The evolution of Santa Maria Island in the context of the Azores Triple Junction

Marques, F.; Hildenbrand, A.; Costa, A.; Sibrant, A.

Document type :

Article dans une revue scientifique

DOI :

10.1007/s00445-020-01378-4

Title :

The evolution of Santa Maria Island in the context of the Azores Triple Junction

Author(s) :

Marques, F. [Auteur]

Hildenbrand, A. [Auteur]
Géosciences Paris Saclay [GEOPS]
Costa, A. [Auteur]
Sibrant, A. [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]

Journal title :

Bulletin of Volcanology

Publisher :

Springer Verlag

Publication date :

2020-05-09

ISSN :

0258-8900

HAL domain(s) :

Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

Santa Maria is the oldest island in the Azores, formerly belonging to the Eurasia plate and currently the only one sitting on the Nubia Plate, thus sharing a geodynamic evolution with the Azores Triple Junction. It is ...
Show more >Santa Maria is the oldest island in the Azores, formerly belonging to the Eurasia plate and currently the only one sitting on the Nubia Plate, thus sharing a geodynamic evolution with the Azores Triple Junction. It is therefore important to evaluate the effects of active tectonics on the evolution of Santa Maria, for example on its vertical movements. We present new stratigraphic, geomorphologic, structural and geochronological data from Santa Maria which shed further light on how a volcanic ocean island evolves in a tectonically active setting. Santa Maria island started with a first shield volcano (Old Volcanic Complex) that emerged ca. 6.0 Ma ago and was active until ca. 5.3 Ma. The short time span between the first and second shield volcanoes (ca. 0.3 Ma) and the preservation of only the western flank of this first shield volcano indicate an initial flank collapse at ca. 5 Ma. The collapse scar was covered by an eastwards dipping sedimentary complex (Intermediate Sedimentary Complex), with a likely tsunami deposit at the base. A second shield volcano (Young Volcanic Complex) rapidly grew on these sediments from 4.8 to 3.8 Ma, and the island subsided by more than 100 m. At 3.7 Ma, a second flank collapse occurred, as inferred from the missing summit and eastern flank. Volcanism then resumed (3.6 to 2.8 Ma), giving rise to Strombolian cones lying unconformably on the collapse scar and conformable parasitic cones on the unaffected flank. Submarine lavas occurring at up to 200 m altitude with a youngest age of 3.0 Ma indicate major uplift of the island since, at most, that time. Here we interpret uplift as the result of rift flank uplift on the southern shoulder of the nearby Terceira Rift in the last ca. 1.5 Ma.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Collections :

Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL

Files

https://hal.archives-ouvertes.fr/hal-03004925/document
Open access
Access the document

https://hal.archives-ouvertes.fr/hal-03004925/document
Open access
Access the document

https://hal.archives-ouvertes.fr/hal-03004925/document
Open access
Access the document

The evolution of Santa Maria Island in the ... BibTeX CSV Excel RIS

Files

The evolution of Santa Maria Island in the ...

BibTeX

CSV

Excel

RIS