Supercooling and the crystallization of plagioclase from a basaltic magma

1974 ◽  
Vol 39 (306) ◽  
pp. 641-653 ◽  
Author(s):  
Fergus G. F. Gibb
Keyword(s):  
Liquidus Temperature ◽  
Basaltic Magma ◽  
Equilibrium Phase ◽  
Phase Relations ◽  
Lava Flows ◽  
Cooling Rates ◽  
Time Space ◽  
Columbia River Basalt ◽  
Temperature Time ◽  
Basaltic Liquid

SummaryThe liquidus temperature (1198 °C) and equilibrium phase relations of a sample of Columbia River basalt from the Picture Gorge section have been determined at I atmosphere by heating in a controlled atmosphere. When this basalt is cooled from above its liquidus temperature the liquidus phase (plagioclase) may fail to crystallize depending on the degree of undercooling and the duration of the experiment. A field in temperature-time space in which plagioclase fails to crystallize on cooling is separated from another in which plagioclase always crystallizes by a third in which the nucleation of plagioclase is unpredictable in terms of temperature and time. The extent to which this basaltic liquid can be supercooled without the crystallization of plagioclase is independent of the time it is held above the liquidus or the temperature in excess of the liquidus to which it is heated.The exceptionally long times required to ensure the nucleation of plagioclase at or near the liquidus temperature suggest that many so-called ‘equilibrium’ phase relations determined from experiments of a few hours' duration could be in serious error if the ‘equilibration’ involves a nucleation process.It is demonstrated that, over a range of cooling rates, the temperature at which plagioclase begins to crystallize on cooling varies markedly and the temperature and times required for both possible and certain nucleation of plagioclase are calculated for a range of constant cooling rates. The range of cooling rates over which the nucleation temperature of plagioclase varies is likely to occur in nature only in certain lava flows and small minor intrusions. In such cases this could lead to changes in the order in which the minerals appear on cooling and other petrologically significant effects.

Equilibrium phase relations in the U–Zr–Fe ternary system

1999 ◽  
Vol 275 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Kinya Nakamura ◽  
Masaki Kurata ◽  
Takanari Ogata ◽  
Akinori Itoh ◽  
Mitsuo Akabori
Keyword(s):  
Ternary System ◽  
Equilibrium Phase ◽  
Phase Relations

Crystallization of basaltic magma as recorded by variation of crystal-size in dikes

1949 ◽  
Vol 28 (205) ◽  
pp. 557-574 ◽  
Author(s):  
Helmut G. F. Winkler
Keyword(s):  
Grain Size ◽  
Quantitative Data ◽  
Crystal Size ◽  
Basaltic Magma ◽  
Size Variation ◽  
Progressive Increase ◽  
Lava Flows ◽  
The Individual

It is a familiar fact that in dikes, lava-flows, and sills the grain-size of the individual minerals normally varies according to the distance from the contacts. At or near the margins of the igneous body the grainsize is usually very much less than in the centre, and this phenomenon has been attributed to differences in the cooling-velocities at these spots. On the basis of measurements carried out by Queneau (8) the opinion seems to have been formed that the crystal-size always shows a progressive increase from the contacts towards the centre. This is not so, however, for as Lane (6) has shown, the crystal-size may increase to a maximum at a certain distance from the margin, and thereafter decrease again towards the centre of the intrusion. Apart from these investigations, carried out by Queneau and Lane, the only additioual quantitative data oil crystal-size variation known to the writer concerns a series of measurements made on an olivine-diabase by B. H. Dollen, under the direction of H. L. Alling.

