Highly explosive basaltic eruptions: magma fragmentation induced by rapid crystallisation

<p>Basaltic eruptions are the most common form of volcanism on Earth and planetary bodies. The low viscosity of basaltic magmas generally favours effusive and mildly explosive volcanic activity. Highly explosive basaltic eruptions occur less frequently and their eruption mechanism still remains subject to debate, with implications for the significant hazard associated with explosive basaltic volcanism. Particularly, highly explosive eruptions require magma fragmentation, yet it is unclear how basaltic magmas can reach the fragmentation threshold.</p><p>In volcanic conduits, the crystallisation kinetics of an ascending magma are driven by degassing and cooling. So far, the crystallisation kinetics of magmas have been estimated through ex situ crystallization experiments. However, this experimental approach induces underestimation of crystallization kinetics in silicate melts. The&#160;&#160; crystallization experiments reported in this study were performed in situ at Diamond Light Source (experiment EE12392 at the I12 beamline), Harwell, UK, using basalt from the 2001 Etna eruption as the starting material. We combined a bespoke high-temperature environmental cell with fast synchrotron X-ray microtomography to image the evolution of crystallization in real time. After 4 hours at sub-liquidus conditions (1170 &#176;C and 1150 &#176;C) the system was perturbed through a rapid cooling (0.4 &#176;C/s), inducing a sudden increase of undercooling. Our study reports the first in situ observation of exceptionally rapid plagioclase and clinopyroxene crystallisation in trachybasaltic magmas. We combine these constraints on crystallisation kinetics and viscosity evolution with a numerical conduit model to show that exceptionally rapid syn-eruptive crystallisation is the fundamental process required to trigger basaltic magma fragmentation under high strain rates. Our in situ experimental and natural observations combined with a numerical conduit model allow us to conclude that pre-eruptive temperatures <1,100&#176;C can promote highly explosive basaltic eruptions, such as Plinian volcanism, in which fragmentation is induced by fast syn-eruptive crystal growth under high undercooling and high decompression rates. This implies that all basaltic systems on Earth have the potential to produce powerful explosive eruptions.</p>

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In situ observation of the martensitic transformation in (Mg,Y)-PSZ

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144036 ◽

1986 ◽

Vol 44 ◽

pp. 500-501

Author(s):

R-R. Lee

Keyword(s):

Martensitic Transformation ◽

High Strength ◽

Nucleation And Growth ◽

In Situ Observation ◽

Considerable Potential ◽

Transmission Electron ◽

Structural Applications ◽

Applied Stresses ◽

Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

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In situ quantification of crystallisation kinetics of plagioclase and clinopyroxene in basaltic magma: Implications for lava flow

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2021.117016 ◽

2021 ◽

Vol 568 ◽

pp. 117016

Author(s):

Nolwenn Le Gall ◽

Fabio Arzilli ◽

Giuseppe La Spina ◽

Margherita Polacci ◽

Biao Cai ◽

...

Keyword(s):

Lava Flow ◽

Basaltic Magma ◽

Crystallisation Kinetics ◽

Kinetics Of

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Advantage of In-situ over Ex-situ techniques as reliability tool: Aging kinetics of Imec’s MCM-D discrete passives devices.

Microelectronics Reliability ◽

10.1016/s0026-2714(03)00301-9 ◽

2003 ◽

Vol 43 (9-11) ◽

pp. 1785-1790

Author(s):

P. Soussan ◽

G. Lekens ◽

R. Dreesen ◽

W. De Ceuninck ◽

E. Beyne

Keyword(s):

Ex Situ ◽

Aging Kinetics ◽

Kinetics Of

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In Situ Observation of an Electrochemical Etching Reaction in Silicon

MRS Proceedings ◽

10.1557/proc-404-69 ◽

1995 ◽

Vol 404 ◽

Author(s):

Frances M. Ross ◽

Peter C. Searson

Keyword(s):

Pore Formation ◽

Electrochemical Etching ◽

Ex Situ ◽

In Situ Observation ◽

Specimen Holder

AbstractWe describe a TEM specimen holder which has been designed and constructed in order to observe the process of electrochemical pore formation in silicon. The holder incorporates electrical feedthroughs and a sealed reservoir for the electrolyte and it accepts lithographically patterned silicon specimens. We present ex situ observations of progressive pore propagation and show dynamic, in situ observations of electrolyte movement within the pores.

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In-Situ Observation Of Aln Formation During Nitridation Of Sapphire By Ultrahigh Vacuum Transmission Electron Microscopy

MRS Proceedings ◽

10.1557/proc-482-99 ◽

1997 ◽

Vol 482 ◽

Cited By ~ 10

Author(s):

M. Yeadon ◽

M. T. Marshall ◽

F. Hamdani ◽

S. Pekin ◽

H. Morkoc ◽

...

Keyword(s):

Ultrahigh Vacuum ◽

Ex Situ ◽

In Situ Observation ◽

Island Growth ◽

Kinetic Measurements ◽

Transmission Electron ◽

Before And After ◽

Subsequent Exposure ◽

Diffraction Patterns

AbstractUsing a novel ultrahigh vacuum transmission electron microscope (UHV TEM) with insitu molecular beam epitaxy capability we have studied the nitridation of (0001) sapphire upon exposure to ammonia. Atomically flat sapphire surfaces for the experiments were obtained by high temperature annealing. Subsequent exposure to ammonia flow at 950°C led to the successful synthesis of epitaxial AIN; the films were characterized in-situ using TEM. Complimentary ex-situ atomic force microscopy (AFM) was also performed in order to characterize the surface morphology before and after nitridation.The experiments indicate that AIN grows by a 3D island growth mechanism. Electron diffraction patterns suggest an abrupt AIN/sapphire interface with no evidence of the formation of Al–O–N compounds. The rate limiting step in the nitridation reaction appears to be the diffusion of nitrogen and oxygen species between the free surface of the growing AIN film and the reaction interface. It is inferred from kinetic measurements that diffusion of these species occurs along the boundaries between coalescing AIN islands.

