Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran
Introduction Erosion and oxidation of massive sulfides when uplifted and exposed to the surface, commonly lead to the formation of gossans. In this process, surface water will dissolve soluble elements, and oxides and hydroxides of iron (goethite and hematite) will form on top of the volcanogenic m...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | fas |
| Published: |
Ferdowsi University of Mashhad
2021-11-01
|
| Series: | Journal of Economic Geology |
| Subjects: | |
| Online Access: | https://econg.um.ac.ir/article_41342.html |
| _version_ | 1818852096864157696 |
|---|---|
| author | Hojatollah Jahangiri Saeed Saadat Seyed Ahmad Mazaheri Mohammad Reza Heidarian Shahri Mohammad Foudazi Jafar Omrani |
| author_facet | Hojatollah Jahangiri Saeed Saadat Seyed Ahmad Mazaheri Mohammad Reza Heidarian Shahri Mohammad Foudazi Jafar Omrani |
| author_sort | Hojatollah Jahangiri |
| collection | DOAJ |
| description | Introduction
Erosion and oxidation of massive sulfides when uplifted and exposed to the surface, commonly lead to the formation of gossans. In this process, surface water will dissolve soluble elements, and oxides and hydroxides of iron (goethite and hematite) will form on top of the volcanogenic massive sulfide (VMS) deposits. The main tectonic settings for Iranian VMS deposits are magmatic arcs, which can be subdivided into volcanic primitive arc, arc/intra-arc rift, and back-arc settings and Sanandaj-Sirjan zone is one of the structural zones that host many VMS deposits in Iran (Mousivand et al., 2018).
The study area is located southwest of Jiroft, Kerman province. The main rock units include vitric tuff, pelagic sediments, volcano-sedimentary rocks, gabbro and intermediate to mafic dykes. Mineralization has occurred in volcano-sedimentary beds. The pelagic sediments which are composed of limestone, shale, sandstone, siltstone and interlayers of pillow lava, are the main hosts for mineralization. Surface oxidation of mineralized zones has led to conversion of primary sulfides to iron oxides and hydroxides to form gossan. This study contributes to mineralogical and geochemical composition and mineralization of gossans to demonstrate how surface oxidation of primary sulfides can play a role in locating VMS mineralization at depth.
Materials and methods
A geological map with a scale of 1:5000 was prepared during field and laboratory studies. Twenty polished section were studied to identify mineral distributions and textures, and some of them were chosen for scanning electron microscopic (SEM) examinations. Fifteen rock samples from the gossan horizons were chosen for geochemical studies. The samples were taken from across the mineralized horizon. Six rock samples were taken from old mining site outcrops to compare the geochemistry of gossans with other surface mineralization. All samples were sent to the laboratory for analysis by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The rare earth element (REEs) values were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). X-ray diffraction (XRD) spectroscopy was used to identify mineralogy of 30 rock samples. All analyses were performed in the central laboratory of the Geological Survey and Mineral Exploration of Iran, in Tehran and Karaj.
Results
The ore and gangue minerals have massive, layered, disseminated, veinlet, breccia and replacement textures. Based on mineralography, XRD and SEM studies, the main minerals are hematite, goethite, quartz, and jarosite-group minerals. The upper horizon of gossan, with 13 meters thickness has large volume of hematite and gothite minerals. The enrichment of gold, arsenic, antimony, silver, lead and bismuth were observed in this zone. The lower horizon, with a thickness of about 1.5 meters show anomalies of copper and zinc elements. The highest amount of gold and silver were measured about 18.5 and 120 g/ton, respectively. The highest amount of lead element is 1.3 wt.%, which shows a positive correlation with silver variations. The other values are copper 0.16 wt.%, arsenic 0.61 wt.%, bismuth 580 g/ton, and antimony 280 g/ton.
