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Comptes Rendus : Geoscience
Journal Prestige (SJR): 0.666

Citation Impact (citeScore): 2
Number of Followers: 9

This is an Open Access Journal

Open Access journal
ISSN (Print) 1631-0713 - ISSN (Online) 1778-7025
Published by Académie des sciences

[7 journals]

Tarik Kernif; Thierry Nalpas et al. - Formation and preservation of
colluvial sedimentary breccias during early extension: processes and
facies organization
- Abstract: Dans cette étude, nous nous sommes intéressés aux processus de formation et de préservation des brèches sédimentaires colluviales dans un contexte d’extension. Les brèches étudiées dans ce travail (provenant de Crète et des Pyrénées) sont caractérisées par des dépôts polygéniques mal triés de clastes carbonatés très anguleux dont la taille varie de galets à blocs mesurant plusieurs millimètres à plusieurs mètres. Cette étude montre que les brèches sédimentaires colluviales formées au cours de la tectonique en extension sont spatialement associées à des failles normales majeures et sont organisées avec des clastes de la taille de petits cailloux à galets près de la pente de la faille et des méga-clastes, tels que des gros cailloux et des blocs, loin de la pente, contrairement à ce que l’on trouve dans les systèmes de cônes alluviaux. Cette étude révèle également que les brèches rencontrées sur les deux flancs du synclinal du Bas Agly, qui sont intercalées entre des calcaires du Jurassique supérieur et du Berriasien, sont liées à une phase d’extension précoce durant le Jurassique supérieur.
  PubDate: Fri, 13 May 2022 09:55:36 +000
Serge Ferry; Danièle Grosheny et al. - Sedimentary record of the
“Austrian” tectonic pulse around the Aptian–Albian boundary in SE
France, and abroad
- Abstract: Une régression forcée d’origine tectonique s’est produite sur la marge occidentale de la mer subalpine au passage Aptien–Albien. Elle a vidangé presque complètement la partie ouest de la fosse vocontienne pendant l’Albien inférieur et moyen. Une pulsation tectonique en régime compressif associée à des mouvements verticaux est suggérée le long du couloir de failles cévenol et satellites. La régression forcée est corrélée avec une tendance inverse transgressive dans le Bassin de Paris et dans les Chaines Subalpines nord. Les black shales vocontiens des événements anoxiques océaniques globaux OAE1a (Aptien) et OAE1b (Albien) s’inscrivent dans des tendances opposées en termes de variations du niveau marin relatif, largement transgressive pour le premier, fortement régressive pour le second. La pulsation tectonique déduite se manifeste à plus grande échelle d’après les données de la bibliographie. Elle est également responsable des déphasages constatés dans les variations locales du niveau marin à grande échelle.
  PubDate: Thu, 12 May 2022 12:13:25 +000
Francesco Vetere; Gianluca Iezzi et al. - Rheological changes in melts and
magmas induced by crystallization and strain rate
- Abstract: This review highlights the rheological and phase proportions variation induced by cooling events from superliquidus temperature (melt) to subliquidus temperatures. It provides a comprehensive view of the rheological response of magmatic systems undergoing dynamic cooling and shear deformation. The two main parameters which are of importance to model the rheological properties of such crystallizing systems and which are simultaneously poorly investigated so far are crystallization and strain rates. The response to relatively high deformation rates results in shear thinning behavior in partly crystallized systems under variable shear rate and it should be considered in magmatic processes. Due to the sluggish crystallization of SiO 2 -rich melts, data are mainly available for mafic systems, which does not allow a general reappraisal. An attempt to model available literature data for less evolved systems in dynamic scenarios and a comparison with MELTS algorithm approach (thermodynamic equilibrium conditions) is provided. Since there are difficulties in comparing experimental data gained using different methodologies, we focus mainly on data obtained with the concentric cylinder technique. This highlights the fact that a general experimental protocol is needed in order to compare and model viscosity data to predict the dynamic rheological evolution for volcanic rocks.
