Volcanogenic–hydrothermal iron-rich materials from the southern part of the Central Indian Ocean Basin

Iyer, Sridhar D.; Gupta, Sandeep K.; Charan, S. N.; Mills, Owen P.

doi:10.1016/s0025-3227(98)00167-4

Cited by 30 publications

(15 citation statements)

References 36 publications

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“…A study of several sediment (surficial and cores) revealed that at specific sites volcanogenic-hydrothermal materials (vhm) occur in the CIOB (Iyer et al, 1997(Iyer et al, , 1999b(Iyer et al, , 2007. The coarse fraction at times hosts 2200 to 2500 particles of vhm=gm.…”

Section: Evidence Of Hydrothermal Activitymentioning

confidence: 99%

“…While there could be several sources for the spherules, such as: (i) industrial, (ii) diagenetic, (iii) biological, (iv) extraterrestrial, and (v) volcanic, we rule out the first four sources based on composition and morphology (Iyer et al, 1997(Iyer et al, , 1999b. On the contrary, the dominance of magnetite, associated with silicate fragments, presence of magmaphile elements and presence of diagnostic elements like Ti and Mn in IONF spherules suggest the spherules to be volcanic in origin (Iyer et al, 1997).…”

Section: Evidence Of Hydrothermal Activitymentioning

confidence: 99%

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A Comprehensive View of Manganese Nodules and Volcanics of the Central Indian Ocean Basin

Jauhari

Iyer

2008

Marine Georesources & Geotechnology

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Section: Evidence Of Hydrothermal Activitymentioning

confidence: 99%

Section: Evidence Of Hydrothermal Activitymentioning

confidence: 99%

A Comprehensive View of Manganese Nodules and Volcanics of the Central Indian Ocean Basin

Jauhari

Iyer

2008

Marine Georesources & Geotechnology

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“…The baked sediments in our core are thus, perhaps formed because of volcanic‐hydrothermal episodes. Such types of baked sediments and magnetite spherules have been noted in cores recovered from the CIOB (Iyer et al, ). The role of the Indrani fracture zone cannot be ruled out as a potential source of hydrothermal inputs to the sediment.…”

Section: Discussionmentioning

confidence: 99%

“…The FZ are associated with chains of seamounts that perhaps grew in multiple stages and some witnessed secondary eruptions, facilitated by tectonic reactivation (Das et al, ). Within the basin, from north to south there are three sediment types, namely terrigenous, siliceous, and pelagic red clay while a small patch of calcareous sediment occurs to the northeast and at places volcanogenic‐hydrothermal materials (vhm) in the sediments (Iyer et al, ).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Alteration Promotes Humic Acid Formation in Sediments: A Case Study of the Central Indian Ocean Basin

et al. 2018

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Anomalously high concentrations of humic‐rich dissolved organic matter (DOM) in extant submarine hydrothermal vent plumes traveled far from source are increasingly being reported. This DOM, able to mobilize trace metals (e.g., Fe2+) has been hypothesized as originating from organic matter produced by thermogenic bacteria. To eliminate a possible abiogenic origin of this DOM, study is required of well‐preserved organic compounds that can be attributed to thermogenic bacteria. The Central Indian Ocean Basin (CIOB) is part of a diffuse plate boundary and an intraplate deformation zone. Coarse fraction (>63 µ) characteristics, mineralogy, magnetic susceptibility, and geochemistry were examined in sediments of a core raised close to a north‐south fracture zone near the Equator. Two horizons of distinctly brown‐colored sediments were shown as hydrothermally altered from their charred fragments and geochemistry (CaCO3, Corg, Ti/Al, Al/(Al + Fe + Mn), Sr/Ba, Mg/Li, Mn micronodules, Fe/Mn). We examined whether humic substances were preserved in these sediments, and if so whether their carbon isotope distribution would support their hydrothermal origin. Alkali extraction of sediments afforded humic acids (HA) in yields up to 1.2% in the brown sediments. The remaining portions of the core had nil or low concentrations of HA. The carbon of hydrothermal HA is isotopically heavier (average δ13C, ∼ −16.3‰) compared to nonhydrothermal HA (–18.1‰), suggesting that they were probably formed from organic matter that remained after elimination of lighter carbon enriched functional groups during diagenesis. The results provide compelling evidence of HA formation from lipids originating from thermogenic bacteria.

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“…Therefore, the discovery of microtektites provides evidence for an impact event. Iyer et al (1999) reported the occurrence of mag netite-rich spherules from the Central Indian Ocean Basin. It has been suggested that they were formed as a result of volcanic activity, whereas the presence of nontronite suggests localized hydrothermal activ ity.…”

Section: Microtektites: Evidence For Meteoritic Impactmentioning

confidence: 99%

Ni-Ir Anomaly, Microtektites, and the Biotic Crisis across the Devonian–Carboniferous Boundary, Southern China

Bai

2001

International Geology Review

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Integrative methods of chemostratigraphy and biostratigraphy were used in the study of microtektites and moderate nickel-iridium anomaly beds in the Devonian-Carboniferous boundary beds at Huangmao (Guangxi Autonomous Region) and Muhua (Guizhou Province) in southern China. Microtektites provide evidence for meteoritic impact event(s), whereas the minerals and the chemical composition of the Ni-Ir anomaly beds likely display a submarine hydrothermal origin. It is postulated that the intensification of the rifting-hydrothermal process, and the ensuing pollution, might have been responsible for the Devonian-Carboniferous biotic crisis. This process began in the late Famennian expansa zone, lasted to the Tournaisian duplicata zone, and produced the largest manganese ore deposits of China.

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Volcanogenic–hydrothermal iron-rich materials from the southern part of the Central Indian Ocean Basin

Cited by 30 publications

References 36 publications

A Comprehensive View of Manganese Nodules and Volcanics of the Central Indian Ocean Basin

A Comprehensive View of Manganese Nodules and Volcanics of the Central Indian Ocean Basin

Hydrothermal Alteration Promotes Humic Acid Formation in Sediments: A Case Study of the Central Indian Ocean Basin

Ni-Ir Anomaly, Microtektites, and the Biotic Crisis across the Devonian–Carboniferous Boundary, Southern China

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