Weifang Yang, Chunhui Tao, Shili Liao, Jin Liang, Wei Li, Teng Ding, Ágata Alveirinho Dias, Xuefeng Wang, Lisheng Wang. Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge: evidence from sulfide chronology[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2194-6
Citation:
Weifang Yang, Chunhui Tao, Shili Liao, Jin Liang, Wei Li, Teng Ding, Ágata Alveirinho Dias, Xuefeng Wang, Lisheng Wang. Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge: evidence from sulfide chronology[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2194-6
Weifang Yang, Chunhui Tao, Shili Liao, Jin Liang, Wei Li, Teng Ding, Ágata Alveirinho Dias, Xuefeng Wang, Lisheng Wang. Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge: evidence from sulfide chronology[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2194-6
Citation:
Weifang Yang, Chunhui Tao, Shili Liao, Jin Liang, Wei Li, Teng Ding, Ágata Alveirinho Dias, Xuefeng Wang, Lisheng Wang. Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge: evidence from sulfide chronology[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2194-6
Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge: evidence from sulfide chronology
Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
2.
School of Oceanography, Shanghai Jiaotong University, Shanghai 200030, China
3.
School of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China
4.
Institute of Science and Environment, University of Saint Joseph, Macao 999078, China
5.
Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
Funds:
The National Key R&D Program of China under contract No. 2022YFE0140200; the National Natural Science Foundation of China under contract No. 42127807; National Natural Science Foundation of China under contract No. 42006074; China Ocean Mineral Resources R & D Association Project under contract No. DY135-S1-1-02, DY135-S1-1-01; Macao Science and Technology Development Fund under contract No. FDCT-002/2018/A1.
The Yuhuang hydrothermal field (YHF) is located between the Indomed and Gallieni fracture zones near the top of the off-axis slope on the south rift wall of Segment 29 on the ultraslow Southwest Indian Ridge (SWIR). Previous studies have shown that sulfides in the YHF formed during different mineralization episodes and the YHF has the greatest potential for the formation of large-scale seafloor massive sulfide deposits. However, the sulfide chronology and hydrothermal activity of the YHF remain poorly constrained. In this study, mineralogical analyses and 230Th/U dating were performed. Hydrothermal activity may start about (35.9±2.3) kyrs from the southwest part of the YHF and may cease about 708±81 years ago from the northeast part of the YHF. The 74 nonzero chronological data from hydrothermal sulfide samples provide the first quantitative characterization of the spatial and temporal history along the SWIR. Hydrothermal activity in the SWIR has been relatively active over the past 20 kyrs. In contrast, between 40 kyrs and 100 kyrs, hydrothermal activity was relatively infrequently and short in duration. The maximum activity occurred at 15–11 kyrs, 9–7 kyrs, 6–0.2 kyrs. There was a slight positive correlation between the maximal age and estimated surface area or estimated tonnage. The minimum mass accumulation rate of YHF is about 278 t/a, which is higher than most HFs related to ultramafic systems. The ultraslow spreading SWIR have the greatest potential to form large-scale SMS deposits. The results of this study provide new insights into the metallogenic mechanism of hydrothermal sulfides along ultraslow-spreading ridges.
Figure 1. Geological setting and topography of the study area. a. Geotectonic setting and topography of the Southwest Indian Ridge (SWIR) (modified from Yang et al., 2023). b. Shipboard bathymetric map of Yuhuang on the SWIR. c. The sampling stations in this study, all the others sampling stations can be seen in Yu et al., 2021. The red star in a represents the study area while the black dots represent the hydrothermal fields which have mentioned in this paper. White dotted lines in b and red dotted lines in c represent the non-transform discontinuity (NTD) and inferred faults, respectively.
Figure 2. Photographs of sulfides from the Yuhuang hydrothermal field (Modified from Liao et al., 2018). a–d represents sample 21-TVG22-3, 34-TVG22-1, 34-TVG22-2 and 34-TVG23-4 respectively. Mineral abbreviations: Py, pyrite; Ccp, chalcopyrite; Mas, marcasite; Sph, sphalerite; Si, amorphous silica.
Figure 3. Represent photomicrographs of sulfides from the Yuhuang HF. a. Sphalerite coexisting with chalcopyrite and replacing pyrrhotite (21VII-TVG22-3). b. Typical varieties of pyrite: predominant fine-grained pyrite (Py1), coarse-grained pyrite (Py2), and colloform pyrite (Py3) (34-TVG22-1). c. Colloform structure of pyrite and marcasite (34-TVG22-1). d. Pyrite replaced by chalcopyrite, and bornite replaced by chalcopyrite (34-TVG22-1). e. Sphalerite shows two generations (Sph1 and Sph2) that replaced by chalcopyrite, bornite replaced by chalcopyrite (34-TVG22-2). f. Chalcopyrite replaced by sphalerite, chalcopyrite has a bornite solid solution and growth edge (34-TVG22-2). g. Pyrite in the amorphous silica vein replaced by sphalerite (34-TVG23-4). h. Banded sphalerite (34-TVG23-4). i. Sphalerite replaced by pyrite (34-TVG23-4).
Figure 4. The temporal variation of U–Th chemistry of sulfides from the YHF the relationship between 232Th and 238U concentrations (a), age versus 232Th (b), age versus 238U (c) and age versus δ234Uinitial (d).
Figure 5. Age distribution of hydrothermal sulfide samples from the YHF. a. Age error bar chart. b. Distribution bar chart (gray: NES, black: SWS).
DownLoad:
