Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model
The study of the physical geology and geochemistry of the Ribeirão Preto basalts was part of a hydrogeologicalresearch, which aimed to investigate the recharge of the Guarani Aquifer System (SAG) through the basalts of the SerraGeral Aquifer (ASG), a project shortly named FRATASG. In addition to the...
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| Format: | Article |
| Language: | English |
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Universidade de São Paulo
2011-12-01
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| Series: | Geologia USP. Série Científica |
| Subjects: | |
| Online Access: | http://ppegeo-local.igc.usp.br/pdf/guspsc/v11n3/v11n3a03.pdf |
| _version_ | 1818383106664562688 |
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| author | Amélia João Fernandes Carlos Henrique Maldaner Alain Rouleau |
| author_facet | Amélia João Fernandes Carlos Henrique Maldaner Alain Rouleau |
| author_sort | Amélia João Fernandes |
| collection | DOAJ |
| description | The study of the physical geology and geochemistry of the Ribeirão Preto basalts was part of a hydrogeologicalresearch, which aimed to investigate the recharge of the Guarani Aquifer System (SAG) through the basalts of the SerraGeral Aquifer (ASG), a project shortly named FRATASG. In addition to the hydrogeological research, a detailed geologicalinvestigation was conducted to develop a conceptual model of groundwater fl ow in complex aquifers, as is the case ofthe fractured basalts of the ASG. Therefore, this study included a thorough structural survey and analysis of horizontaland subvertical fractures, which resulted in the identifi cation of four tectonic events. It was concluded that the verticalgroundwater flow is important up to 10 m in depth and, secondarily, up to 25 m. Horizontal fl ow, more evident up to thedepth of 50 m, predominates and occurs along sub-horizontal fractures, which occur mainly at the contact between basalts2 and 3 and in its vicinity. Because the great majority of subvertical fractures do not propagate into the vesicular layers,which occur at the basalt contacts, it is suggested that these layers act as regional hydraulic barriers, and greatly hamperthe recharge of the SAG through the ASG. As a consequence, groundwater flow in the basalt stack is of stratabound type,as it occurs mainly along the basalt contacts. Based on diagnostic features of the fl ow, it is proposed in this study that the vertical flow,which crosses the basalt stack reaching the SAG, is local and probably occurs along NE structures. |
| first_indexed | 2024-12-14T03:01:06Z |
| format | Article |
| id | doaj.art-2212a16614f94521b6234ea4bdf266b9 |
| institution | Directory Open Access Journal |
| issn | 1519-874X |
| language | English |
| last_indexed | 2024-12-14T03:01:06Z |
| publishDate | 2011-12-01 |
| publisher | Universidade de São Paulo |
| record_format | Article |
| series | Geologia USP. Série Científica |
| spelling | doaj.art-2212a16614f94521b6234ea4bdf266b92022-12-21T23:19:31ZengUniversidade de São PauloGeologia USP. Série Científica1519-874X2011-12-011134364Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological ModelAmélia João FernandesCarlos Henrique MaldanerAlain RouleauThe study of the physical geology and geochemistry of the Ribeirão Preto basalts was part of a hydrogeologicalresearch, which aimed to investigate the recharge of the Guarani Aquifer System (SAG) through the basalts of the SerraGeral Aquifer (ASG), a project shortly named FRATASG. In addition to the hydrogeological research, a detailed geologicalinvestigation was conducted to develop a conceptual model of groundwater fl ow in complex aquifers, as is the case ofthe fractured basalts of the ASG. Therefore, this study included a thorough structural survey and analysis of horizontaland subvertical fractures, which resulted in the identifi cation of four tectonic events. It was concluded that the verticalgroundwater flow is important up to 10 m in depth and, secondarily, up to 25 m. Horizontal fl ow, more evident up to thedepth of 50 m, predominates and occurs along sub-horizontal fractures, which occur mainly at the contact between basalts2 and 3 and in its vicinity. Because the great majority of subvertical fractures do not propagate into the vesicular layers,which occur at the basalt contacts, it is suggested that these layers act as regional hydraulic barriers, and greatly hamperthe recharge of the SAG through the ASG. As a consequence, groundwater flow in the basalt stack is of stratabound type,as it occurs mainly along the basalt contacts. Based on diagnostic features of the fl ow, it is proposed in this study that the vertical flow,which crosses the basalt stack reaching the SAG, is local and probably occurs along NE structures.http://ppegeo-local.igc.usp.br/pdf/guspsc/v11n3/v11n3a03.pdfSerra Geral FormationStructural geologyTectonicsGroundwater flowFractured aquiferRecharge of the Guarani Aquifer System |
| spellingShingle | Amélia João Fernandes Carlos Henrique Maldaner Alain Rouleau Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model Geologia USP. Série Científica Serra Geral Formation Structural geology Tectonics Groundwater flow Fractured aquifer Recharge of the Guarani Aquifer System |
| title | Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model |
| title_full | Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model |
| title_fullStr | Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model |
| title_full_unstemmed | Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model |
| title_short | Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model |
| title_sort | fracture analysis of the ribeirao preto basalts sp application for developing a conceptual hydrogeological model |
| topic | Serra Geral Formation Structural geology Tectonics Groundwater flow Fractured aquifer Recharge of the Guarani Aquifer System |
| url | http://ppegeo-local.igc.usp.br/pdf/guspsc/v11n3/v11n3a03.pdf |
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