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Journal articles on the topic 'Amphibolis'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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1

BOGDANOVA, Alyona Romanovna, Nadezhda Vladimirovna VAKHRUSHEVA, and Pavel Borisovich SHIRYAEV. "Main and rare earth elements of amphibolites of the Ray-Iz massif (Polar Urals)." NEWS of the Ural State Mining University, no. 4 (December 20, 2020): 19–27. http://dx.doi.org/10.21440/2307-2091-2020-4-19-27.

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Relevance. The Ray-Iz massif contains the Tsentralnoye chromium ore deposit and is unique in terms of variety of metamorphic rock associations. It has been studied since 1932. However, some aspects of geology and petrology in the literature are not fully covered. One of these areas is a vein series of rocks localized in ultramafic rocks. The spatial confinement of amphibolites to the Central zone of metamorphism, which is consistent with the zone of distribution of deposits and ore occurrences of chromites, determines the need for a detailed study. Purpose of work. Study of mineralogical and petrographic characteristics, as well as the geochemistry of lanthanides of amphibolites of the Ray-Iz massif (Polar Urals). Results. The study of the nature of REE distribution in rock-forming minerals made it possible to determine that the variation in the amount of REE (33–75 g/t) within one rock is associated with the quantitative content of the main minerals-concentrators. The main mineral concentrator lanthanides in garnet amphibolites is garnet, while amphibole is in garnet-free pyroxene-bearing amphibolites. Based on the results of the chemical composition of amphibole and coexisting plagioclases and amphibolite garnets, the temperature was calculated using amphiboleplagioclase by T. Holland, J. Blundy, as well as the garnet amphibolite by L. L. Perchuk geothermometers and pressure based on amphibole geobarometer by M. W. Schmidt. Conclusion. The nature of the distribution of lanthanides in the main rock-forming minerals, amphibole and garnet, has been revealed. Comparison of parameters and compositional features of amphiboles made it possible to conclude that there is a direct relationship between temperature, pressure, the sum of REE and TiO2 , as well as (La/Yb)n , in the mineral.

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2

Rao, Rameshwar, and Hakim Rai. "Mineral chemistry of eclogites to investigate the evolutionary metamorphic history of UHP rocks from Tso-Morari region, Ladakh, India." Journal of Nepal Geological Society 40 (December 1, 2010): 13–20. http://dx.doi.org/10.3126/jngs.v40i0.23592.

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Micro textures of metabasics from the Tso-Morari region, Ladakh were studied in order to understand the evolutionary metamorphic history of eclogites. The mineral chemistry, paragenesis of mineral inclusions in garnet, and zoning in omphacite, garnet and amphibole suggest three main metamorphic stages: (i) an eclogite stage with late blueschist facies metamorphism, (ii) a medium-pressure amphibolite facies stage, and (iii) a low-pressure amphibolite to greenschist facies stage. The high Si content in phengite, presence of rutile besides almandine-rich garnet and omphacite in eclogites indicate the attainment of high pressures. Also, the textural features and composition of amphiboles indicate that blueschist facies conditions represented by growth of glaucophane at high pressure and low temperature were followed by a lower-pressure stage of metamorphism represented by partial and in some cases complete reaction of glaucophane to calcic green amphibole such as magnesio-hornblende. The relationships define a clock-wise P-T path with the involvement of an isothermal uplift path for the eclogites and associated garnet-amphibolites of Tso-Morari region.

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3

Verduin, Jennifer J., Anke Seidlitz, Mike van Keulen, and Erik I. Paling. "Maximising establishment success of Amphibolis antarctica seedlings." Journal of Experimental Marine Biology and Ecology 449 (November 2013): 57–60. http://dx.doi.org/10.1016/j.jembe.2013.08.016.

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4

Zhang, Xiaoli, Jinxian He, Zeqiang Ren, Taotao Zhou, Wenjie Cao, and Ben Xu. "Analysis of the Submicrostructural Deformation of Amphibole in a Ductile Shear Zone Based on the TEM Technique." Journal of Nanoscience and Nanotechnology 21, no. 1 (January 1, 2021): 765–71. http://dx.doi.org/10.1166/jnn.2021.18466.

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Deformed amphibole in the plagioclase amphibolite mylonite of the Guandi Complex, Xishan, Beijing, is the research object in this study. The amphibole nanodeformation under the middle crust was analyzed using microstructural analysis and high-resolution transmission electron microscopy (TEM). Microscope observations show that the amphibolite deformations in the plagioclase amphibolite mylonite are δ and σ type porphyroclasts, and the porphyroclast tail is composed of new long-columnar crystals. Using transmission electron microscopy (TEM, and this acronyms would be defined only once), the authors observed the nanodeformation characteristics of the amphibole porphyroclast core and mantle. Dislocation tangles are dominant in the porphyroclast core, and inside the new crystal, there is little or no dislocation. Swelled new crystals surrounded by dislocation can be observed in the transition zone between the porphyroclasts and new crystals. The deformed amphibole microstructure and submicrostructure represent typical brittle–ductile transitional deformation. The deformation process can be divided into two stages: the disordered dislocation increment stage and the dislocation reduction and ordering stage. Crystalline plastic deformation occurs in the amphibole in the plagioclase amphibolite mylonite of the Xishan area, Beijing. The crystalline plastic deformation temperature in amphiboles is higher than that in plagioclase.

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5

Dunlop, Robert W. "Diterpenoid hydrocarbons in the sea grass Amphibolis antartica." Phytochemistry 24, no. 5 (January 1985): 977–79. http://dx.doi.org/10.1016/s0031-9422(00)83165-9.

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6

Waycott, Michelle, Diana I. Walker, and Sidney H. James. "Genetic uniformity in Amphibolis antarctica, a dioecious seagrass." Heredity 76, no. 6 (June 1996): 578–85. http://dx.doi.org/10.1038/hdy.1996.83.

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7

Wartho, Jo Anne, David C. Rex, and Philip G. Guise. "Excess argon in amphiboles linked to greenschist facies alteration in the Kamila Amphibolite Belt, Kohistan island arc system, northern Pakistan: insights from 40Ar/39Ar step-heating and acid leaching experiments." Geological Magazine 133, no. 5 (September 1996): 595–609. http://dx.doi.org/10.1017/s0016756800007871.

