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Plagioclase from
Thingmuli, Fljótsdalshérað, Múlaþing, Eastern Region, Iceland


Locality type:Volcano
Classification
Species:'Plagioclase' (not an IMA approved species)
Formula:(Na,Ca)[(Si,Al)AlSi2]O8
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Plagioclase data
Locality Data:Click here to view Thingmuli, Fljótsdalshérað, Múlaþing, Eastern Region, Iceland
Data Identifiers
Mindat Occurrence Record ID:770481
Long-form Identifier:1:3:770481:9
GUID (UUID V4):d2f0e5b9-44bc-47d2-9bff-1d0207ea330f
Nearest other occurrences of Plagioclase
13.8km (8.6 miles) Reydarfjördur drill hole, Reyðarfjörður, Fjarðabyggð, Eastern Region, Iceland
67.5km (41.9 miles) Austurhorn Intrusion, Hornafjörður, Southern Region, Iceland
References
Reference Search (possible matching items)
Journal (article/letter/editorial)
The Petrology of Thingmuli, a Tertiary Volcano in Eastern Iceland by I. S. E. CARMICHAEL Department of...of Tertiary flood-basalts so prominent in eastern Iceland has been interrupted from time to time by central...1959) there is one of these central volcanoes (Thingmuli), and like the Breiddalur volcano to the south-east...enveloping flood-basalts. The main lava-types found at Thingmuli are olivine-tholeiite, olivine-free tholeiite...lava types. The. relatively infrequent groups of ICELAND 1 Present address: Department of Geology and Geophysics
Journal (article/letter/editorial)
Springer-Verlag 1973 Magmatic Evolution of Hekla, Iceland* W. Scott Baldridge**, Thom~s 1%. McGetchin, Fred...separation of magnesian olivine, augite, and calcic plagioclase from an olivine tholeiite parent, producing an...ratios of the lavas and from compositions of the plagioclase phenocrysts the water pressure of the basaltic...crystallization in a shallow magma chamber. Introduction Iceland is situated on a broad platform astride the mid-Atlantic...o r t h e r n Atlantic Ocean (Fig. 1). Within Iceland the mid-Atlantic ridge is app a r e n t l y offset
Journal (article/letter/editorial)
assemblages olivine-calcic plagioclase-groundmass, (olivine-)plagioclase-clinopyroxenegroundmass, and...and (olivine-)plagioclase-clinopyroxene-glass. The residual glass can be equated in composition with tholeiitic...increased Fe/Mg ratios, and a more sodic normative plagioclase, and thus are appropriate to tholeiitic andesite...primarily by the early separation of olivine and plagioclase which, when associated with clinopyroxene as...beautifully fresh olivine (Fa22_26) and zoned plagioclase of slightly later crystallization. The final
Journal (article/letter/editorial)
Tertiary Lavas of Eastern Iceland and their Significance with respect to the Iceland Geochemical Anomaly...sciences demonstrating the anomalous nature of Iceland with respect to the surrounding mid-ocean rift...wider spectrum of basalt compositions exist in the Iceland area in comparison to the rest of the Mid-Atlantic...isotopes of Sr and Pb are particularly abundant in Iceland (Schilling, 1973; Hart et al., 1973; Sun et al... A. WOOD GEOLOGICAL SUMMARY OF EASTERN ICELAND The eastern Iceland lava pile has an approximate stratigraphic
Journal (article/letter/editorial)
Jorullo, Mexico, (2) an olivine tholeiite from Iceland, and (3) an "olivine boninite" from a marginal...spinel (chromite); olivine appears at 1,260 ~ C. Plagioclase precipitates at 1,192 ~ C, and both low-Ca pyroxene...84 94 104 119 129 123 I I I I I I 1 plagioclase mole % An olivine mole % Fo mode volume % ...Calculated mineral proportions and olivine and plagioclase compositions for the equilibrium crystallization...values while the measured An-contents of the plagioclase seem to define a compositional trend which does
Journal (article/letter/editorial)
AMSTERDAM K-Ar AGES OF THE OLDEST EXPOSED ROCKS IN ICELAND S. MOORBATH Department of Geology and Mineralogy...The University Research Institute, Reyk/avik, Iceland and R. GOODWIN Department of Geology and Mineralogy...oldest exposed lavas in Iceland. The mean values are 12.5 + 0.2 m.y. for eastern Iceland and 16.0 4- 0.3 m...m.y. for northwestern Iceland, or Middle Miocene. The significance of these ages is discussed in relation...production. Several additional age determinations from Iceland are presented which supplement and confirm previously
