Titre :

Using detrital zircon petrochronology fordiscriminating sourcing from magmatic arcsemplaced in continental and oceanic crusts:the case of the Ecuadorian forearc

Auteur(s) :

Witt, César [Auteur correspondant]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Bruguier, Olivier [Auteur]
Géosciences Montpellier
Poujol, Marc [Auteur]
Géosciences Rennes [GR]
Armynot Du Châtelet, Eric [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Ventalon, sandra [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Bosch, Delphine [Auteur]
Géosciences Montpellier
Seyler, Monique [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]

Titre de la manifestation scientifique :

19 ème Congrès français de sédimentologie (ASF 2024)

Ville :

Villeneuve d'Ascq (Lille)

Pays :

France

Date de début de la manifestation scientifique :

2024-11-26

Titre de l’ouvrage :

Livre des résumés, Publication ASF

Date de publication :

2024

Discipline(s) HAL :

Planète et Univers [physics]/Sciences de la Terre/Stratigraphie

Résumé en anglais : [en]

The Cenozoic magmatic arc in Ecuador (north of 3◦S) can be defined as a continentalarc emplaced in a transitional continental upper plate (i.e., oceanic crust of plateau affinityaccreted to the continent). This configuration ...
Lire la suite >The Cenozoic magmatic arc in Ecuador (north of 3◦S) can be defined as a continentalarc emplaced in a transitional continental upper plate (i.e., oceanic crust of plateau affinityaccreted to the continent). This configuration is very different from the southern Ecuadorian andnorthern Peruvian arcs, which were built on autochthonous crust. The Cenozoic Ecuadorianmagmatic arc (~60-7 Ma) and forearc basin pair is an excellent laboratory to test zircongeochemistry as a sedimentary provenance indicator. Indeed, the location of the study area,close to the limit of accretionary terrains in the Northern Andes, is key to analyze the differentinputs from autochthonous and allochthonous crusts towards the forearc basins.Zircon petrochronology is emerging as a powerful tool for unravelling the sedimentaryhistory of orogenic basins. To explore the geochemical characteristics of zircons derived fromeither continental or oceanic crust, in this study we use detrital zircons from the Coastal Cordillera(CC) of Ecuador complemented with published data (zircon ages and chemistry) obtained fromsedimentary rocks of SW Ecuador. Preliminary results show that eHf defines a long-lived trendcharacterized by juvenile sources in the CC and enriched/recycled sources in SW Ecuador. Thus,eHf and d18O define two distinct ~60 Ma mantellic magmatic reservoirs: a juvenile arc emplacedin immature accreted crust to the north and a highly differentiated arc emplaced in the continentalcrust to the south.To achieve our provenance goals, we performed a clustering and multivariate analysis onzircon trace elements on a dataset of ~300 zircon grains with concordant ages. Preliminary resultsshow that characteristic trace elements such as U, La, Ta and Nb and ratios such as U/Yb, Th/U,Ce/Y and Nb/Ta and L/H REE clearly distinguish the two arc signatures and are considered asgood markers for sediment provenance in this particular arc-forearc setting.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Nationale

Vulgarisation :

Non

Collections :

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

Source :

Harvested from HAL