The role of bathymetry in shaping sediment deposition: a case study from the Alleppey Terrace and adjacent shelf, southwestern India

IF 2.3 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research Pub Date : 2026-02-01 Epub Date: 2025-11-27 DOI:10.1016/j.csr.2025.105620

A. Prajith , Reji Srinivas , M.K. Sreeraj , N. Sreejith , S. Suja , A.V. Sijinkumar

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Abstract

Seamounts and bathymetric highs are prominent features of the southwestern continental margin of India, yet their influence on sediment transport and deposition remains poorly understood. This study investigates the Alleppey Terrace (AT) and adjacent shelf using sediment texture, clay mineralogy, microfossil assemblages, suspended particulate matter fluxes, and regional circulation data to elucidate depositional dynamics and environmental controls. Grain-size analysis reveals a clear contrast between the sand-dominated outer shelf and the clay-rich AT sediments, indicating distinct depositional settings. Clay mineralogy signatures suggest that shelf sediments are primarily riverine in origin, whereas AT sediments derive largely from in situ weathering of local basaltic basement rocks. Microfossil assemblages indicate low surface productivity and minimal sediment reworking over the AT. Seasonal suspended particulate matter flux measurements using a submersible particle-size analyzer (LISST) confirm that land-derived material does not reach the AT regions. Overall, the interplay between limited sediment sources, bathymetric controls, and hydrodynamic processes has created a unique low-energy depositional environment in the AT, contrasting with the more dynamic adjacent shelf. These findings highlight the critical role of bathymetric highs in modulating sediment flux, preserving relic deposits, and influencing paleoenvironmental conditions along the continental margin.

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水深测量在形成沉积物沉积中的作用：以印度西南部阿勒皮阶地及其邻近陆架为例

海山和深海高地是印度西南大陆边缘的突出特征，但它们对沉积物运输和沉积的影响仍然知之甚少。本研究利用沉积物结构、粘土矿物学、微化石组合、悬浮颗粒物通量和区域环流数据对阿勒佩阶地及其邻近陆架进行了研究，以阐明沉积动力学和环境控制因素。粒度分析揭示了以砂为主的外陆架与富含粘土的AT沉积物之间的明显对比，表明了不同的沉积背景。粘土矿物学特征表明陆架沉积物主要来源于河流，而陆架沉积物主要来源于当地玄武岩基底岩的原位风化作用。微化石组合表明AT上的地表生产力较低，沉积物改造最少。使用潜水粒度分析仪（LISST）进行的季节性悬浮颗粒物通量测量证实，陆地来源的物质不会到达AT区域。总的来说，有限的沉积物来源、水深控制和水动力过程之间的相互作用，在AT中创造了一个独特的低能量沉积环境，与更动态的相邻陆架形成对比。这些发现强调了水深高点在调节沉积物通量、保存遗迹沉积物和影响大陆边缘古环境条件方面的关键作用。

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来源期刊

Continental Shelf Research 地学-海洋学

CiteScore

4.30

自引率

4.30%

发文量

136

审稿时长

6.1 months

期刊介绍： Continental Shelf Research publishes articles dealing with the biological, chemical, geological and physical oceanography of the shallow marine environment, from coastal and estuarine waters out to the shelf break. The continental shelf is a critical environment within the land-ocean continuum, and many processes, functions and problems in the continental shelf are driven by terrestrial inputs transported through the rivers and estuaries to the coastal and continental shelf areas. Manuscripts that deal with these topics must make a clear link to the continental shelf. Examples of research areas include: Physical sedimentology and geomorphology Geochemistry of the coastal ocean (inorganic and organic) Marine environment and anthropogenic effects Interaction of physical dynamics with natural and manmade shoreline features Benthic, phytoplankton and zooplankton ecology Coastal water and sediment quality, and ecosystem health Benthic-pelagic coupling (physical and biogeochemical) Interactions between physical dynamics (waves, currents, mixing, etc.) and biogeochemical cycles Estuarine, coastal and shelf sea modelling and process studies.