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Mt Tchivira, Lubango City Council, Huíla Province, Angola

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Ref.: Eur. J. Mineral. , 1993, 5, pp. 1001-1024.

Lower Cretaceous alkaline-carbonatite complex (10 km diameter) in Precambrian granito-gneissic basement.
Carbonatite ring, rimmed to the east by fenitized ijolites, within nepheline syenite body.
Younger alkali gabbro/syenite intrusion.

References:
-Mariano, A. N., Roeder, P. L., 1989. Wöhlerite: chemical composition, cathodoluminescence and environment of crystallization. Canadian Mineralogist, 27: 709-720.





Mineral List:
  		•  Aegirine
    NaFe
    3+
     
    		[Si
     
    2
    		O
     
    6
    		]
    Description: Acmite, rims salite in nepheline syenite.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Albite
    Na[AlSi
     
    3
    		O
     
    8
    		]
    Description: Rims orthoclase in alkali gabbro/syenite intrusion.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  'Albite-Anorthite Series'
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Analcime
    Na
     
    2
    		[Al
     
    2
    		Si
     
    4
    		O
     
    12
    		] · 2H
     
    2
    		O
    Description: In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Ankerite
    Ca(Fe
    2+
     
    		 ,Mg,Mn
    2+
     
    		)(CO
     
    3
    		)
     
    2
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Anorthite
    Ca[Al
     
    2
    		Si
     
    2
    		O
     
    8
    		]
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Anorthite
    var: Bytownite
    (Ca,Na)[Al(Al,Si)Si
     
    2
    		O
     
    8
    		]
    Description: In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Anorthite
    var: Labradorite
    (Ca,Na)[Al(Al,Si)Si
     
    2
    		O
     
    8
    		]
    Description: In alkali gabbro/syenite intrusion. In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Anorthoclase
    (Na,K)[AlSi
     
    3
    		O
     
    8
    		]
    Description: In phonolite dykes surrounding the alkaline-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  'Apatite'
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Baryte
    BaSO
     
    4
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Biotite
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Calcite
    CaCO
     
    3
    Description: Primary calcite interstitial in ijolite. Replaces forsterite in tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Cancrinite
    Na
     
    6
    		Ca
     
    2
    		[(CO
     
    3
    		)
     
    2
    		|Al
     
    6
    		Si
     
    6
    		O
     
    24
    		] · 2H
     
    2
    		O
    Description: Replaces nepheline in nepheline syenite.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Diopside
    CaMg[Si
     
    2
    		O
     
    6
    		]
    Description: Salite in nepheline syenites. Ti-salite in tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Dolomite
    CaMg(CO
     
    3
    		)
     
    2
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Ferropargasite
    [Na][Ca
     
    2
    		][Fe
    2+
    4
    		Al][(OH)
     
    2
    		|Al
     
    2
    		Si
     
    6
    		O
     
    22
    		]
    Description: In phonolite dykes surrounding the alkaline-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Forsterite
    Mg
     
    2
    		[SiO
     
    4
    		]
    Description: In alkali gabbro/syenite intrusion.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Hastingsite
    [Na][Ca
     
    2
    		][Fe
    2+
    4
    		Fe
    3+
     
    		][(OH)
     
    2
    		|Al
     
    2
    		Si
     
    6
    		O
     
    22
    		]
    Description: In alkali gabbro/syenite intrusion (in syenite).
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Kaersutite
    [Na][Ca
     
    2
    		][Mg
     
    4
    		Ti][O|OH|Al
     
    2
    		Si
     
    6
    		O
     
    22
    		]
    Description: In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Magnesiokatophorite
    Na[CaNa][Mg
     
    4
    		(Al,Fe
    3+
     
    		)][(OH)
     
    2
    		|AlSi
     
    7
    		O
     
    22
    		]
    Description: In trachyphonolite dykes surrounding the carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Magnetite
    Fe
    2+
     
    		Fe
    3+
    2
    		O
     
    4
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Magnetite
    var: Titaniferous Magnetite
    Fe
    2+
     
    		(Fe
    3+
     
    		,Ti)
     
    2
    		O
     
    4
    Description: In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Nepheline
    (Na,K)[AlSiO
     
    4
    		]
    Description: In syenites. In tephritic dykes surrounding the alkali-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Orthoclase
    K[AlSi
     
    3
    		O
     
    8
    		]
    Description: In alkali gabbro/syenite intrusion.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Phlogopite
    KMg
     
    3
    		[(OH,F)
     
    2
    		|AlSi
     
    3
    		O
     
    10
    		]
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Pyrite
    FeS
     
    2
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Pyrochlore
    (Ca,Na)
     
    2
    		Nb
     
    2
    		O
     
    6
    		(OH,F)
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Quartz
    SiO
     
    2
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Sanidine
    K[AlSi
     
    3
    		O
     
    8
    		]
    Description: In phonolite dykes surrounding the alkaline-carbonatite complex.
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Titanite
    CaTi[O|SiO
     
    4
    		]
    Reference: [Eur. J. Mineral. , 1993, 5, pp. 1001-1024.]
  		•  Wöhlerite
    NaCa
     
    2
    		(Zr,Nb)[(O,OH,F)
     
    2
    		|Si
     
    2
    		O
     
    7
    		]
    Reference: [Mariano, A. N., Roeder, P. L., 1989. Wöhlerite: chemical composition, cathodoluminescence and environment of crystallization. Canadian Mineralogist, 27: 709-720. ]
  		•  Zirconolite
    CaZrTi
     
    2
    		O
     
    7
    Reference: [Mariano, A. N., Roeder, P. L., 1989. Wöhlerite: chemical composition, cathodoluminescence and environment of crystallization. Canadian Mineralogist, 27: 709-720. ]


    33 entries listed. 27 valid minerals.

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