Mapeamento de feições deposicionais e erosivas no estuário do Rio Açu/RN (NE do Brasil) utilizando o método hidroacústico de alta resolução e sondagem geológica
The mapping of features in the subsurface can be established in detail by the seismic using sub-bottom profiler, high resolution hydroacoustic equipment. The study area is located in the Açu river, bounded by its estuary, northern coast of the Rio Grande do Norte state, NE Brazil. Locally, the estua...
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| Materialtyp: | Dissertação |
| Språk: | por |
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Brasil
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| Länkar: | https://repositorio.ufrn.br/jspui/handle/123456789/23702 |
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| Sammanfattning: | The mapping of features in the subsurface can be established in detail by the seismic using sub-bottom profiler, high resolution hydroacoustic equipment. The study area is located in the Açu river, bounded by its estuary, northern coast of the Rio Grande do Norte state, NE Brazil. Locally, the estuary is inserted in a coastal environment consisting of: fluvio-marine floodplain, mangrove ecosystem, sandy banks, dune fields, spits and sandy beaches. This study aimed to characterize the depositional and erosional features from Açu River estuary, through the acquisition, processing and interpretation of high-resolution seismic data and cores. Using the X-Star sub-bottom profiler (chirp), with frequency range between 0.5 to 7.2 kHz, were acquired seven seismic profiles (four horizontal and three parallel to the river course), totalizing approximately 16 km of seismic acquisition. The cores were done in seven different points along the estuary, using two drilling methods: vibracore and percussive. The length of the cores varied between 0.42 m and 4.27 m. Processed seismic data showed excellent quality and allowed the visualization of several architectural elements characteristic of estuarine deposits, such as: lateral accretion deposits, channel concave erosional base, infill deposits. Moreover, subaqueous dunes and flat bottom bedforms were also observed. Additionally, well market reflectors were interpreted as: (1) erosional truncation surface; and (2) possible Pleistocene-Holocene contact. The cores showed an intercalation between clayey and sandy layers (ranging from very fine to course) which allowed the correlation between geophysics and geology on the study area. |
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