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AbstractA mineralogical and 4OAr/39Ar study of 13 amphibole samples in the Kamila Amphibolite Belt and Kamila Shear Zone in northern Pakistan has found a correlation between the degree of greenschist facies alteration and quantity of excess 40Ar. Additionally, there is a north–south divide with amphibole samples from the northern region showing larger degrees of gree schist facies alteration, brittle deformation, and excess 40Ar incorporation compared to the predominantly plastically deformed, less altered, amphibole samples from the Kamila Shear Zone in the south. Acid leaching of two amphiboles from the Kamila Amphibolite Belt indicates that a large proportion of the excess 40Ar is correlated with later greenschist facies alteration hases, and can be easily removed by acid etching, thus revealing acceptable regional 40Ar/39Ar plateau ages.

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8

Walker, D. I., and M. L. Cambridge. "An experimental assessment of the temperature responses of two sympatric seagrasses, Amphibolis antarctica and Amphibolis griffithii, in relation to their biogeography." Hydrobiologia 302, no. 1 (March 1995): 63–70. http://dx.doi.org/10.1007/bf00006399.

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9

Pedersen, Morten F., Eric I. Paling, and Diana I. Walker. "Nitrogen uptake and allocation in the seagrass Amphibolis antarctica." Aquatic Botany 56, no. 2 (March 1997): 105–17. http://dx.doi.org/10.1016/s0304-3770(96)01100-x.

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10

Gartner, A., P. Lavery, K. McMahon, A. Brearley, and H. Barwick. "Light reductions drive macroinvertebrate changes in Amphibolis griffithii seagrass habitat." Marine Ecology Progress Series 401 (February 22, 2010): 87–100. http://dx.doi.org/10.3354/meps08367.

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11

Ahmid-Said, Y., and B. E. Leake. "The composition and origin of the Kef Lakhal amphibolites and associated amphibolite and olivine-rich enclaves, Edough, Annaba, NE Algeria." Mineralogical Magazine 56, no. 385 (December 1992): 459–68. http://dx.doi.org/10.1180/minmag.1992.056.385.02.

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AbstractThe Kef Lakhal amphibolitcs and associated amphibolitc and olivine-rich enclaves are dcscribcd and their major and trace element chemistry indicates that both amphibolites were evolved medium to high alumina tholeiitic basalts with talc-alkaline affinities probably formed within plate settings. The olivine-rich enclaves are disrupted periodotites of the type lherzolite-harzburgite and probably represent mantle residua after melting.

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12

van Keulen, Mike. "Multiple climate impacts on seagrass dynamics: Amphibolis antarctica patches at Ningaloo Reef, Western Australia." Pacific Conservation Biology 25, no. 2 (2019): 211. http://dx.doi.org/10.1071/pc18050.

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The impacts of tropical cyclones combined with a marine heatwave are reported for a seagrass community at Ningaloo Reef, Western Australia. A community of 9.5ha of Amphibolis antarctica was lost following a combination of cyclone-induced burial and a marine heatwave. No new seedlings have been observed since the loss; recruitment of seedlings may be impeded by local ocean circulation.

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13

Verduin, JJ, DI Walker, and J. Kuo. "In situ submarine pollination in the seagrass Amphibolis antarctica: research notes." Marine Ecology Progress Series 133 (1996): 307–9. http://dx.doi.org/10.3354/meps133307.

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14

Wear, Rachel J., Jason E. Tanner, and Sonja L. Hoare. "Facilitating recruitment of Amphibolis as a novel approach to seagrass rehabilitation in hydrodynamically active waters." Marine and Freshwater Research 61, no. 10 (2010): 1123. http://dx.doi.org/10.1071/mf09314.

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Worldwide, 29% of seagrass habitats have been lost over the past century. Compared with large-scale losses, successful restoration programs are usually only small scale (a few hectares). One area of significant seagrass loss (>5200 ha) is Adelaide, South Australia. Improvements to wastewater management have raised the possibility of rehabilitation in this area. Traditional methods of seagrass restoration are expensive and have had limited success owing to high wave energy. We investigated a range of biodegradable substrates, mostly made of hessian (burlap), to enhance Amphibolis recruitment as an alternative. After 5 weeks, 16 514 seedlings, or 157 seedlings m–2, had recruited. Survival declined over the following 12 months to 31.4%, and down to 7.2% after 3 years, in part as a result of breakdown of the hessian, and the wave-exposed nature of the sites. During the initial 12 months, above- and belowground biomass increased 2.6- and 6.4-fold, respectively. The technique may represent a non-destructive, cost-effective (<AU$10 000 ha–1) method to restore Amphibolis over large spatial scales and in areas that are hydrodynamically too active for traditional techniques, thus helping ameliorate some of the large-scale losses of seagrasses that have occurred globally.

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15

Mackey, P., CJ Collier, and PS Lavery. "Effects of experimental reduction of light availability on the seagrass Amphibolis griffithii." Marine Ecology Progress Series 342 (July 24, 2007): 117–26. http://dx.doi.org/10.3354/meps342117.

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16

Kuo, J., I. H. Cook, and H. Kirkman. "Observations of propagating shoots in the seagrass genus Amphibolis C. Agardh (Cymodoceaceae)." Aquatic Botany 27, no. 3 (March 1987): 291–93. http://dx.doi.org/10.1016/0304-3770(87)90048-9.

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17

van Dijk, Kor-jent, Gina Digiantonio, and Michelle Waycott. "New microsatellite markers for the seagrass Amphibolis antarctica reveal unprecedented genetic diversity." Aquatic Botany 148 (August 2018): 25–28. http://dx.doi.org/10.1016/j.aquabot.2018.04.002.

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18

Tanner, Jason E. "Restoration of the Seagrass Amphibolis antarctica—Temporal Variability and Long-Term Success." Estuaries and Coasts 38, no. 2 (May 23, 2014): 668–78. http://dx.doi.org/10.1007/s12237-014-9823-4.

