scholarly journals A Possible Primary Melt Composition For the Ultramafic Lavas of the Margi area, Troodos Ophiolite, Cyprus

1992 ◽  
Author(s):  
A V Sobolev ◽  
L V Dmitriev ◽  
O P Tsameryan ◽  
N N Kononkova ◽  
P T Robinson
Keyword(s):  
Troodos Ophiolite ◽  
Melt Composition ◽  
Primary Melt

Further Observations on A533-B Steel Plate Tailored for Improved Radiation Embrittlement Resistance

1976 ◽  
Vol 98 (2) ◽  
pp. 111-117 ◽  
Author(s):  
J. R. Hawthorne
Keyword(s):  
Radiation Resistance ◽  
Test Performance ◽  
Copper Content ◽  
Radiation Embrittlement ◽  
Copper Addition ◽  
Melt Composition ◽  
Impurity Elements ◽  
Irradiation Behavior ◽  
Embrittlement Resistance ◽  
Primary Melt

A series of advanced investigations on the radiation performance of four 6-in-thick plates from a large (30-ton) commercial melt of A533-B steel is described. The melt represented the first commercial scale demonstration test of improved radiation embrittlement resistance through the control (minimization) of selected residual impurity elements. Melt specifications emphasized the attainment of a low copper and phosphorus content; one half of the melt was modified, however, by a copper addition (0.03 percent Cu increased to 0.13 percent Cu). Initial plate tests described superior 550 F (288 C) radiation resistance, in terms of notch ductility retention, for the primary melt composition and verified the detrimental influence of impurity copper on irradiation behavior. Promising capability of the primary melt composition for very high fluence (∼2.5 × 1020 n/cm2 > 1 MeV) service is shown by the current investigations. In addition, a significant influence of copper content on radiation resistance is revealed for a broad range of exposure temperatures. A dependence of 650 F (343 C) postirradiation heat treatment response (notch ductility recovery) on copper content was also found. Charpy-V versus dynamic tear test performance and tensile strength trends with temperature are examined for low (<450 F, 121 C) and elevated (550 to 585 F, 288 to 307 C) temperature irradiation conditions.

scholarly journals Eruption style at Kīlauea Volcano in Hawai‘i linked to primary melt composition

2014 ◽  
Vol 7 (6) ◽  
pp. 464-469 ◽  
Author(s):  
I. R. Sides ◽  
M. Edmonds ◽  
J. Maclennan ◽  
D. A. Swanson ◽  
B. F. Houghton
Keyword(s):  
Kilauea Volcano ◽  
Eruption Style ◽  
Kīlauea Volcano ◽  
Melt Composition ◽  
Primary Melt

Metallographic analysis of M2 high speed steel granules

2019 ◽  
pp. 78-85
Author(s):  
L. E. Afanasieva
Keyword(s):  
Solid Solution ◽  
Cellular Structure ◽  
High Speed ◽  
Solution Structure ◽  
Supersaturated Solid Solution ◽  
High Speed Steel ◽  
Metallographic Analysis ◽  
M2 High Speed Steel ◽  
Melt Composition

The article is devoted to the metallographic analysis of the M2 high-speed steel granules. The study is based on the investigation of the microstructure of the M2 high-speed steel granules obtained by melt atomization. It is demonstrated that granules of similar size can harden both by chemically separating and chemically non-separating mechanism. These last ones have supersaturated solid solution structure of the liquid melt composition, a dispersed dendritic-cellular structure and an increased microhardness HV = 10267±201 MPa.

