scholarly journals He–Ar–S Isotopic Compositions of Polymetallic Sulphides from Hydrothermal Vent Fields along the Ultraslow-Spreading Southwest Indian Ridge and Their Geological Implications

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 512 ◽  
Author(s):  
Yan Wang ◽  
Zhongwei Wu ◽  
Xiaoming Sun ◽  
Xiguang Deng ◽  
Yao Guan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Low Temperature ◽  
Sea Water ◽  
Hydrothermal Systems ◽  
Southwest Indian Ridge ◽  
Sulphide Minerals ◽  
Fast Spreading ◽  
The Indian Ocean ◽  
Indian Ridge ◽  
Sulphide Deposits

Noble gases have become a powerful tool to constrain the origin and evolution of ore-forming fluids in seafloor hydrothermal systems. The aim of this study was to apply these tracers to understand the genesis of newly discovered polymetallic sulphide deposits along the ultraslow-spreading Southwest Indian Ridge (SWIR). The helium, argon, and sulphur isotope compositions of metal sulphide minerals were measured for a number of active/inactive vent fields in the Indian Ocean. The helium concentrations and isotopic ratios in these ore samples are variable (4He: 0.09–2.42 × 10−8 cm3STP∙g−1; 3He: 0.06–3.28 × 10−13 cm3STP∙g−1; 3He/4He: 1.12–9.67 Ra) and generally greater than the modern atmosphere, but significantly lower than those in massive sulphides from the fast-spreading East Pacific Rise (EPR), especially for three Cu–Fe-rich samples from the ultramafic-hosted Tianzuo and Kairei vent fields. On the contrary, most of the SWIR sulphide deposits have somewhat higher 40Ar/36Ar ratios of trapped fluids (ranging from 290.6 to 303.4) when compared to the EPR ore samples. Moreover, the majority of sulphide minerals from the Indian Ocean have much higher δ34S values (3.0‰–9.8‰, ~5.9 on average, n = 49) than other basaltic-hosted active hydrothermal systems on the EPR. Overall, these He–Ar–S results are well within the range of seafloor massive sulphide deposits at global sediment-starved mid-ocean ridges (MORs), lying between those of air-saturated water (ASW) and mid-ocean ridge basalt (MORB) end members. Therefore, our study suggests that the helium was derived mainly from the MORB mantle by degassing during the high-temperature stage of hydrothermal activity, as well as from a mixture of vent fluids with variable amounts of ambient seawater during either earlier or late-stage low-temperature hydrothermal episodes, whereas the argon in ore-forming fluids trapped within sulphide minerals was predominantly derived from deep-sea water. Additionally, relatively high δ34S values exhibit a great estimated proportion (up to nearly 40%) of seawater-derived components. In summary, sub-seafloor extensive fluid circulation, pervasive low-temperature alteration, shallow seawater entrainment, and mixing processes, may make a larger contribution to the SWIR hydrothermal ore-forming systems, compared to fast-spreading centres.

scholarly journals New insights into the origin and distribution of the DUPAL isotope anomaly in the Indian Ocean mantle from MORB of the Southwest Indian Ridge

2005 ◽  
Vol 6 (11) ◽  
pp. n/a-n/a ◽  
Author(s):  
Christine M. Meyzen ◽  
John N. Ludden ◽  
Eric Humler ◽  
Béatrice Luais ◽  
Michael J. Toplis ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southwest Indian Ridge ◽  
The Indian Ocean ◽  
Indian Ridge

scholarly journals Out of the Pacific: A New Alvinellid Worm (Annelida: Terebellida) From the Northern Indian Ocean Hydrothermal Vents

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuru Han ◽  
Dongsheng Zhang ◽  
Chunsheng Wang ◽  
Yadong Zhou
Keyword(s):  
Indian Ocean ◽  
Hydrothermal Vents ◽  
Southwest Indian Ridge ◽  
Rrna Genes ◽  
Northwest Pacific ◽  
Northern Indian Ocean ◽  
West Pacific ◽  
The Pacific ◽  
The Indian Ocean ◽  
Indian Ridge

Alvinellids have long been considered to be endemic to Pacific vents until recent discovery of their presence in the Indian Ocean. Here, a new alvinellid is characterized and formally named from recently discovered vents, Wocan, and Daxi, in the northern Indian Ocean. Both morphological and molecular evidences support its placement in the genus Paralvinella, representing the first characterized alvinellid species out of the Pacific. The new species, formally described as Paralvinella mira n. sp. herein, is morphologically most similar to Paralvinella hessleri from the northwest Pacific, but the two species differ in three aspects: (1), the first three chaetigers are not fused in P. mira n. sp., whereas fused in P. hessleri; (2), paired buccal tentacles short and pointed in P. mira but large and strongly pointed in P. hessleri; (3), numerous slender oral tentacles ungrouped in P. mira but two groups in P. hessleri. Phylogenetic inference using the concatenated alignments of the cytochrome c oxidase I (COI), 16S rRNA and 18S rRNA genes strongly supports the clustering of P. mira with two West Pacific congeners, P. hessleri and an undescribed species (Paralvinella sp. ZMBN). The resulting Indian/West Pacific lineage suggests a possible invasion into the Indian Ocean from the West Pacific. This is the third polychaete reported from Wocan hydrothermal field. Among the three species, two including P. mira and Hesiolyra heteropoda (Annelida:Hesionidae) are present in high abundance, forming an alvinellids/hesionids-dominated polychaete assemblage distinct from that at all other Central Indian Ridge and Southwest Indian Ridge vents. Thus, this study expands our understanding of alvinellid biogeography beyond the Pacific, and adds to the unique biodiversity of the northern Indian Ocean vents, with implications for biogeographic subdivision across the Indian Ocean ridges.