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19

Smit, A. J., A. Brearley, G. A. Hyndes, P. S. Lavery, and D. I. Walker. "Carbon and nitrogen stable isotope analysis of an Amphibolis griffithii seagrass bed." Estuarine, Coastal and Shelf Science 65, no. 3 (November 2005): 545–56. http://dx.doi.org/10.1016/j.ecss.2005.07.002.

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20

Bailey, R. Mark. "Asbestiform Minerals of the Franciscan Assemblage in California with a Focus on the Calaveras Dam Replacement Project." Environmental and Engineering Geoscience 26, no. 1 (February 20, 2020): 21–28. http://dx.doi.org/10.2113/eeg-2264.

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ABSTRACT The San Francisco Bay Area is underlain by bedrock of the Franciscan Assemblage, which outcrops in numerous places. A significant portion of these outcrops consists of rock types that contain both regulated and unregulated asbestiform minerals, including ultra-mafic serpentinites, various greenstones, amphibolites, blueschist, and other schists (talc-tremolite, actinolite, etc.). These rocks are a legacy of tectonic activity that occurred on the west coast margin of the North American plate ∼65–150 MY ago during subduction of the East Pacific and Farallon plates. The Calaveras Dam Replacement Project (CDRP), located in Fremont, California, is an example of an area within the Franciscan Assemblage that is substantially underlain by metamorphosed oceanic sedimentary, mafic, and ultra-mafic rocks in a tectonic subduction zone mélange with highly disrupted relationships between adjoining rock bodies with different pressure/temperature metamorphic histories. In order to protect the health of workers and residents in the surrounding area, an extensive effort was taken to identify, categorize, and monitor the types, locations, and concentrations of naturally occurring asbestos at the site. Using a combination of geologic field observations and transmission electron microscopy, energy dispersive X-ray, and selected area electron diffraction analysis of airborne particulate and rock/soil samples, the CDRP was discovered to contain chrysotile-bearing serpentine. It also had as a range of amphibole-containing rocks, including blueschist, amphibolite schist, and eclogite, with at least 19 different regulated and non-regulated fibrous amphibole minerals identified. The extensive solid solution behavior of the amphiboles makes definitive identification difficult, though a scheme was created that allowed asbestos mineral fingerprinting of various areas of the project site.

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21

Altherr, Rainer, Stefan Hepp, Hans Klein, and Michael Hanel. "Metabasic rocks from the Variscan Schwarzwald (SW Germany): metamorphic evolution and igneous protoliths." International Journal of Earth Sciences 110, no. 4 (March 22, 2021): 1293–319. http://dx.doi.org/10.1007/s00531-021-02016-w.

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AbstractIn the Variscan Schwarzwald metabasic rocks form small bodies included within anatectic plagioclase-biotite gneisses. Many metabasites first underwent an eclogite-facies metamorphism at about 2.0 GPa and 670–700 °C, resulting in the assemblage garnet + omphacite + rutile + quartz ± epidote ± amphibole ± kyanite. Since these eclogites are nearly free of an OH-bearing phase, they underwent almost complete dehydration during subduction, suggesting formation along an average to warm top-of-the-slab geotherm of 10–13 °C/km. The age of the Variscan high-P/high-T metamorphism is > 333 Ma. After partial exhumation from ~ 65 to ~ 15 km depth, the eclogites were overprinted under increasing activity of H2O by a number of retrograde reactions. The degree of this overprint under amphibolite-facies conditions (0.4–0.5 GPa/675–690 °C) was very different. Up to now, only retrograde eclogites have been found, but some samples still contain omphacite. Kyanite is at least partially transformed to aggregates of plagioclase + spinel ± corundum ± sapphirine. On the other hand, there are amphibolites that are extensively recrystallized and show the assemblage amphibole + plagioclase + ilmenite/titanite ± biotite ± quartz ± sulphides. The last relic phase that can be found in such otherwise completely recrystallized amphibolites is rutile. After the amphibolite-facies metamorphism at ~ 333 Ma, the metabasites underwent a number of low-temperature transformations, such as sericitization of plagioclase, chloritization of amphibole, and formation of prehnite. The intimate association of metabasite bodies with gneisses of dominantly meta-greywacke compositions suggests derivation from an active plate margin. This view is corroborated by bulk-rock geochemical data. Excluding elements that were mobile during metamorphism (Cs, Rb, Ba, K, Pb, Sr, U), the concentrations of the remaining elements in most of the metabasites are compatible with a derivation from island-arc tholeiites, back-arc basin basalts or calc-alkaline basalts. Only some samples have MORB precursor rocks.

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22

Lavery, PS, K. McMahon, M. Mulligan, and A. Tennyson. "Interactive effects of timing, intensity and duration of experimental shading on Amphibolis griffithii." Marine Ecology Progress Series 394 (November 18, 2009): 21–33. http://dx.doi.org/10.3354/meps08242.

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23

Rivers, David O., Gary A. Kendrick, and Diana I. Walker. "Microsites play an important role for seedling survival in the seagrass Amphibolis antarctica." Journal of Experimental Marine Biology and Ecology 401, no. 1-2 (May 2011): 29–35. http://dx.doi.org/10.1016/j.jembe.2011.03.005.

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24

Dolníček, Zdeněk, and Jana Ulmanová. "Mineralogická charakteristika křemenné žíly se scheelitem a alpské žíly s prehnitem z lomu v Plaňanech u Kolína (kutnohorské krystalinikum)." Bulletin Mineralogie Petrologie 28, no. 1 (2020): 74–85. http://dx.doi.org/10.46861/bmp.28.074.

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Two new types of hydrothermal veins were found in the quarry at Plaňany. Both mineralizations are hosted by a lenticular body of amphibolites embedded in migmatites and gneisses of the Kutná Hora Crystalline Complex. The first type of mineralization is represented by subvertical scheelite-bearing quartz vein, which strikes WNW-ESE, perpendicularly to foliation planes of host rocks. In addition to quartz, the vein also contains a small amount of sulphides (especially chalcopyrite and molybdenite, less pyrite and sphalerite, rarely pyrrhotite and argentopentlandite), calcite, silicates [zoned amphibole (with compositions ranging from magnesiohornblende to actinolite), chlorite (clinochlore), plagioclase (andesine to albite) and prehnite] and scheelite, which forms up to 3 cm big nests in quartz. We cannot exclude the possibility that magnesiohornblende cores of amphibole crystals as well as andesine cores of plagioclases represent relics of host rock. Second type of mineralization is vein with prevailing prehnite, which is oblique to foliation of host amphibolites. Besides prehnite, it contains adularia, calcite and actinolitic amphibole. Both studied mineralizations represent retrograde-metamorphic mobilisates similar to the Alpine-type veins. Chlorite thermometry suggests that chlorite from scheelite-bearing quartz vein originated at temperatures between 253 and 298 °C. The source of Mo and W necessary for formation of molybdenite and scheelite is not clear, but one cannot exclude that these elements were transported by parent fluids from felsic rocks outside of the host amphibolite body.

