PARTIAL PRESSURES OF CRYSTALLIZATION AND MAGMA PLUMBING SYSTEMS BENEATH HAWAIIAN VOLCANOES

2016 ◽  
Author(s):  
Yuyu Li ◽  
◽  
Jameson Scott ◽  
Michael Barton
Keyword(s):  
Partial Pressures ◽  
Plumbing Systems ◽  
Magma Plumbing

scholarly journals Sunda arc mantle source δ18O value revealed by intracrystal isotope analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Frances M. Deegan ◽  
Martin J. Whitehouse ◽  
Valentin R. Troll ◽  
Harri Geiger ◽  
Heejin Jeon ◽  
...  
Keyword(s):  
Mantle Source ◽  
Secondary Ion Mass Spectrometry ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Sunda Arc ◽  
Mid Ocean Ridge ◽  
Plumbing Systems ◽  
Ocean Ridge ◽  
Secondary Ion ◽  
Magma Plumbing

AbstractMagma plumbing systems underlying subduction zone volcanoes extend from the mantle through the overlying crust and facilitate protracted fractional crystallisation, assimilation, and mixing, which frequently obscures a clear view of mantle source compositions. In order to see through this crustal noise, we present intracrystal Secondary Ion Mass Spectrometry (SIMS) δ18O values in clinopyroxene from Merapi, Kelut, Batur, and Agung volcanoes in the Sunda arc, Indonesia, under which the thickness of the crust decreases from ca. 30 km at Merapi to ≤20 km at Agung. Here we show that mean clinopyroxene δ18O values decrease concomitantly with crustal thickness and that lavas from Agung possess mantle-like He-Sr-Nd-Pb isotope ratios and clinopyroxene mean equilibrium melt δ18O values of 5.7 ‰ (±0.2 1 SD) indistinguishable from the δ18O range for Mid Ocean Ridge Basalt (MORB). The oxygen isotope composition of the mantle underlying the East Sunda Arc is therefore largely unaffected by subduction-driven metasomatism and may thus represent a sediment-poor arc end-member.

scholarly journals What lies beneath

2021 ◽  
Vol 62 (3) ◽  
pp. 3.38-3.42
Author(s):  
Craig Magee ◽  
Chris Jackson
Keyword(s):  
Seismic Reflection ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Plumbing Systems ◽  
Magma Plumbing

Abstract Craig Magee and Chris Jackson examine how geophysical seismic reflection data can be used to study the inner workings of volcanoes and magma plumbing systems

scholarly journals Insight into subvolcanic magma plumbing systems

Geology ◽  
2007 ◽  
Vol 35 (8) ◽  
pp. 767 ◽  
Author(s):  
Wendy A. Bohrson
Keyword(s):  
Plumbing Systems ◽  
Insight Into ◽  
Magma Plumbing

scholarly journals Magmatic Ni-Cu-(PGE) deposits in magma plumbing systems: Features, formation and exploration

2011 ◽  
Vol 2 (3) ◽  
pp. 375-384 ◽  
Author(s):  
Xieyan Song ◽  
Yushan Wang ◽  
Liemeng Chen
Keyword(s):  
Plumbing Systems ◽  
Magma Plumbing

Deep into magma plumbing systems: Interrogating the crystal cargo of volcanic deposits

Geology ◽  
2018 ◽  
Vol 46 (5) ◽  
pp. 415-418 ◽  
Author(s):  
J. Ganne ◽  
O. Bachmann ◽  
X. Feng
Keyword(s):  
Volcanic Deposits ◽  
Plumbing Systems ◽  
Magma Plumbing

scholarly journals Upper crustal shear wave velocity and radial anisotropy beneath Jeju Island volcanoes from ambient noise tomography

2021 ◽  
Author(s):  
Sang-Jun Lee ◽  
Seongryong Kim ◽  
Junkee Rhie ◽  
Tae-Seob Kang ◽  
YoungHee Kim
Keyword(s):  
Shear Wave ◽  
Ambient Noise ◽  
Volcanic Eruptions ◽  
Jeju Island ◽  
Cinder Cones ◽  
Phase Velocity Dispersion ◽  
Plumbing Systems ◽  
Anisotropic Structures ◽  
Radial Anisotropy ◽  
Magma Plumbing

Summary Jeju Island offshore of the southern Korean Peninsula is an isolated intraplate volcano formed by multiple basaltic eruptions from the Pleistocene (∼1.8 Ma) to the Holocene (∼3.7 ka). Due to the lack of available seismic data, magma structures at upper crustal depths of the island have not been clearly revealed. In this study, we imaged upper crustal isotropic and radial anisotropic structures beneath the island using ambient noise data from a temporary seismic network. A series of transdimensional hierarchical Bayesian inversions were performed to construct upper crustal (1–10 km) isotropic and anisotropic structures. Surface wave (Rayleigh and Love wave) group and phase velocity dispersion data were jointly inverted for 2–15 s. The results show that layers of negative anisotropy (VSH < VSV) are predominant at shallower (<2 km) and deeper (>5 km) depths, which was interpreted as reflecting dyke swarms responsible for the more than 400 cinder cones at the surface and the vertical plumbing systems supplying magma from deeper sources, respectively. Additionally, a layer with significantly positive radial anisotropy (VSH > VSV, up to 5 per cent) was found at middle depths (2–5 km), and was interpreted as horizontally aligned magma plumbing systems (e.g. sills) through comparisons with several other volcanoes worldwide. In comparison with the isotropic structure, the positive anisotropic layer was separated into upper and lower layers with locally neutral to slightly fast and slower shear wave velocities, respectively, beneath the largest central crater (Mt. Halla). Such a structure indicates that the cooled upper part of the magma plumbing systems formed within the horizontally developed sill complex, and is underlain by still-warm sill structures, potentially with a small fraction of melting. With dykes predominant above and below, the island-wide sill layer and locally high-temperature body at the center explain the evolution of the Jeju Island volcanoes by island-forming surface lava flows and central volcanic eruptions before and after the eruptions of cinder cones.