scholarly journals Nearest vent, dearest friend: biodiversity of Tiancheng vent field reveals cross-ridge similarities in the Indian Ocean

2020 ◽  
Vol 7 (3) ◽  
pp. 200110 ◽  
Author(s):  
Jin Sun ◽  
Yadong Zhou ◽  
Chong Chen ◽  
Yick Hang Kwan ◽  
Yanan Sun ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Hydrothermal Vents ◽  
Southwest Indian Ridge ◽  
Central Indian Ridge ◽  
Diffuse Flow ◽  
Dispersal Barrier ◽  
The Indian Ocean ◽  
Biological Sampling ◽  
Indian Ridge ◽  
Key Barrier

Biodiversity of hydrothermal vents in the Indian Ocean, particularly those on the Southwest Indian Ridge (SWIR), are still relatively poorly understood. The Tiancheng field on the SWIR was initially reported with only a low-temperature diffuse flow venting area, but here we report two new active areas, including a chimney emitting high-temperature vent fluids. Biological sampling in these new sites doubled the known megafauna and macrofauna richness reported from Tiancheng. Significantly, we found several iconic species, such as the scaly-foot snail and the first Alviniconcha population on the SWIR. Tiancheng shares a high proportion of taxa with vents on the Central Indian Ridge (CIR) and lacks a number of key taxa that characterize other vents investigated so far on the SWIR. Population genetics of the scaly-foot snail confirmed this, as the Tiancheng population was clustered with populations from the CIR, showing low connectivity with the Longqi field. Unlike the previously examined populations, scales of the Tiancheng scaly-foot snail were coated in zinc sulfide, although this results only from precipitation. The close connection between Tiancheng and CIR vents indicates that the dispersal barrier for vent endemic species is not the Rodriguez Triple Junction as previously suggested but the transformation faults between Tiancheng and Longqi, warranting further studies on deep currents in this area to resolve the key barrier, which has important implications for biological conservation.

scholarly journals Carbon-14 in the Southern Indian Ocean

Radiocarbon ◽  
1980 ◽  
Vol 22 (3) ◽  
pp. 684-692 ◽  
Author(s):  
Georgette Delibrias
Keyword(s):  
Surface Water ◽  
Indian Ocean ◽  
Water Samples ◽  
Sea Water ◽  
Time Lag ◽  
Vertical Profiles ◽  
Carbon 14 ◽  
Middle Latitudes ◽  
The North ◽  
The Indian Ocean

14C measurements were carried out on sea water samples collected in 1973, in the Indian ocean. The results obtained for 9 vertical profiles between 27° S and 48°S are presented. In surface water, the bomb 14C content is maximum at middle latitudes. A time lag relative to the north hemisphere bomb 14C delivery is apparent. In the more southern latitudes, 14C content remains very low.

Segmentation of the Central Indian Ridge between 12°12′ S and the Indian Ocean Triple Junction

1993 ◽  
Vol 15 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Lindsay M. Parson ◽  
Philippe Patriat ◽  
Roger C. Searle ◽  
Anne R. Briais
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Central Indian Ridge ◽  
The Indian Ocean ◽  
Indian Ridge

scholarly journals Pararhodobacter marinus sp. nov., isolated from deep-sea water of the Indian Ocean

2019 ◽  
Vol 69 (4) ◽  
pp. 932-936 ◽  
Author(s):  
Qiliang Lai ◽  
Xiupian Liu ◽  
Jun Yuan ◽  
Shuchen Xie ◽  
Zongze Shao
Keyword(s):  
Indian Ocean ◽  
Deep Sea ◽  
Type Species ◽  
Sea Water ◽  
Rrna Gene ◽  
Chromosomal Dna ◽  
Content Type ◽  
Deep Sea Water ◽  
Link Type ◽  
The Indian Ocean

A taxonomic study was carried out on strain CIC4N-9T, which was isolated from deep-sea water of the Indian Ocean. The bacterium was Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and non-motile. Growth was observed at salinities of 0–9% and at temperatures of 4–41 °C. The isolate was able to degrade gelatin but not aesculin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CIC4N-9T belonged to the genus Pararhodobacter , with the highest sequence similarity to the only recognized species, Pararhodobacter aggregans D1-19T (96.9 %). The average nucleotide identity and estimated DNA–DNA hybridization values between strain CIC4N-9T and P. aggregans D1-19T were 80.4 and 23.0 %, respectively. The principal fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0, C18 : 1ω7c 11-methyl, C18 : 0 and C17 : 0. The G+C content of the chromosomal DNA was 66.8 mol%. The sole respiratory quinone was determined to be Q-10. Phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, two unknown phospholipids, four unknown aminolipids and one unknown polar lipid were present. The combined genotypic and phenotypic data show that strain CIC4N-9T represents a novel species within the genus Pararhodobacter , for which the name Pararhodobacter marinus sp. nov. is proposed. The type strain is CIC4N-9T (=MCCC 1A01225T=KCTC 52336T).

scholarly journals Eocene to recent development of the South-west Indian Ridge, a consequence of the evolution of the Indian Ocean Triple Junction

1981 ◽  
Vol 64 (3) ◽  
pp. 587-604 ◽  
Author(s):  
John G. Sclater ◽  
Robert L. Fisher ◽  
Phillippe Patriat ◽  
Christopher Tapscott ◽  
Barry Parsons
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
West Indian ◽  
The South ◽  
South West ◽  
The Indian Ocean ◽  
Indian Ridge
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