scholarly journals The dynamics of the Campi Flegrei caldera magma chamber.

2021 ◽  
Author(s):  
Chiara Montagna ◽  
Paolo Papale ◽  
Antonella Longo
Keyword(s):  
Mathematical Modelling ◽  
Magma Chamber ◽  
Magma Mixing ◽  
Campi Flegrei ◽  
Magmatic System ◽  
Remarkable Case ◽  
Volcanic System ◽  
First Order ◽  
Magma Convection

The Campi Flegrei volcanic system is certainly a remarkable case study for what concerns magma chamber dynamics. In fact, its magmatic and volcanic history appears to have been largely driven by chamber processes like fractional crystallization, magma mixing, and volatile degassing. These processes have been intensely investigated with a variety of approaches that are described in many chapters of this book, and more specifically, in Chapters 2 to 5. Here we employ physico-mathematical modelling and numerical simulations in order to study the dynamics of magma convection and mixing in a vertically extended, geometrically complex, compositionally heterogeneous magmatic system representing a schematic simplification of an overall picture emerging from previous studies at Campi Flegrei. Although clearly a simplification, a number of first order characteristics of possible real magmatic systems at Campi Flegrei are accounted for, including the more chemically evolved, partially degassed nature of magmas emplaced at shallow depths, and the likely occurrence of multiple reservoirs with different depth, size and shape which can be connected at certain stages during system evolution, allowing deeper, CO2-rich magmas to rise and rejuvenate the shallow magmas.

Modelling the production of linear trends in granitoids using the Magma Chamber Simulator: a case study of the Jindabyne Suite from the Lachlan Fold Belt, Australia

2021 ◽  
Author(s):  
Kieran Iles ◽  
Jussi Heinonen
Keyword(s):  
Phase Equilibria ◽  
New England ◽  
Magma Chamber ◽  
Magma Mixing ◽  
Major Elements ◽  
Fractional Crystallisation ◽  
Geochemical Evolution ◽  
Geochemical Data ◽  
Linear Trends

<p>Understanding the causes of major and trace element variations of granite samples as well as their isotopic signatures is central to attempts to place these rocks in the context of broader geologic processes and continent evolution. For the granites of the Lachlan and New England Fold Belts (LFB and NEFB) of Australia there has been great debate between competing petrogenetic models. The open-system view that the isotopic variability and within-suite compositional trends can be accounted for by magma mixing and fractional crystallisation stands in contrast to the restite unmixing model, in which the geochemical features of certain granites are inherited from protoliths that underwent partial melting to produce magmas entraining varying proportions of residual material. Reconciling all aspects of the geochemical data in a mixing model is contingent on a plausible fractionation regime to produce the observed consistently linear (or near-linear) trends on Harker diagrams; however, the plausibility of existing fractional crystallisation models for LFB granites has not previously been tested with consideration of phase equilibria.</p><p>The Magma Chamber Simulator (MCS) models fractional crystallisation alone or with assimilation (AFC), constraining phase equilibria using MELTS and accounting for the thermal budget. This sophisticated modelling tool was used to conduct a case study of the I-type Jindabyne Suite of granites from the LFB, testing whether thermodynamically feasible geochemical trends matching the observed linear variations can arise through fractional crystallisation (with or without assimilation of supracrustal material). The results of 112 MCS models show (1) that for major elements liquid lines of descent (LLDs) may be sensibly linear over limited compositional ranges, (2) that the involvement of assimilation extends the range in which trends are relatively simple and near-linear, and (3) that, despite these observations, neither fractional crystallisation nor AFC are able to correctly reproduce the geochemical evolution of the I-type Jindabyne Suite granitoids as an LLD (contrary to existing models), instead persistently producing curved and kinked trends. The output of these simulations were further used to explore models in which: (a) crystal-bearing magmas evolve via fractional crystallisation or AFC (with chemical isolation assumed to be achieved through crystal zoning) and undergo varying degrees of melt-crystal segregation at different stages to produce the sample compositions; and (b) in situ crystallisation occurs via fractional crystallisation within the crystallisation zone, driving the evolution of a liquid resident magma, which the samples represent. These models are able to reproduce the Jindabyne Suite trends reasonably well. The modelling implies that fractional crystallisation, or some variant thereof, is a viable explanation for the linear trends in Jindabyne; however, tendency for grossly non-linear LLDs highlights that it should not be assumed that fractional crystallisation can generally explain linear trends in granites without careful modelling such as shown here.</p>

scholarly journals Mechanisms controlling explosive-effusive transition of Teide-Pico Viejo complex dome eruptions.