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25

Misseri, Maxime, and Didier Lahondere. "Characterisation of chemically related asbestos amphiboles of actinolite: proposal for a specific differentiation in the diagram (Si apfu versus Mg/Mg+Fe2+)." International Journal of Metrology and Quality Engineering 9 (2018): 16. http://dx.doi.org/10.1051/ijmqe/2018014.

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Aggregates and rocks from quarries located in metropolitan France and New Caledonia, all likely to contain asbestiform amphiboles, were analysed by a routine laboratory (AD-LAB). Morphological observations were made using transmission electron microscopy and chemical analyses were obtained with energy dispersive X-ray spectroscopy. The chemical analyses obtained from amphiboles were treated in such a way that they could be plotted in a diagram (Si apfu versus Mg/Mg+Fe2+). The points corresponding to analysed particles, classified as asbestos, define a broader compositional domain than that corresponding to the compositional areas of actinolite and tremolite. The creation of two new domains is proposed. Samples of basic metavolcanics and amphibolites collected by the Geological and Mining Research Bureau (BRGM) in different quarries of the Armorican Massif and the Massif Central containing calcic amphibole fibres have been the subject of polarized light microscope and electron microprobe analyses. The representative points of the spot chemical analyses performed on the very fine and ultrafine fibres are contained in the range defined previously. The diagram that has been determined from chemical analyses coupled with morphological and dimensional observations can help the “routine laboratories” to better characterise asbestiform calcic amphiboles, but it also allows comparisons with geological observations.

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26

Nayar, S., G. J. Collings, D. J. Miller, S. Bryars, and A. C. Cheshire. "Uptake and resource allocation of ammonium and nitrate in temperate seagrasses Posidonia and Amphibolis." Marine Pollution Bulletin 60, no. 9 (September 2010): 1502–11. http://dx.doi.org/10.1016/j.marpolbul.2010.04.018.

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27

Nayar, S., G. J. Collings, D. J. Miller, S. Bryars, and A. C. Cheshire. "Uptake and resource allocation of inorganic carbon by the temperate seagrasses Posidonia and Amphibolis." Journal of Experimental Marine Biology and Ecology 373, no. 2 (May 2009): 87–95. http://dx.doi.org/10.1016/j.jembe.2009.03.010.

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28

Paling, E. I., and A. J. McComb. "Nitrogen and phosphorus uptake in seedlings of the seagrass Amphibolis antarctica in Western Australia." Hydrobiologia 294, no. 1 (December 1994): 1–4. http://dx.doi.org/10.1007/bf00017618.

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29

Meza-Figueroa, Diana, Joaquin Ruiz, Oscar Talavera-Mendoza, and Fernando Ortega-Gutierrez. "Tectonometamorphic evolution of the Acatlan Complex eclogites (southern Mexico)." Canadian Journal of Earth Sciences 40, no. 1 (January 1, 2003): 27–44. http://dx.doi.org/10.1139/e02-093.

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The Acatlan Complex of southern Mexico is linked to the evolution of the AppalachianCaledonian chains and records events related to the Taconian, Acadian, and Alleghanian orogenies of northeastern North America. Mafic eclogites and garnet amphibolites from two selected localities are used to partially reconstruct the tectonometamorphic evolution of this complex. Eclogites contain garnet (almandine) + CaNa pyroxene + phengitic mica + zoisiteclinozoisite + quartz ± CaNa amphibole (barroisite, katophorite) ± albitic plagioclase ± rutile. Phase and textural relationships, thermobarometric determinations, and available radiometric ages indicate that eclogite-facies metamorphism took place during the Ordovician at temperatures around 560 ± 60°C and pressures between 11 and 15 kbar (1 kbar = 100 MPa). Eclogites underwent widespread retrogression to epidote-amphibolite then greenschist facies during exhumation, most probably during Devonian times. Epidoteamphibolite facies include the critical assemblage calcic pyroxene + calcic amphibole (magnesiohornblende and pargasite) + muscovite + garnet + plagioclase + epidote ± quartz, whereas greenschist facies is defined by the assemblage actinolite + albitic plagioclase + epidote + chlorite. Thermobarometric data suggest that retrogression occurred at temperatures between 510 ± 20°C and 300 ± 25°C and pressures ranging from 6 to 3.5 kbar. The obtained PT (pressuretemperature) path suggest that the Acatlan Complex evolved in a more complex continental collisional setting, including intraoceanic arcs, than shown in previously proposed models.

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30

Hawthorne, F. C., M. Schindler, Y. Abdu, E. Sokolova, B. W. Evans, and K. Ishida. "The crystal chemistry of the gedrite-group amphiboles. II. Stereochemistry and chemical relations." Mineralogical Magazine 72, no. 3 (June 2008): 731–45. http://dx.doi.org/10.1180/minmag.2008.072.3.731.

