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首页> 外文期刊>Current Science: A Fortnightly Journal of Research >Radiocarbon dates and Holocene sea-level change along the Cuddaloreand Odinur Coast, Tamil Nadu
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Radiocarbon dates and Holocene sea-level change along the Cuddaloreand Odinur Coast, Tamil Nadu

机译：泰米尔纳德邦Cuddaloreand Odinur海岸的放射性碳年代和全新世海平面变化

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Five sediment cores from the tidal flats and estuaries between Cuddalore and Odinur, Tamil Nadu at similar to 50-70 cm water depth were collected to study the down core variations in organic matter, calcium carbonate content and sediment texture. Quartz, feldspar and moderately rounded to well-round, garnet-rich sand were present in all cores except core 4th collected from Marakkanam. Cuddalore (cores 1-3) sediments were coarse-grained and those from Odinur (core 5th) varied from sand to silty sand to clay. Smectite, kaolinite, illite and vermiculite occurred as clay minerals. High content of organic matter was observed in cores from Marakkanam and Odinur. Radiocarbon dates on shell, organic carbon at the base and at intervals of the cores from Marakkanam (core 4) and Odinur (core V) are 8200 plus or minus 230, 9170 plus or minus 290, 5540 plus or minus 430, 2700 plus or minus 140 yrs BP respectively. The sea-level curve presented for the Marakkanam site indicates a gradual and slow sea-level rise since 9000 to 1800 yrs BP. Data on sediment texture, mineralogy, organic matter content supplemented by radiocarbon dates indicate that the deposition of these sediments has taken place in phases since the early Holocene. Reworking of the inner shelf sediments as a result of the dropping sea-level provided the ultimate sediment source for the progradation of the present coastline.
机译：收集了泰米尔纳德邦库德达洛和奥迪努尔之间潮汐平面和河口的五个沉积物岩心，水深接近50-70厘米，以研究有机质，碳酸钙含量和沉积物质地的下降岩心变化。除从马拉卡加南采集的第四岩心外，所有岩心中均存在石英，长石和适度倒圆至圆形，富含石榴石的砂。 Cuddalore（1-3号岩心）的沉积物是粗粒状的，而Odinur（第5号岩心）的沉积物则从沙子到粉质砂子再到粘土。绿土，高岭石，伊利石和ver石是粘土矿物。在马拉卡纳姆和奥迪努尔的岩心中观察到高有机质含量。壳层的放射性碳日期，马拉卡加南（核心4）和奥迪努尔（核心V）的基部以及核心间隔的有机碳分别为8200正负230、9170正负290、5540正负430、2700正负分别负140岁。呈现给Marakkanam站点的海平面曲线表明，自9000至1800年BP以来，海平面逐渐缓慢上升。有关沉积物质地，矿物学，有机质含量以及放射性碳数据的数据表明，这些沉积物的沉积自全新世以来就开始发生。由于海平面下降，对内陆架子的沉积物进行了修复，为当前海岸线的发展提供了最终的沉积物来源。

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