  PubDate: Fri, 06 May 2022 13:44:36 +000
Charles Le Losq; Bjorn O. Mysen et al. - Water solution mechanism in
calcium aluminosilicate glasses and melts: insights from in and ex situ
Raman and 29 Si NMR spectroscopy
- Abstract: New Raman and NMR spectroscopy data on hydrous Ca aluminosilicate melts and glasses, with eutectic quartz–anorthite–wollastonite composition, are presented here. The glasses were obtained by rapid quench of melts equilibrated at high P and high T in a piston–cylinder apparatus. In situ Raman observations of the structure of the melts were also performed during hydrothermal diamond cell experiments. Using the intensities of the ∼860cm -1 and ∼1630cm -1 Raman signals, respectively assigned to vibrations of T–OH and H 2 O mol species, we determined the speciation of water in the glasses. T–OH and H 2 O mol values compare well with those determined from infrared (IR) spectra, except above ∼5 wt% total water where IR determinations actually underestimate the proportion of hydroxyl groups. The analysis of the polarized Raman spectra and of the 29 Si MAS NMR spectra of the hydrous glasses suggests limited changes in glass polymerization with variations in dissolved water content. However, at high temperatures, in situ Raman spectroscopy observations indicate that the hydrous melt structure differs very strongly from that of a glass containing a comparable concentration of dissolved water. Because of this, this study reinforces the fact that using glass data to try understanding high temperature processes in hydrous melts, like viscous flow or water diffusion toward bubbles during volcanic degassing, may not be very appropriate.
  PubDate: Fri, 06 May 2022 13:44:36 +000
Han Liu; Zhangji Zhao et al. - Challenges and opportunities in atomistic
simulations of glasses: a review
- Abstract: La modélisation et simulations atomiques ont joué un rôle important pour notre connaissance de l’état vitreux. En effet, la modélisation atomique offre un accès direct à la structure et dynamique des atomes dans les verres — qui n’est typiquement pas accessible par les techniques expérimentales classiques. Les simulations offrent également une alternative économique et rapide aux expériences systématiques pour décoder les relations composition-propriétés et accélérer la découverte de nouveaux verres offrant des propriétés et fonctionnalités de choix. Cependant, la modélisation atomique des verres reste limitée par une série de défis, par exemple, le coût de calcul élevé, l’échelle de temps accessible limitée, le manque de champs de force interatomiques précis, etc. Ces défis induisent souvent l’existence de divergences entre les résultats simulés et expérimentaux, ce qui limite le pouvoir prédictif de la modélisation atomistique. Dans cette contribution, nous passons en revue les récents progrès et les défis restants auxquels est confrontée la modélisation atomistique des verres. Nous discutons les opportunités futures offertes par les intégrations de simulations, connaissances, données expérimentales et d’intelligence artificielle pour faire avancer la modélisation du verre vers une nouvelle ère.
  PubDate: Mon, 02 May 2022 10:18:01 +000
Joël Constantin; Bertrand Saint-Bezar - Normal fault growth in layered
rocks with contrasting lithologies: a case study from the upper tip of the
Argence Fault (Charente, France)
- Abstract: Increasing displacement along an isolated fault is generally associated with fault propagation within the host rock. This propagation is controlled by several factors, including host-rock lithology, tectonic context and the presence of preexisting structures. Consequently, fault propagation is rarely linear and continuous, instead often alternating between periods of propagation and arrest, or propagation locking. We present structural data collected in a field at the terminal tip of the Argence Fault, one of the regional normal faults in the northern part of the Aquitaine Basin. At the outcrop, the fault cuts a heterogeneously layered sequence of limestones, marls and clays. We observed a well-exposed tip of this fault, and analyzed the deformation patterns. This analysis provided insights into the processes involved in the formation of fault zones, the fault damage zone in particular, and the effects of contrasting mechanical properties on modes of fault growth.