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AbstractThe general formula of the amphiboles of this series may be written as NaxMg2(Mg(5-y)Aly,)(Si(8-z)Alz)O22(OH)2, where Mg = Mg + Fe2+ + Mn2+ and Al = Al + Fe3+ + Ti. The individual <T–O> distances are linear functions of their [4]Al content, and the [4]Al content is strongly ordered in the following way: T1B > T1A » T2B » T2A. The <M1-O>, <M2-O> and <M3–O> distances are linear functions of the mean ionic radius of their constituent cations. End-member compositions may be written as follows: A☐Mg2Mg5Si8O22(OH)2O22(OH)2; A☐Mg2(Mg3Al2)(Si6Al2)O22(OH)2; ANaMg2Mg5(Si7Al) These compositions define a plane in xyz space across which the data of Schindler et al. (2008), measured on amphiboles from amphibolites, follow a tightly constrained trajectory. Anthophyllite–gedrite amphiboles equilibrated under significantly different P-T conditions (e.g. igneous rocks, contact-metamorphic rocks) follow trends that diverge from this trajectory, with greater Na and [4]Al contents and relatively smaller [6]Al contents. Detailed examination of the local bond topology involving the A and M2 sites indicates that the maximum degree of bond-valence compensation will occur for incorporation of ANa and M2Al in the ratio 4:10, and hence 2.5 ANa = M2Al in these amphiboles. This relation closely fits the data of Schindler et al. (2008), suggesting that the variation in chemical composition in anthophyllite–gedrite amphiboles is strongly constrained by the anion bond-valence requirements of the Pnma amphibole structure. We further suggest that different compositional trends for ortho-amphiboles equilibrated under different P-T conditions are the result of the valence-sum rule operating with (different) bond-lengths characteristic of these P-T conditions.

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31

Ilnicki, S. "Variscan progradeP-Tevolution and contact metamorphism in metabasites from the Sowia Dolina, Karkonosze-Izera massif, SW Poland." Mineralogical Magazine 75, no. 1 (February 2011): 185–212. http://dx.doi.org/10.1180/minmag.2011.075.1.185.

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AbstractSeveral bodies of moderately foliated and porphyroblastic metabasites crop out on the SE side of the metamorphic cover of the Karkonosze granite within metapelites of the Sowia Dolina area (West Sudetes, Saxothuringian zone). Depending on the microstructural setting of the Ca-amphiboles in the rocks, different mineral-chemical trends have been determined for Si,XMg, AlVI,A[Na+K] which serve as semi-quantitative indicators of temperature and pressure changes. Porphyroblasts and prisms oblique to the main foliation in schistose metabasites show zoning from Mg-hornblende and actinolite to tschermakite, and then to Mg-hornblende (or actinolite). Matrix amphiboles and those in pressure shadows around some porphyroblasts have tschermakitic cores and actinolitic rims. Rarely, Ca-amphibole is accompanied in schists by late- to post-tectonic cummingtonite. Thermobarometric calculations involving empirically calibrated amphibole equilibria enable a reconstruction ofP-Tpaths for individual rocks and the unravelling of the metamorphic evolution of the metabasites. Peak metamorphic temperatures of 615–640°C and pressures of 7.3–8.2 kbar were preceded by a variably preserved earlier stage (T = 370–550°C, P = 2.8–6.2 kbar). The final metamorphic episode took place at 450–550°C and 2.5–4.8 kbar and is recorded particularly in rocks close to the Karkonosze pluton. The metabasites shed new light on the history of metamorphism in the Sowia Dolina area. The first two stages ofMP-MTmetamorphism, coeval with Variscan deformation events (continental collision, burial and subsequent exhumation), took place under epidote-amphibolite then amphibolite facies conditions. The last stage partly concurred with the final stages of Variscan deformation and overlapped the onset of thermal activity associated with the Karkonosze granite. This metamorphic event is documented by metabasites (occasionally cummingtonite-bearing) outcropping close to the granite. Finally, a prehnitebearing assemblage reflects retrograde re-equilibration under greenschist/sub-greenschist facies conditions (T<300–350°C,P<2.5–3 kbar), which might also be partly due to hydrothermal activity around the pluton.

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Soret, Mathieu, Philippe Agard, Benoît Ildefonse, Benoît Dubacq, Cécile Prigent, and Claudio Rosenberg. "Deformation mechanisms in mafic amphibolites and granulites: record from the Semail metamorphic sole during subduction infancy." Solid Earth 10, no. 5 (October 23, 2019): 1733–55. http://dx.doi.org/10.5194/se-10-1733-2019.

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Abstract. This study sheds light on the deformation mechanisms of subducted mafic rocks metamorphosed at amphibolite and granulite facies conditions and on their importance for strain accommodation and localization at the top of the slab during subduction infancy. These rocks, namely metamorphic soles, are oceanic slivers stripped from the downgoing slab and accreted below the upper plate mantle wedge during the first million years of intraoceanic subduction, when the subduction interface is still warm. Their formation and intense deformation (i.e., shear strain ≥5) attest to a systematic and transient coupling between the plates over a restricted time span of ∼1 Myr and specific rheological conditions. Combining microstructural analyses with mineral chemistry constrains grain-scale deformation mechanisms and the rheology of amphibole and amphibolites along the plate interface during early subduction dynamics, as well as the interplay between brittle and ductile deformation, water activity, mineral change, grain size reduction and phase mixing. Results indicate that increasing pressure and temperature conditions and slab dehydration (from amphibolite to granulite facies) lead to the nucleation of mechanically strong phases (garnet, clinopyroxene and amphibole) and rock hardening. Peak conditions (850 ∘C and 1 GPa) coincide with a pervasive stage of brittle deformation which enables strain localization in the top of the mafic slab, and therefore possibly the unit detachment from the slab. In contrast, during early exhumation and cooling (from ∼850 down to ∼700 ∘C and 0.7 GPa), the garnet–clinopyroxene-bearing amphibolite experiences extensive retrogression (and fluid ingression) and significant strain weakening essentially accommodated in the dissolution–precipitation creep regime including heterogeneous nucleation of fine-grained materials and the activation of grain boundary sliding processes. This deformation mechanism is closely assisted with continuous fluid-driven fracturing throughout the exhumed amphibolite, which contributes to fluid channelization within the amphibolites. These mechanical transitions, coeval with detachment and early exhumation of the high-temperature (HT) metamorphic soles, therefore controlled the viscosity contrast and mechanical coupling across the plate interface during subduction infancy, between the top of the slab and the overlying peridotites. Our findings may thus apply to other geodynamic environments where similar temperatures, lithologies, fluid circulation and mechanical coupling between mafic rocks and peridotites prevail, such as in mature warm subduction zones (e.g., Nankai, Cascadia), in lower continental crust shear zones and oceanic detachments.