A quantitative study of five thousand years of volcanism on Sao Miguel, Azores

1978 ◽  
Vol 288 (1352) ◽  
pp. 271-319 ◽  
Keyword(s):  
Quantitative Study ◽  
Basaltic Magma ◽  
Volcanic Eruptions ◽  
Lava Flows ◽  
Explosive Eruptions ◽  
Lateral Movement ◽  
The Past ◽  
Pumice Fall ◽  
Eruptive Fissures ◽  
Fall Deposits

The activity of the three stratovolcanoes on the island of Sao Miguel is documented by tephrochronology, and during the past 5000 years a total of some 57 volcanic eruptions have taken place, mostly of magnitudes 4-6 on Tsuya’s scale. Approximately half were trachytic, and half basaltic. Each stratovolcano has a caldera within which each has had one historic eruption. The trachytic eruptions were predominantly explosive, and most took place from vents situated within the calderas. Isopach and isograde maps of most of the resulting pumice fall deposits are given. The basaltic eruptions produced both lava flows and pyroclastics, and isopach and isograde maps are given for some of the main fall deposits. The Agua de Pau volcano has had particularly large explosive eruptions, several of them (including Fogo A, the largest in the past 5000 years) being of plinian type. The output of the three volcanoes over the 5000 years is equivalent to 4.6 km 3 of dense rock, at which rate the exposed parts of the volcanoes could have accumulated in 150000 years. At least half of the erupted material is trachytic, a proportion typical of the entire accessible parts of the volcanoes. The 50 known eruptive vents of the past 5000 years are distributed in a zone 55 km long by 8 km wide which may lie above a major fracture zone. Some eruptive fissures trend obliquely across this zone, suggesting right-lateral movement along the fracture. Basaltic eruptions were confined to a much smaller area than in the preceding millennia perhaps due to the formation, at the time of the great Fogo A eruption 5000 years ago, of a broad trachytic magma chamber underlying the Agua de Pau and Furnas volcanoes which basaltic magma has since been unable to penetrate.

Equilibrium Phase Relations of the CaO-SiO2-Ti3O5 System at 1400 °C and a p(O2) of 10−16 atm

JOM ◽  
2022 ◽  
Author(s):  
Junjie Shi ◽  
Yuchao Qiu ◽  
Xingbang Wan ◽  
Bin Yu ◽  
Min Chen ◽  
...  
Keyword(s):  
Equilibrium Phase ◽  
Phase Relations

Composition changes in a basalt melt contained in a wire loop of Pt80Rh20: effects of temperature, time, and oxygen fugacity

1979 ◽  
Vol 43 (325) ◽  
pp. 115-119 ◽  
Author(s):  
Colin H. Donaldson
Keyword(s):  
Oxygen Fugacity ◽  
Liquidus Temperature ◽  
Olivine Basalt ◽  
Wire Loop ◽  
Alkali Olivine Basalt ◽  
Effects Of Temperature ◽  
The Wire ◽  
Increasing Temperature ◽  
Temperature Time ◽  
Composition Changes

SummaryLosses of FeO, Na2O, and K2O from an alkali olivine basalt melted above the liquidus temperature in Pt80Rh20 wire loops are reported as a function of temperature, time, and PO2. Increasing temperature and decreasing PO2 increase the losses. Compared to open capsules the wire-loop container reduces FeO loss to a minimum but may exacerbate Na2O loss. Nonetheless for most types of experiment involving melt these losses are acceptable.

scholarly journals Impact of Conductor Temperature Time–Space Variation on the Power System Operational State

Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 760 ◽  
Author(s):  
Yanling Wang ◽  
Yang Mo ◽  
Mingqiang Wang ◽  
Xiaofeng Zhou ◽  
Likai Liang ◽  
...  
Keyword(s):  
Power System ◽  
Time Space ◽  
Conductor Temperature ◽  
Temperature Time

scholarly journals Non-Equilibrium Processing of Ni-Si Alloys at High Undercooling and High Cooling Rates

2014 ◽  
Vol 790-791 ◽  
pp. 22-27 ◽  
Author(s):  
Andrew M. Mullis ◽  
Lei Gang Cao ◽  
Robert F. Cochrane
Keyword(s):  
Metastable Phase ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Eutectic Structure ◽  
Eutectic Solidification ◽  
Drop Tube ◽  
High Undercooling ◽  
Cooling Rates ◽  
Β Phase ◽  
High Cooling Rates

