single depot and multiple demand sites for wildfire suppression and disaster relief. For the first layer, a fire propagation model is first built using both the flame-igniting attributes of wildfires and the factors affecting wildfire propagation and patterns. Second, based on the forecasted propagation behavior, the emergency levels of fire sites in terms of demand on suppression resources are evaluated and prioritized. For the second layer, considering the prioritized fire sites, the corresponding resource allocation problem and vehicle routing problem (VRP) are investigated and addressed. The former is approached using a model that can minimize the total forest loss (from multiple sites) and suppression costs incurred accordingly. This model is constructed and solved using principles of calculus. To address the latter, a multi-objective VRP model is developed to minimize both the travel time and cost of the resource delivery vehicles. A heuristic algorithm is designed to provide the associated solutions of the VRP model. As a result, this paper provides useful insights into effective wildfire suppression by rationalizing resources regarding different fire propagation rates. The supporting models can also be generalized and tailored to tackle logistics resource optimization issues in dynamic operational environments, particularly those sharing the same feature of single supply and multiple demands in logistics planning and operations (e.g., allocation of ambulances and police forces). © 2017 The Author(s

Evolution from magmatic to hydrothermal activity beneath the Cerro Escorial volcano (NW Argentina) as sampled by erupted quartz and brines

Large quartz pebbles erupted with the Escorial ignimbrite provide insight into the late-magmatic evolution of the shallow, cooling magmatic-hydrothermal system below the Cerro Escorial volcano of the Southern Central Volcanic Zone in the Argentine Andes. The ignimbrite is of relatively small volume, crystal-rich, dacitic in composition, and not particularly water-rich, as amphibole is absent. Eruption temperature was estimated to be close to 850 °C. The quartz pebbles provide insight into the magmatic-hydrothermal transition beneath the volcano. Based on textures, trace element composition (analyzed by laser-ablation inductively-coupled plasma mass spectrometry), and inclusion content, the pebbles can be separated into pegmatite-like megacrysts and lower-temperature, epithermal microcrystalline quartz. Both types are distinct from magmatic phenocrysts present in porphyritic clasts ejected by the ignimbrite. The megacrysts show a wide range of trace element concentrations, with elevated Al concentrations and Al/Ti and Ge/Ti ratios compared to quartz phenocrysts. Although some contamination by submicroscopic inclusions and cooling to near-solidus temperatures may perturb the signal in some cases, the range of trace element concentrations in quartz crystals from this system may reflect a change in crystallization conditions from initial precipitation from typical evolved silicate melt to fast growth from residual melt and/or fluid in pegmatitic pockets or coarse-grained hydrothermal “veins” at locally variable precipitation conditions. Abundant primary and secondary silicate melt inclusions and a variety of secondary fluid inclusions are present within the megacrysts. In particular, brine inclusions are densely packed with salt crystals, sometimes anhydrite and/or a silicate crystal, but no visible liquid at room temperature, and co-existing vapor inclusions are of very low density. Heating experiments of brine inclusions reveal last salt and vapor bubble dissolution temperatures around 600–700 °C, but an immiscible silicate melt surrounding the homogenized salt globule remains even at unreasonably high temperature. The co-existence of silicate melt and fluid inclusions reinforces the magmatic nature of the fluids, while boiling trails of brine (with Cu concentrations of several percent) and vapor point to relatively low pressures (<100 MPa). © 2020 Elsevier B.V.ISSN:0024-493

Melt and fluid evolution in an upper-crustal magma reservoir, preserved by inclusions in juvenile clasts from the Kos Plateau Tuff, Aegean Arc, Greece

ISSN:0016-7037ISSN:1872-953