TY - JOUR
T1 - A tool for Zn-Pb MVT exploration by combining C and O isotopes and REE geochemistry of dolomite
AU - Navarro-Ciurana, Dídac
AU - Corral, Isaac
AU - Corbella, Mercè
N1 - Funding Information:
The authors would like to acknowledge Dr. Albert Griera, Dr. David Gómez-Gras (Universitat Autònoma de Barcelona) and Federico Ballesta (Ciencia y Aventura Company) for their help and assessment during fieldwork. The authors would like to acknowledge the technicians of the Laboratori de Preparació de Làmines Primes of Universitat Autònoma de Barcelona for their support in the preparation of thin sections, the Serveis Científics Tècnics of the Universitat de Barcelona and the Geochronology and the Isotope Geochemistry Centre of the Universidad Complutense de Madrid for their support during isotopic analysis. The authors are grateful to the AGAUR-SGR2017-1485 research group. We would like to thank Saulo de Oliveira and anonymous referee for their critical and valuable reviews, as well as to the Associated Editor Huayong Che for handling this manuscript. Funding for this research was provided by the Spanish projects CGL2011-26488 and PID2019-109018RB-I00 to M. Corbella granted by the Spanish Ministerio de Economía y Competitividad and Ministerio de Ciencia e Innovación, respectivelly. Additional support was provided by the Universitat Autònoma de Barcelona and Universitat de Barcelona.
Funding Information:
Funding for this research was provided by the Spanish projects CGL2011-26488 and PID2019-109018RB-I00 to M. Corbella granted by the Spanish Ministerio de Economía y Competitividad and Ministerio de Ciencia e Innovación, respectivelly. Additional support was provided by the Universitat Autònoma de Barcelona and Universitat de Barcelona.
Publisher Copyright:
© 2023 The Author(s)
PY - 2023/5
Y1 - 2023/5
N2 - An exploration guide for Mississippi Valley-type (MVT) deposits is proposed and illustrated in the Riópar area (SE Spain), where extensive dolostone geobodies hosting Zn-(Fe-Pb) MVT mineralization occur. These base metal deposits are found within stratabound and patchy dolostones replacing Upper Jurassic to Lower Cretaceous limestones. However widespread stratabound dolostones, with no Zn-(Fe-Pb) mineralization associated, are also found in the same area replacing Lower Jurassic to Upper Cretaceous carbonates. A detailed sampling of both, Zn-(Fe-Pb) mineralized dolostones (fertile), as well as unmineralized ones (barren), has been performed in an area of ∼106 km2 to characterize their rare earth element (REE) and isotopic (C, O, Sr) compositions. Barren Lower and Middle Jurassic and Upper Cretaceous dolostones show C, O and Sr isotopic characteristics (δ13C = +2.1 to +3.8‰ VPDB, δ18O = +27.6 to +29.8 ‰ VSMOW, 87Sr/86Sr = 0.70736 to 0.70764) like the Jurassic-Cretaceous undolomitized limestones and marine carbonates, and consistent with dolostones produced by low temperature seawater. On the contrary, barren and fertile Upper Jurassic to Lower Cretaceous stratabound and patchy dolomitized limestones are depleted in δ13C and δ18O and relatively enriched in 87Sr/86Sr compared to the host limestones. This δ13C and δ18O composition can be explained by an interaction of warm fluids with regional carbonates (2–3% of fluid/rock interaction at 190–230 °C). The hydrothermal character for the dolomitizing fluid is supported by REE geochemical data (e.g., (Pr/Pr*)PAASN and (Ce/Ce*)PAASN anomalies). Thus, C and O isotopes, as well as (Ce/Ce*)PAASN and (Pr/Pr*)PAASN ratios, can be used to discriminate between low temperature dolostones, formed from cold seawater that do not contain Zn-(Fe-Pb) mineralization (barren), from hydrothermal dolomites (HTDs), which may host Zn-(Fe-Pb) mineralization. Furthermore, most barren HTDs show more restricted and higher δ13C (+0.4 to +0.9 ‰ VPDB) and δ18O values (+26.4 to +27.1 ‰ VSMOW), as well as lower ∑REE contents (5.41 to 7.38 mg kg−1), compared to Zn-(Fe-Pb) mineralized HTDs (δ13C: −2.3 to +0.6 ‰ VPDB; δ18O: +25.1 to +27.1 ‰ VSMOW; ∑REE 14.10 to 54.79 mg kg−1). Therefore, the obtained REE contents, and partially the δ13C values, can be used to discriminate between HTDs associated with Zn-(Fe-Pb) mineralization (fertile dolostones) and barren HTDs, revealing their potential as a new geochemical tool for MVT exploration in dolomitized terrains.