Metamorphism in the Troodos ophiolite: implications for marine magnetic anomalies

Nature ◽  
1980 ◽  
Vol 285 (5766) ◽  
pp. 563-564 ◽  
Author(s):  
Suzanne Beske-Diehl ◽  
Subir K. Banerjee
Keyword(s):  
Magnetic Anomalies ◽  
Troodos Ophiolite ◽  
Marine Magnetic Anomalies

Emergence of continents above sea‐level influences sediment melt composition

Terra Nova ◽  
2021 ◽  
Author(s):  
J. Liebmann ◽  
C.J. Spencer ◽  
C.L. Kirkland ◽  
C.E. Bucholz ◽  
X. He ◽  
...  
Keyword(s):  
Sea Level ◽  
Melt Composition

scholarly journals New insights on Br speciation in volcanic glasses and structural controls on halogen degassing

2020 ◽  
Vol 105 (6) ◽  
pp. 795-802 ◽  
Author(s):  
Marion Louvel ◽  
Anita Cadoux ◽  
Richard A. Brooker ◽  
Olivier Proux ◽  
Jean-Louis Hazemann
Keyword(s):  
Atmospheric Chemistry ◽  
Divalent Cations ◽  
Stratospheric Ozone ◽  
High Energy ◽  
Aluminosilicate Glass ◽  
High Energy Resolution ◽  
Magma Chambers ◽  
Structural Controls ◽  
Volcanic Glasses ◽  
Melt Composition

Abstract The volcanic degassing of halogens, and especially of the heavier Br and I, received increased attention over the last 20 years due to their significant effect on atmospheric chemistry, notably the depletion of stratospheric ozone. While the effect of melt composition on halogen diffusion, solubility, or fluid-melt partitioning in crustal magma chambers has been thoroughly studied, structural controls on halogen incorporation in silicate melts remain poorly known, with only few studies available in simplified borosilicate or haplogranite compositions. Here, we demonstrate that high-energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD-XAS) with a crystal analyzer spectrometer (CAS) is well-suited for the study of Br speciation in natural volcanic glasses which can contain lower Br concentrations than their laboratory analogs. Especially, HERFD-XAS results in sharper and better-resolved XANES and EXAFS features than previously reported and enables detection limits for EXAFS analysis down to 100 ppm when previous studies required Br concentrations above the 1000 ppm level. XANES and EXAFS analyses suggest important structural differences between synthetic haplogranitic glass, where Br is surrounded by Na and next-nearest oxygen neighbors, and natural volcanic glasses of basaltic to rhyodacitic compositions, where Br is incorporated in at least three distinct sites, surrounded by Na, K, or Ca. Similar environments, involving both alkali and alkaline earth metals have already been reported for Cl in Ca-bearing aluminosilicate glass and our study thus underlines that the association of Br with divalent cations (Ca2+) has been underestimated in the past due to the use of simplified laboratory analogs. Overall, similarities in Cl and Br structural environments over a large array of compositions (46–67 wt% SiO2) suggest that melt composition alone may not have a significant effect on halogen degassing and further support the coupled degassing of Cl and Br in volcanic systems.

The Monchegorsk Intrusion: Reconstruction (Parent Magma (Melt) Composition, P–T Conditions, and Intrusion Thickness)

2021 ◽  
Vol 76 (3) ◽  
pp. 300-315
Author(s):  
V. S. Semenov ◽  
E. V. Koptev–Dvornikov ◽  
S. V. Semenov ◽  
S. I. Korneev
Keyword(s):  
Parent Magma ◽  
Melt Composition ◽  
Magma Melt

scholarly journals Spring and surface water quality of the Cyprus ophiolites

2002 ◽  
Vol 6 (5) ◽  
pp. 797-817 ◽  
Author(s):  
C. Neal ◽  
P. Shand
Keyword(s):  
Water Quality ◽  
Sea Water ◽  
Stream Water ◽  
Chemical Reactivity ◽  
Surface Water Quality ◽  
Calcium Sulphate ◽  
Stream Water Quality ◽  
Troodos Ophiolite ◽  
High Calcium ◽  
Hydrolysis Of

Abstract. A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1) Mg-HCO3, (2) Na-SO4-Cl-HCO3, (3) Na-Ca-Cl-SO4-OH-CO3, (4) Na-Cl-SO4 and (5) Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water) and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high. Keywords: Cyprus, Troodos, ophiolite, serpentinisation, spring, stream, water quality, bromide, iodine, boron, trace elements, hyperalkaline.

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