Ferkan Sipahi Geochemistry of Dacitic volcanics in the eastern Pontides (NE Turkey) [Text] / Ferkan Sipahi, Burhan Sadklar M. // Геохимия. - 2014. - № 4. - С. 329-349 : ил. - Библиогр.: с. 346-349 (89 назв.) . - ISSN 0016-7525
Рубрики: Геология Геохимия--Турция--Восточные Понтиды--Зигана, гора; Гюмюшхане, город Кл.слова (ненормированные): амфиболы -- биотиты -- дацитовые вулканиты -- дациты -- кварцы -- литосферные расплавы -- мусковиты -- пириты -- плагиоклазы -- рутил -- санидины -- халькопирит -- циркон Аннотация: Dacitic rocks that crop out around the Zigana Mountain (Gumushane) in the eastern Pontide (NE Turkey) are mainly composed of quartz, plagioclase, sanidine, amphibole, muscovite, and biotite as the main minerals. Zircon and rutile are the accessory minerals. Pyrite, chalcopyrite, and covellite are the opaque components. On the basis of trace-element data, dacites have been classified as Dacite-I and Dacite-II. Dacite-I is tholeitic-transitional, whereas Dacite-II is transitional-calc-alkaline. The geochemical variation can be explained by the fractionation of the common mineral phases, such as plagioclase, hornblende, magnetite, and apatite. Dacites also show island-arc properties, with negative Nb, Sr, P, and Ti anomalies. The trace-element distrubitions of the dacitic rocks reflect the typical characteristics of rocks from the subduction-related tectonic setting, with enrichment of large-ion lithofile elements and light rare-earth element, but depletion in high-field-strength elements. The dacitic rocks are developed through plagioclase ± hornblende-controlled fractionation from the same parental magma that settled in two successive stages and are derived from an enriched source, probably by the mixing of slab-derived and lithospheric melts. Доп.точки доступа: Burhan Sadklar M. Имеются экземпляры в отделах: всего 1 : ч.з. (1) Свободны: ч.з. (1) |