Journal (article/letter/editorial)
nsmicrophenocrysts of augite, h ypersthene, plagioclase and olivine,andgroundmass crystalsof acicularplagioclase...containsmicrophenocrystsof ferroaugite,ferrohypersthene and plagioclase , and groundmass crystalsof acicular plagioclaseand...hornblende-augite andesite which contain abundant plagioclase and pyroxene phenocrysts. They are mostly tholeiitic...augite, hypersthene and unzoned plagioclase (An 82), and of acicular plagioclase (An 55), minute 1983). grains...xenoliths of basalt which carries lath-shaped plagioclase (An 72) and small groundmass pigeonite in the
Journal (article/letter/editorial)
more basic members is olivine-clinopyroxene-plagioclase-opaques-(glass). Petrographic criteria that characterize...manifestations of Tertiary volcanic activity in eastern Australia, the volcanic rocks extending approximately...regional aspects of Tertiary volcanic activity in eastern Australia. 2. PETROGRAPHY Table I lists 16 analyses...atom per cent) and plagioclase (An54 mol. per cent) in a groundmass of plagioclase, clinopyroxene (2Vy...augite in a hyalopilitic groundmass containing plagioclase and augite (Richards, op. cit., p. 161). A brief
Journal (article/letter/editorial)
Rocks from the Kroksfjordur Central Volcano, NW Iceland by K. JONASSON 1 *, P. M. HOLM 1 , AND A. K. PEDERSEN...and higher in Ca and Al than other rocks from Iceland with comparable silica percentages. They are significantly...rocks in Iceland compared with the mid-Atlantic ridge. The volume of exposed silicic rocks in Iceland amounts...in the axial rift zones (Saemundsson, 1978) of Iceland are tholeiitic (Jakobsson, 1972), closely comparable...rocks from the Tertiary Thingmuli volcano (Carmichael, 1964, 1967a) in eastern Iceland. These rocks typically
Journal (article/letter/editorial)
196? THE MINERALOGY OF THINGMULI, A TERTIARY VOLCANO IN EASTERN ICELAND IaN S. E. Canlrrcn.r.or-,...which make up a Tertiary central volcano in eastern Iceland have been examined mineralogically with the...tholeiites and basaltic-andesites. The groundmass plagioclase becomes progressively more sodic in the basalts...types forming part of one of these volcanoes, Thingmuli, are olivine-tholeiite, olivine-free tholeiite...phenocrysts of which plagioclase is predominant. Their mineralogy is simple, as pyroxene,plagioclase,occasionalolivine
Journal (article/letter/editorial)
that followed by the Thingmuli, Icelandic magmas (Carmichael, 1964). Both the Thingmuli and the experimental...the crystallization of olivine, pyroxene, and plagioclase, and a later SiO2 enrichment primarily as a result...present in such areas of the oceanic crust as Iceland (Carmichael, 1964; Walker, 1966; Sigvaldson, 1974;...graphite-methane hydrogen buffer. c 0 = olivine; P = plagioclase; Cpx = calcium-rich pyroxene; Lpx = low-calcium...representative compositions of the minerals olivine, plagioclase and pyroxene analyzed in the 1 kb series of experiments
Journal (article/letter/editorial)
Petrology of the Western Reykjanes Peninsula, Iceland by S. P. JAKOBSSON 1 , J. JONSSON 2 ,artrf F. SHIDO...mineralogy with chromite, olivine (Fo 89) and plagioclase (An 90) as phenocrysts and may represent a primary...mantle. Simultaneous crystallization of olivine, plagioclase and augite to form glomerocrysts in the fissure... T w o main features of the Recent basalts of Iceland are first, the active volcanic belts can be divided...tholeiitic zones reaches a maximum range in central Iceland. The variation has been demonstrated for the submarine
Journal (article/letter/editorial)
formation of intermediate and silicic melts in Iceland. The new data define two compositional tholeiitic...silicic rocks with c. 1 wt% MgO, as well as sodic plagioclase and hedenbergite phenocrysts. A low-iron trend...3–5 wt% FeO at c. 1 wt% MgO, which is typical of Iceland but higher than MORB compositions. The most evolved...therefore, should be avoided. Keywords Thingmuli volcano  Iceland  Rhyolite  Basalt  Intermediate rocks...plutonic rocks make up about 10 % of the crust in Iceland (Walker 1966; Sæmundsson 1979) and are often studied
