TY - JOUR

T1 - Signature of off-axis hydrothermal sulfide mineralization at 23.19◦S of Central Indian Ridge: Insights from mineralogy, geochemistry, geochronology and near-seabed AUV survey

AU - Кузнецов, Владислав Юрьевич

AU - Sen, Koushick

AU - Kurian, P. John

AU - Roy, Parijat

AU - Vadakkepuliyambatta, Sunil

AU - Черкашёв, Георгий Александрович

AU - Prakash, L. Surya

AU - Кукса, Катерина Александровна

AU - Кузнецов, Владислав Юрьевич

AU - Firstova, Anna

AU - Tyagi, Abhishek

AU - K. Agarwal, Deepak

AU - Максимов, Федор Евгеньевич

PY - 2025/4/1

Y1 - 2025/4/1

N2 - Seafloor hydrothermal systems and associated sulfide mineralization have been reported along all types of mid-oceanic spreading ridges, island arcs, and back-arc settings. This study reports the occurrence of a distal ridge (∼35 km off-axis) hydrothermal mineralization zone from the slow-spreading Central Indian Ridge (23.19°S) of the Indian Ocean. The hydrothermal precipitates were recovered during dredging operations and mainly comprised of massive sulfides, sulfide breccias, and their secondary oxidized alteration products. The mineralogical quantification of pyrites (significant Cu enrichment, a strong negative correlation with Fe), and bulk sulfide geochemistry (concentrations and ratio of Ba, Co, and Pb) hint at a possible mixed type of mafic-ultramafic host-rock influence in the formation of sulfides. The 230Th/U chronological estimations of pyrites from massive sulfide and sulfide breccia suggest a wide range of hydrothermal activity from 144 ± 11 to 52 ± 7 ka. The AUV-assisted near sea floor sub-bottom profiling (SBP) and High-resolution Interferometric Synthetic Aperture Sonar (HISAS) images suggest that the study area is covered by thin layers of sediments with occasional exposure of hard rock outcrops. The reporting mineralization site stands out to be the most distant and one of the chronologically oldest hydrothermal mineralization zones within the Indian Ocean. The study provides insights into the broader geological processes at off-axis locations concerning the hydrothermal mineralization at slow-spreading ridges and indicates the possibility that such undiscovered buried hydrothermal fields may exist located far from the present-day ridge axis.

AB - Seafloor hydrothermal systems and associated sulfide mineralization have been reported along all types of mid-oceanic spreading ridges, island arcs, and back-arc settings. This study reports the occurrence of a distal ridge (∼35 km off-axis) hydrothermal mineralization zone from the slow-spreading Central Indian Ridge (23.19°S) of the Indian Ocean. The hydrothermal precipitates were recovered during dredging operations and mainly comprised of massive sulfides, sulfide breccias, and their secondary oxidized alteration products. The mineralogical quantification of pyrites (significant Cu enrichment, a strong negative correlation with Fe), and bulk sulfide geochemistry (concentrations and ratio of Ba, Co, and Pb) hint at a possible mixed type of mafic-ultramafic host-rock influence in the formation of sulfides. The 230Th/U chronological estimations of pyrites from massive sulfide and sulfide breccia suggest a wide range of hydrothermal activity from 144 ± 11 to 52 ± 7 ka. The AUV-assisted near sea floor sub-bottom profiling (SBP) and High-resolution Interferometric Synthetic Aperture Sonar (HISAS) images suggest that the study area is covered by thin layers of sediments with occasional exposure of hard rock outcrops. The reporting mineralization site stands out to be the most distant and one of the chronologically oldest hydrothermal mineralization zones within the Indian Ocean. The study provides insights into the broader geological processes at off-axis locations concerning the hydrothermal mineralization at slow-spreading ridges and indicates the possibility that such undiscovered buried hydrothermal fields may exist located far from the present-day ridge axis.

KW - 230Th/U chronology

KW - Central Indian Ridge

KW - Hydrothermal

KW - Indian Ocean

KW - Mid-Ocean ridge

KW - Seafloor massive sulfides (SMS)

UR - https://www.mendeley.com/catalogue/f8458e97-eb2a-37df-8905-41fa05fc5b3d/

U2 - 10.1016/j.margeo.2025.107500

DO - 10.1016/j.margeo.2025.107500

M3 - Article

VL - 482

JO - Marine Geology

JF - Marine Geology

SN - 0025-3227

M1 - 107500

ER -