Discussion
Trace and REEs geochemistry are useful in identifying gossans and probable sources (Scott et al., 2001). Geochemical studies also can be used to separate mature from immature gossans. Although the composition of gossans is influenced by early composition of the ore, gossans with high content of Pb (more than 4 wt.%) are usually considered immature. The average Pb measured in the studied gossans is about 2210 g/ton. The Ag content is also low (less than 150 g/ton) and there is a relatively linear relationship between increasing Ag and Pb content. High values of copper often refer to a lower degree of maturity. In the studied gossans, the average amount of Cu is about 2900 g/ton, which is much lower than the immature gossans with average 1.6 wt.%. Therefore, the results of chemical analysis indicate that these gossans are in the category of mature ore bearing gossan.
The REE from La to Lu, is relatively consistent with the shape of REE profiles for volcanogenic massive sulfide mineralization and concurrent massive sulfide gossans (Peter et al., 2003; Volesky et al., 2017; Gieré, 1993). The pattern of distribution of REEs shows small positive Eu enrichment and zoning of precious mineral elements confirms the possibility of orebody under the gossans. Further exploration of volcanogenic massive sulfide deposits is recommended for this area.
References
Gieré, R., 1993. Transport and deposition of REE in H2S-rich fluids: evidence from accessory mineral assemblages. Chemical Geology, 110(1–3): 251–268. https://doi.org/10.1016/0009-2541(93)90257-J
Mousivand, F., Rastad, E., Peter, J.M. and Maghfouri, S., 2018. Metallogeny of volcanogenic massive sulfide deposits of Iran. Ore Geology Reviews, 95: 974–1007. https://doi.org/10.1016/j.oregeorev.2018.01.011
Peter, J.M., Goodfellow, W.D. and Doherty, W., 2003. Hydrothermal sedimentary rocks of the Heath Steele Belt, Bathurst Mining Camp, New Brunswick: Part 2. Bulk and rare earth element geochemistry and implications for origin. In: W.D. Goodfellow, S.R. McCutcheon and J.M. Peter (Editors), Massive Sulphide Deposits of the Bathurst Mining Camp, New Brunswick, and Northern Maine, Littleton, CO, Society of Economic Geologists, pp. 391–415.
https://doi.org/10.5382/Mono.11.17
Scott, K.M., Ashley, P.M. and Lawie, D.C., 2001. The geochemistry, mineralogy and maturity of gossans derived from volcanogenic Zn–Pb–Cu deposits of the eastern Lachlan Fold Belt, NSW, Australia. Journal of Geochemical Exploration, 72(3): 169–191. https://doi.org/10.1016/S0375-6742(01)00159-5
Volesky, J.C., Leybourne, M.I., Stern, R.J., Peter, J.M., Layton-Matthews, D., Rice, S. and Johnson, P.R., 2017. Metavolcanic host rocks, mineralization, and gossans of the Shaib al Tair and Rabathan volcanogenic massive sulphide deposits of the Wadi Bidah Mineral District, Saudi Arabia. International Geology Review, 59(16): 1975–2002. https://doi.org/10.1080/00206814.2017.1307789 |
| first_indexed | 2024-12-19T07:15:30Z |
| format | Article |
| id | doaj.art-0fc78b3b2fe14f558c63c3550bae29b1 |
| institution | Directory Open Access Journal |
| issn | 2008-7306 |
| language | fas |
| last_indexed | 2024-12-19T07:15:30Z |
| publishDate | 2021-11-01 |
| publisher | Ferdowsi University of Mashhad |
| record_format | Article |
| series | Journal of Economic Geology |
| spelling | doaj.art-0fc78b3b2fe14f558c63c3550bae29b12022-12-21T20:31:04ZfasFerdowsi University of MashhadJournal of Economic Geology2008-73062021-11-0113353755910.22067/ECONG.V13I3.86658Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of IranHojatollah Jahangiri 0Saeed Saadat1Seyed Ahmad Mazaheri2Mohammad Reza Heidarian Shahri3Mohammad Foudazi4Jafar Omrani 5Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranDepartment of Geology and Petroleum Engineering, Mashhad Branch, Islamic Azad University, Mashhad, IranDepartment of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranDepartment of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IranDepartment of Geology, Islamshahr Branch, Islamic