J 2022

Effects of Mantle Hybridization by Interaction with Slab Derived Melts in the Genesis of Alkaline Lavas across the Back-Arc Region of South Shetland Subduction System

ALTUNKAYNAK, Safak, Ercan ALDANMAZ a Daniel NÝVLT

Základní údaje

Originální název

Effects of Mantle Hybridization by Interaction with Slab Derived Melts in the Genesis of Alkaline Lavas across the Back-Arc Region of South Shetland Subduction System

Autoři

ALTUNKAYNAK, Safak (garant), Ercan ALDANMAZ a Daniel NÝVLT (203 Česká republika, domácí)

Vydání

Journal of Petrology, Oxford University Press, 2022, 0022-3530

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

Impakt faktor

Impact factor: 3.900

Kód RIV

RIV/00216224:14310/22:00127807

Organizační jednotka

Přírodovědecká fakulta

UT WoS

000882064100002

Klíčová slova anglicky

Antarctic Peninsula; alkali magmatism; radiogenic isotopes; mantle source; petrogenesis

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 9. 1. 2023 14:04, Mgr. Marie Šípková, DiS.

Anotace

V originále

Late Miocene to Late Pleistocene alkaline lavas in the northernmost part of the Antarctic Peninsula and its off-lying islands are the latest stage of magmatic activity that took place in response to lithospheric extension in the back-arc region of the South Shetland subduction system. The alkaline magmatism occurred much later than the main pulse of Cretaceous arc magmatism and generated basaltic extrusive rocks during several sub-aqueous/sub-glacial and sub-aerial eruption periods. The suite consists primarily of alkali olivine basalts with oceanic island basalt (OIB)-like trace element signatures, characterized by elevated highly to less incompatible element ratios compared to MORB. The samples have higher Sr-87/Sr-86 (0.70301-0.70365), and lower Nd-143/Nd-144 (0.51283-0.51294) and Hf-176/Hf-177 (0.28291-0.28298) than depleted MORB mantle. Their lead isotope ratios vary within a limited range with Pb-206/Pb-204, Pb-207/Pb-204, Pb-208/Pb-204 ratios of 18.797-18.953, 15.577-15.634, and 38.414-38.701, respectively. Sr, Nd, Hf and Pb isotope systematics suggest involvement of diverse source materials in the genesis of the alkaline magmas. Evaluation of radiogenic isotope and trace element data indicates that the source of the alkaline melts had a complex petrogenetic history, reflecting the effects of mantle hybridization along the slab mantle interface through interaction of mantle wedge peridotites with volatile-bearing, siliceous melts produced by melting of subducted sediments and basaltic oceanic crust. Hf-Nd isotope and trace element projections further demonstrate that the metasomatizing melt was likely generated by eclogite partial melting at sub-arc to post-arc depths, in equilibrium with a garnet-bearing residue and involved breakdown of high field strength elements (HFSE) retaining phases. Consumption of metasomatic amphibole during partial melting of hybridized peridotite at the wet solidus appears to have had a significant effect on the final melt compositions with high HFSE, Na and H2O contents.