Artigo Revisado por pares

Partial Melting Processes and Cu-Ni-PGE Mineralization in the Footwall of the South Kawishiwi Intrusion at the Spruce Road Deposit, Duluth Complex, Minnesota

2015; Volume: 110; Issue: 5 Linguagem: Inglês

10.2113/econgeo.110.5.1269

ISSN

1554-0774

Autores

Zsolt Benkó, Aberra Mogessie, Ferenc Molnár, Mark J Severson, S. A. Hauck, Snigdha Rai,

Tópico(s)

High-pressure geophysics and materials

Resumo

Research Article| August 01, 2015 Partial Melting Processes and Cu-Ni-PGE Mineralization in the Footwall of the South Kawishiwi Intrusion at the Spruce Road Deposit, Duluth Complex, Minnesota Zsolt Benkó; Zsolt Benkó † 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria †Corresponding author: e-mail, zsoltbenkoo@gmail.com) Search for other works by this author on: GSW Google Scholar Aberra Mogessie; Aberra Mogessie 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria Search for other works by this author on: GSW Google Scholar Ferenc Molnár; Ferenc Molnár 2Geological Survey of Finland, 02151 Espoo, Finland Search for other works by this author on: GSW Google Scholar Mark J. Severson; Mark J. Severson 3Natural Resources Research Institute, University of Minnesota, Duluth, Minnesota 55811 Search for other works by this author on: GSW Google Scholar Steven A. Hauck; Steven A. Hauck 3Natural Resources Research Institute, University of Minnesota, Duluth, Minnesota 55811 Search for other works by this author on: GSW Google Scholar Sara Raič Sara Raič 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria Search for other works by this author on: GSW Google Scholar Author and Article Information Zsolt Benkó † 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria Aberra Mogessie 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria Ferenc Molnár 2Geological Survey of Finland, 02151 Espoo, Finland Mark J. Severson 3Natural Resources Research Institute, University of Minnesota, Duluth, Minnesota 55811 Steven A. Hauck 3Natural Resources Research Institute, University of Minnesota, Duluth, Minnesota 55811 Sara Raič 1Institute of Earth Sciences, Mineralogy and Petrology, Karl-Franzens University of Graz, Universitätsplatz 2, 8010 Graz, Austria †Corresponding author: e-mail, zsoltbenkoo@gmail.com) Publisher: Society of Economic Geologists Received: 03 Nov 2013 Accepted: 07 Jan 2015 First Online: 09 Mar 2017 Online ISSN: 1554-0774 Print ISSN: 0361-0128 © 2015 Society of Economic Geologists. Economic Geology (2015) 110 (5): 1269–1293. https://doi.org/10.2113/econgeo.110.5.1269 Article history Received: 03 Nov 2013 Accepted: 07 Jan 2015 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Zsolt Benkó, Aberra Mogessie, Ferenc Molnár, Mark J. Severson, Steven A. Hauck, Sara Raič; Partial Melting Processes and Cu-Ni-PGE Mineralization in the Footwall of the South Kawishiwi Intrusion at the Spruce Road Deposit, Duluth Complex, Minnesota. Economic Geology 2015;; 110 (5): 1269–1293. doi: https://doi.org/10.2113/econgeo.110.5.1269 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract A strong relationship was documented in the charnockitic footwall at the Spruce Road Cu-Ni sulfide deposit (South Kawishiwi intrusion, Duluth Complex) between the contact metamorphic processes, mineralogy, texture, and ore mineral assemblages.Textural evidences of partial melting, including partial melt films, granophyric intergrowth of feldspar and quartz, as well as in situ partial melt pockets and veins, indicate that partial melting occurred in the granitic footwall even up to 125 m from the footwall-intrusion contact. Temperature in the proximal 10-m segment of the footwall was around 850° to 920°C based on the observed mineral assemblage and two-pyroxene thermometry and decreases to around 700°C 100 m from the intrusion footwall contact. Partial melting of the footwall granite in this segment gave rise to sulfide liquid to sink and infiltrate into the partially molten rock.Fe- and Cu-rich sulfide mineral assemblages have been distinguished in the partially molten footwall. In the proximal 10-m part of the footwall, the sulfide assemblage is pyrrhotite and pentlandite rich, whereas in the distal part, 10 to 100 m from the contact the dominant minerals are chalcopyrite, bornite, millerite, platinum group minerals (PGMs), native gold, and other base and semimetal minerals. Systematic variation of Pd/Rh and Au/Pd ratios indicate that the formation of the sulfide mineral zonation can be interpreted with fractional crystallization of a parent sulfide liquid. Biotite, associated with the Cu-rich assemblage, indicates that fluids may have expelled from the fractionated sulfide liquid. Variation of the Cl/F ratio in the biotite and apatite that crystallized during the peak metamorphism indicates that fluids may have also played a role in the metal and sulfur transport. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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