Journal (article/letter/editorial)
features such as cotectic crystallization of plagioclase and the onset of liquid immiscibility, the latter...remarkable correspondence of the Skaergaard and Thingmuli pyroxene fractionation trends. THE problem of...Carmichael (1967) who pointed out that at Thingmuli in Iceland, although a single pyroxene phenocryst phase...miscibility gap (fig. 1). Carmichael suggested that the Thingmuli trends might be explained by the more Fe-rich...coarsegrained centre follows the early part of the Thingmuli phenocryst trend, while in the chilled margins
Journal (article/letter/editorial)
andesites are characterized by phenocrysts of plagioclase, orthopyroxene, clinopyroxene and titanomagnetite...near-surface fractionation, with the dominance of plagioclase in the crystal residuum producing an iron-rich...r i t i c , w i t h p h e n o c r y s t s of plagioclase, clinopyroxene, o r t h o p y r o x e n e a n...distinctive feature of the Talasea series. Feldspars Plagioclase is the only feldspar in the lavas from Talasea;...is crystal-rich. Inclusions (mostly glass) in plagioclase are frequent and occur both regularly and haphazardly
Journal (article/letter/editorial)
involves dominantly crystallization of olivine and plagioclase, with pyroxene fractionation playing a minor...iron-titanium oxides and apatite accompanies olivine and plagioclase extraction and leads to silica enrichment, with...Hillebrand of a Recent lava from the Cinder Buttes region, now included in the Craters of the Moon National...shown to be unrepresentative of the basalts of the region lying to the south. Later, Washington [4] published...plateau basalts. In the course of his studies of the region Powers [5a] noted the petrographic character of
Journal (article/letter/editorial)
as the Aleutian-Alaskan and Kuril island arcs, Iceland, and Ascension Island). In the series of magmatic...185:38 = 4.9 The Tertiary basaltoid association of Iceland. The rock series, embracing the Tertiary central-type...comagmatic gabbro-granophyric in­ trusive rocks of Iceland, are comparable with the Unalaska series in the...the presence of cumulates en­ riched in calcic plagioclase and pyroxene, among the mafic varieties, and...nature of the magmatism of the central volcanoes of Iceland, dif­ fering from either typical plateau-basalts
Journal (article/letter/editorial)
later times remained a tectonic 'high'. The south-eastern portion of the Pelagonian Zone, termed the AtticaCyclades...The compositional range of minerals other than plagioclase is very limited in the two xenolithic series...distribution of volcanic rocks (solid black) in the Aegean region. Tectonic divisions after Aubouin (1965, fig. 11)...layers of volcanic tephra found in sediments of the eastern Mediterranean floor (Ninkovich & Heezen, 1965,1967)...the Lumaravi-Archangelo dacites are corroded plagioclase (An6S-An3o) with strong oscillatory zoning, green-brown
Journal (article/letter/editorial)
Pitchstones and obsidians from Arran, Eigg, and Iceland, are shown to have small but distinct differences...includes the almost completely volcanic island of Iceland, where volcanicity has continued from Tertiary...chilled facies of an intrusive felsite, and from Iceland where pitchstones and obsidians are abundantly...1 and 2) both contain phenocrysts of quartz, plagioclase, rare iron-rich olivine or its pseudomorph, and...Tables 1, 2) containing scattered phenocrysts of plagioclase, and considerably rarer dark green ferroaugite
Journal (article/letter/editorial)
from differentiation by crystal fractionation (Thingmuli Volcano; Red Hill Dyke) are immediately discernible...degree of freedom, but the presence of albite (plagioclase) reduces by one the degrees of freedom (Thompson...bulk of CaO of most plutonic rocks resides in plagioclase so that no other major phase is introduced to...equilibrated with quartz, alkali-feldspar and plagioclase as well as being buffered with respect to H20...to be stable in the presence of quartz plus plagioclase and potassium-feldspar. 139 A B . . . .
