Crustal Structure and Stratigraphy of the South Mozambique Margin to South Mozambique Ridge From Combined Wide‐Angle and Reflection Seismic and Drill Hole Data - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Earth and Space Science Année : 2023

Crustal Structure and Stratigraphy of the South Mozambique Margin to South Mozambique Ridge From Combined Wide‐Angle and Reflection Seismic and Drill Hole Data

Philippe Schnürle
A. Leprêtre
  • Fonction : Auteur
Mikael Evain
Fanny Verrier
  • Fonction : Auteur
P. De‐clarens
  • Fonction : Auteur
Joseph Thompson
  • Fonction : Auteur
N. Dias
A. Afilhado
  • Fonction : Auteur
Sylvie Leroy
Elia d'Acremont
  • Fonction : Auteur
  • PersonId : 1117531
Daniel Aslanian
Maryline Moulin

Résumé

We have analyzed the MZ6 onshore‐offshore wide‐angle seismic profile of the MOZ3‐5 survey to investigate the crustal structure of the South Mozambique passive margin. The NNW‐SSE, 625 km‐long profile runs across the Mozambique coastal plain (MCP), the Continental Shelf and Slope, the Almirante Leite Ridge (ALR), the North Natal Valley (NNV), the Ariel Graben and the Dana Plateau of the Mozambique Ridge. Forward modeling through combined interpretation of the multichannel seismic, the main reflected and refracted phases of the wide‐angle, drill hole data and bathymetric data reveal: (a) a sedimentary cover poorly compacted up to 3 km‐thick, intruded by magmatic dykes that reach the seafloor at the ALR forming 0.5 to 5 km‐wide corrugated mounts, (b) between 2 and 7 km, thick magmatic or volcano‐clastic deposits are observed both at the MCP and NNV, forming a 40 km‐wide terrace at the center of MZ6 and southward‐dipping reflectors in the southern part interpreted as the Pre‐Neocomian Formation contemporary of the Karroo and/or Bombeni‐Movene magmatic events reached in several wells, (c) onshore, the 3‐layered crust reaches 39 km thickness, gradually thinning to ∼27 km at the southern end of MZ6. In the deepest layer, velocities exceed 7.15 km/s, reaching at its base 7.55 km/s at the vertical of the ALR. (d) the seismic Moho is marked by a strong reflection on the wide‐angle data. These results suggests that the basement is composed of slightly thinned and altered continental crust, most likely intruded by several phases of intense magmatism.
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Dates et versions

hal-04304351 , version 1 (25-11-2023)

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Paternité - Pas d'utilisation commerciale - Partage selon les Conditions Initiales

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Philippe Schnürle, A. Leprêtre, Mikael Evain, Fanny Verrier, P. De‐clarens, et al.. Crustal Structure and Stratigraphy of the South Mozambique Margin to South Mozambique Ridge From Combined Wide‐Angle and Reflection Seismic and Drill Hole Data. Earth and Space Science, 2023, 10 (10), e2021EA001902 (28p.). ⟨10.1029/2021EA001902⟩. ⟨hal-04304351⟩
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