AB - An exploration guide for Mississippi Valley-type (MVT) deposits is proposed and illustrated in the Riópar area (SE Spain), where extensive dolostone geobodies hosting Zn-(Fe-Pb) MVT mineralization occur. These base metal deposits are found within stratabound and patchy dolostones replacing Upper Jurassic to Lower Cretaceous limestones. However widespread stratabound dolostones, with no Zn-(Fe-Pb) mineralization associated, are also found in the same area replacing Lower Jurassic to Upper Cretaceous carbonates. A detailed sampling of both, Zn-(Fe-Pb) mineralized dolostones (fertile), as well as unmineralized ones (barren), has been performed in an area of ∼106 km2 to characterize their rare earth element (REE) and isotopic (C, O, Sr) compositions. Barren Lower and Middle Jurassic and Upper Cretaceous dolostones show C, O and Sr isotopic characteristics (δ13C = +2.1 to +3.8‰ VPDB, δ18O = +27.6 to +29.8 ‰ VSMOW, 87Sr/86Sr = 0.70736 to 0.70764) like the Jurassic-Cretaceous undolomitized limestones and marine carbonates, and consistent with dolostones produced by low temperature seawater. On the contrary, barren and fertile Upper Jurassic to Lower Cretaceous stratabound and patchy dolomitized limestones are depleted in δ13C and δ18O and relatively enriched in 87Sr/86Sr compared to the host limestones. This δ13C and δ18O composition can be explained by an interaction of warm fluids with regional carbonates (2–3% of fluid/rock interaction at 190–230 °C). The hydrothermal character for the dolomitizing fluid is supported by REE geochemical data (e.g., (Pr/Pr*)PAASN and (Ce/Ce*)PAASN anomalies). Thus, C and O isotopes, as well as (Ce/Ce*)PAASN and (Pr/Pr*)PAASN ratios, can be used to discriminate between low temperature dolostones, formed from cold seawater that do not contain Zn-(Fe-Pb) mineralization (barren), from hydrothermal dolomites (HTDs), which may host Zn-(Fe-Pb) mineralization. Furthermore, most barren HTDs show more restricted and higher δ13C (+0.4 to +0.9 ‰ VPDB) and δ18O values (+26.4 to +27.1 ‰ VSMOW), as well as lower ∑REE contents (5.41 to 7.38 mg kg−1), compared to Zn-(Fe-Pb) mineralized HTDs (δ13C: −2.3 to +0.6 ‰ VPDB; δ18O: +25.1 to +27.1 ‰ VSMOW; ∑REE 14.10 to 54.79 mg kg−1). Therefore, the obtained REE contents, and partially the δ13C values, can be used to discriminate between HTDs associated with Zn-(Fe-Pb) mineralization (fertile dolostones) and barren HTDs, revealing their potential as a new geochemical tool for MVT exploration in dolomitized terrains.
KW - Exploration tool
KW - Fertile/barren hydrothermal dolomite
KW - Mississippi Valley-Type deposits
KW - Rare earth element geochemistry
KW - Sr ratios
KW - Stable isotopes
UR - http://www.scopus.com/inward/record.url?scp=85150934617&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/fe3d88b5-d437-34a8-a1f4-a45463fcb48a/
U2 - 10.1016/j.oregeorev.2023.105405
DO - 10.1016/j.oregeorev.2023.105405
M3 - Article
AN - SCOPUS:85150934617
SN - 0169-1368
VL - 156
JO - Ore Geology Reviews
JF - Ore Geology Reviews
M1 - 105405
ER -