2020 ◽  
Author(s):  
Olaya Dorado ◽  
Joan Andújar ◽  
Joan Martí ◽  
Adelina Geyer
Keyword(s):  
Magma Chamber ◽  
Magma Mixing ◽  
Mafic Magma ◽  
Main Body ◽  
Density Currents ◽  
Volcanic System ◽  
Effusive Activity ◽  
Tenerife Island ◽  
Explosive Phase ◽  
The One

<p>The Teide-Pico Viejo (PT-PV) stratovolcanoes constitute one of the major potentially active volcanic complexes in Europe. PT-PV was traditionally considered as non-explosive system however, recent studies (ie. García et al. 2014) have pointed out that the explosive character of phonolitic magmas, including plinian and subplinian eruptions and generation of pyroclastic density currents, have also been significant within the last 30 kyr volcanological record. This explosive activity is mostly associated to satellite dome vents, like the one studied in this work, Pico Cabras. Dome-forming eruptions usually present sudden transitions between explosive and effusive activity. A better knowledge of this type of eruptions and about the main mechanisms controlling the changes in eruptive dynamics is required to undertake a comprehensive volcanic hazard assessment of Tenerife Island. In this study, we conduct a petrological and mineral characterization of the different eruption phases of Pico Cabras (pumice and lava flow samples for the explosive and effusive activity, respectively) with the aim of determining the factors that control these changes in the volcanic activity. Products were characterized with Scanning Electrom Microscope, and mineral phases, glass and volatile species (F, Cl) were analysed with electron microprobe and micro-XRF. The pre-eruptive conditions of the magma (pressure, temperature and water dissolved in the magma) were determined first by using available geothermobarometers, geohygrometers (Masotta et al., 2013; Mollo et al., 2015) and compared to those retrieved by using available phase equilibria experiments from the literature (ie. Andújar and Scaillet, 2012).</p><p>Our results suggest the presence of a compositionally stratified magma chamber at 1 kbar±0.5kbar prior to Pico Cabras eruption in which the differences in the eruptive styles are controlled by the temperature and the amount of volatiles dissolved in the melt. The explosive phase is related to the upper part of the magma chamber at 725ºC±25ºC and 3,5-5 wt% H<sub>2</sub>O and the effusive phase with the main body of the chamber at 880ºC±30ºC and 2,5-3 wt% H<sub>2</sub>O. Feldspar zonations show that overturn events occurred in the different layers of the magma chambers (“self-mixing”) and suggest that the eruption was triggered by underplating of mafic magma without magma mixing. Chemical composition of some feldspars from the explosive phase are equivalent to those found in El Abrigo eruption, the last caldera-forming episode (ca. 190 ka), demonstrating that PT-PV volcanic system is still capable of producing evolved and very explosive magmas.</p><p>This research has been partially funded by a CSIC JaeIntro grant and the EC Grant EVE (DG ECHO Ref: 826292).</p>

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

scholarly journals Nucleation is more than critical: A case study of the electroweak phase transition in the NMSSM

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Sebastian Baum ◽  
Marcela Carena ◽  
Nausheen R. Shah ◽  
Carlos E. M. Wagner ◽  
Yikun Wang
Keyword(s):  
Phase Transition ◽  
Parameter Space ◽  
Local Minima ◽  
Critical Temperatures ◽  
Electroweak Phase Transition ◽  
First Order ◽  
Vacuum Structure ◽  
The Universe ◽  
Scalar Sector

Abstract Electroweak baryogenesis is an attractive mechanism to generate the baryon asymmetry of the Universe via a strong first order electroweak phase transition. We compare the phase transition patterns suggested by the vacuum structure at the critical temperatures, at which local minima are degenerate, with those obtained from computing the probability for nucleation via tunneling through the barrier separating local minima. Heuristically, nucleation becomes difficult if the barrier between the local minima is too high, or if the distance (in field space) between the minima is too large. As an example of a model exhibiting such behavior, we study the Next-to-Minimal Supersymmetric Standard Model, whose scalar sector contains two SU(2) doublets and one gauge singlet. We find that the calculation of the nucleation probabilities prefers different regions of parameter space for a strong first order electroweak phase transition than the calculation based solely on the critical temperatures. Our results demonstrate that analyzing only the vacuum structure via the critical temperatures can provide a misleading picture of the phase transition patterns, and, in turn, of the parameter space suitable for electroweak baryogenesis.

