Multiple source interaction in the genesis of Triassic rift-related alkaline lavas in SW Turkey: constrains from trace element and Hf-Nd-Pb isotope systematics
LITHOS, cilt.544, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 544
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.lithos.2026.108768
- Dergi Adı: LITHOS
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Geobase, INSPEC, Academic Search Ultimate (EBSCO)
- Kocaeli Üniversitesi Adresli: Evet
Özet
Late Triassic basaltic rocks exposed as isolated lava sheets within several tectonic slices of the Antalya nappes in SW Turkey are interpreted to have formed during extensive rift-related submarine volcanism. The volcanic successions consist predominantly of pillow lavas and, locally, massive lava flows interbedded with Upper Triassic pelagic and/or carbonate platform-derived sedimentary units. Based on bulk-rock geochemical characteristics, the lavas are classified as alkaline basalts and display distinctive OIB-type trace element patterns, marked by substantial enrichment in LILE and HFSE relative to N-MORB compositions. Trace element modelling indicates that the parental melts of these alkaline magmas were generated by small degrees (<10%) of partial melting of anhydrous peridotite and did not subsequently undergo compositional modification through crustal melt contribution. The samples exhibit considerable variation in radiogenic isotope compositions, with age-corrected values of Hf-176/Hf-177 = 0.28272-0.28287, Nd-143/Nd-144 = 0.51251-0.51272, Pb-206/Pb-204 = 18.41-20.18, Pb-207/Pb-204 = 15.56-15.72 and Pb-208/Pb-204 = 38.17-39.53, indicating contributions from more than one isotopically distinct mantle source. The principal components involved include a typical depleted MORB mantle source, a HIMU-like component characterized by elevated Pb-206/Pb-204 and Nd-143/Nd-144 ratios, and an EMI-type component distinguished by lower Hf-176/Hf-177, Nd-143/Nd-144 and Pb-206/Pb-204 ratios. In the absence of evidence for anomalously high mantle potential temperatures, the simultaneous involvement of HIMU and EMI components is interpreted to reflect melt derivation from a multiply enriched lithospheric mantle source. Negative decoupling of HfNd isotope systems, indicating time evolution of source material with less radiogenic Hf-176/Hf-177 than Nd-143/Nd-144, further suggests metasomatic imprints of melts derived from garnet-bearing recycled lithologies. Overall, these results support a model in which magma generation was associated with continental rifting and lithospheric destabilization, promoting decompression melting of depleted sub-lithospheric mantle together with previously enriched continental lithospheric mantle.