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Courgeon, Simon; Bachelery, Patrick; Jouet, Gwenael; Jorry, Stephan; Bou, Esther; Boudagher-fadel, Marcelle K.; Revillon, Sidonie; Camoin, Gilbert; Poli, Emmanuelle. |
The offshore branch of the East African Rift System (EARS) has developed during late Cenozoic time along the eastern Africa continental margin. While Neogene–Pleistocene extensional tectonic deformation has been evidenced along the northern segment of the Davie Ridge, the spatial extent of deformation further south remains poorly documented. Based on recent and various oceanographic data sets (bathymetric surveys, dredge samples and seismic profiles), our study highlights active normal faulting, modern east–west extensional tectonic deformation and Late Cenozoic alkaline volcanism at the Sakalaves Seamounts (18°S, Davie Ridge) that seem tightly linked to the offshore EARS development. In parallel, rift‐related tectonic subsidence appears responsible for... |
Tipo: Text |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00452/56344/57934.pdf |
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Courgeon, Simon; Jorry, Stephan; Jouet, Gwenael; Camoin, G.; Boudagher-fadel, M. K.; Bachelery, P.; Caline, B.; Boichard, R.; Revillon, Sidonie; Thomas, Yannick; Thereau, Estelle; Guerin, Charline. |
Understanding the impact of tectonic activity and volcanism on long-term (i.e. millions years) evolution of shallow-water carbonate platforms represents a major issue for both industrial and academic perspectives. The southern central Mozambique Channel is characterized by a 100 km-long volcanic ridge hosting two guyots (the Hall and Jaguar banks) and a modern atoll (Bassas da India) fringed by a large terrace. Dredge sampling, geophysical acquisitions and submarines videos carried out during recent oceanographic cruises revealed that submarine flat-top seamounts correspond to karstified and drowned shallow-water carbonate platforms largely covered by volcanic material and structured by a dense network of normal faults. Microfacies and well-constrained... |
Tipo: Text |
Palavras-chave: Carbonate platform; Drowning; Volcanism; Tectonic; Mozambique Channel. |
Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00384/49554/50048.pdf |
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Miramontes, Elda; Jorry, Stephan; Jouet, Gwenael; Counts, John; Courgeon, Simon; Roy, Philippe; Guerin, Charline; Hernández-molina, F. Javier. |
Subaqueous sand dunes are common bedforms on continental shelves dominated by tidal and geostrophic currents. However, much less is known about sand dunes in deep‐marine settings that are affected by strong bottom currents. In this study, dune fields were identified on drowned isolated carbonate platforms in the Mozambique Channel (south‐west Indian Ocean). The acquired data include multibeam bathymetry, multi‐channel high‐resolution seismic reflection data, sea floor imagery, a sediment sample and current measurements from a moored current meter and hull‐mounted acoustic Doppler current profiler. The dunes are located at water depths ranging from 200 to 600 m on the slope terraces of a modern atoll (Bassas da India Atoll) and within small depressions... |
Tipo: Text |
Palavras-chave: Bedform; Bottom currents; Contourite; Deep-marine environment; Eddy; Geostrophic current; Oceanic circulation. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00472/58418/60989.pdf |
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Courgeon, Simon; Bourget, Julien; Jorry, Stephan. |
During the Plio-Quaternary, the Bonaparte Basin is characterized by a very wide (> 600 km, > 370 mi) carbonate platform and 200 km-wide (125 mi-wide) intra-shelf basin (the Malita ISB). Using 3D and 2D seismic data combined with exploration well data, this study characterizes the stratigraphic evolution of the Malita ISB during the last 3.5 million years. Two third-order transgressive sequences can be distinguished. A late Pliocene transgression occurred over an irregular topography resulting from the flexural reactivation of the Malita graben. In the centre of the intra-shelf basin, carbonate aggradation resulted in the formation of isolated carbonate platforms separated by deeper water seaways and inter-platform areas. Wider and more numerous... |
Tipo: Text |
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Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00319/42985/46567.pdf |
