 | | Journal (article/letter/editorial) | | Deposits of the Bacuri Mafic-Ultramafic Layered Complex, Guyana Shield, Amapá State, Brazil CARLOS ALBERTO...Brasileiras Reunidas, Av. de Ligação 3000, Nova Lima, MG, 34000-000, Brazil AND CESAR FONSECA FERREIRA FILHO...70910-900, Brazil Abstract The chromite deposits of the Bacuri mafic-ultramafic layered complex consist...largest reserves of chromite in Brazil. The complex is a major stratiform complex overprinted by ductile deformation...terranes of the Guyana Shield. The Bacuri mafic-ultramafic complex consists of a lower mafic zone (>500 |  | | Journal (article/letter/editorial) | | COMPOSITION IN THE ALTERED AND DEFORMED BACURI COMPLEX, AMAPA, NORTHEASTERN BRAZIL HAZEL M. PRICHARD§ Department...Universidade Federal da Bahia, 40.170-290 Salvador, Bahia, Brazil PETER C. FISHER Department of Earth Sciences,...CF10 3YE, Wales, U.K. ABSTRACT In the Bacuri complex, Amapa, Brazil, there is good evidence for Pd mobility...compositions most typical of chromite from a stratiform complex of continental origin. Keywords: platinum-group...serpentinization, Bacuri complex, Amapa, Brazil. SOMMAIRE Le complexe igné de Bacuri, dans l’état d’Amapa |  | | Journal (article/letter/editorial) | | ultramafic rocks from the Bacuri, Niquelândia and Ipueira-Medrado layered complexes in Brazil were investigated...investigated. The Bacuri Complex (2?2 Ga) is a large layered intrusion of the Amazon Craton. Chromitite layers...layers of the Bacuri mafic-ultramafic complex are restricted to a 30–120 m-thick sequence of ultramafic cumulates...Niquelândia Complex (0?8 Ga) is a large layered intrusion in central Brazil. The Niquelândia Complex has a...note that chromitite seams in the Niquelândia Complex are mainly hosted by dunite. Different from chromitites |  | Prichard, Hazel M., Mondal, Sisir K., Mukherjee, Ria, Fisher, Peter C., Giles, Nicolas (2018) Geochemistry and mineralogy of Pd in the magnetitite layer within the upper gabbro of the Mesoarchean Nuasahi Massif (Orissa, India) Mineralium Deposita, 53 (4) 547-564 doi:10.1007/s00126-017-0754-4 | Journal (article/letter/editorial) | | layer occurs at a high stratigraphic level in the complex and is nearly 4-km long and 5–12-m thick. The sections...The magnetite grains with exsolved fine laths of ilmenite at centers are referred to as central magnetite...magnetite grains are commonly surrounded by blebs of ilmenite and magnetite that contain the majority of the...the alteration event that produced the blebby ilmenite and magnetite, led to the more primary PGM being...Magnetitite . Chromitite . Sill-like layered igneous complex . Upper gabbro unit . Nuasahi Massif Introduction |  | | Journal (article/letter/editorial) | | linnaeite in the massive ores. Granular magnetite and ilmenite are the predominant oxides in these samples. ...obviously different from those of the Bacuri complex, Amapa, Brazil (Prichard et al. 2001). In the South... In contrast, in the serpentinized Bacuri complex, Amapa, Brazil, the most common PGM are Pd bismuthides...hydrothermal deposits are distinctive, with irregular and complex compositional zoning (e.g., Ohnenstetter et al...hollingworthite from the Two Duck Lake intrusion, Coldwell complex, Ontario. Am. Mineral. 76, 1694-1700. PEACH, C |  | Bowles, J. F. W., Prichard, H. M., Suarez, S., Fisher, P. C. (2013) THE FIRST REPORT OF PLATINUM-GROUP MINERALS IN MAGNETITE-BEARING GABBRO, FREETOWN LAYERED COMPLEX, SIERRA LEONE: OCCURRENCES AND GENESIS. The Canadian Mineralogist, 51 (3) 455-473 doi:10.3749/canmin.51.3.455 | Journal (article/letter/editorial) | | IN MAGNETITE-BEARING GABBRO, FREETOWN LAYERED COMPLEX, SIERRA LEONE: OCCURRENCES AND GENESIS John F.W...magnetite-bearing gabbroic rocks of the Freetown Layered Complex, Sierra Leone for the first time. The PGM occurrences...than the eluvial and alluvial PGM of the Freetown complex, which are predominantly Pt-Fe alloys, laurite...canadian mineralogist Introduction The Freetown complex of Sierra Leone is one of the platinum-group element-bearing...