  PubDate: Thu, 28 Apr 2022 15:09:09 +000
Ary Bruand; Adriana Reatto - Morphology, chemical composition and origin
of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central
Plateau: contribution to the discussion of the microgranular structure
origin
- Abstract: Polished sections of two Bw horizons collected in latosols located on the South American Surface (LSAS) and the Velhas Surface (LVS) in the Brazilian Central Plateau were studied using backscattered scanning images (BESI) in scanning electron microscopy and energy dispersive spectroscopy (EDS). BESI showed areas with a strong microgranular structure associated with areas having a weak to moderate microgranular structure. BESI at high magnification also showed the presence of elongated particles 1 to 30μm long and 0.2 to 5μm wide, most of them exhibiting an internal layer organization of 2:1 phyllosilicate particles. Chemical composition determined using EDS showed that the core of the largest particles was consistent with the chemical composition of poorly weathered muscovite with a small proportion of Al in the interlayer space as hydroxy-Al. Results also showed that when the K 2 O content decreased, indicative of a stronger weathering of the primary minerals such as muscovite, the chemical analysis showed that the proportion of hydroxy-Al in the interlayer increased. From our results, it can be assumed that these particles correspond to weathered micas and hydroxy-Al interlayered vermiculites (HIVs) recognized earlier in the literature. They are interpreted as having been brought in the Bw horizons by the burrowing activity of termites and originating from deep horizons of the latosols studied or from the saprolite in which the latosol has developed. This explains their presence associated with minerals resulting from intense weathering of the mineral present in the parent material. In line with this interpretation, the strong microgranular structure of the Bw horizons results from fragmentation and transport activity while the weak to moderate microgranular structure corresponds to old portions of channels and cavity walls. Finally, our results show that some latosols should be considered as a biomantle in which the physical properties related to the microstructure development and chemical properties related to the presence of poorly to intensely weathered muscovites and of HIVs result from faunal activity.
  PubDate: Mon, 25 Apr 2022 12:25:23 +000
Edoardo Sanità; Jean-Marc Lardeaux et al. - Kinematics of the Helminthoid
Flysch–Marguareis Unit tectonic coupling: consequences for the tectonic
evolution of Western Ligurian Alps
- Abstract: We investigated the kinematics of the coupled Helminthoid Flysch–Marguareis Unit outcropping in the High Tanaro Valley in order to constraint the tectonic evolution of the Western Ligurian Alps. Field mapping highlights a tectonic pile composed of, from top to bottom: the Marguareis Unit (Briançonnais Domain); the Helminthoid Flysch Unit (Ligurian Domain) and several continental-derived tectonic slices (Chambeuil Slices) showing affinity to the Briançonnais Domain. Each unit recorded different deformation histories represented by pre-, syn- and post-stacking structures. The syn-stacking structures are represented by thrusts and folds, both responsible for the coupling of the units and for their current structural relationships. In other sectors of the Alpine chain previous authors have highlighted similar structural architectures. We maintain that syn-stacking deformation events played a key role in the tectonic evolution of the Western Ligurian Alps.
  PubDate: Fri, 08 Apr 2022 11:29:53 +000
Ikumi Asano; Nodoka Harada et al. - Impact of radiocesium contamination in
flood sediment deposited after the 2019 typhoon on decontaminated fields
of Fukushima Prefecture, Japan
- Abstract: Sediment that has deposited after the flood generated by the 2019 typhoon (referred to as Flood Sediment, FS) was collected along two rivers in eastern Fukushima Prefecture, Japan to determine the total and exchangeable radiocesium ( 137 Cs), and acid-extractable potassium (K) contents. Then, these FS parameters were compared with those of decontaminated soils (DS) in nearby agricultural fields to discuss the potential transfer risk of 137 Cs from rivers to nearby remediated soils. While FS had about four times higher total 137 Cs content, it showed a three-times lower exchangeable 137 Cs content than DS. Furthermore, acid-extractable K referred to as non-exchangeable K (Nex-K) content was high enough to restrict 137 Cs transfer from soil to crops for both FS and DS. From these comparisons, we concluded that deposition of FS onto DS may not increase the transfer of 137 Cs from soil to crops.
  PubDate: Thu, 31 Mar 2022 08:21:28 +000
Laurent Cormier; Louis Hennet et al. - Structure from glass to melt: a
case study along the MgSiO 3 –CaSiO 3 join using neutron and X-ray
diffraction
- Abstract: Glass and melt structures are inherently complex and disordered with significant changes expected to occur with temperature. In the present paper, a comparison of the structure of glasses and liquids along the MgSiO3–CaSiO3 join is carried out using neutron and X-ray diffraction (XRD). Empirical Potential Structure Refinement (EPSR) simulations were used to fit the experimental data. The average coordination number (CN) and site distribution is obtained for Mg and Ca showing distinct sites between the two cations and higher coordinated sites in the liquids. The major glass to melt modifications is observed at the scale of intermediate range order (IRO) by rearrangement of the (Ca,Mg)–Si and (Ca,Mg)–(Ca,Mg) connections. The structural evolution with temperature, especially concerning the cationic environments, illustrates the differences between glass and melt organization. These changes highlight the important contribution of cations to thermodynamical properties, diffusion and glass forming ability.