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Jorry, Stephan; Jouet, Gwenael; Edinger, Evan N.; Toucanne, Samuel; Counts, John W.; Miramontes, Elda; Courgeon, Simon; Riveiros, Natalia Vázquez; Le Roy, Pascal; Camoin, Gilbert F.. |
Over the past ten years, a huge amount of source-to-sink studies have aimed to unravel the tectonic, climatic and other processes that shape the landscape from mountains to the deep ocean. Interestingly, these studies have been mainly dedicated to siliciclastic or mixed systems, for which the connection between drainage basins, continental shelves, slope and basin environments are often well constrained. Here we present a study focusing on a source-to-sink study dedicated to a pure carbonate system, located in the SW Indian Ocean (Glorieuses archipelago). Extensive field sampling and geophysical acquisition across the carbonate platform have allowed us to estimate the composition, the lateral variability, and volumes of neritic sands deposited on the... |
Tipo: Text |
Palavras-chave: Carbonate platform; Coral reef; Calciturbidite; Aragonite; Carbonate budget; Indian Ocean. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71879/70574.pdf |
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Courgeon, Simon; Jorry, Stephan; Camoin, G. F.; Boudagher-fadel, M. K.; Jouet, Gwenael; Revillon, Sidonie; Bachelery, P.; Pelleter, Ewan; Borgomano, J.; Poli, E.; Droxler, A. W.. |
Although long-term evolutions of isolated shallow-water carbonate platforms and demise episodes leading to guyot formation have been the subject of numerous studies during the last decades, their driving processes are still the subject of active debates. The Mozambique Channel (SW Indian Ocean) is characterized by several flat-topped seamounts ranging from 11°S to 21°S in latitudes. Based on a comprehensive geomorphologic study and on dredged samples analysis, we show that these features correspond to tropical isolated shallow-water carbonate platforms. Coupling strontium isotopy and foraminifera biostratigraphy, well-constrained chronostratigraphy results indicate that shallow-water carbonate production started in the Mozambique Channel during distinct... |
Tipo: Text |
Palavras-chave: Carbonate platform; Drowning; Cenozoic; Mozambique Channel; East African rift system. |
Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45827/46634.pdf |
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Courgeon, Simon; Bourget, Julien; Jorry, Stephan. |
During the Plio-Quaternary, the Bonaparte Basin is characterized by the development of a wide (up to 200km) intra-shelf basin (the Malita ISB) evolving under conditions of low tectonic activity. Based on 3D and 2D seismic surveys combined with exploration well data, this study demonstrates that the stratigraphic organisation of the Malita ISB is mainly driven by fluctuations of the relative sea-level. It can be divided in three main 3rd-order system tracts: (1) a transgressive system tract, corresponding to a period of active carbonate aggradation during the late Pliocene, (2) a highstand system tract, associated with a period of strong carbonate progradation during the early-middle Quaternary, and; (3) a last system tract phasing late Quaternary... |
Tipo: Text |
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Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00202/31284/29691.pdf |
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Jorry, Stephan; Camoin, Gilbert F.; Jouet, Gwenael; Le Roy, Pascal; Vella, Claude; Courgeon, Simon; Prat, Sophie; Fontanier, Christophe; Paumard, Victorien; Boulle, Julien; Caline, Bruno; Borgomano, Jean. |
Isolated carbonate platforms occur throughout the geologic record, from Archean to present. Although the respective roles of tectonics, sediment supply and sea-level changes in the stratigraphical architecture of these systems are relatively well constrained, the details of the nature and controls on the variability of sedimentological patterns between and within individual geomorphologic units on platforms have been barely investigated. This study aims at describing and comparing geomorphological and sedimentological features of surficial sediments and fossil reefs from three isolated carbonate platforms located in the SW Indian Ocean (Glorieuses, Juan de Nova and Europa). These carbonate platforms are relatively small and lack continuous reef margins,... |
Tipo: Text |
Palavras-chave: Mozambique channel; Carbonate sediments; Fossil reefs; Isolated carbonate platforms. |
Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00292/40329/39074.pdf |
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