Geological processes in the Indian Ocean – Understanding the input fluxes, sinks and Paleoceanography (Project No. PSC0106)
Characterize the sources of organic carbon in the sediments, estimate the amount of (i) terrestrial organic carbon from peninsular Indian rivers reaching the sea (ii) organic carbon stored in continental margins around India, and (iii) Holocene carbon burial rates.
To quantify and geochemically fingerprint the amounts of mineral dust and anthropogenic aerosols reaching the northern Indian Ocean, their interactions and effect on ocean productivity, carbon cycle, rainwater chemistry.
Estimate the fluvial trace and rare earth elemental fluxes from peninsular Indian rivers reaching the sea.
Estimate the fluxes of volcanogenic and extra-terrestrial material in Central Indian and Wharton Basins and investigate the timing, causes, products and processes of volcanism and extra-terrestrial events.
Quantitative estimation of various past climatic parameters (SST, surface salinity, carbonate ion concentration, and productivity), and reconstruction of paleo- monsoon intensity.
Understanding relationship between monsoon and other regional coupled phenomena such as Indian Ocean Dipole (IOD), Indonesian Throughflow (ITF), at glacial-interglacial, millennial and centennial time-scales.
Map the cobalt rich Fe-Mn oxides on three seamounts in the Arabian Sea.
To map the zones of hydrothermal mineralization at the Central Indian Ridge.
Define the elemental and isotopic composition and the depositional environments of marine minerals and understand metal accumulation processes in relation to tectonics, climate and ocean processes.
To understand the active tectonics and the biogeochemistry of the associated ecosystems at the mid-ocean ridges, seamounts and fracture zones.
The GEOSINKS proposal targets to understand the processes that are fundamental to Marine Geosciences, which include source to sink and depositional environments and their changes over the time in the Indian Ocean. The objectives of the GEOSINKS Program aim to investigate various geological, oceanographic and climatic processes that govern the source characteristics, dispersal pathways of various geological components and their reactivity in water and sediments, and the ultimate sinks viz., minerals and sediments. The proposal envisages to utilize intra- and inter-disciplinary approaches to understand these processes.
The proposed investigations aim to (a) define the input pathways of mineral dust, riverine particulates, volcanogenic, hydrothermal and extra-terrestrial material in few key regions of the Indian Ocean, and assess the associated elemental supply to the ocean; (b) evaluate the response processes such as authigenesis, diagenesis and biogenesis within the reservoir at different time-scales; (c) assess the depositional environment of the ultimate sinks such as minerals and sediments. The time-series of above parameters utilizing selected proxies will be reconstructed to understand the past climatic and geological changes in the Indian Ocean. Thus, the objectives of the GEOSINKS initiative have relevance to climate, environment and mineral formation. Indian Ocean is chosen in view of its uniqueness in terms of tectonics, material input, ocean-atmosphere coupled dynamics and it’s proximity and relevance to India.
The study involves seven major investigations supported by 50 permanent scientists and technical specialists (46 from CSIR-NIO and 4 from CSIR-NGRI) and also proposes to engage nearly equal number of students. The program involves extensive data and sample collection at sea.
Assess the geological processes which have relevance to climate, depositional environment and mineral resources. Oceans receive large quantity of material from various sources, the type and amount of which depends on several processes. These processes vary with time and the components deposit in various forms. Here, we plan to study “How and when” these are deposited and utilize this knowledge to enhance our understanding of the geological processes operating in the Indian Ocean. The study is important in view of the uniqueness of the Indian Ocean in terms of its tectonics, geology, and climate. The principal elements of the program include the studies on type and quantity of input fluxes, material and sediment transport pathways, occurrence and depositional environment characteristics of mineral resources and the unique deep-sea ecosystems associated with these mineral formations and changes in these processes under different geological time-scales.
