R. J. Angulo, M. C. Souza, Luiz Henrique Sielski, Raissa Araújo Nogueira, Marcelo Eduardo José Müller
{"title":"Morphology, bedforms and bottom sediments of Mar do Ararapira, southern Brazil","authors":"R. J. Angulo, M. C. Souza, Luiz Henrique Sielski, Raissa Araújo Nogueira, Marcelo Eduardo José Müller","doi":"10.5380/ABEQUA.V10I1.59468","DOIUrl":null,"url":null,"abstract":"Mar do Ararapira is an unusual estuary located at the border of Parana and Sao Paulo states, in a relevant area of ecological interest and where an opening of a new inlet occurred in August 2018. Differing from classical estuarine models Mar do Ararapira has three inlets, one with open sea and two with the estuarine systems of Baia de Trapande and Baia dos Pinheiros, the latter through an artificial channel named Canal do Varadouro. Mar do Ararapira also has multiple riverine inputs and the estuary head is not well defined. This paper presents: (a) Mar do Ararapira watershed characteristics, (b) an update of coastline shift close to the inlet and (c) a characterization of the estuarine bathymetry, bottom sediments and bedforms in 2009 and 2011. Comparison of parameters before and after an opening of a new inlet will help both the management of the estuary`s natural resources and the lives of the people inhabiting the surroundings. It is concluded that Mar do Ararapira corresponds to the lower part of an estuary. Its watershed extends 221.6 km 2 and is composed by three different morphologic sectors, which drains mountains and coastal plains. It presents a significant fresh-water input, estimated to range from 6.6 to 9.1 m 3 /s, and weak connectivity with its neighbor estuarine complexes. It is a shallow water body, with a mean depth of 4 m, where a deep main channel suggests intense bottom erosion by tidal currents. The ocean inlet migrates southwestward, mainly under the influence of high energy events. Prevailing bottom sediments are sand and muddy-sand. Subaqueous-sand-dunes and plane-beds are the most common bedforms at Mar do Ararapira. Three estuarine dynamically different sectors were recognized: (a) an inner sector with low tidal-current velocities and finer sediments; (b) a middle sector similar to a fluvial meander in dynamics, with higher tidal-current velocities and sandy sediments, where concave coasts are continuously eroded and convex coasts are silted; and (c) an outer sector, in which tidal-currents are segregated.","PeriodicalId":37504,"journal":{"name":"Quaternary and Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2019-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5380/ABEQUA.V10I1.59468","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Quaternary and Environmental Geosciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5380/ABEQUA.V10I1.59468","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
引用次数: 1
Abstract
Mar do Ararapira is an unusual estuary located at the border of Parana and Sao Paulo states, in a relevant area of ecological interest and where an opening of a new inlet occurred in August 2018. Differing from classical estuarine models Mar do Ararapira has three inlets, one with open sea and two with the estuarine systems of Baia de Trapande and Baia dos Pinheiros, the latter through an artificial channel named Canal do Varadouro. Mar do Ararapira also has multiple riverine inputs and the estuary head is not well defined. This paper presents: (a) Mar do Ararapira watershed characteristics, (b) an update of coastline shift close to the inlet and (c) a characterization of the estuarine bathymetry, bottom sediments and bedforms in 2009 and 2011. Comparison of parameters before and after an opening of a new inlet will help both the management of the estuary`s natural resources and the lives of the people inhabiting the surroundings. It is concluded that Mar do Ararapira corresponds to the lower part of an estuary. Its watershed extends 221.6 km 2 and is composed by three different morphologic sectors, which drains mountains and coastal plains. It presents a significant fresh-water input, estimated to range from 6.6 to 9.1 m 3 /s, and weak connectivity with its neighbor estuarine complexes. It is a shallow water body, with a mean depth of 4 m, where a deep main channel suggests intense bottom erosion by tidal currents. The ocean inlet migrates southwestward, mainly under the influence of high energy events. Prevailing bottom sediments are sand and muddy-sand. Subaqueous-sand-dunes and plane-beds are the most common bedforms at Mar do Ararapira. Three estuarine dynamically different sectors were recognized: (a) an inner sector with low tidal-current velocities and finer sediments; (b) a middle sector similar to a fluvial meander in dynamics, with higher tidal-current velocities and sandy sediments, where concave coasts are continuously eroded and convex coasts are silted; and (c) an outer sector, in which tidal-currents are segregated.
Mar do Ararapira是一个不同寻常的河口,位于巴拉那州和圣保罗州的边界,位于一个具有生态价值的相关地区,2018年8月在这里开辟了一个新的入口。与经典的河口模型不同,Mar do Ararapira有三个入口,一个是公海,两个是Baia de Trapande和Baia dos Pinheiros的河口系统,后者通过一个名为Canal do Varadouro的人工通道。Mar do Ararapira也有多条河流输入,河口水头定义不明确。本文介绍了:(a)Mar do Ararapira流域特征,(b)靠近进水口的海岸线偏移的更新,以及(c)2009年和2011年河口水深、海底沉积物和底形的特征。比较新河口开放前后的参数将有助于河口自然资源的管理和周围居民的生活。得出的结论是,Mar do Ararapira对应于河口的下部。流域面积221.6平方公里,由三个不同的地貌区组成,分别为山区和沿海平原。它的淡水输入量很大,估计在6.6至9.1立方米/秒之间,与邻近的河口复合体的连通性较弱。它是一个浅水体,平均深度为4米,其中一个深的主河道表明潮汐流对底部的强烈侵蚀。海洋入口主要在高能事件的影响下向西南迁移。主要的海底沉积物是沙子和泥质沙子。水下沙丘和平面床是Mar do Ararapira最常见的床型。已识别出三个河口动态上不同的扇区:(a)潮汐流速低、沉积物较细的内部扇区;(b) 动力学上类似于河流曲流的中间部分,具有较高的潮流速度和砂质沉积物,其中凹海岸被持续侵蚀,凸海岸被淤积;和(c)一个外部区域,潮流在其中被隔离。
期刊介绍:
Quaternary and Environmental Geosciences (QEG) is for the publication of unpublished works in the areas of quaternary and environmental geosciences. QEG aims to publish high quality works on all Quaternary areas and environmental geosciences, from laboratory techniques to synthesis works. It aims to publish works from areas as diverse as climate variability and change, paleovegetation, paleoclimate and paleoenvironments, coastal geology and geomorphology, sea level variations, neotectonics, continental morphogenetic processes and products, sediment and soil geochemistry, geological hazards and paleoenvironment. , relationships between natural and anthropic geological processes, among others. We emphasize interest in interdisciplinary work. We discourage the publication of works that are not clearly linked with the Quaternary or the Environmental Geosciences. The main criterion for acceptance of the papers is their quality, originality, significance and interest to a broad regional to international community.