Quaternary mafic lavas in Central Anatolia provide geochemical insights into melt generation processes following regional delamination of the subducted Tethyan slabs. New geochemical data from the Pleistocene Hasandağ Cinder Cone Province (HCCP) and Karapınar Volcanic Field (KVF) record contributions from subduction-modified lithospheric and sub-lithospheric source domains that are distinct from those sampled elsewhere across Anatolia (e.g., Pearce et al., 1990; Aldanmaz et al., 2006; Keskin, 2007; Chakrabarti et al., 2012; Reid et al., 2017). Hasandağ cinder cones are primarily basaltic, with subordinate trachybasalt and basaltic trachyandesite; Karapınar lavas comprise basalts and andesites with subordinate basaltic trachyandesite and basaltic andesite. Anomalously high Li, Na, Ti and Zr abundances and Ba/Rb values in these South-Central Anatolian primitive mafic lavas suggest significant contribution from metasomatic phases (i.e., amphibole, zircon and rutile); Dy/Ybn values measured in the mafic volcanics indicate melting in the spinel stability field. Correlation between ⁸⁷Sr/⁸⁶Sr and ^ε_Nd in HCCP and KVF lavas indicate pseudo-binary mixing between enriched and depleted endmembers, while ^ε_Nd-^ε_Hf isotopic values that plot above the terrestrial array extend toward sediment compositions sampled from the eastern Mediterranean Sea (Klaver et al., 2015). Together, trace element chemistry and Sr-Nd-Hf-Pb isotope compositions suggest input from a spatially heterogeneous mantle with contributions from depleted MORB-like and recycled sediment sources. The apparent presence of pyroxenite and hydrous metasomes within the HCCP and KVF source regions, and abundant dense mafic cumulates associated with the adjacent Hasandağ stratovolcano, support an unstable small-scale lithospheric density structure in South-Central Anatolia. We suggest regional delamination of the Neotethyan slab on a regional scale caused upwelling asthenosphere to destabilize the remaining Central Anatolian lithosphere and resulted in localized drip melting to produce the mafic volcanism at the HCCP and KVF. Geochemical similarities to Miocene alkali basalts from Galatia and Sivas (Wilson et al., 1997; Varol et al., 2014; Kürkcüoğlu et al., 2015) suggest that this mechanism occurred across Central Anatolia subsequent to Tethys subduction, and thus the ages of monogenetic volcanic activity record the descent of the slab beneath Anatolia. We infer that slab foundering played a more important role in this process than lithospheric loss beneath a tectonically shortened orogen (Göğüs et al., 2017) although further mapping of sedimentary basins and structures is required to resolve this interpretation.

安纳托利亚中部的第四纪基性熔岩提供了对俯冲特提斯板块区域分层后熔体生成过程的地球化学见解。来自更新世 Hasandağ Cinder Cone Province (HCCP) 和 Karapınar Volcanic Field (KVF) 的新地球化学数据记录了俯冲修正的岩石圈和亚岩石圈源域的贡献，这些域与安纳托利亚其他地方采样的那些域不同（例如，Pearce 等人， 1990；Aldanmaz 等，2006；Keskin，2007；Chakrabarti 等，2012；Reid 等，2017）。Hasandağ煤渣锥主要是玄武岩，其次是粗面玄武岩和玄武质粗面岩；Karapınar 熔岩包括玄武岩和安山岩，其次是玄武质粗安山岩和玄武质安山岩。异常高的 Li, Na, 这些中南部安纳托利亚原始镁铁质熔岩中的 Ti 和 Zr 丰度以及 Ba / Rb 值表明交代相（即角闪石、锆石和金红石）的显着贡献；镝/镱在基性火山岩中测得的n值表明在尖晶石稳定性场中熔化。HCCP 和 KVF 熔岩中⁸⁷ Sr / ⁸⁶ Sr 与^ε _Nd之间的相关性表明富集端元和耗尽端元之间存在伪二元混合，而^ε _Nd - ^ε _Hf绘制在陆地阵列上方的同位素值延伸至从东地中海采样的沉积物成分（Klaver 等人，2015 年）。总之，微量元素化学和 Sr-Nd-Hf-Pb 同位素组成表明来自空间异质地幔的输入以及耗尽的 MORB 样和循环沉积物来源的贡献。HCCP 和 KVF 源区内明显存在辉石岩和含水后体，以及与相邻的 Hasandağ 成层火山相关的大量致密镁铁质堆积，支持安纳托利亚中南部不稳定的小规模岩石圈密度结构。我们认为，新特提斯板块在区域尺度上的区域分层导致上涌的软流圈破坏了其余的安纳托利亚中部岩石圈的稳定性，并导致局部滴熔，从而在 HCCP 和 KVF 产生基性火山作用。与来自加拉太和锡瓦斯的中新世碱性玄武岩的地球化学相似性（Wilson 等人，1997 年；Varol 等人，2014 年；Kürkcüoglu 等人，2015 年）表明这种机制发生在特提斯俯冲之后的安纳托利亚中部，因此单生火山活动记录了安纳托利亚下方板块的下降。我们推断，与构造缩短的造山带下的岩石圈损失相比，板块沉没在该过程中发挥了更重要的作用（Göğüs 等，2017），尽管需要进一步绘制沉积盆地和结构图来解决这一解释。