(Butcher et al. 1999), from the Skaergaard igneous complex in Greenland (Andersen et al. 1998, Andersen 2006) |  | | Journal (article/letter/editorial) | | Complex multistage genesis for the Ni–Cu–PGE mineralisation in the southern region of the Platreef, Bushveld...Bushveld Complex, South Africa D. Hutchinson and Judith A. Kinnaird In the southern portion of the Platreef...Ni–Cu–Pt-group element (PGE) mineralisation results from a complex interplay of pre-, syn- and post-magmatic processes...to the footwall contact. More compositionally complex sulphides are associated with felsic melt phases...antimonides, bismuthides, bismutho-antimonides and complex bismuthotellurides. Pt-bearing phases mostly occur |  | | Journal (article/letter/editorial) | | Rocks in the Rio Jacaré Intrusion, Northeastern Brazil J. H. S. SÁ, Centro de Pesquisa em Geofísica e...Universidade Federal da Bahia 40.170-290 Salvador, Bahia, Brazil S-J. BARNES, Sciences de la Terre, Université...bodies in the Rio Jacaré intrusion of northeastern Brazil. The intrusion hosting these magnetite bodies consists...or within silicate inclusions in magnetite and ilmenite grains and are associated with Co-bearing pentlandite...associated with silicates interstitial to magnetite and ilmenite grains and sometimes with Co-Ni arsenides. At |  | Fan, Hong-Peng, Zhu, Wei-Guang, Zhong, Hong, Bai, Zhong-Jie, He, De-Feng, Ye, Xian-Tao, Chen, Cai-Jie, Cao, Chong-Yong (2014) Platinum-group element geochemistry of the Zhuqing Fe-Ti-V oxide ore-bearing mafic intrusions in western Yangtze Block, SW China: control of platinum-group elements by magnetite. Mineralogy and Petrology, 108 (3) 419-438 doi:10.1007/s00710-013-0310-6 | Journal (article/letter/editorial) | | the Rio Jacaré intrusion in Brazil (Sá et al. 2005), the Bushveld Complex (Harney et al. 1990; Barnes...the lower part of the Upper Zone of the Bushveld Complex have much lower Pd/Ir ratios (Harney et al. 1990)...Au in the Main Magnetite Layer in the Bushveld Complex. Thus, magnetite seems to preferentially fractionate...consist of >20 vol.% Fe–Ti oxides (magnetite and ilmenite), approximately 40 vol.% plagioclase, 30 vol.%...biotite. The magnetites in the Zhuqing gabbros have ilmenite exsolutions with different shapes such as trellis-shaped |  | Suárez, Saioa, Prichard, Hazel M., Velasco, Francisco, Fisher, Peter C., McDonald, Iain (2010) Alteration of platinum-group minerals and dispersion of platinum-group elements during progressive weathering of the Aguablanca Ni–Cu deposit, SW Spain. Mineralium Deposita, 45 (4) 331-350 doi:10.1007/s00126-009-0275-x | Journal (article/letter/editorial) | | the northeastern part the Santa Olalla plutonic complex (Fig. 1). This is a small and highly heterogeneous...volcanoclastic and carbonate rocks (Bodonal-Cala Complex) overlying Late Precambrian metasedimentary rocks...hypersthene–hornfels aureole surrounding the plutonic complex (Casquet 1980; Velasco 1976). The deposit consists...marcasite, covellite and violarite. Magnetite and ilmenite are often present, and lesser amounts of PGM,...showing the location of the Santa Olalla Pluton Complex and the Aguablanca mine (Agb). Modified from Casquet |  | Mondal, Sisir K., Khatun, Sarifa, Prichard, Hazel M., Satyanarayanan, M., Kumar, G.R. Ravindra (2019) Platinum-group element geochemistry of boninite-derived Mesoarchean chromitites and ultramafic-mafic cumulate rocks from the Sukinda Massif (Orissa, India) Ore Geology Reviews, 104. 