  PubDate: Wed, 16 Mar 2022 12:45:35 +000
Annie Pradel; Andrea Piarristeguy - Thio and selenosilicates, sulfide and
selenide counterparts of silicates: similarities and differences
- Abstract: Thiosilicate and selenosilicate glasses are the sulfide and selenide counterparts of the well-known silicate glasses. This paper reviews the main investigations carried out to shed light on the structural, thermal and electrical characteristics of these glasses, showing their particularities compared to their oxide counterparts, such as a more complex structure with the presence of both, corner- and edge-sharing tetrahedra and much higher ion conductivity due to the larger polarizability of the chalcogen and the more covalent nature of the bonds, but also, their similarities with the presence of both, bridging and non-bridging S or Se or the existence of a mixed alkali effect when two mobile Li + and Na + cations coexist in the glassy network. Structural consequences of competition between SiS 2 and another former, GeS 2 , PS 5/2 or BS 3/2 are also discussed.
  PubDate: Wed, 16 Mar 2022 12:45:35 +000
The+Cu–Pb–Zn-bearing+veins+of+the+Bou+Skour+deposit+(Eastern+Anti-Atlas,+Morocco):+structural+control+and+tectonic+evolution&rft.title=Comptes+Rendus+:+Geoscience&rft.issn=1631-0713&rft.date=2022&rft.volume=">Ayoub Aabi; Lahssen Baidder et al. - Reply to comment by El Ouardi et al.
on The Cu–Pb–Zn-bearing veins of the Bou Skour deposit (Eastern
Anti-Atlas, Morocco): structural control and tectonic evolution
- Abstract: This note is a reply to the « Comment on The Cu-Pb-Zn-bearing veins of the Bou Skour deposit (Eastern Anti-Atlas, Morocco): structural control and tectonic evolution » by Hmidou El Ouardi et al., published in Comptes Rendus Géoscience in Volume 354, 2022, pages 119–123 (https://doi.org/10.5802/crgeos.115). It concerns the article « The Cu-Pb-Zn-bearing veins of the Bou Skour deposit (Eastern Anti-Atlas, Morocco): structural control and tectonic evolution » by Aabi et al., published online on May 04, 2021, in Comptes Rendus Geoscience in Volume 353, 2021, pages 81–99 (https://doi.org/10.5802/crgeos.54).
  PubDate: Mon, 28 Feb 2022 16:12:27 +000
The+Cu–Pb–Zn-bearing+veins+of+the+Bou+Skour+deposits+(Eastern+Anti-Atlas,+Morocco):+structural+control+and+tectonic+evolution+by+Aabi+A.,+et+al.&rft.title=Comptes+Rendus+:+Geoscience&rft.issn=1631-0713&rft.date=2022&rft.volume=">Hmidou El Ouardi; Brahim Karaoui et al. - Comment on The
Cu–Pb–Zn-bearing veins of the Bou Skour deposits (Eastern Anti-Atlas,
Morocco): structural control and tectonic evolution by Aabi A., et al.
- Abstract: This note is a comment to the article « The Cu–Pb–Zn-bearing veins of the Bou Skour deposit (Eastern Anti-Atlas, Morocco): structural control and tectonic evolution » by Aabi et al., published online on May 04, 2021, in Comptes Rendus Geoscience in Volume 353, 2021, pages 81–99 (https://doi.org/10.5802/crgeos.54). The authors’ response to this comment has also been published in Comptes Rendus Géoscience in Volume 354, 2022, pages 125–130 (https://doi.org/10.5802/crgeos.117).
  PubDate: Mon, 28 Feb 2022 16:12:27 +000
John S. McCloy; Sophie Schuller - Vitrification of wastes: from unwanted
to controlled crystallization, a review
- Abstract: In this review, we provide a perspective on the science and technology of vitrification of waste. First, we provide a background on the general classes of wastes for which vitrification is currently used for immobilization or is proposed, including nuclear and industrial hazardous wastes. Next, we summarize the issues surrounding solubility of waste ions and resulting uncontrolled crystallization or phase separation. Some newer waste form designs propose a controlled crystallization, resulting in a glass-ceramic. A summary of glass systems and glass-ceramic systems is given, with the focus on immobilizing waste components at high waste loading. Throughout, design and processing considerations are given, and the difference between uncontrolled undesirable and controlled desirable crystallization is offered.
