The Aunei floristic assemblage from the upper Cretaceous volcanic deposits of the Okhotsk-Chukotka volcanogenic belt

L. B. Golovneva, S. V. Shczepetov

DOI: https://doi.org/10.31111/palaeobotany/2013.4.96

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Annotation

The Aunei floristic assemblage comes from volcanic-sedimentary deposits of the Aunei unit. The locality is situated in the middle course of the Eropol River (Anadyr River basin). This area belongs to the Anadyr segment of the Okhotsk-Chukotka volcanogenic belt (Belyi, 1977).

The Aunei floristic assemblage consists of 21 species. Among them gymnosperms (Phoenicopsis ex gr. angustifolia Heer, Podozamites sp., Elatocladus zheltovskii Philipp., Elatocladus sp., Araucarites subacutensis Philipp., Sequoia sp., Metasequoia sp., Cupressinocladus sp., Pityophyllum sp., Pityostrobus sp., Pityolepis sp.) predominate. Ferns (Tchaunia tchaunensis Samyl. et Philipp., Kolymella raevskii Samyl. et Philipp., Cladophlebis tschuktschorum Philipp.) and angiosperms (Trochodendroides microphylla Philipp., Trochodendroides sp. 1, 2, Dicotylophyllum nanum Golovn., Dicotylophyllum sp. 1, 2, Quereuxia angulata (Newb.) Krysht. ex Baik.) are not abundant. This assemblage is characterized by presence of the Early Cretaceous relicts (Phoenicopsis and Podozamites), by rarity of angiosperms and by small sizes of their leaves.

Taxonomic composition of the Aunei floristic assemblage most closely resembles the composition of the Chaun flora, which comes from the Coniacian deposits of the Chaun Group of Central Chukotka. From 21 species of the Aunei assemblage 14 species are common with the Chaun ones. Among them there are the characteristic endemic plants of the Chaun flora: Tchaunia tchaunensis, Kolymella raevskii, Araucarites subacutensis, Elatocladus zheltovskii, Trochodendroides microphylla.

The great systematic similarity of these floras indicate that they were even-aged and belonged to the single regional Chaun flora, which was distributed not only at Central Chukotka but also at area of the Anadyr segment of the Okhotsk-Chukotka volcanogenic belt. Age of the Aunei floristic assemblage is also determined as the Coniacian.

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How to cite

Golovneva L. B., Shczepetov S. V. 2013. The Aunei floristic assemblage from the upper Cretaceous volcanic deposits of the Okhotsk-Chukotka volcanogenic belt. Palaeobotany, 4: 96—115. https://doi.org/10.31111/palaeobotany/2013.4.96

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