Northern Indian Ocean is a fluvial sediment dominated system as major Asian river systems such as Ganges-Brahmaputra, Irrawaddy-Salween supply enormous amount of dissolved and particulate loads. In addition, Arabian Sea is one of the dustiest regions in the world oceans. Terrestrial organic matter transport and supply from Peninsular Indian Rivers may play a significant role in carbon sequestration. The monsoon is the dominant climatic feature of the Northern Indian Ocean having a strong bearing on the Indian economy. The sedimentary records of the region preserve the signatures of past monsoonal variability. South of the equator, Central Indian and Wharton Basins are repositories of major volcanogenic input from the Indonesian Volcanic Arc. These abyssal areas are also the major sinks for dissolved metals in the form of authigenic precipitates such as ferromanganese oxides. Slow-spreading ridges in the Indian Ocean are potential sites for the occurrence of hydrothermal mineralization. In view of the importance of the above, this Project needs to be undertaken to understand the processes that are fundamental to Marine Geosciences such as (i) sediment source to sink; (ii) past geological changes and (iii) depositional environments.
Key questions to be addressed:
Scientific Knowledge Creation:
Understanding the geological processes operating in the Northern Indian Ocean and the equatorial Indian Ocean with respect to input fluxes, Paleoceanography, offshore mineral formation and the ecosystems associated with these mineral occurrences. An attempt to understand the impact of input fluxes on ocean system will be made.
Capabilities for working in the deep-sea will be augmented with the use of gadgets such as remotely operated vehicles.
Technical and scientific deliverables are tabulate below. d in Annexure 6. Deliverables envisaged from each work package are included in the WP description tables.
Quantifiable Deliverables / Targets
Recruitment of staff; Procurement of equipments; Compilation of various geological and oceanographic data of CIR; Wharton Basin (WB):
Sampling rivers, estuaries, coastal lagoons and inner shelf-Phase I; Setting up 3 field stations (for dust); Deployment of Sediment Traps; Reconnaissance sampling of seamounts ;
Boat/coastal cruises for sediment thickness and sampling in west coast; Sampling in BOB, Andaman Sea and CIB; Swath bathymetric mapping of parts of 90°E, Broken Ridges and WB. Deployment of deep-sea moorings. Calibration of IRMS, LA-ICP-MS, AMS dating
Sampling coastal areas, west coast continued; TIMS lab set-up and installation; Field station on east coast; sediment traps; Generation of High resolution bathymetric maps and delineation of tectonic and structural features of Ridge; .
Elemental analyses of particulates for budget; Map of dust source regions and hot spots; long cores in AS, BOB, And. Sea and CIB; AUV to Central Indian Ridge; High resolution bathymetric maps of WB, CIB and seafloor images. Completion of WB-Phase I studies
Stable isotope measurement for terrestrial organic matter content; AUV surveys in CIB; redeployment of traps; cruise to WB-Phase II; Tectonic and structural maps of CIR. Locating plumes; Bathymetric maps of 90°E, Broken ridge. 10Be dating of deep-sea sediments; Publications (P); dissertations (D)
Sed.thickness maps (part of AS); Estimating the elemental budgets at land-sea interfaces; Map of dust transport pathways; AMS dating for paleoclimatic studies; Exploration for Co-crusts on the 3 seamounts (AS); Imaging &sampling hydrothermal vents;cosmic dust fluxes; P&D
Seasonal Rainwater quality Map; redeployment of sediment traps; elemental budgets at land-sea interfaces; High resolution (1 m) bathy- maps of CIR; Biostratigraphic age estimates of sediment cores (WB); Exploring Laxmi B seamounts for Co-crusts; Database & interpretation of the bathymetry, deep-water samples, rocks analysed and AUV surveys undertaken; P&D
Estimation of annual settling fluxes in BOB, And. Sea and CIB; Repository and database of mineral dust and aerosols for climate change studies;;Estimates of past seawater temperature, salinity changes; delineation of zones of hydrothermal mineralisation; Generation of high resolution bathymetric & tectonic maps; micrometeorite flux; P & D
Regional dust transport model; Terrestrial carbon accumulation rates around India during the Holocene; Demarcation of the areas of sediment removal and bottom focusing; Reconstruction of regional seawater temperature and salinity changes from the northern Indian Ocean over the last 150 kyr.; Ridge processes controlling mineralisation, tectono-magmatism and ecosystems; synthesis volume on WB; P & D; Project Completion Reports