scholarly journals Pleistocene-Holocene Monogenetic Volcanism at Malko-Petropavlovsk Zone of Transverse Dislocations on Kamchatka: Geological Setting, Spatial, Geochemical Paticular Features and Potential Volcanic Hazards

2021 ◽  
Author(s):  
Olga Bergal-Kuvikas ◽  
Ilya Bindeman ◽  
Andrey Chugaev ◽  
Yulia Larionova ◽  
Alexander Perepelov ◽  
...  
Keyword(s):  
Volcanic Hazards ◽  
Trace Element Geochemistry ◽  
Monogenetic Volcanism ◽  
Element Geochemistry ◽  
Cinder Cones ◽  
Magma Plumbing System ◽  
Plumbing Systems ◽  
Moho Boundary ◽  
Monogenetic Volcanoes ◽  
Magma Plumbing

Abstract Based on government statistical data ~80% of the local Kamchatkan population (~250 ka people) live in the major cities on the coastal line of Avacha Gulf . It is the main transport seaway to Kamchatka , and and important Asia - North America air transport corridor. The Avacha Gulf is located in the Malko-Petropavlovsk zone of transverse dislocations (MPZ) on the extension of deep transform fault on the boundary between various ly aged slabs. Most of monogenetic cinder cones chaotic distributed in relation to the trench and belong to the long-living rupture zones of MPZ. Some of the monogenetic volcanoes are parasitic cones on the slopes of Koryaksky and Avachinsky stratovolcanoes and related with their magma plumbing systems. We here present new results of the geochemical and isotopic stud ies of monogenetic volcanism in MPZ. Based on whole rock and trace element geochemistry, Sr-Nd-Pb isotopic ratios of monogenetic volcanism, ­­ magmas were shown to sample the enriched mantle source with dominance decompression melting without significant inputs of the slab`s components. Calculations of the P, T conditions suggest magma residence of monogenetic cinder cones on the Moho boundary. That correlates with the geophysical observation of crustal discontinuity under the MPZ. Monogenetic cinder cones have an active magma plumbing system because during the Holocene time were several periods of activations. Presented results show necessary install continuous monitoring of environment changing around the Avacha Gulf and more serious attention from government and science. A more detailed investigation of MPZ will help degrease potential risks of eruptions from monogenetic volcanoes for human and infrastructures.

scholarly journals A machine learning based approach to clinopyroxene thermobarometry: model optimisation and distribution for use in Earth Sciences

2021 ◽  
Author(s):  
Corin Jorgenson ◽  
Oliver Higgins ◽  
Maurizio Petrelli ◽  
Florence Bégué ◽  
Luca Caricchi
Keyword(s):  
Earth Sciences ◽  
Machine Learning ◽  
Random Forest ◽  
Model Performance ◽  
Mean Value ◽  
Performance Tuning ◽  
Plumbing Systems ◽  
Data Driven Approach ◽  
Methodological Assessment ◽  
Magma Plumbing

Thermobarometry is a fundamental tool to quantitatively interrogate magma plumbing systems and broaden our appreciation of volcanic processes. Developments in random forest-based machine learning lend themselves to a more data-driven approach to clinopyroxene thermobarometry. This can include allowing users to access and filter large experimental datasets that can be tailored to individual applications in Earth Sciences. Here we present a methodological assessment of random forest thermobarometry, using the R freeware package “extraTrees”, by investigating the model performance, tuning hyperparameters, and evaluating different methods for calculating uncertainties. We determine that deviating from the default hyperparameters used in the “extraTrees” package results in little difference in overall model performance (<0.2 kbar and <3 ⁰C difference in mean SEE). However, accuracy is greatly affected by how the final pressure or temperature (PT) value from the voting distribution of trees in the random forest is selected (mean, median or mode). This thus far has been unapproached in machine learning thermobarometry. Using the mean value leads to a higher residual between experimental and predicted PT, whereas using median values produces smaller residuals. Additionally, this work provides two comprehensive R scripts for users to apply the random forest methodology to natural datasets. The first script permits modification and filtering of the model calibration dataset. The second script contains pre-made models in which users can rapidly input their data to recover pressure and temperature estimates. These scripts are open source and can be accessed at https://github.com/corinjorgenson/RandomForest-cpx-thermobarometer.

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