Scholarlink

<p>This study applies a multi-proxy approach to investigate beach sediments from Colachel and Paraikkal, located along the southern Tamil Nadu coast, India, to reconstruct depositional processes, sediment maturity, provenance, and paleo-weathering in a high-energy, monsoon-influenced coastal system. Two sediment cores were collected Core 1 from Colachel and Core 2 from Paraikkal to capture vertical variations in grain size, mineralogy, and geochemical composition. Analytical techniques including grain size analysis, heavy mineral analysis, major oxide geochemistry, and standard geochemical indices (e.g., Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA) Index of Compositional Variability (ICV) and classification plots were used to interpret chemical maturity and source composition. Textural study indicated medium to fine sands, exhibiting sorting from moderately well sorted to poorly sorted. The sediments of Colachel (Core 1) were mostly symmetrical to fine-skewed, suggesting moderate-energy depositional conditions. Paraikkal (Core 2) sediments exhibited a broader skewness range, reflecting energy fluctuations likely controlled by tidal and wave dynamics. Kurtosis values (mesokurtic to leptokurtic) and statistical plots confirmed transitional to high-energy beach settings. Bivariate plots, discriminant functions, and C-M (C-Coarse fraction, M- median grain size) diagrams suggest beach to shallow marine environments shaped by wave and tractive currents. The presence of opaques, garnet, zircon, tourmaline, rutile, and kyanite in heavy mineral assemblages suggests that they are derived from granitic and charnockitic source rocks. ZTR (Zircon–Tourmaline–Rutile) index values (39.96–60.81) suggest sub-mature to immature sediments with minimal recycling. Geochemical ratios (e.g., Al<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> = 14.42–29.57) and discriminant function analysis point to felsic to intermediate igneous sources. Enrichment in TiO<sub>2</sub> and P<sub>2</sub>O<sub>5</sub>, alongside weathering indices (CIA, PIA, ICV) and A-CN-K (A (Aluminium oxide)–CN (Calcium and Sodium oxide)–K (Potassium oxide)) plots, indicate low to moderate chemical weathering under sub-humid conditions. The findings provide a global reference framework for understanding sedimentary processes along coastal environments.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Sedimentary characteristics of Paraikkal and Colachel Beaches, Tamil Nadu, India: A geochemical and mineralogical perspective on provenance and paleo-weathering influence

  • 期刊论文

  • 发表日期：

    2026年1月7日

查看全文
  • Bakayisire Fabiola,
  • Venkatesan Selvaraj,
  • Parthasarathy Pandu,
  • Saradhambal Ramachandran Singarasubramanian,
  • Gnanachandrasamy Gopalakrishnan,
  • Aishajiang Aili,
  • Hailiang Xu

摘要

This study applies a multi-proxy approach to investigate beach sediments from Colachel and Paraikkal, located along the southern Tamil Nadu coast, India, to reconstruct depositional processes, sediment maturity, provenance, and paleo-weathering in a high-energy, monsoon-influenced coastal system. Two sediment cores were collected Core 1 from Colachel and Core 2 from Paraikkal to capture vertical variations in grain size, mineralogy, and geochemical composition. Analytical techniques including grain size analysis, heavy mineral analysis, major oxide geochemistry, and standard geochemical indices (e.g., Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA) Index of Compositional Variability (ICV) and classification plots were used to interpret chemical maturity and source composition. Textural study indicated medium to fine sands, exhibiting sorting from moderately well sorted to poorly sorted. The sediments of Colachel (Core 1) were mostly symmetrical to fine-skewed, suggesting moderate-energy depositional conditions. Paraikkal (Core 2) sediments exhibited a broader skewness range, reflecting energy fluctuations likely controlled by tidal and wave dynamics. Kurtosis values (mesokurtic to leptokurtic) and statistical plots confirmed transitional to high-energy beach settings. Bivariate plots, discriminant functions, and C-M (C-Coarse fraction, M- median grain size) diagrams suggest beach to shallow marine environments shaped by wave and tractive currents. The presence of opaques, garnet, zircon, tourmaline, rutile, and kyanite in heavy mineral assemblages suggests that they are derived from granitic and charnockitic source rocks. ZTR (Zircon–Tourmaline–Rutile) index values (39.96–60.81) suggest sub-mature to immature sediments with minimal recycling. Geochemical ratios (e.g., Al2O3/TiO2 = 14.42–29.57) and discriminant function analysis point to felsic to intermediate igneous sources. Enrichment in TiO2 and P2O5, alongside weathering indices (CIA, PIA, ICV) and A-CN-K (A (Aluminium oxide)–CN (Calcium and Sodium oxide)–K (Potassium oxide)) plots, indicate low to moderate chemical weathering under sub-humid conditions. The findings provide a global reference framework for understanding sedimentary processes along coastal environments.