The Late Cretaceous Aarya flora of the northern Okhotsk region and phytostratigraphy of the lower part of the Okhotsk-Chukotka volcanogenic belt section

Results of comprehensive study of the Kholokhovchan floral assemblage collection is summarized. These plant fossils were collected in 1978 by E. L. Lebedev from volcanogenic deposits in Penzhina and Oklan rivers interfluve, North-Eastern Russia. This assemblage was previously known as a list of Lebedev’s preliminary identifi cations only. He had suggested that the Kholokhovchan assemblage is correlative to the latest Albian — early Turonian Grebenka flora from the Anadyr River middle reaches. However, our study demonstrates that the Kholokhovchan assemblage is most similar to the presumably the Turonian-Coniacian Arman flora of the Okhotsk-Chukotka volcanogenic belt and, therefore, should be dated as the Turonian-Coniacian or Turonian.

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Ginkgophytes of the Ul’ya flora (the Ul’ya depresiion, the Okhotsk-Chukotka volcanogenic belt)

Palaeobotany ◽

10.31111/palaeobotany/2016.7.80 ◽

2016 ◽

Vol 7 ◽

pp. 80-95 ◽

Cited By ~ 2

Author(s):

L. B. Golovneva

Keyword(s):

New Species ◽

Early Cretaceous ◽

Late Cretaceous ◽

Middle Part ◽

Leaf Length ◽

Volcanogenic Belt ◽

Short Shoots ◽

Volcanogenic Deposits

The Ul’ya flora comes from the Coniacian volcanogenic deposits of the Amka Formation (the Ul'ya depression, southern part of the Okhotsk-Chukotka volcanogenic belt). Ginkgoaleans are diverse in this flora and represented by three genera: Ginkgo, Sphenobaiera and Baiera. All specimens have no cuticle and were assigned to morphotaxa. Genus Ginkgo includes two species: G. ex gr. adiantoides (Ung.) Heer with entire leaves and G. ex gr. sibirica Heer with dissected leaves. Genus Sphenobaiera also consists of two species: S. ex gr. longifolia (Pom.) Florin with 4–8 leaf lobes and S. ex gr. biloba Prynada with two leaf lobes. Genus Baiera is represented by new species B. lebedevii Golovn., sp. nov.Leaves of this species are 25–30 cm long and 13–16 cm wide, narrowly wedge-shaped with flat slender petiole, dichotomously dissected 4–5 times into linear segments 3–6 mm wide with 6–12 veins. The length of ultimate segments is equal to about a half of leaf length. Leaves attached spirally to ovoid short shoots about 2 cm long. Among the Late Cretaceous floras similar diversity of ginkgoaleans was recorded only in the Turonian-Coniacian Arman flora from middle part of the Okhotsk-Chukotka volcanogenic belt (Herman et al., 2016). Four species of ginkgoaleans from the Ul’ya flora (except G. ex gr. adiantoides) are considered as the Early Cretaceous relicts.

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The Gedan floristic assemblage from the Late Cretaceous deposits of the Kholchan Formation of the Okhotsk-Chukotka volcanogenic belt

Palaeobotany ◽

10.31111/palaeobotany/2014.5.73 ◽

2014 ◽

Vol 5 ◽

pp. 73-93 ◽

Cited By ~ 3

Author(s):

L. B. Golovneva ◽

S. V. Shczepetov

Keyword(s):

River Basin ◽

Late Cretaceous ◽

Middle Part ◽

Isotopic Data ◽

Volcanogenic Belt ◽

Stratigraphic Position ◽

Cretaceous Deposits

The Gedan floristic assemblage occurs from upper layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at the Gedan River in the middle part of the Arman River basin. The Gedan assemblage is composed of 6 taxa: Cladophlebis sp., Sphenobaiera sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Taxodium amguemensis (Efimova) Golovn., Metasequoia sp., Pagiophyllum sp. The similarity of the Gedan floristic assemblage with the Karamken and the Khirumki floristic assemblages from the Kholchan Formation of the Okhotsk sector of the OCVB allows us to join them in the Kholchan flora. This flora is distinct from more ancient Arman flora, which dated as the Turonian-Coniacian and from younger Ola flora, which dated as the Santonian-early Campanian. The age of the Kholchan flora is estimated as the Coniacian on the basis of stratigraphic position, presence of Podozamites, Metasequoia and Quereuxia and also isotopic data. This flora is equivalent with the Chaun flora of Central Chukotka, with the Aleeki flora from the Villigha and Toomahni Rivers interfluve and with the Ulya flora from the southern part of the Okhotsk-Chukotka volcanogenic belt.