722-744 doi:10.1016/j.oregeorev.2018.11.027 | Journal (article/letter/editorial) | | Sukinda Massif as part of an Archean ophiolitic complex. Acharyya (1993) suggested possibilities of the...craton; the Singhbhum Granite Complex is the largest batholithic complex (3.3 – 3.1 Ga; Mishra et al....planes (Fig. 3f). An assemblage of magnetite and ilmenite is commonly developed within the altered parts...and the Bacuri Complex in Amapa, Brazil (e.g., Prichard et al., 2017a). In the Kemi Complex in Finland...example in the chromitites in Campo Formosa and Bacuri and in a breccia zone and in the magnetitite bands |  | Barnes, Sarah-Jane, Prichard, Hazel M., Cox, Richard A., Fisher, Peter C., Godel, Belinda (2008) The location of the chalcophile and siderophile elements in platinum-group element ore deposits (a textural, microbeam and whole rock geochemical study): Implications for the formation of the deposits. Chemical Geology, 248 (3) 295-317 doi:10.1016/j.chemgeo.2007.08.004 | Journal (article/letter/editorial) | | of unmetamorphosed layered intrusions (Busveld Complex, South Africa and Great Dyke, Zimbabwe) ∼ 30 to...Zimbabwe, and the Merensky Reef of the Bushveld Complex, South Africa, primary igneous silicate minerals...sills, and hence the reef BMS could have a more complex crystallization history than the subvolcanic sills...fine grained plagioclase, pyroxene, magnetite and ilmenite with 1 to 2 cm base metal sulfide droplets (Fig...present, these are both sulfarsenides. 3.4. Bushveld Complex, Merensky Reef We have performed a detailed study |  | | Journal (article/letter/editorial) | | Hydromagnesite Hydrozincite Hypersthene Illite Ilmenite Ilvaite Indite Indium native Inyoite Iranite Isoferroplatinum...mineralization may either be the product of a complex polyphase mineralizing process, reflecting a combination...potassic igneous rocks dominated by Mg olivine, Mg ilmenite, Cr pyrope, Cr diopside, phlogopite, enstatite...group minerals, Nb-bearing rutile and Mn-bearing ilmenite. Komatiites are composed of Mg olivine, Ca and...gold-bearing quartz veins in the southern Para State, Brazil (Angelica et al., 1997). Chromium muscovite named | | | Journal (article/letter/editorial) | | Hydromagnesite Hydrozincite Hypersthene Illite Ilmenite Ilvaite Indite Indium native Inyoite Iranite Isoferroplatinum...mineralization may either be the product of a complex polyphase mineralizing process, reflecting a combination...potassic igneous rocks dominated by Mg olivine, Mg ilmenite, Cr pyrope, Cr diopside, phlogopite, enstatite...group minerals, Nb-bearing rutile and Mn-bearing ilmenite. Komatiites are composed of Mg olivine, Ca and...gold-bearing quartz veins in the southern Para State, Brazil (Angelica et al., 1997). Chromium muscovite named |  | | Book | | Basement to the Shetland Ophiolite-complex 4 The Shetland Ophiolite-complex and Skaw Granite Information...geology of the basement to the Shetland Ophiolite-complex 26 Structure of the Valla Field and Lamb Hoga blocks...Saxa Vord Block 34 Six The Shetland Ophiolite-complex Introduction 37 The ophiolite nappes 37 The imbricate...Shetland Ophiolite-complex: tectonics and origins 92 A model for the Shetland Ophiolite-complex 92 Nine Cenozoic...Diagrammatic section through the Shetland Ophiolite-complex parallel to the restored Lamb Hoga Fault 7 5 Idealised |  | | Book | | elements (PGE). Using examples from the Bushveld complex of South Africa and other intrusions, this book...Deposits: Examples 2.4.1 The Bushveld Complex 2.4.2 The Stillwater Complex 2.4.3 Skaergaard Intrusion 10 10...1 Silicate Liquid Inclusions in the Stillwater Complex 7.2.2 Other Examples of Silicate Liquid Inclusions...Inclusions 7.3.1 Fluid Inclusions in the Stillwater Complex 7.3.2 Fluid Inclusions and Hydrosaline Melt Inclusions...Ultramafic Pegmatoids and Pipes of the Bushveld Complex 8.4 Bushveld Plutonic Diatreme 8.5 Existing Bushveld |
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