Late pleistocene sedimentation: a case study of the central Indian Ocean Basin

Borole, D.V.

doi:10.1016/0967-0637(93)90070-j

Cited by 45 publications

(30 citation statements)

References 16 publications

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“…An average accumulation rate of 2 mm/ka in the CIB as reported by Banaker et al (1991), and Borole (1993) gave a range of 1 to S mm/ka for sediment accumulation rates. Thus, variable and erosional sedimentation rates have been reported in the basin.…”

Section: A B Valsangkar and N C! Ambrementioning

confidence: 61%

Distribution of Grain Size and Clay Minerals in Sediments from the INDEX Area, Central Indian Basin

Valsangkar

Ambre

2000

Marine Georesources & Geotechnology

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Section: A B Valsangkar and N C! Ambrementioning

confidence: 61%

Distribution of Grain Size and Clay Minerals in Sediments from the INDEX Area, Central Indian Basin

Valsangkar

Ambre

2000

Marine Georesources & Geotechnology

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“…Siliceous, calcareous, and pelagic sediments are dominant in the CIB where low accumulation rates of 1 to 5 mm=ka have been reported (Borole 1993). Comparison between pre-and postdisturbance values showed three-fold increase in the sediment flux during INDEX and two-fold reduction after the experiment (Parthiban 2000) suggesting sediment resuspension in the near bottom water column and redistribution of fine particles.…”

Section: Discussionmentioning

confidence: 87%

First Phase Monitoring Studies of Simulated Benthic Disturbance Delineating Movement of Fine Particles in the Central Indian Basin

Valsangkar

2005

Marine Georesources & Geotechnology

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Benthic disturbance due to future deep-sea polymetallic nodule mining would involve extensive sediment plume generation and resedimentation on the sea floor. In order to evaluate the effects of resedimentation on benthic environment, the Indian Deepsea Environment Experiment (INDEX) was conducted in 1997, and pre-, and postdisturbance studies on grain size were carried out. The initial increase in clay content after the experiment, continued to increase further as measured in the first monitoring phase samples, 44 months later. Increase in clay-sized particles during monitoring-1 (M-1) was highest within the simulated (disturbed) zone and to the north of it, which is attributed to the combined effects of disaggregation, abrasion, and powderization of sediments during transportation. Due to this fractionation (breaking up), the particles appear to have remained in suspension over a prolonged period of time after they were discharged in the water column 5 m above the seabed during INDEX. The travel effects of INDEX plume appears to be localized and confined within and around the disturbed zone (DZ) as resettlement of fine particles from the benthic plume was traced up to 2 km south and 12 to 18 km north of the DZ. The evidence does not suggest the existence of strong currents and benthic storms in the CIB.Mining of deep-sea minerals, such as the polymetallic nodules, would disturb the sediments on the seafloor and create a large sediment plume similar to that from a benthic storm (Hollister and Nowell 1991). Deep-sea nodule mining activities are associated with erosion and deposition of the bottom sediments. If the nodules are screened close to the seafloor and the sediments are released from certain heights above the seabed, then the sediment plume would migrate in the direction dictated by bottom water currents (Murty et al. 1999), affecting the benthic community

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“…The low C org values determined here are typical of pelagic sediments as most of the degradable C org is decomposed below a threshold sedimentation rate of between 1 and 4 mm year −1 (Müller and Mangini 1980). The study area is characterized by very low sedimentation rates (Banakar et al 1991;Borole 1993).…”

Section: Resultsmentioning

confidence: 99%

“…where S is the linear sedimentation rate (cm year −1 ), which is about 0.0002 cm year −1 in the Central Indian Basin (Banakar et al 1991;Borole 1993), ρ is the dry bulk density calculated from wet bulk density and porosity ( ) values.…”

Section: Organic Carbon Burialmentioning

confidence: 99%

Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment

Nath

Khadge

Nabar

et al. 2011

Environ Monit Assess

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An area of 0.6 km(2) in the manganese nodule field of the Central Indian Basin was physically disturbed and sediments discharged in the near bottom waters to simulate seabed mining and study its impact on benthic ecosystem. An estimated 2 to 3 tonnes of sedimentary organic carbon (C(org)) was resuspended into the water column during a 9-day experiment. The majority of the sediment cores from within the disturbed area and areas towards the south showed a ~30% increase in C(org) content as well as an increase in carbon burial rates after disturbance, though with a reduction in carbon/phosphorus ratios. High specific surface area (SSA~25 m(2) g(-1)) and low C(org)/SSA ratios (mostly <0.5) are typical of deep-sea sediments. The increased C(org) values were probably due to the organic matter from dead biota and the migration and redeposition of fine-grained, organic-rich particles. Spatial distribution patterns of C(org) contents of cores taken before and after disturbance were used to infer the direction of plume migration and re-sedimentation. A positive relationship was observed between total and labile C(org) and macrobenthos density and total bacterial numbers prior to disturbance, whereas a negative relationship was seen after disturbance owing to drastic reduction in the density of macrofauna and bacteria. Overall decrease in labile organic matter, benthic biota and redistribution of organic matter suggest that the commercial mining of manganese nodules may have a significant immediate negative effect on the benthic ecosystem inducing changes in benthic community structure.

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Late pleistocene sedimentation: a case study of the central Indian Ocean Basin

Cited by 45 publications

References 16 publications

Distribution of Grain Size and Clay Minerals in Sediments from the INDEX Area, Central Indian Basin

Distribution of Grain Size and Clay Minerals in Sediments from the INDEX Area, Central Indian Basin

First Phase Monitoring Studies of Simulated Benthic Disturbance Delineating Movement of Fine Particles in the Central Indian Basin

Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment

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