Feldspar crystallization under magma-mixing conditions shown by cathodoluminescence and geochemical modelling – a case study from the Karkonosze pluton (SW Poland)

2004 ◽  
Vol 68 (4) ◽  
pp. 561-577 ◽  
Author(s):  
E. Słaby ◽  
J. Götze
Keyword(s):  
Magma Mixing ◽  
Main Tool ◽  
Precise Determination ◽  
Geochemical Modelling ◽  
Magma Evolution ◽  
Sw Poland ◽  
Crystallization Path ◽  
Geochemical Mass Balance

AbstractFeldspars from the Karkonosze pluton (SW Poland) display many features compatible with magma mixing. The mixing hypothesis has been tested using a geochemical mass balance law resulting in two possible paths of magma hybridization. Based on the results of the geochemical calculation, feldspar samples have been chosen along both mixing lines for cathodoluminescence (CL) investigation which was used as the main tool for the reconstruction of their crystallization path. Changes in the conditions of nucleation and crystallization of the feldspars as well as their movement within the magma chamber have been recognized due to different luminescence characteristics. These changes in the conditions of crystallization obtained by CL allow a precise determination of the genetic affinity of the samples to more mafic or more felsic environments.The results of the present study proved CL to be a valuable tool for the study of crystal-growth morphologies in a dynamic, turbulent environment and also as a geochemical tool for the reconstruction of various petrogenetic mechanisms (e.g. magma hybridization). Accordingly, the combination of CL with geochemical modelling provides corresponding information about magma evolution in an open system.

scholarly journals Macroscopic and Multi-Scale Models for Multi-Class Vehicular Dynamics with Uneven Space Occupancy: A Case Study

Axioms ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 102
Author(s):  
Maya Briani ◽  
Emiliano Cristiani ◽  
Paolo Ranut
Keyword(s):  
Road Network ◽  
Real Data ◽  
Second Order ◽  
Heavy Vehicles ◽  
First Order ◽  
Multi Scale ◽  
Stop And Go ◽  
Scale Models ◽  
Road Space

In this paper, we propose two models describing the dynamics of heavy and light vehicles on a road network, taking into account the interactions between the two classes. The models are tailored for two-lane highways where heavy vehicles cannot overtake. This means that heavy vehicles cannot saturate the whole road space, while light vehicles can. In these conditions, the creeping phenomenon can appear, i.e., one class of vehicles can proceed even if the other class has reached the maximal density. The first model we propose couples two first-order macroscopic LWR models, while the second model couples a second-order microscopic follow-the-leader model with a first-order macroscopic LWR model. Numerical results show that both models are able to catch some second-order (inertial) phenomena such as stop and go waves. Models are calibrated by means of real data measured by fixed sensors placed along the A4 Italian highway Trieste–Venice and its branches, provided by Autovie Venete S.p.A.

scholarly journals The thermal regime of the Campi Flegrei magmatic system reconstructed through 3D numerical simulations

2016 ◽  
Vol 328 ◽  
pp. 210-221 ◽  
Author(s):  
Valeria Di Renzo ◽  
Kenneth Wohletz ◽  
Lucia Civetta ◽  
Roberto Moretti ◽  
Giovanni Orsi ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Thermal Regime ◽  
Campi Flegrei ◽  
Magmatic System

Microstructure Sensitive Design with First Order Homogenization Theories and Finite Element Codes

2005 ◽  
Vol 495-497 ◽  
pp. 23-30 ◽  
Author(s):  
Surya R. Kalidindi ◽  
J. Houskamp ◽  
G. Proust ◽  
H. Duvvuru
Keyword(s):  
Finite Element ◽  
Inverse Problems ◽  
Mechanical Design ◽  
Materials Design ◽  
Mathematical Framework ◽  
First Order

A mathematical framework called Microstructure Sensitive Design (MSD) has been developed recently to solve inverse problems of materials design, where the goal is to identify the class of microstructures that are predicted to satisfy a set of designer specified objectives and constraints [1]. This paper demonstrates the application of the MSD framework to a specific case study involving mechanical design. Processing solutions to obtain one of the elements of the desired class of textures are also explored within the same framework.

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