Azad University, Islamshahr, IranGeological Survey and Mineral Exploration of Iran, Tehran, IranIntroduction Erosion and oxidation of massive sulfides when uplifted and exposed to the surface, commonly lead to the formation of gossans. In this process, surface water will dissolve soluble elements, and oxides and hydroxides of iron (goethite and hematite) will form on top of the volcanogenic massive sulfide (VMS) deposits. The main tectonic settings for Iranian VMS deposits are magmatic arcs, which can be subdivided into volcanic primitive arc, arc/intra-arc rift, and back-arc settings and Sanandaj-Sirjan zone is one of the structural zones that host many VMS deposits in Iran (Mousivand et al., 2018). The study area is located southwest of Jiroft, Kerman province. The main rock units include vitric tuff, pelagic sediments, volcano-sedimentary rocks, gabbro and intermediate to mafic dykes. Mineralization has occurred in volcano-sedimentary beds. The pelagic sediments which are composed of limestone, shale, sandstone, siltstone and interlayers of pillow lava, are the main hosts for mineralization. Surface oxidation of mineralized zones has led to conversion of primary sulfides to iron oxides and hydroxides to form gossan. This study contributes to mineralogical and geochemical composition and mineralization of gossans to demonstrate how surface oxidation of primary sulfides can play a role in locating VMS mineralization at depth. Materials and methods A geological map with a scale of 1:5000 was prepared during field and laboratory studies. Twenty polished section were studied to identify mineral distributions and textures, and some of them were chosen for scanning electron microscopic (SEM) examinations. Fifteen rock samples from the gossan horizons were chosen for geochemical studies. The samples were taken from across the mineralized horizon. Six rock samples were taken from old mining site outcrops to compare the geochemistry of gossans with other surface mineralization. All samples were sent to the laboratory for analysis by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The rare earth element (REEs) values were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). X-ray diffraction (XRD) spectroscopy was used to identify mineralogy of 30 rock samples. All analyses were performed in the central laboratory of the Geological Survey and Mineral Exploration of Iran, in Tehran and Karaj. Results The ore and gangue minerals have massive, layered, disseminated, veinlet, breccia and replacement textures. Based on mineralography, XRD and SEM studies, the main minerals are hematite, goethite, quartz, and jarosite-group minerals. The upper horizon of gossan, with 13 meters thickness has large volume of hematite and gothite minerals. The enrichment of gold, arsenic, antimony, silver, lead and bismuth were observed in this zone. The lower horizon, with a thickness of about 1.5 meters show anomalies of copper and zinc elements. The highest amount of gold and silver were measured about 18.5 and 120 g/ton, respectively. The highest amount of lead element is 1.3 wt.%, which shows a positive correlation with silver variations. The other values are copper 0.16 wt.%, arsenic 0.61 wt.%, bismuth 580 g/ton, and antimony 280 g/ton. Discussion Trace and REEs geochemistry are useful in identifying gossans and probable sources (Scott et al., 2001). Geochemical studies also can be used to separate mature from immature gossans. Although the composition of gossans is influenced by early composition of the ore, gossans with high content of Pb (more than 4 wt.%) are usually considered immature. The average Pb measured in the studied gossans is about 2210 g/ton. The Ag content is also low (less than 150 g/ton) and there is a relatively linear relationship between increasing Ag and Pb content. High values of copper often refer to a lower degree of maturity. In the studied gossans, the average amount of Cu is about 2900 g/ton, which is much lower than the immature gossans with average 1.6 wt.