Abstract The Kerala coast displays a spectrum of varied geomorphic features that are evolved as a function of Late Quaternary land-sea interaction. The southern Kerala coast, south of Achankovil Shear Zone (ASZ) has been characterised by cliffed coast with entrenched estuarine basins, pocket beaches, promontories, older and younger strand plains, etc., that are evolved as a result of the transgressive-regressive phases to which the coast has been subjected during late Quaternary Period. In spite of having varied geomorphic features, lacuna in comprehending the evolutionary phases of the coastal landform features is the primary impediment that bolstered us to unravel the Late Quaternary land-sea interactions and landform changes of the coast between Thottapally and Vizhinjam. Moreover, the last two centuries are known to have been witnessing many natural as well as human induced environmental perturbations in the area. The Late Quaternary landform dynamics were reconstructed based on the satellite data while the last century changes were extracted from Digital Shoreline Analysis System (DSAS). The evidences based on geomorphic variations suggest that the present study area hosts two distinct paleo-coastlines – 1) coincides with the eastern boundary of the older strand plains (accreted during Late Pleistocene) and, 2) marks the boundary between older and younger strand plains (accreted during Early–Middle Holocene). A sector-wise analysis reveals that the northern half of the study area is characterised by many coast perpendicular estuarine basins with well-developed Bay Head Deltas in its fluvial end, and Flood Tide Islands near the estuarine mouth. On the contrary, the southern half is characterized by pocket beaches and coast parallel backwater bodies developed during the regressive phases of the sea. A high-resolution study of the shoreline changes during the period, 1920–2018 reveals that the younger strandlines are vulnerable to severe coastal erosion and shoreline retreat at many places compared to coastal accretion. The study stresses the imminent need for continuous monitoring and implementation of site-specific mitigation measures for the conservation and management of this coast known for its outstanding natural beauty and strategic beach placer deposits.

中文翻译：

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印度西南部喀拉拉邦南部海岸的晚第四纪陆海相互作用和地貌动态特征

摘要 喀拉拉邦海岸显示出一系列不同的地貌特征，这些地貌特征是随着晚第四纪陆海相互作用而演化的。喀拉拉邦南部海岸，Achankovil 剪切带 (ASZ) 以南的悬崖海岸，其特征是具有根深蒂固的河口盆地、袖珍海滩、海角、较老和较年轻的河岸平原等，这些都是由于海进-海退阶段而演变的海岸在第四纪晚期受到的影响。尽管具有不同的地貌特征，但在理解海岸地貌特征的演化阶段方面的缺失是支持我们解开 Thottapally 和 Vizhinjam 之间海岸的晚第四纪海陆相互作用和地貌变化的主要障碍。而且，众所周知，在过去的两个世纪里，该地区见证了许多自然和人为引起的环境扰动。基于卫星数据重建晚第四纪地貌动态，数字海岸线分析系统（DSAS）提取上世纪变化。基于地貌变化的证据表明，目前的研究区拥有两条不同的古海岸线——1) 与较旧的平原东部边界重合（在晚更新世期间堆积），2) 标志着较老和较年轻的平原之间的边界（在早-中全新世期间吸积）。部门分析表明，研究区北半部的特点是许多海岸垂直的河口盆地，其河流末端有发育良好的湾头三角洲，和河口附近的潮汐岛。相反，南半部的特点是在海退阶段形成的口袋海滩和与海岸平行的回水体。对 1920 年至 2018 年期间海岸线变化的高分辨率研究表明，与海岸增生相比，较年轻的海岸线在许多地方容易受到严重的海岸侵蚀和海岸线后退。该研究强调迫切需要持续监测和实施针对特定地点的缓解措施，以保护和管理这个以其杰出的自然美景和战略性海滩砂矿沉积而闻名的海岸。对 1920 年至 2018 年期间海岸线变化的高分辨率研究表明，与海岸增生相比，较年轻的海岸线在许多地方容易受到严重的海岸侵蚀和海岸线后退。该研究强调迫切需要持续监测和实施针对特定地点的缓解措施，以保护和管理这个以其杰出的自然美景和战略性海滩砂矿沉积而闻名的海岸。对 1920 年至 2018 年期间海岸线变化的高分辨率研究表明，与海岸增生相比，较年轻的海岸线在许多地方容易受到严重的海岸侵蚀和海岸线后退。该研究强调迫切需要持续监测和实施针对特定地点的缓解措施，以保护和管理这个以其杰出的自然美景和战略性海滩砂矿沉积而闻名的海岸。