Melt encasement (fluxing) and drop-tube techniques have been used to solidify a Ni-25 at.% Si alloy under conditions of high undercooling and high cooling rates respectively. During undercooling experiments a eutectic structure was observed, comprising alternating lamellae of single phase γ (Ni31Si12) and Ni-rich lamellae containing of a fine (200-400 nm) dispersion of β1-Ni3Si and α-Ni. This is contrary to the equilibrium phase diagram from which direct solidification to β-Ni3Si would be expected for undercoolings in excess of 53 K. Conversely, during drop-tube experiments a fine (50 nm) lamellar structure comprising alternating lamellae of the metastable phase Ni25Si9 and β1-Ni3Si is observed. This is also thought to be the result of primary eutectic solidification. Both observations would be consistent with the formation of the high temperature form of the β-phase (β2/β3) being suppressed from the melt.

Equilibrium phase relations in the Bi–Ca–Sr–Cu–O system at 850 and 900°C

1990 ◽  
Vol 5 (7) ◽  
pp. 1403-1408 ◽  
Author(s):  
C-L. Lee ◽  
J-J. Chen ◽  
W-J. Wen ◽  
T-P. Perng ◽  
J-M. Wu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Equilibrium Phase ◽  
Superconducting Phase ◽  
Phase Relations ◽  
The Other ◽  
Boundary Line ◽  
X Ray ◽  
Tie Lines ◽  
Boundary Lines

The phase relations of equilibrium compounds in the pseudoternary system Bi2O3–(Ca,Sr)O–CuO at 850 and 900°C were studied. The ratio of Ca : Sr was fixed at 1:2. Starting materials of Bi2O3, CaCO3, SrCO3, and CuO with various ratios were mixed, pressed into pellets, and heated at or above and then brought back to 850 or 900°C for different durations to ensure that equilibrium had been reached. The products were cooled in air or quenched in liquid nitrogen and then identified by x-ray powder diffraction. At 850°C, only the superconducting phase, Bi2CaSr2Cu2Ox (2122), was observed inside the triangle. The other stable phases were all positioned on the boundary lines, and included CuO·⅗MO, CuO·MO, CuO·2MO, 1.½Bi2O3·0.9MO, Bi2O3·4MO, Bi2O3·9MO, and a solid solution, Bi2O3·xMO, where 0.16  x  0.82 and MO represents ⅓(CaO·2SrO). At 900°C, the above boundary line phases remained stable but the 2122 phase was not observed. The tie lines among the stable phases in the two isotherms were established.

Effect of Oxygen Partial Pressure and Temperature on Liquidus for the CaO-SiO2-FeOx-Al2O3 System

2011 ◽  
Vol 295-297 ◽  
pp. 2279-2282 ◽  
Author(s):  
Nan Wang ◽  
Zong Shu Zou ◽  
Zhan Zhang ◽  
Yan Xiao ◽  
Yong Yang
Keyword(s):  
Thermodynamic Properties ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Equilibrium Phase ◽  
Bottom Ash ◽  
Oxide System ◽  
Phase Relations ◽  
Efficient Utilization ◽  
Oxide Systems ◽  
Effect Of Oxygen

To provide essential data for an efficient utilization of vitrified bottom ash slag, the thermodynamic properties of the CaO-Al2O3-SiO2-FeOx-MgO-Na2O oxide system is highly required. As one of the related oxide subsystems, the equilibrium phase relations and liquidus of CaO-SiO2-FeOx-Al2O3 system is of great significance to interpret and predict the thermodynamic properties in multi-component oxide systems. In this paper, phase diagrams for the CaO-Al2O3-FeOx and SiO2-Al2O3-FeOx systems were calculated by using CALPHAD method with FactSage program. The liquid phase area changed with changing oxygen partial pressure from 1Pa to 10-3Pa and temperature from 1673K to 1773K. The equilibrium phase relations of CaO-Al2O3-FeOx and SiO2-Al2O3-FeOx systems were discussed.

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