%. Therefore, the results of chemical analysis indicate that these gossans are in the category of mature ore bearing gossan. The REE from La to Lu, is relatively consistent with the shape of REE profiles for volcanogenic massive sulfide mineralization and concurrent massive sulfide gossans (Peter et al., 2003; Volesky et al., 2017; Gieré, 1993). The pattern of distribution of REEs shows small positive Eu enrichment and zoning of precious mineral elements confirms the possibility of orebody under the gossans. Further exploration of volcanogenic massive sulfide deposits is recommended for this area. References Gieré, R., 1993. Transport and deposition of REE in H2S-rich fluids: evidence from accessory mineral assemblages. Chemical Geology, 110(1–3): 251–268. https://doi.org/10.1016/0009-2541(93)90257-J Mousivand, F., Rastad, E., Peter, J.M. and Maghfouri, S., 2018. Metallogeny of volcanogenic massive sulfide deposits of Iran. Ore Geology Reviews, 95: 974–1007. https://doi.org/10.1016/j.oregeorev.2018.01.011 Peter, J.M., Goodfellow, W.D. and Doherty, W., 2003. Hydrothermal sedimentary rocks of the Heath Steele Belt, Bathurst Mining Camp, New Brunswick: Part 2. Bulk and rare earth element geochemistry and implications for origin. In: W.D. Goodfellow, S.R. McCutcheon and J.M. Peter (Editors), Massive Sulphide Deposits of the Bathurst Mining Camp, New Brunswick, and Northern Maine, Littleton, CO, Society of Economic Geologists, pp. 391–415. https://doi.org/10.5382/Mono.11.17 Scott, K.M., Ashley, P.M. and Lawie, D.C., 2001. The geochemistry, mineralogy and maturity of gossans derived from volcanogenic Zn–Pb–Cu deposits of the eastern Lachlan Fold Belt, NSW, Australia. Journal of Geochemical Exploration, 72(3): 169–191. https://doi.org/10.1016/S0375-6742(01)00159-5 Volesky, J.C., Leybourne, M.I., Stern, R.J., Peter, J.M., Layton-Matthews, D., Rice, S. and Johnson, P.R., 2017. Metavolcanic host rocks, mineralization, and gossans of the Shaib al Tair and Rabathan volcanogenic massive sulphide deposits of the Wadi Bidah Mineral District, Saudi Arabia. International Geology Review, 59(16): 1975–2002. https://doi.org/10.1080/00206814.2017.1307789https://econg.um.ac.ir/article_41342.htmlgossanvolcanogenic massive sulfidegeochemistryrare earth elementsjiroftiran |
| spellingShingle | Hojatollah Jahangiri Saeed Saadat Seyed Ahmad Mazaheri Mohammad Reza Heidarian Shahri Mohammad Foudazi Jafar Omrani Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran Journal of Economic Geology gossan volcanogenic massive sulfide geochemistry rare earth elements jiroft iran |
| title | Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran |
| title_full | Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran |
| title_fullStr | Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran |
| title_full_unstemmed | Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran |
| title_short | Geochemistry, Mineralography and Rare Earth Elements Distribution of Gossans related to Volcanogenic Massive Sulfide Deposit, Case Study: Ghaleh-Rigi, Southwest of Jiroft, South of Iran |
| title_sort | geochemistry mineralography and rare earth elements distribution of gossans related to volcanogenic massive sulfide deposit case study ghaleh rigi southwest of jiroft south of iran |
| topic | gossan volcanogenic massive sulfide geochemistry rare earth elements jiroft iran |
| url | https://econg.um.ac.ir/article_41342.html |
| work_keys_str_mv | AT hojatollahjahangiri geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran AT saeedsaadat geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran AT seyedahmadmazaheri geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran AT mohammadrezaheidarianshahri geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran AT mohammadfoudazi geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran AT jafaromrani geochemistrymineralographyandrareearthelementsdistributionofgossansrelatedtovolcanogenicmassivesulfidedepositcasestudyghalehrigisouthwestofjiroftsouthofiran |