+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

The character of the fluorspar deposits at Okorusu, Namibia; mineralogy, paragenesis, and ore controls



The character of the fluorspar deposits at Okorusu, Namibia; mineralogy, paragenesis, and ore controls



Abstracts with Programs - Geological Society of America 36(3): 20



The fluorite ored deposits at Okorusu, Namibia, occur within and adjacent to highly fenitized host rocks along the south and southwest margin of the Cretaceous Okorusu alkaline igneous-carbonatite complex that intruded Precambrian Damara Sequence quartzites, marbles, and schists. Sparce exposures of carbonatite probably reflect the presence of a ring-like intrusion of carbonatite at depth beneath the one kilometer-wide area of fenitization. Most of the fluorite orebodies have formed by the replacement of small intrusions of carbonatite into the brittle highly brecciated fenites. Early fluorite introduction formed replacement ores; whereas, slightly later fluorite deposition occurred as well-formed crystals deposited in open spaces, and those euhedral crystals are highly prized as mineral specimens. Two open pits, A and B, have received extensive mining, and a third open pit, C, is currently being developed. All of the ore pods in the A pit, except for one, formed by the replacement of carbonatite bodies. Similarly, the fluorite ores in the B pit have formed dominantly by the replacement of carbonatite, but fluorite ore replacement of marble has recently been exposed on the lowest two levels, 1650 and 1640, of mining in the B pit. Examination of drill core, together with geophysical evidence, suggests the the fluorite ores in the C pit orebody have been formed by the replacement of marble. The Okorusu fluorspar ores consist dominantly of fluorite. Smaller amounts of calcite, apatite, diopsite, magnetite, ilmenite, ulvospinel, and pyrrhotite are present as remnants from the replaced carbonatites. Small amounts of aegirine and potash feldspar are present in the fluorite ores as remnants of locally replaced fenite. Synchysite and quartz were introduced into the carbonatites by an early hydrothermal event prior to their replacement by fluorite. Pyrrhotite was altered to secondary magnetite, hematite, marcasite, and pyrite during that hydrothermal event. Pyroxene, magnetite, and the iron sulfides were altered to goethite during the introduction of the oxidizing fluorite-depositing fluids. Minor amounts of post-fluorite stalactitic calcite, quartz, manganite, and goethite were deposited locally in vugs on top of the latest fluorite crystals.

Accession: 020301522

Download citation: RISBibTeXText


Related references

Variations in ores, host rocks, and ore controls for the carbonatite-related fluorspar deposits at Okorusu, north-central Namibia. Abstracts with Programs - Geological Society of America 29(4): 18, 1997

Character of fenitized host rocks and fluorspar ores at Okorusu, north-central Namibia. Abstracts with Programs - Geological Society of America 31(5): 18, 1999

Comparisons of three carbonatite-related fluorspar deposits at Okorusu, north-central Namibia. Transactions of the Missouri Academy of Science 31: 71-72, 1997

New field interpretations of fluorspar ore controls at Okorusu, Namibia; replacements of pegmatitic carbonatite and fenite breccias. Transactions of the Missouri Academy of Science: 101, 2000

Fluorite ore deposits, Okorusu, Namibia; role of pegmatitic carbonatite in the genesis of the fluorspar ores. Abstracts with Programs - Geological Society of America 31(7): 404, 1999

Similarities and dissimilarities between the fluorspar deposits at the Amba Dongar, India and Okorusu, Namibia carbonatite complexes. Abstract Volume (Geological Association of Canada) 31: 62, 2006

Petrography and cathodoluminescence microscopy of fenites associated with carbonatite-related fluorspar deposits at Okorusu, north-central Namibia. Transactions of the Missouri Academy of Science: 34, 1999

The recognition of marble replacement in the genesis of the Okorusu carbonatite-related fluorspar deposits, north-central Namibia. Abstracts with Programs - Geological Society of America 35(6): 231, 2003

Mineralogical, geochemical, and host rock variations in the carbonatite-related fluorspar deposits at Okorusu, north-central Namibia. Program with Abstracts - Geological Association of Canada(Mineralogical Association of Canada(Canadian Geophysical Union, Joint Annual Meeting 22: 60, 1997

Carbonatite-related fluorspar deposits at Okorusu, Namibia, Amba Dongar, India, and Mato Preto, Brazil; similarities and dissimilarities. Abstracts with Programs - Geological Society of America 30(2): 20, 1998

Fluorspar deposits at Okorusu, Namibia with emphasis upon electron microprobe analyses of carbonatite minerals and fluorite fluid inclusion temperatures and salinities. Australasian Institute of Mining and Metallurgy 8/2008: 631-641, 2008

Geology and ore controls of fluorite deposits at Okorusu, north-central Namibia. Abstracts with Programs - Geological Society of America 26(7): 312, 1994

The geology of the Okorusu fluorspar deposit, Namibia. Transactions of the Missouri Academy of Science 28: 116-117, 1994

Fluorite beneficiation problems, Okorusu fluorspar mine, Namibia. Proceedings of the, 2000

Use of fluorspar ore textures to predict potential beneficiation problems at Okorusu, Namibia. International Geological Congress, Abstracts = Congres Geologique International, Resumes 31: (unpaginated, 2000