Results 1 to 10 of about 202 (128)

A SEQUENCE OF FORMATION OF «URANPYROCHLORE» AND FLUOROCALCIOPYROCHLORE IN ALKALI PEGMATITES FROM THE VISHNEVYE MOUNTAINS, SOUTH URALS [PDF]

Минералогия, 2022
The sequence of formation of pyrochlore crystals of various morphology and composition is considered in an aggregate with ilmenite and feldspar from nepheline-feldspar pegmatite at Mt.
V.I. Popova, V.A. Popov, I.A. Blinov, V.A. Kotlyarov, S.M. Lebedeva   +4 more
doaj   +3 more sources

Pegmatites and alkali feldspar granites as sources of industrial K-feldspar: A study from Borucu, Aksaray, Central Türkiye

Bulletin of the Mineral Research and Exploration
The Borucu (Aksaray) region, within the Central Anatolian Crystalline Complex, comprises a variety of rocks, including granite, alkali feldspar granite (AFG), pegmatite, and aplite dikes.
Gökhan Demirela, Mustafa Haydar Terzi, Ahmet Fatih Oskay   +2 more
doaj   +3 more sources

Amazonitic alkali feldspar from the Tanakami Granitic pegmatite, southwest Japan

Journal of Mineralogical and Petrological Sciences, 2010
This is the first detailed description of amazonitic alkali feldspar in Japan. The amazonitic feldspar is from pegmatite in the Tanakami Granite, southwest Japan. Macroscopically, the feldspar is characterized by the coexistence of pale blue and white parts.
Satoshi NAKANO, Kuniaki MAKINO
openaire   +3 more sources

Diffusion-controlled and replacement microtextures in alkali feldspars from two pegmatites: Perth, Ontario and Keystone, South Dakota [PDF]

Mineralogical Magazine, 2015
AbstractMacro- and micro-perthitic microclines from pegmatites from Perth, Ontario (Wards catalogue 46 E 0510) and Keystone, South Dakota (Wards 46 E 5125) have been studied using light and electron microscopy. A sample of the type perthite from Perth, Ontario (Hunterian Museum, Glasgow, M2361)was compared using light microscopy.
Lee, Martin R., Parsons, Ian
openaire   +3 more sources

Mineralogy and geochemistry of alkali feldspars from the Tanco pegmatite, southeastern Manitoba

The Canadian Mineralogist, 2001
The alkali feldspar paragenetic sequence in the Tanco pegmatite at Bernic Lake, Manitoba, spans the entire crystallization and cooling history of the pegmatite, and includes six different K(Rb)-feldspar and six different albite varieties. Total feldspar modal abundances approach 50% for the entire pegmatite volume. Blocky K-feldspar, aplitic albite and
Jarrod A. Brown, Tânia Martins, Petr černý   +2 more
  +5 more sources

Color mantle-zoning of alkali feldspar from small pegmatites in the Tanakami Granite Pluton, Shiga Prefecture, southwest Japan

The Journal of the Geological Society of Japan, 2008
滋賀県大津市田上花崗岩体小ペグマタイト中にできている長径数cm程度のマントル長石は，白色コア部を薄い無色透明リム部が包んでいるアルカリ長石である．鏡下では，コア部は汚濁を伴ったラメラ－パッチマイクロパーサイト組織を示しているが，リム部はほぼ均質であり清澄である．鏡下での汚濁・清澄の違いはコア部にはマイクロポアが圧倒的に多いこと，清澄なリム部には殆どないことに対応する．本長石の形成過程は，次のようである．最初に，550～600℃程度（PH2O＝2～3 kb）でOr76Ab24のコア部が晶出した．その後，450℃前後で離溶クリプトパーサイトが形成されそれが少しずつ粗大化した．クリプトパーサイトは，熱水反応によりマイクロパーサイトへと変化し，200 ...
Toshio Kohno, Satoshi Nakano, Norimasa Shimobayashi   +2 more
openaire   +3 more sources

Extreme alkali bicarbonate- and carbonate-rich fluid inclusions in granite pegmatite from the Precambrian Rønne granite, Bornholm Island, Denmark

Contributions to Mineralogy and Petrology, 2010
Our study of fluid and melt inclusions in quartz and feldspar from granite pegmatite from the Precambrian Ronne granite, Bornholm Island, Denmark revealed extremely alkali bicarbonate- and carbonate-rich inclusions. The solid phases (daughter crystals) are mainly nahcolite [NaHCO3], zabuyelite [Li2CO3], and in rare cases potash [K2CO3] in addition to ...
Thomas, R., Davidson, P., Schmidt, C.
openaire   +6 more sources

Diffusion and fluid interaction in Itrongay pegmatite (Madagascar): Evidence from in situ 40Ar/39Ar dating of gem-quality alkali feldspar and U Pb dating of protogenetic apatite inclusions

Chemical Geology, 2020
Alkali feldspar 40Ar/39Ar and apatite UPb geochronological studies have typically invoked two mechanisms to account for apparent loss of radiogenic 40Ar and 206-208Pb. Some studies have suggested that the radiogenic isotopes were lost by volume diffusion and used these dates to constrain temporal variations of rock temperatures; others have argued that
Popov, Daniil V., Spikings, Richard A., Scaillet, Stéphane, O'Sullivan, Gary, Chew, David, Badenszki, Eszter, Daly, J. Stephen, Razakamanana, Théodore, Davies, Joshua H.F.L.   +8 more
openaire   +5 more sources

SYNTAXY OF TITANITE, AEGIRINE AND ECKERMANNITE IN ALKALI SYENITE PEGMATITES OF THE VISHNEVYE MOUNTAINS (SOUTH URALS) [PDF]

Минералогия, 2016
Crystallographic orientation of titanite intergrowths with aegirine and eckermannite was found in alkali syenite pegmatites of the Vishnevye Mountains: the titanite face ( 1 11) is parallel to pyroxene and amphibole face (010) and the titanite face (110)
V.A. Popov, I.A. Blinov, V.I. Popova
doaj   +1 more source

New investigations on Dunje pegmatite, Macedonia I: the contribution to the knowledge about alkali feldspars and its mineral paragenesis [PDF]

Geologica Macedonica, 2016
Selečka Mountain was thoroughly investigated in the past mostly because of the interesting mineral paragenesis presented in granites, gneisses, amphibolites, different schists and pegmatite bodies. In the valley Smilevski Dol, around 3 km SW from the village of Dunje (Mariovo plateau), in the vicinity of small spring Šohlehov Kladenec hydrothermal ...
Zebec, Vladimir, Mikulčic Pavlakovic, Snjezana, Soufek, M., Boev, Blazo, Boev, Ivan, Bermanec, Vladimir   +5 more
  +6 more sources