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Carlsbad twin law

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Journal Article
Published: 01 January 2010
European Journal of Mineralogy (2010) 22 (1): 139–145.
... laws (Albite, Carlsbad, Albite-Carlsbad, Pericline, Baveno- d , - l , Prismatic- d , - l , and Periclinic twins), whose development and hierarchy can be described with the triad theory of L.A. Vardanianz. There are two genetic types of twins: (1) post-growth twins resulted from the thermal stress...
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Journal Article
Published: 01 October 1968
American Mineralogist (1968) 53 (9-10): 1579–1602.
... the Albite law and penetration twins of two individuals after the X-Carlsbad law. Both twin types contain the hourglass structure. Lattice parameters of the albite are: a = 8.1380 Å, b = 12.7881 Å, c = 7.1571 = Å, α = 94.229°, β= 116.605°, γ = 87.807°. Both optical and lattice parameters indicate that the Al...
Image
Development of the complex <span class="search-highlight">twin</span> intergrowth in the crystal-lapilli from the...
Published: 01 January 2010
Fig. 1. Development of the complex twin intergrowth in the crystal-lapilli from the GTFE. (a) First stage – formation of an Albite-Carlsbad triad; (b) Schematic outline of the triad; (c) Second stage – adhering of the second order triads to the initial triad in accordance with the Baveno
Journal Article
Published: 01 February 1992
American Mineralogist (1992) 77 (1-2): 121–125.
... of layers by c/2 are proposed to explain the phenomenon: (l) twinning by the Carlsbad law, (2) coesite-like distortion, and (3) faulting in the (100) plane. A comparison of observed and calculated peak widths showed that the third model was not applicable. The trend in the change in lattice parameters...
Journal Article
Published: 01 January 2019
European Journal of Mineralogy (2019) 31 (1): 99–110.
... the two twins may be very difficult. The deviation from monoclinicity in Erebus anorthoclase is strongly enhanced by the anisotropy of growth for the {110} pinacoid versus the {1 1 ̅ 0} pinacoid. In that case, the X and the Carlsbad laws do not give the same twin shapes. For the Carlsbad B...
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Journal Article
Published: 01 January 2013
American Mineralogist (2013) 98 (1): 41–52.
... interpreted as erroneous data. However, the majority of determinations group in a relatively clear unique orientation of the c axis and the two alternative orientations of both a and the b axes ( Fig. 5 ). For the a axis the two directions are observed conforming to the Carlsbad twin law, one of them dominant...
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Journal Article
Published: 27 November 2017
European Journal of Mineralogy (2017) 29 (6): 939–947.
... + (buddingtonite). They frequently occur as twins, either as reflection twins – the most common laws being Albite (0 1 0), Manebach (0 0 1) and Baveno (0 2 1) – or as rotation twins – mainly Ala [1 0 0], Pericline [0 1 0] and Carlsbad [0 0 1]; several other twin laws have been reported but are rarer or doubtful...
FIGURES
Journal Article
Published: 01 February 2015
American Mineralogist (2015) 100 (2-3): 385–395.
... only one type of twinning and 20 contain more than one type ( Table 2 ). Pericline and Carlsbad twins are the two most commonly observed twin laws, with 50 and 21 examples of each, respectively ( Table 3 ). There are also 19 examples of twinning that involve a compound Pericline-Carlsbad twin...
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Journal Article
Published: 01 February 2009
Mineralogical Magazine (2009) 73 (1): 119–130.
...-monclinic transition shows an activation energy of 101±12 kcal, less than, but still close to, that observed for Al-Si order in anorthite. TEM investigation shows antiphase domains and Carlsbad twins the size of which increases with annealing. IR spectroscopy was performed on a series of samples of An 30...
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Journal Article
Published: 01 July 2019
European Journal of Mineralogy (2019) 31 (4): 785–790.
... in melilite ( Marzouki et al. , 2014a ), aragonite ( Marzouki et al. , 2015 ), marcasite ( Nespolo & Souvignier, 2015a ), cassiterite/rutile ( Nespolo & Souvignier, 2015b ), forsterite ( Azevedo & Nespolo, 2017 ), chalcostibite ( Nespolo, 2018 ) as well as the Carlsbad twin in orthoclase...