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Simakin, A. G., V. N. Devyatova, T. P. Salova, and O. Yu Shaposhnikova. "Experimental study of amphibole crystallization from the highly magnesian melt of Shiveluch volcano." Петрология 27, no. 5 (August 18, 2019): 476–95. http://dx.doi.org/10.31857/s0869-5903275476-495.

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The paper reports results of an experimental study of amphibole crystallization from the highly magnesian andesite melt of Shiveluch volcano, Kamchatka. The experiments were carried out in IHPV at 300 MPa and 940–980°С in iron-saturated platinum capsules, using rapid quenching and temperature oscillations (in some experiments). The redox state of iron in the system was measured before and after the experiments using Mössbauer spectroscopy. The maximum size of the experimental amphibole crystals (up to 200 μm) was close to those of natural amphibole phenocrysts in the volcanic rocks of Shiveluch volcano. The experimental data show that the content of octahedrally coordinated Al (Al6) in the amphibole considerably varies with small variations in the intensive parameters (P, T, and fO2) and composition of the melt, and the maximum Al6 concentration can be evaluated only by using a reasonably large dataset of amphibole analyses. A modified 13eCNK method is suggested to calculate the values of Al6 and Fe3+/Fe2+ with regard for the Ti concentration and the probable partial transfer of Mg into site B in high-Mg amphibole. Calculations with this modified technique yield lower Fe3+/Fe2+ and higher Al6 values. Our experimental data show that the temperature of amphibole liquidus crystallization decreases from about 990 to 960°C when the oxygen fugacity drops from NNO + 1.5 to NNO + 0.4. In view of this, the transition from amphibole-bearing to anhydrous mineral assemblage in the magmas of Shiveluch volcano might have been caused by variations of the oxygen fugacity but not water. The application of our geobarometer to amphiboles from Shiveluch volcano (extrusions Krasnaya and Karan) yields the highest pressure estimate of above 1 GPa, corresponding to the P-T conditions of the melting of garnet-bearing amphibolite in the lower crust.

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Seddon, S., and AC Cheshire. "Photosynthetic response of Amphibolis antarctica and Posidonia australis to temperature and desiccation using chlorophyll fluorescence." Marine Ecology Progress Series 220 (2001): 119–30. http://dx.doi.org/10.3354/meps220119.

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35

Verduin, J. J., and J. O. Backhaus. "Dynamics of Plant–Flow Interactions for the Seagrass Amphibolis antarctica: Field Observations and Model Simulations." Estuarine, Coastal and Shelf Science 50, no. 2 (February 2000): 185–204. http://dx.doi.org/10.1006/ecss.1999.0567.

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36

Neumayr, P., J. R. Ridley, and D. I. Groves. "sPhysicochemical conditions of fluid–wall rock interaction at amphibolite-facies conditions in two Archean hydrothermal gold deposits in the Mt. York District, Pilbara Craton, Western Australia." Canadian Journal of Earth Sciences 32, no. 7 (July 1, 1995): 993–1016. http://dx.doi.org/10.1139/e95-083.

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Synamphibolite facies Archean gold mineralization in the Mt. York District, Pilbara Craton, Western Australia, is hosted in metamorphosed banded iron formation (Main Hill–Breccia Hill prospect), amphibolites, and ultramafic schists (Zakanaka prospect). Mineralization at Main Hill occurs in quartz breccias with sulfide matrices and in altered wall rock adjacent to quartz–biotite–amphibole ± clinopyroxene veins. Alteration associated with quartz veins is zoned, with biotite—pyrrhotite vein selvedges and a distal calcic-amphibole, arsenopyrite–lôllingite zone. Hydrothermal biotite and actinolite have highest Mg/(Mg + Fe) ratios where associated with abundant sulfarsenides in the distal alteratin zone. Whole-rock geochemical analyses and calculated metasomatic reactions indicate the addition of K, Al, S, As, Au, Ag, and Ni during hydrothermal alteration. Mineralization at Zakanaka is characterized by a broad wall rock alteration halo of biotite–amphibole, and zoned quartz–calc silicate veins proximal to ore. Wall rock adjacent to the veins contains pyrrhotite, pyrite, and gold. The alteration is explained by K-metasomatism distal to mineralization and K and Ca metasomatism proximal to mineralization. Balanced metasomatic reactions and mass-balance calculations indicate addition of K and depletion of Na, Ca, Mg, and Fe in distal alteration zones and addition of K, Ca, Mg, Fe, and Ti in proximal zones. Gold precipitation at both prospects occurred through loss of S, and possibly As, from the ore fluid during sulfidation reactions with Fe-rich amphiboles and biotites to form Mg-enriched equivalents and sulfarsenides. Changes in the oxidation state of the ore fluid may have enhanced gold precipitation, though pH changes are unlikely to have been important. The controls on mineralization are thus similar to those at many lower temperature, mesothermal deposits. The lack of consistently increasing Mg ratios of calc-silicate phases with increasing intensity of alteration and sulfidation at Main Hill may be the result of coupled substitutions in amphiboles and biotites during infiltration of a fluid with high-S, but low-As, activities.

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McMahon, Kathryn, Paul S. Lavery, and Michael Mulligan. "Recovery from the impact of light reduction on the seagrass Amphibolis griffithii, insights for dredging management." Marine Pollution Bulletin 62, no. 2 (February 2011): 270–83. http://dx.doi.org/10.1016/j.marpolbul.2010.11.001.

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38

Carruthers, T. J. B., and D. I. Walker. "Light climate and energy flow in the seagrass canopy of Amphibolis griffithii (J.M. Black) den Hartog." Oecologia 109, no. 3 (February 7, 1997): 335–41. http://dx.doi.org/10.1007/s004420050091.

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McMahon, Kathryn, and Paul S. Lavery. "Canopy-scale modifications of the seagrass Amphibolis griffithii in response to and recovery from light reduction." Journal of Experimental Marine Biology and Ecology 455 (June 2014): 38–44. http://dx.doi.org/10.1016/j.jembe.2014.02.015.

