The development of mantle-derived basaltic rocks in the Develidağ Volcanic Complex: New Sr and triple O isotope evidence

The Develidağ volcanic complex is a part of the Middle Miocene-Quaternary Cappadocian Volcanic Province (CVP), which is located on the eastern side of the Plio-Quaternary Sultansazlığı pull-apart basin along the Ecemiş left-lateral strike-slip fault in central Anatolia. Volcanic rocks are classified as basalt, basaltic andesite, and minor amounts of andesites.

Primitive mantle-normalized multi-element patterns reveal that basaltic rocks are depleted in LIL and HFS elements compared to an OIB signature except for Ba and Pb. In contrast, andesites are represented by high LIL element content and differ from an OIB source magma by Nb, Ta, P, Ti depletion, and Pb enrichments.

High Zr/Ba (0.49-1.42), Zr/Hf (42.19–47.46), and Th/U (3.13–4.69) ratios are attributed to contributions from an asthenospheric source component. The ⁸⁷Sr/⁸⁶Sr ratios of basaltic samples range between 0.703656 and 0.703940. Oxygen isotope compositions are characterized by δ¹⁸O values ranging from +4.8 to +6.1‰ and Δ¹⁷O values of -57 to -51 ppm, consistent with a mantle signature. These isotopic insights imply that basaltic rocks are related to mantle-derived processes and are consistent with a spinel peridotite source without much crustal contamination. Recent studies widely suggest that the geodynamic development of the region may be linked to processes such as slab break-off, asthenospheric upwelling, and lithospheric mantle drip. Within this framework, δ¹⁸O values and their combined usage with Sr isotope data will provide significant insight for the evolution of the basaltic rocks and for the mantle dynamics in terms of interpreting the contamination processes in the CVP.