Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization
Abstract The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Feder...
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crwiley:10.1111/j.1751-3928.2012.00188.x 2023-12-03T10:29:18+01:00 Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization NOKU, Shadrach K. MATSUEDA, Hiroharu ESPI, Joseph O. AKASAKA, Masahide 2012 http://dx.doi.org/10.1111/j.1751-3928.2012.00188.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1751-3928.2012.00188.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1751-3928.2012.00188.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Resource Geology volume 62, issue 2, page 187-207 ISSN 1344-1698 1751-3928 Geochemistry and Petrology Geology journal-article 2012 crwiley https://doi.org/10.1111/j.1751-3928.2012.00188.x 2023-11-09T14:36:17Z Abstract The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Federal Flag deposits were investigated to clarify physiochemical conditions of the mineralization at both deposits. The two deposits are located about 2 km apart and they are stratigraphically hosted by siliceous to carbonaceous claystone and rare gray chert of Paleocene–Eocene age. Massive sulfide ore and host rock samples were collected from each deposit for mineralogical, geochemical, and fluid inclusion studies. Mineralization at the Laloki deposit consists of early‐stage massive sulfide mineralization (sphalerite‐barite, chalcopyrite, and pyrite–marcasite) and late‐stage brecciation and remobilization of early‐stage massive sulfides that was accompanied by late‐stage sphalerite mineralization. Occurrence of native gold blebs in early‐stage massive pyrite–marcasite‐chalcopyrite ore with the association of pyrrhotite‐hematite and abundant planktonic foraminifera remnants was due to reduction of hydrothermal fluids by the reaction with organic‐rich sediments and seawater mixing. Precipitation of fine‐grained gold blebs in late‐stage Fe‐rich sphalerite resulted from low temperature and higher salinity ore fluids in sulfur reducing conditions. In contrast, the massive sulfide ores from the Federal Flag deposit contain Fe‐rich sphalerite and subordinate sulfarsenides. Native gold blebs occur as inclusions in Fe‐rich sphalerite, along sphalerite grain boundaries, and in the siliceous‐hematitic matrix. Such occurrences of native gold suggest that gold was initially precipitated from high‐temperature, moderate to highly reduced, low‐sulfur ore fluids. Concentrations of Au and Ag from both Laloki and Federal Flag deposits were within the range (<10 ppm Au and <100 ppm Ag) of massive sulfides at a mid‐ocean ridge ... Article in Journal/Newspaper Planktonic foraminifera Wiley Online Library (via Crossref) Astrolabe ENVELOPE(140.000,140.000,-66.733,-66.733) Resource Geology 62 2 187 207 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Geochemistry and Petrology Geology |
spellingShingle |
Geochemistry and Petrology Geology NOKU, Shadrach K. MATSUEDA, Hiroharu ESPI, Joseph O. AKASAKA, Masahide Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
topic_facet |
Geochemistry and Petrology Geology |
description |
Abstract The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Federal Flag deposits were investigated to clarify physiochemical conditions of the mineralization at both deposits. The two deposits are located about 2 km apart and they are stratigraphically hosted by siliceous to carbonaceous claystone and rare gray chert of Paleocene–Eocene age. Massive sulfide ore and host rock samples were collected from each deposit for mineralogical, geochemical, and fluid inclusion studies. Mineralization at the Laloki deposit consists of early‐stage massive sulfide mineralization (sphalerite‐barite, chalcopyrite, and pyrite–marcasite) and late‐stage brecciation and remobilization of early‐stage massive sulfides that was accompanied by late‐stage sphalerite mineralization. Occurrence of native gold blebs in early‐stage massive pyrite–marcasite‐chalcopyrite ore with the association of pyrrhotite‐hematite and abundant planktonic foraminifera remnants was due to reduction of hydrothermal fluids by the reaction with organic‐rich sediments and seawater mixing. Precipitation of fine‐grained gold blebs in late‐stage Fe‐rich sphalerite resulted from low temperature and higher salinity ore fluids in sulfur reducing conditions. In contrast, the massive sulfide ores from the Federal Flag deposit contain Fe‐rich sphalerite and subordinate sulfarsenides. Native gold blebs occur as inclusions in Fe‐rich sphalerite, along sphalerite grain boundaries, and in the siliceous‐hematitic matrix. Such occurrences of native gold suggest that gold was initially precipitated from high‐temperature, moderate to highly reduced, low‐sulfur ore fluids. Concentrations of Au and Ag from both Laloki and Federal Flag deposits were within the range (<10 ppm Au and <100 ppm Ag) of massive sulfides at a mid‐ocean ridge ... |
format |
Article in Journal/Newspaper |
author |
NOKU, Shadrach K. MATSUEDA, Hiroharu ESPI, Joseph O. AKASAKA, Masahide |
author_facet |
NOKU, Shadrach K. MATSUEDA, Hiroharu ESPI, Joseph O. AKASAKA, Masahide |
author_sort |
NOKU, Shadrach K. |
title |
Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
title_short |
Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
title_full |
Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
title_fullStr |
Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
title_full_unstemmed |
Petrology, Geochemistry, and Fluid Inclusion Microthermometry of Sphalerite from the Laloki and Federal Flag Strata‐Bound Massive Sulfide Deposits, Papua New Guinea: Implications for Gold Mineralization |
title_sort |
petrology, geochemistry, and fluid inclusion microthermometry of sphalerite from the laloki and federal flag strata‐bound massive sulfide deposits, papua new guinea: implications for gold mineralization |
publisher |
Wiley |
publishDate |
2012 |
url |
http://dx.doi.org/10.1111/j.1751-3928.2012.00188.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1751-3928.2012.00188.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1751-3928.2012.00188.x |
long_lat |
ENVELOPE(140.000,140.000,-66.733,-66.733) |
geographic |
Astrolabe |
geographic_facet |
Astrolabe |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Resource Geology volume 62, issue 2, page 187-207 ISSN 1344-1698 1751-3928 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1751-3928.2012.00188.x |
container_title |
Resource Geology |
container_volume |
62 |
container_issue |
2 |
container_start_page |
187 |
op_container_end_page |
207 |
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1784254574841823232 |