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40

Green, Carlin J., Robert R. Seal, Nadine M. Piatak, William F. Cannon, Ryan J. McAleer, and Julia A. Nord. "Metamorphic amphiboles in the Ironwood Iron-Formation, Gogebic Iron Range, Wisconsin: Implications for potential resource development." American Mineralogist 105, no. 8 (August 1, 2020): 1259–69. http://dx.doi.org/10.2138/am-2020-7211.

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Abstract The Paleoproterozoic Ironwood Iron-Formation, a Superior-type banded iron formation located in the western Gogebic Iron Range in Wisconsin, is one of the largest undeveloped iron ore resources in the United States. Interest in the development of this resource is complicated by potential environmental and health effects related to the presence of amphibole minerals in the Ironwood, a consequence of Mesoproterozoic contact metamorphism. The presence of these amphiboles and their contact metamorphic origin have long been recognized; however, recent interest in this resource has highlighted the lack of detailed knowledge on their distribution, mineral chemistry, and morphology. Optical microscopy, X-ray diffraction, scanning electron microscopy, and electron microprobe analysis were utilized to investigate the origin, distribution, morphology, and chemistry of amphiboles in the Ironwood. Amphibole is present in the western portion of the study area due to regional-scale contact meta-morphism associated with the intrusion of the 1.1 Ga Mellen Intrusive Complex. Locally amphibole is also present, adjacent to diabase and/or gabbro dikes and sills in the lower-grade Ironwood in the eastern portion of the study area. In both localities, amphiboles in the Ironwood most commonly developed in massive and prismatic habits, and locally assumed a fibrous habit. Fibrous amphiboles were recognized locally in the two potential ore zones of the Ironwood but were not observed in the portion likely to be waste rock. Massive and prismatic amphiboles show a wide range of Mg# [molar Mg/(Mg+Fe2+)] values (0.06 to 0.87), whereas Mg# values of fibrous amphiboles are restricted from 0.14 to 0.35. Factors that influenced the compositional variability of amphiboles in the Ironwood may have included temperature of formation, morphology, bulk chemistry of the iron formation, and variations in prograde and retrograde metamorphism. The presence of amphiboles in the Ironwood is a known issue that will need to be factored into any future mine plans. This study provides an objective assessment of the distribution and character of amphiboles in the Ironwood to aid all decision-makers in any future resource development scenarios.

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41

Mogessie, A., K. Ettinger, and B. E. Leake. "AMPH-IMA04: a revised Hypercard program to determine the name of an amphibole from chemical analyses according to the 2004 International Mineralogical Association scheme." Mineralogical Magazine 68, no. 5 (October 2004): 825–30. http://dx.doi.org/10.1180/0026461046850223.

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AbstractIn 2004, the International Mineralogical Association (IMA) amended the IMA 97 amphibole classification and nomenclature scheme byadding a fifth group to include the recently discovered B(LiNa) amphiboles ferriwhittakeriite and ferri-ottoliniite, which cannot be fitted into the four major amphibole groups. New root-names such as sodic-pedrizite in the Mg-Fe-Mn-Li group and obertiite and dellaventuraite in the sodic group along with two new prefixes, parvo and magno have also been added. As result it has become necessary to modify the AMPH-IMA97 amphibole-naming program. The new program (AMPH-IMA04) allows single input or automatic input of as many amphibole analyses as are available following a set input format. Any of three different calculation schemes for dealing with an amphibole analysis can be chosen: (1) complete chemical analyses can be calculated to 24(O,OH,F,Cl); (2) analyses with determined FeO and Fe2O3, MnO and Mn2O3 but without H2O can be calculated to 23(O); and (3) electron microprobe analyses with only total Fe determined and without H2O can be calculated to 23(O) with IMA97-recommended normalization for Fe3+ and Fe2+ values. In addition a stoichiometric calculation of Mn2+ and Mn3+ is considered and implemented for the Mn-bearing sodic amphiboles in order to take care of electron microprobe analyses of such amphiboles where the total Mn is given as Mn2+.

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Kullerud, Kåre. "Chlorine-rich amphiboles: interplay between amphibole composition and an evolving fluid." European Journal of Mineralogy 8, no. 2 (April 26, 1996): 355–70. http://dx.doi.org/10.1127/ejm/8/2/0355.

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43

ÇELİK, ÖMER FARUK, MICHEL DELALOYE, and GILBERT FERAUD. "Precise 40Ar–39Ar ages from the metamorphic sole rocks of the Tauride Belt Ophiolites, southern Turkey: implications for the rapid cooling history." Geological Magazine 143, no. 2 (February 28, 2006): 213–27. http://dx.doi.org/10.1017/s0016756805001524.

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The Tauride Belt Ophiolites in southern Turkey are located on both sides of the E–W-trending, Mesozoic Tauride carbonate platform. They comprise the Lycian, Antalya, Beyşehir, Mersin, Alihoca and Pozantı-Karsantı ophiolites from west to east. Each ophiolite has a metamorphic rock unit either at the base of the peridotites or in the mélange units. The metamorphic sole rocks generally consist of amphibolite at the top and near the contact with the overlying tectonized harzburgite of the ophiolites, and mica schists mostly at the base, near the tectonic contact with the underlying ophiolitic mélange. 40Ar–39Ar measurements from the metamorphic sole rocks of the Lycian, Antalya and Beyşehir ophiolites are the first precise ages dating intra-oceanic thrusting and the cooling age history during the closure of the Neotethyan Ocean. Amphiboles and white micas from the metamorphic sole rocks of the ophiolites yielded 40Ar–39Ar ages between 90.7 ± 0.5 Ma and 93.8 ± 1.7 Ma and between 91.2 ± 2.3 Ma and 93.6 ± 0.8 Ma, respectively. Hornblende plateau ages from the amphibolites of the Lycian ophiolites (near Köyceǧiz) agree with those of Antalya, indicating that they were metamorphosed simultaneously in the Neotethyan Ocean. The white micas display plateau ages concordant with the amphiboles from the same units in Köyceǧiz and Yeşilova (Lycian ophiolites) and from the Pozantı-Karsantı ophiolite, suggesting that the metamorphic sole rocks were rapidly cooled after their generation.