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Journal Article
Published: 01 December 2007
Mineralogical Magazine (2007) 71 (6): 715–718.
..., and is colorless. It may be distinguished from quartz because it is biaxial. K-Feldspars do not have twinning”. But they do! Microcline and anorthoclase have polysynthetic twinning on the same laws as plagioclase, and all feldspars can develop Carlsbad twins. To discover the chemical range of the subdivisions...
Journal Article
Published: 01 September 2016
American Mineralogist (2016) 101 (9): 2118–2122.
.... It is observed a gradual conversion of the TL signal from a very asymmetric peak with exponential rise and power law decay in microcline and orthoclase, where a τ coefficient in log-log plots decreases with twin/domain size, to a more symmetric signal in a partially disordered sanidine, up to reach a completely...
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Journal Article
Published: 01 August 1948
Journal of Sedimentary Research (1948) 18 (2): 74–78.
...- dorite, is the chief feldspar in schists. It has well developed albite with Carlsbad twinning, extinction angle of about 30 degrees (according to albite law), and numerous inclusions of zircon and ruffle. Some of the fragments disclose undulose extinction and bent lamellae. SUMMARY The mineral content...
Journal Article
Published: 01 September 2018
European Journal of Mineralogy (2018) 30 (5): 967–973.
... , G. ( 2006 ): The derivation of twin laws in non-merohedric twins − Application to the analysis of hybrid twins . Acta Crystallogr. , A62 , 336 – 349 . Nespolo , M. & Ferraris , G. ( 2009 ): A survey of hybrid twins in non-silicate minerals . Eur. J. Mineral. , 21...
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Journal Article
Published: 01 November 2007
Scottish Journal of Geology (2007) 43 (2): 143–153.
... of alkali feldspar, clinopyroxene, feldspathoids, magnetite and apatite. The tabular feldspars, up to c. 8 mm long, have highly sericitized cores and water-clear outer zones of sanidine containing crystallites of apatite. The sanidine displays no discernible exsolution and has simple carlsbad twins...
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Journal Article
Journal: Geosphere
Published: 05 January 2023
Geosphere (2023) 19 (1): 19–46.
.... (B) Hand sample of Walker Top Granite from the Brushy Mountains with garnet inclusions rimmed by biotite in microcline megacrysts (white arrows). The light-gray microcline megacrysts are weakly aligned, and Carlsbad twinning and white myrmekite rims are readily observable. (C) Pavement outcrop...
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Journal Article
Published: 01 June 2010
Mineralogical Magazine (2010) 74 (3): 529–551.
.... There are about 20 twin laws but only five are common. The large number of twin laws is a consequence of the high pseudosymmetry of the feldspar structure. For example, an individual Albite twin in PL is close to monoclinic in symmetry, and a pair of Albite twins has overall monoclinic symmetry. Simple Carlsbad...
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Journal Article
Published: 18 January 2024
The Canadian Journal of Mineralogy and Petrology (2024) 62 (1): 3–41.
.... The plagioclase is exsolved (antiperthite), and this sample lacks the larger, Carlsbad-twinned crystals seen in other samples ( cf. Figs. 11 and 12 ). As such, the relatively uniform grain size in this case may reflect static recrystallization. Figure 11 is from sample #09, a coarse-grained norite...
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Published: 01 January 2013
EISBN: 9780903056434
... twins on the Albite and/or Pericline laws are the most common of all, Albite twinning rarely being absent, and twins on other laws (e.g. Ala, Albite-Carlsbad, Albite-Ala) are not uncommon; see Table % 35 , p. 265. Pericline and Albite twinning commonly occur in one crystal, and other combinations of two...
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Journal Article
Published: 01 June 1967
Bulletin of Canadian Petroleum Geology (1967) 15 (2): 138–149.
.... STRATIGRAPHIC POSITION : Ten feet above the base of Tranquille beds (Type Locality) . PETROGRAPHIC DATA .. Oligoclase : size minus 100 plus 200 mesh ; grains clear, unaltered, and twinned by the albite and carlsbad-albite law . Compositio n determined by extinction perpendicular to 010 and by the Carlsbad...