Database name: |
World Fe-oxide+/-Cu-Au-U (IOCG) deposits |
Compilers: |
Sunil S. Gandhi |
Release date: |
2015-03-04 |
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Deposit name(s): |
Terra Nera; Tera Nera |
Political location(s): |
Italy; Province or state: Tuscany; Subprovince or locality: Elba Island; Nearest community: Rome (194 km 301°) |
Deposit clan (type): |
Iron Skarn-type |
Deposit (sub) types: |
primary mineralization is reportedly massive iron skarn-type; it was fragmented during tectonic transportation and later affected by surface oxidation and redeposition of second generation specularite; Reference: Duenkel, I.; Kuhlemann, J.; Nohlen, U., 2003: Iron Ore Formation and Neotectonic Evolution in Elba (Tuscany, Italy) during Messinian Plutonism; Neues Jahrbuch fur Geologie und Palaontologie. Abhandlungen, Volume 230, p. 391 - 407 |
Deposit status: |
past producer; Size category: unknown |
Geologic province: |
Alpine Orogen |
Geologic subprovince: |
Apennines |
Geologic district: |
Northern Apennines |
Deposit object located: |
centre-deposit on surface |
Commodities: |
Fe |
Mineralization styles: |
massive magnetite pods in skarn; skarn boudins in brecciated and sheared zone; specularite disseminations in fault gouge; fracture-fillings by late stage hematite and pyrit |
Geological ages: |
Late Miocene (mineralization) Late Miocene (related magmatics) |
Tectonic setting: |
continental unstated-unqualified; extensional; Formal name: Late Miocene extension and related plutonism (related igneous rocks) |
Coincident features: |
low angle nappe (skarns formed at contact of Monte Cappane intrusion carried east by nappes; boudins of skarn in 3 to 7 m thick cataclastic zone at base of Zucalle det); Coincident feature name: Zucalle Detachment Fault gouge in cataclastic fault zone (late stage, disseminated specularite mineralization in fault gouge; fractured specularite crystals healed by fine grained hematite); Coincident feature name: Zucalle Detachment Fault |
Regional tectonic structure: |
shallow-dipping extensional slides of Late Miocene age with eastward transport (Capo Calamita, Terra Nera, Rio Marina and Rio Albano deposits transported with detachments) Tectonic structure name: Extensional Allochthons A group of breccia bodies indicaing forceful injection of mineralizing fluids (low angle flysch nappes formed during rise of Monte Cappane intrusion moved east due to gravitational gliding ) Tectonic structure name: early detachments late stage detachment (continued differential updoming of the intrusion developed second low angle nappe cutting earlier ones) Tectonic structure name: Zucalle Detachment Fault |
Host rocks: |
(1) metamorphic; metasedimentary schist (Late Paleozoic-Mesozoic strata); Depositional setting: continental; Metamorphic grade: greenschistExternal host rock forms: | schists and quartzites | Host rock protoliths: | carbonaceous shale, siliciclastic sediments, carbo (Carboniferous, Triassic and Jurassic sediments deformed and metamorphosed to greenschist facies); Host rock protolith name: Complex III of Elba Island | Internal host rock structures: | foliated to layered; crenulated | Individual lithologies: | graphitic schist (Tuscan continental sediments deposited on western Adriatic microplate deformed during Oligicene-Miocene Apennitic collision phase) quartzite marble | Host rock stratigraphy: | Complex III of Elba Island |
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Metallogenic signatures: |
Fe |
Alteration signatures: |
skarn: hedenbergite, garnet, epidote in skarn iron ore; What was altered: carbonates |
Mineralogy: |
(alteration): hedenbergite, garnet, epidote (mineralization): magnetite, specularite, pyrite |
Radiometric ages: |
Object dated: Host Rocks(1); Age - Ma: 19.7; +0.5; -0.5; Dating method: Ar-Ar; Concentrate: muscovite; Source rock: calcschist; Formal name: Apenninic orogenic event; Event dated: metamorphism; Interpretive comment: the plateau age dates the last compressive event of Apenninic collision recorded in Elba Island; Reference: Deino, A.; Keller, J. V. A.; Minelli, G.; Pialli, G., 1992: Datazioni 40Ar/39Ar del Metamorfismo dell' Unità di Ortano - Rio Marina (Isola d'Elba): Risulta di Preliminari; Studi Geologica Camerti, Volume 2, p. 187 - 192 |
Deposit shape: |
unknown |
Qualified comments: |
(Applies to: mineralization) One of the Elba deposits mined since 2500 years ago; Terra Nera and nearby Capo Bianco deposits resemble Ginevro deposit; total ore production in Elba estimated at 50 Mt and resources at some 26 Mt. |
References: |
Deino, A.; Keller, J. V. A.; Minelli, G.; Pialli, G., 1992 |
Datazioni 40Ar/39Ar del Metamorfismo dell' Unità di Ortano - Rio Marina (Isola d'Elba): Risulta di Preliminari |
Studi Geologica Camerti, Volume 2, p. 187 - 192 |
Duenkel, I.; Kuhlemann, J.; Nohlen, U., 2003 |
Iron Ore Formation and Neotectonic Evolution in Elba (Tuscany, Italy) during Messinian Plutonism |
Neues Jahrbuch fur Geologie und Palaontologie. Abhandlungen, Volume 230, p. 391 - 407 |
Keller, J. V. A. ; Pialli, G., 1990 |
Tectonics of the Island of Elba |
Bollettino della Società Geologica Italiana, Volume 109, p. 413 - 425 |
Keller, J. V. A.; Minelli, G.; Pialli, G., 1994 |
Anatomy of Late Orogenic Extension: The Northern Apennine Case |
Tectonophysics, Volume 238, p. 275 - 294 |
Kligfield, R., 1979 |
The Northern Apennines as a Collisional Orogen |
American Journal of Science, Volume 279, p. 676 - 691 |
Zitzmann, A., 1977 |
The Iron Deposits of Italy |
in The Iron Ore Deposits of Europe and Adjacent Areas: Explanatory Notes to the International Map of the Iron Ore Deposits of Europe, 1:2,500,000 (Text and Figures), Edited by Walther, H. W.; Zitzmann, A., International Geological Congress, Commission for the Geological Map of the World, Subcommission for the Metallogenic Map of the World, Bundesanstalt fur Geowissenschaften und Rohstoffe, Postfach 51 01 53, D-3000 Hannover 51, Volume I, 418 p, p. 209 - 218 |
Zitzmann, A. Editor(s)), 1978 |
The Iron Ore Deposits of Europe and Adjacent Areas: Explanatory Notes to the International Map of the Iron Ore Deposits of Europe, 1:2,500,000 (Lists and Tables) |
International Geological Congress, Commission for the Geological Map of the World, Subcommission for the Metallogenic Map of the World, Bundesanstalt fur Geowissenschaften und Rohstoffe, Postfach 51 01 53, D-3000 Hannover 51, Volume II, 386 p. |
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