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Leake, Bernard E., Alan R. Woolley, C. E. S. Arps, W. D. Birch, M. C. Gilbert, J. D. Grice, F. C. Hawthorne, et al. "Nomenclature of Amphiboles; Report of the Subcommittee on Amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names." Mineralogical Magazine 61, no. 405 (April 1997): 295–310. http://dx.doi.org/10.1180/minmag.1997.061.405.13.

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AbstractThe International Mineralogical Association's approved amphibole nomenclature has been revised in order to simplify it, make it more consistent with divisions generally at 50%, define prefixes and modifiers more precisely and include new amphibole species discovered and named since 1978, when the previous scheme was approved. The same reference axes form the basis of the new scheme and most names are little changed but compound species names like tremolitic hornblende (now magnesiohornblende) are abolished and also crossite (now glaucophane or ferroglaucophane or magnesioriebeckite or riebeckite), tirodite (now manganocummingtonite) and dannemorite (now manganogrunerite). The 50% rule has been broken only to retain tremolite and actinolite as in the 1978 scheme so the sodic calcic amphibole range has therefore been expanded. Alkali amphiboles are now sodic amphiboles. The use of hyphens is defined. New amphibole names approved since 1978 include nyböite, leakeite, kornite, ungarettiite, sadanagaite and cannilloite. All abandoned names are listed. The formulae and source of the amphibole end member names are listed and procedures outlined to calculate Fe3+ and Fe2+ when not determined by analysis.

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45

Gartner, Adam, Paul S. Lavery, and Hector Lonzano-Montes. "Trophic implications and faunal resilience following one-off and successive disturbances to an Amphibolis griffithii seagrass system." Marine Pollution Bulletin 94, no. 1-2 (May 2015): 131–43. http://dx.doi.org/10.1016/j.marpolbul.2015.03.001.

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46

Burnell, O. W., S. D. Connell, A. D. Irving, J. R. Watling, and B. D. Russell. "Contemporary reliance on bicarbonate acquisition predicts increased growth of seagrass Amphibolis antarctica in a high-CO2 world." Conservation Physiology 2, no. 1 (November 27, 2014): cou052. http://dx.doi.org/10.1093/conphys/cou052.

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47

Borowitzka, MA, RC Lethbridge, and L. Charlton. "Species richness, spatial distribution and colonisation pattern of algal and invertebrate epiphytes on the seagrass Amphibolis griffithii." Marine Ecology Progress Series 64 (1990): 281–91. http://dx.doi.org/10.3354/meps064281.

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48

Walker, D. I., and A. J. McComb. "Salinity response of the seagrass Amphibolis antarctica (Labill.) Sonder et Aschers.: an experimental validation of field results." Aquatic Botany 36, no. 4 (April 1990): 359–66. http://dx.doi.org/10.1016/0304-3770(90)90052-m.

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49

Korinevsky, V. G., K. A. Filippova, V. A. Kotlyarov, E. V. Korinevsky, and D. A. Artemyev. "Trace-elements in minerals from unusual rocks of the Southern Urals." LITHOSPHERE, no. 2 (June 12, 2019): 269–92. http://dx.doi.org/10.24930/1681-9004-2019-19-2-269-292.

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Research subject. This articles presents the data obtained in the course of 75 analytical studies on a wide range of minerals (amphiboles, pyroxenes, garnets, spinels, olivines, anorthites, corundums, epidotes, apatites, clinochlore, dolomite, calcite, zircon) contained in igneous and metamorphic Southern Urals rocks. In addition, information is provided about the content of trace elements, including rare earth (REE) ones, in these rocks. The data on the content of trace elements in some minerals are presented for the first time (höegbomite, sapphirine, zoisite, clinozoisite, gedrite, cummingtonite, anthophyllite, potassium-magnesiohastingsite). Materials and methods. A petrographic analysis of rocks containing the minerals under study was carried out. A particular attention was paid to petrographic analysis of rocks containing the minerals under study was carried out. A particular attention was paid to “fresh” rocks, containing the mineral under study which rarely occur in the Urals. These rocks feature inclusions of serpentinite melange in the form of plates and lenses among the metamorphic strata (schists, gneisses, and amphibolites) and are characterized by the preservation of primary structures, relative chemical homogeneity, as well as the presence of simultaneous growth surfaces between most minerals. Of particular research interest were minerals from rocks, the composition of which had been relatively poorly studied (pyroxene-amphibole anorthite gabbro and gabbro-amphibolites, scapolite rocks, hornblendite, gedrite-cummingtonite-anthophyllitic crystallo-schists and amphibolites, ore-less carbonatites). The composition of mineral samples was determined using a scanning microscope REMMA-202 M equipped with an energy dispersive console and a mass-spectrometer Agilent 7700x (ICP-MS and LA-ICP-MS methods). Results. Petrographic characteristics of the rocks containing the minerals under study are given. The geographical coordinates of locations, where mineral sampling was performed, are provided. The content of trace elements is shown to vary greatly within related species of minerals (amphiboles, garnets, pyroxenes, olivines, epidotes, spinels, mica, etc.), with the fluctuations being independent of the alkalinity of host rocks or their geological nature.Conclusions. For the first time, a significant role of zoisite and clinozoisite in the process of concentrating trace elements, including REE, has been revealed. The role of apatite as one of the main mineral concentrators of REE has not been confirmed either in the main and ultrabasic rocks, or in some calcite-dolomite carbonatites.

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Pearce, N. J. G. "Zirconium-bearing amphiboles from the Igaliko Dyke Swarm, South Greenland." Mineralogical Magazine 53, no. 369 (March 1989): 107–10. http://dx.doi.org/10.1180/minmag.1989.053.369.12.

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AbstractSodic-calcic and alkali amphiboles from benmoreitic members of the Igaliko Dyke Swarm contain up to 4.13 wt. % ZrO2. It is proposed that Zr enters the amphiboles by a coupled substitution of(where C = octahedral site and T = tetrahedral site) to produce the richest Zr-bearing amphiboles so far identified, with compositions ranging up toThese amphiboles crystallize at a late stage from magmas which were Zr-rich, highly peralkaline and hydrous, with an fo2 close to the synthetic QMF buffer. The incorporation of Zr in to the amphibole is a consequence of the failure of other Zr-bearing phases (such as zircon, baddeleyite, eudialyte) to crystallize.

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