Journal (article/letter/editorial)
intersertal texture. In ranging outside the Saar region for examples of the rock type Rosenbusch drew on...intrusive hypabyssal rock with an alkali feldspar/plagioclase relation which is greater than 12-5 : 87-5, and...tholeiitic series— Thingmuli, Iceland (Carmichael, 1964); Hekla (1947^8), Iceland (Tryggvason, 1965);...342 series of Japan (Kuno, 1950), the Thingmuli series of Iceland (Carmichael, 1964) and the Hekla eruption...rocks of three series: (1) tholeiitic, Thingmuli series of Iceland, (2) the Hawaiian alkali series, averages
Journal (article/letter/editorial)
2172–2184, 2015 An updated calibration of the plagioclase-liquid hygrometer-thermometer applicable to basalts...updated and expanded data set that consists of 214 plagioclase-liquid equilibrium pairs from 40 experimental...recalibrate the thermodynamic model for the plagioclase-liquid hygrometer of Lange et al. (2009); the...revised model. The activities of the crystalline plagioclase components are taken from Holland and Powell...composition (45–80 wt% SiO2; 1–10 wt% Na2O+K2O), plagioclase composition (An17–95), temperature (750–1244
Journal (article/letter/editorial)
mats. Average of 7 similar samples, Skjaldbreid, Iceland (column 1, table 5, Tryggvason, 1943). Ollvine...and very sparse plagioclase microphenocrysts. Sample 983 has 1-1 per cent of plagioclase (0-5-2 mm) and...microphenocrysts. The groundmass of 946 consists of thin plagioclase plates (mostly <0-5 mm long), very abundant small...& Dunham (1969), for 946 gave 53-1 per cent plagioclase, 29-0 per cent clinopyroxene, 15-3 per cent olivine...determinations of Ca in both phenocryst and groundmass plagioclase show normal zoning from An95 to An 70 (wt percent)
Journal (article/letter/editorial)
mats. Average of 7 similar samples, Skjaldbreid, Iceland (column 1, table 5, Tryggvason, 1943). Ollvine...and very sparse plagioclase microphenocrysts. Sample 983 has 1-1 per cent of plagioclase (0-5-2 mm) and...microphenocrysts. The groundmass of 946 consists of thin plagioclase plates (mostly <0-5 mm long), very abundant small...& Dunham (1969), for 946 gave 53-1 per cent plagioclase, 29-0 per cent clinopyroxene, 15-3 per cent olivine...determinations of Ca in both phenocryst and groundmass plagioclase show normal zoning from An95 to An 70 (wt percent)
Journal (article/letter/editorial)
pegmatites and plagiogranites in the Porthoustock region. Mineralogical layering is restricted to two small...foliation defined by the planar grouping of plagioclase phenocrysts, and to a lesser extent by augite...appearance of oxide concentrations within the gabbro. Plagioclase and augite phenocrysts within the foliated oxide-rich...thin grain boundary films separating groundmass plagioclase grains; hairline microfractures which traverse...and interstitial spaces between ground- mass plagioclase. Aligned primary magmatic textures occur within
 
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