  PubDate: Mon, 28 Feb 2022 10:56:32 +000
Myrtille Odile Jacqueline Yvonne Hunault; Fanny Bauchau et al. - The rose
of the Sainte-Chapelle in Paris: sophisticated stained glasses for late
medieval painters
- Abstract: The restoration of the rose (15th century) of the Sainte-Chapelle in Paris, France, offered a unique opportunity to investigate the color and chemical composition of these emblematic medieval French stained glasses with non-destructive analyses. The obtained results are aimed at complementing the knowledge from art historians and thus together trying to compensate for the total absence of archives on the construction of the rose. Comparison with the glasses of the nave (13th century) reveals an important evolution of the aesthetics based on new types of glasses: new colors and extensive use of flashed glass. The systematic study of the chemical composition of both sides of each glass piece revealed that about half of the studied glasses were flashed. For non-flashed glasses, this comparison allowed evaluating the influence of glass surface weathering, although very moderate, on the composition variability. In light of the variability criteria, the multivariate analysis of the chemical composition allowed inferring that most glasses originate from the same production glasshouse. The new colors result from the original composition of flashed glass, allowing superimposing otherwise incompatible redox states of the coloring transition elements. The comparison with the glasses of the nave reveals the glass technology evolution that occurred over two centuries and allowed the production of new glasses for the medieval glaziers at the eve of the Parisian Renaissance.
  PubDate: Mon, 28 Feb 2022 10:56:32 +000
Hossein Mohammadrezaei; Seyed Ahmad Alavi et al. - The effects of
wrench-dominated basement-involved faults on folding of overlying strata
in the Bahregansar anticline, western Persian Gulf, Iran
- Abstract: Basement-involved fault geometry and kinematics has a systematic effect on the structural style of the tectonic setting. In this study, 2D and 3D seismic datasets, well data as well as thickness and depth maps were utilized to consider and reconstruct the characteristics and effects of the wrench-dominated basement-involved fault underlying the Bahregansar anticline, which is a gentle, elongated and NW–SE-trending structure in the NW Persian Gulf, on the nature of its folded strata. Moreover, using the 2D sequential restoration, the deformation of the basement structural features was modelled and analysed for its influence on the reactivation of faulting. The results show that the major basement-involved fault, called the Hendijan–Bahregansar–Nowrooz Fault (HBNF), extends along the NE–SW-trending orientation and consist of several key anticlines. The structural evolution of the Bahregansar anticline has been deeply affected by Turonian folding phase and Pliocene Zagros orogeny associated with the HBNF. In the Upper Cretaceous, the HBNF propagated upward through the overlying sedimentary sequences when the inherited normal fault contractionally reactivated in the sinistral-reverse sense as the transpression zone in response to the Neo-Tethys oceanic plate subduction under the Eurasian plate. In this regard, the NNE–SSW-trending Bahregansar anticline (i.e., Arabian trend) formed as a forced fold. Continuing oblique convergence and associated deformation was accommodated by a change in the HBNF displacement sense from sinistral to dextral movement and buckling of the Bahregansar anticline as a result of the Pliocene Zagros orogeny.
  PubDate: Wed, 09 Feb 2022 13:46:06 +000
Kangsheng Xu; Ying Li et al. - A seismological phenomenon preceding the
2017 Ms7.0 Jiuzhaigou earthquake
- Abstract: On 8 August 2017, a Ms7.0 earthquake occurred in Jiuzhaigou in the Sichuan Province of China. In this study, we obtained the vertical continuous data recorded at 12 nearby broadband seismometers from April to December 2017, in order to characterize the temporal and spatial variations in the vertical ground motion prior to the onset of the earthquake. Using the self-mutual information method, we determined that from July to August 2017, the self-mutual information value of the vertical ground motion increased at several stations. The spatiotemporal evolution also shows that the region of highest value migrates from south to north toward the earthquake epicenter. Among them, the change of SPA (the station closest to the epicenter) is the most prominent. We believe that this phenomenon is related to the formation of the Jiuzhaigou earthquake. Our work, in combination with other published works, indicates that the Jiuzhaigou earthquake was caused by the continued eastward movement and obstruction of the Qinghai Tibet Plateau by the Sichuan Basin, and the movement of Longmenshan fault is also one of the causes of the earthquake.