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New data about the Late Cretaceous floras of the Ulya depression (western coast of Sea of Okhotsk)

Palaeobotany ◽

10.31111/palaeobotany/2013.4.148 ◽

2013 ◽

Vol 4 ◽

pp. 148-167 ◽

Cited By ~ 10

Author(s):

L. B. Golovneva

Keyword(s):

River Basin ◽

Early Cretaceous ◽

Late Cretaceous ◽

Sea Of Okhotsk ◽

Northeastern Russia ◽

Western Coast ◽

Fossil Plants ◽

Sedimentary Deposits ◽

Volcanogenic Belt ◽

Systematic Composition

New investigation of fossil plants from volcanic-sedimentary deposits of the Amka Formation in Ulya River basin (southern part of the Okhotsk-Chukotka volcanogenic belt, Northeastern Russia) shows, that the Arinda, Uenma, Ust-Amka and Gyrbykan floristic assemblages from diff erent localities of this formation have very close systematic composition. We propose to joint these assemblages in the single regional flora, which is named the Ulya flora. The Ulya flora consists of almost 40 species. The majority of them are represented by new undescribed taxa. In this flora gymnosperms (Phoenicopsis ex gr. speciosa Heer, Ginkgo ex gr. adiantoides (Ung.) Heer, G. ex gr. sibirica Heer, Sphenobaiera sp., Podozamites sp., Elatocladus spp., Araucarites sp., Sequoia sp., Metasequoia sp., Cupressinocladus sp., Ditaxocladus sp., Pityophyllum sp., Pityostrobus sp.) predominate. Ferns (Asplenium dicksonianum Heer, Arctopteris sp., Cladophlebis spp. and several undescribed taxa) and angiosperms (Trochodendroides spp., undetermined Platanaceae, Dicotylophyllum spp., Quereuxia angulate (Newb.) Krysht. ex Baik.) are not abundant. This flora is characterized by presence of the Early Cretaceous relicts (Phoenicopsis, Sphenobaiera and Podozamites), by rarity of angiosperms and by high endemism. On the base of comparison of the Ulya flora with other floras from middle and northern parts of the Okhotsk-Chukotka volcanogenic belt, the age of the Ulya flora is estimated as the Coniacian.

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The late cretaceous flora from volcanogenic deposits of northern Priokhotie (The Okhotsk-Chukotka volcanogenic belt)

Palaeobotany ◽

10.31111/palaeobotany/2010.1.45 ◽

2010 ◽

Vol 1 ◽

pp. 45-95 ◽

Cited By ~ 15

Author(s):

S. V. Shczepetov ◽

L. B. Golovneva

Keyword(s):

New Species ◽

Late Cretaceous ◽

Fossil Plants ◽

Main Species ◽

Systematic Description ◽

Volcanogenic Belt ◽

The Common ◽

Volcanogenic Deposits

Assemblage of fossil plants from the Gydra, Yum and Kananyga Formations (the Villigha and Toomahni Rivers interfluve, Okhotsk-Chukotka volcanogenic belt) are joined in the Aleeki flora. The systematic description of main species is given and floristic and phytostratigraphical analysis of this flora is carried out. New species Lobifolia alikensis Golovn. et Shczep. is described. The Aleeki flora is typical flora of the Okhotsk-Chukotka volcanogenic belt. It contain few angiosperms and significant amount relic elements among ferns (Hausmannia, Lobifolia), cycadophytes (Heilungia), czekanowskiales (Phoenicopsis) and ginkgoales (Sphenobaiera, Ginkgo ex gr. sibirica). In consequence of its stratigraphical position the Aliky flora is slightly younger than the Chingandzha flora (the Turonian-Coniacian) and it is compositionally similar with the Chaun flora (Coniacian). On this basis the age of the Aleeki flora is estimated as the Coniacian. The common taxa of the Aleeki and Chingandzha floras are Coniopteris tschuktschorum, Asplenium dicksonianum, