Late Cretaceous high‐K volcanism in the eastern Pontide orogenic belt: implications for the geodynamic evolution of NE Turkey
Late Cretaceous high‐K volcanism in the eastern Pontide orogenic belt: implications for the geodynamic evolution of NE Turkey
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DOI：
10.1080/00206810902757164
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发表时间：
2010-03
影响因子：
2.6
通讯作者：
Y. Eyuboglu
中科院分区：
文献类型：
--
作者：
Y. Eyuboglu
High‐K volcanics were produced in two different Late Cretaceous cycles during the infilling of back‐arc basins of the eastern Pontides. The first cycle, represented by shoshonitic trachyandesites and associated pyroclastics, containing high K2O (2.74–4.81 wt‐%) and Na2O (3.60–5.51 wt‐%), overlies a mid‐Cretaceous ophiolitic‐olistostromal melange formed during the rifting stage of a back‐arc basin (Neotethys). 40Ar/39Ar dating of biotite from trachyandesite at the base of the first cyle indicates that shoshonitic volcanism in the far south of the eastern Pontides started in the early Campanian. Volcanic rocks of this cycle are overlain by upper Campanian‐Maastrichtian rudist‐bearing reefal limestones. The second cycle of high‐K volcanism is represented by analcime‐bearing volcanic rocks erupted in a Neotethyan lagoonal environment. These volcanic rocks, intercalated with continental detritus, are characterized by high Na2O (3.22–7.16 wt‐%), now concentrated in secondary analcime crystals. Their K2O content...