  PubDate: Wed, 09 Feb 2022 13:46:06 +000
Nazanin Eslamirezaei; Seyed Ahmad Alavi et al. - Understanding the role of
décollement thickness on the evolution of décollement folds: insights
from discrete element models
- Abstract: We explored the influence of a variety of geometric and mechanical factors in the evolution of décollement folds above a weak décollement level in a sedimentary sequence. Under an applied overburden pressure, we construct nine discrete element models (DE-models) to test the effects of mechanical stratigraphy, the thickness of the décollement layer, and the number of strong and weak layers within the sedimentary cover sequence. The effects of the aforementioned parameters on the structural style of fold belts and the mechanical evolution of décollement folds that develop during a progressive deformation are what we are searching for. The one-way lateral motion of a rigid, vertical boundary wall was used to shorten the particle assemblage. The models presented in this study were then compared to a natural structure in Iran and demonstrated that the combined effects of mechanical behaviour, the thickness of décollement layer, and the number of strong and weak layers within the sedimentary cover sequence are playing the decisive role in the structural style, kinematic and mechanical evolution of décollement folds.
  PubDate: Wed, 09 Feb 2022 13:46:06 +000
Pierangelo Romano; Ida Di Carlo et al. - Water solubility in trachytic and
pantelleritic melts: an experimental study
- Abstract: Solubility experiments were performed on a trachyte and a pantellerite from Pantelleria. The trachyte has SiO 2 =65.2 wt%, Al 2 O 3 =15.2 wt% and a peralkaline index (P.I.=molar[(Na 2 O+K 2 O)/Al 2 O 3 ])∼1 while the pantellerite has SiO 2 =72.2 wt%, Al 2 O 3 =11 wt% and a P.I.=1.3. Solubility experiments were performed in the pressure range of 50–300 MPa at T=950°C for the trachyte and 50–200 MPa at T=850°C for the pantellerite. The water content of experimental glasses was determined by Karl Fischer titration, elemental analyser and FT–IR spectroscopy. Water content appears similar in both compositions for analogous pressure conditions, varying from ∼2.5 wt% at 50 MPa to ∼5.8 at 200 MPa. Comparison of the experimental data with the thermodynamic models shows that the empirical model of Moore et al. [1998] better matches the experimental data for both compositions, while the thermodynamic models of Papale et al. [2006] and Ghiorso and Gualda [2015] tend to overestimate melt water content, probably due to the paucity of peralkaline melt compositions used for calibration. One inference of these new solubility data is on MI-derived depth of felsic reservoirs at Pantelleria which deepens from 2.4 to 3.5 km.
  PubDate: Fri, 28 Jan 2022 14:25:51 +000
+2+ O+and+CO
+2+ +solubilities+of+mafic+alkaline+magmas+from+Canary+Islands&rft.title=Comptes+Rendus+:+Geoscience&rft.issn=1631-0713&rft.date=2021&rft.volume=">María Jiménez-Mejías; Joan Andújar et al. - Experimental determination
of H 2 O and CO 2 solubilities of mafic alkaline magmas from Canary
Islands
- Abstract: We present new H2O and CO2 solubility data in mafic to intermediate alkaline magmas from Fasnia and Garachico volcanoes, Tenerife. H2O- and CO2-saturated experiments were conducted at ∼50–400 MPa, 1200 °C, and fO2 from 2 log units below the NiNiO solid buffer to 3.2 log units above it. Although existing solubility models for alkali-rich mafic magmas broadly describe H2O and CO2 behaviour, associated errors are worthy of consideration since they usually exceed 15–20%. For this reason, we have determined the specific solubility laws of basanitic and phonotephritic melts from the Canary Islands. Results show similar H2O solubilities for both compositions, whereas the basanite can dissolve an average of ∼45% more CO2 than the phonotephrite. By combining these data, we have established a simple empirical model that allows us to calculate melt inclusion entrapment pressures accurately and, therefore, better understand the inner workings of volcanic oceanic islands. Application to El Hierro 2011–2012 and young (<20 ka) basanites from this location shows that previous barometric estimates were, on average, overestimated by 15–28%. Our results suggest that magmas rising from depth experienced a first but short episode of equilibration at 8–10 km, whereas the bulk of the crystallization occurred during the subsequent dyke injection, ascent, and degassing at P⇐200MPa (6–1.5 km).
  PubDate: Fri, 05 Nov 2021 10:31:14 +000