Contrasting origin of two A-type rhyolite series from the Early Permian Nomgon bimodal volcanic association (Southern Mongolia)


Дәйексөз келтіру

Толық мәтін

Ашық рұқсат Ашық рұқсат
Рұқсат жабық Рұқсат берілді
Рұқсат жабық Тек жазылушылар үшін

Аннотация

A-type rhyolites of contrasting compositions and eruption characters were revealed among two volcanic series of the Early Permian bimodal association in the Nomgon graben. Rhyolites of the lower volcanic series formed extrusions, lava domes, and tuff horizons. They had low FeOt, Zr, Hf, Nb, Ta, Y, and REE concentrations and also a moderately depleted Nd isotope composition (εNd(Т) = 6.7–7.1). Their formation was related to anatexis of the juvenile continental crust, triggered by the thermal effect of mafic magmas. Rhyolites of the upper volcanic series formed extensive lava flows and dikes. Their composition was characterized by high FeOt, Zr, Hf, Nb, Ta, Y, and REE concentrations, and also depleted Nd isotope characteristics (εNd(Т) = 7.7–9.0). These rhyolite melts formed under long-term crystallizational differentiation of basaltoids in the intracrustal magmatic chambers, with limited participation of crustal contamination. The source of magmas for the upper volcanic series was the sublithospheric mantle.

Авторлар туралы

A. Kozlovsky

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry

Хат алмасуға жауапты Автор.
Email: amk@igem.ru
Ресей, Staromonetnyi per. 35, Moscow, 119017

V. Yarmolyuk

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry

Email: amk@igem.ru
Ресей, Staromonetnyi per. 35, Moscow, 119017

V. Savatenkov

Institute of Precambrian Geology and Geochronology; Institute of Earth Sciences

Email: amk@igem.ru
Ресей, nab. Makarova 2, St. Petersburg, 199034; Universitetskaya nab. 7-9, St. Petersburg, 199034

E. Kudryashova

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry

Email: amk@igem.ru
Ресей, Staromonetnyi per. 35, Moscow, 119017

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