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In-Situ Observation of Chemical Vapor Deposition of Thin Sige Films by Optical Reflection Interferometry

MRS Proceedings ◽

10.1557/proc-375-51 ◽

1994 ◽

Vol 375 ◽

Author(s):

G. Ritter ◽

B. Tillack ◽

M. Weidner ◽

F. G. Böbel ◽

B. Hertel

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Chemical Vapor ◽

Deposition Process ◽

Ex Situ ◽

In Situ Observation ◽

Optical Reflection ◽

Initial Stage

AbstractChemical Vapor Deposition of Si1-x Gex – films on Si (100) and of polycrystalline Si1-x Gex, layers on SiO2 – coated substrates have been performed at a pressure of 200 Pa in the temperature range of 500°C – 800°C, correspondingly. To observe the growth process and to characterize the growing thin films at deposition conditions an optical reflection interferometer (PYRITIERS) has been used. Comparing the data obtained at growth temperature with ex- situ measurements by spectroscopic ellipsometry the temperature dependence of optical constants of SiGe films have been evaluated. The reflectivity measurements during the deposition process allow to study the quality of the heteroepitaxial film, even in the initial stage of epitaxial growth.

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Ex situ and in situ X-ray absorption spectroscopy: On the kinetics of precipitation formation in (Mg1$minus;xCux)O

Solid State Ionics ◽

10.1016/s0167-2738(97)84064-7 ◽

1997 ◽

Vol 101-103 ◽

pp. 431-435

Author(s):

N HILBRANDT

Keyword(s):

Absorption Spectroscopy ◽

Ex Situ ◽

X Ray ◽

Kinetics Of Precipitation ◽

X Ray Absorption ◽

Kinetics Of ◽

Precipitation Formation

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Direct Observation of Monolayer MoS2 Prepared by CVD Using In-Situ Differential Reflectance Spectroscopy

Nanomaterials ◽

10.3390/nano9111640 ◽

2019 ◽

Vol 9 (11) ◽

pp. 1640 ◽

Cited By ~ 4

Author(s):

Yina Wang ◽

Lei Zhang ◽

Chenhui Su ◽

Hang Xiao ◽

Shanshan Lv ◽

...

Keyword(s):

Growth Mechanism ◽

Transition Metal Dichalcogenides ◽

Chemical Vapor ◽

Reflectance Spectroscopy ◽

Ex Situ ◽

In Situ Observation ◽

Two Dimensional ◽

Monolayer Mos2 ◽

Metal Dichalcogenides

The in-situ observation is of great significance to the study of the growth mechanism and controllability of two-dimensional transition metal dichalcogenides (TMDCs). Here, the differential reflectance spectroscopy (DRS) was performed to monitor the growth of molybdenum disulfide (MoS2) on a SiO2/Si substrate prepared by chemical vapor deposition (CVD). A home-built in-situ DRS setup was applied to monitor the growth of MoS2 in-situ. The formation and evolution of monolayer MoS2 are revealed by differential reflectance (DR) spectra. The morphology, vibration mode, absorption characteristics and thickness of monolayer MoS2 have been confirmed by optical microscopy, Raman spectroscopy, ex-situ DR spectra, and atomic force microscopy (AFM) respectively. The results demonstrated that DRS was a powerful tool for in-situ observations and has great potential for growth mechanism and controllability of TMDCs prepared by CVD. To the best of the authors’ knowledge, it was the first report in which the CVD growth of two-dimensional TMDCs has been investigated in-situ by reflectance spectroscopy.

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Direct Observation of Single Displacement Cascade in Pyrochlore by Tv-Rate In-Situ TEM and Ex-Situ HRTEM

Microscopy and Microanalysis ◽

10.1017/s1431927600028117 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 408-409

Author(s):

J. Lian ◽

L. M. Wang ◽

S. X. Wang ◽

R. C. Ewing

Keyword(s):

Ion Irradiation ◽

Heavy Ion ◽

Ex Situ ◽

In Situ Tem ◽

Direct Impact ◽

Displacement Cascade ◽

Amorphous Domain ◽

Rapid Kinetics ◽

Kinetics Of

The ion irradiation-induced crystalline-to-amorphous transformation has been studied in many complex ceramics. Direct impact amorphization has been considered to be one of the fundamental amorphization mechanisms for complex ceramics under heavy ion irradiation . Based on the directimpact model, a highly energetic incident ion transfers its kinetic energy to the target as a thermal spike within 10“13 sec creating a “molten-like” displacement cascade, typically nanometer-scaled in diameter (as indicated by the result of a computer simulation in Fig. 1). This “molten” zone quickly quenches to a small amorphous domain within a few pico-seconds. Epitaxial recrystallization occurs around the amorphous/crystalline interface, so that the size of amorphous domains decrease with time. The accumulation and overlap of small amorphous domains eventually leads to complete amorphization of the irradiated material. Although the in-situTEM technique with the setup shown in Fig. 2 has been extensively applied to the study of the amorphization process in complex ceramics, most of the previous studies relied on in-situobservation of the electron diffraction pattern, and there has been a lack of solid evidence of direct impact amorphization due to the small nature of the cascades and the rapid kinetics of its evolution.

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