Geochemical characterization of a Quaternary monogenetic volcano in Erciyes Volcanic Complex: Cora Maar (Central Anatolian Volcanic Province,Turkey) |
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Authors: | Gonca Gencalioglu-Kuscu |
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Institution: | (1) Department of Geological Engineering, Mugla University, 48000 Mugla, Turkey |
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Abstract: | Central Anatolian Volcanic Province (CAVP) is a fine example of Neogene-Quaternary post-collisional volcanism in the Alpine-Mediterranean
region. Volcanism in the Alpine-Mediterranean region comprises tholeiitic, transitional, calc-alkaline, and shoshonitic types
with an “orogenic” fingerprint. Following the orogenic volcanism, subordinate, within-plate alkali basalts (sl) showing little or no orogenic signature are generally reported in the region. CAVP is mainly characterized by widespread
calc-alkaline andesitic-dacitic volcanism with orogenic trace element signature, reflecting enrichment of their source regions
by subduction-related fluids. Cora Maar (CM) located within the Erciyes pull-apart basin, is an example to numerous Quaternary
monogenetic volcanoes of the CAVP, generally considered to be alkaline. Major and trace element geochemical and geochronological
data for the CM are presented in comparison with other CAVP monogenetic volcanoes. CM scoria is basaltic andesitic, transitional-calc-alkaline
in nature, and characterized by negative Nb–Ta, Ba, P and Ti anomalies in mantle-normalized patterns. Unlike the “alkaline”
basalts of the Mediterranean region, other late-stage basalts from the CAVP monogenetic volcanoes are classified as tholeiitic,
transitional and mildly alkaline. They display the same negative anomalies and incompatible element ratios as CM samples.
In this respect, CM is comparable to other CAVP monogenetic basalts (sl), but different from the Meditterranean intraplate alkali basalts. Several lines of evidence suggest derivation of CM and
other CAVP monogenetic basalts from shallow depths within the lithospheric mantle, that is from a garnet-free source. In a
wider regional context, CAVP basalts (sl) are comparable to Apuseni (Romania) and Big Pine (Western Great Basin, USA) volcanics, except the former have depleted Ba
contents. This is a common feature for the CAVP volcanics and might be related to crustal contamination or source characteristics.
Indeed, HFS and other incompatible element ratios suggest the role of crustal contamination in the genesis of the CAVP monogenetic
basalts. |
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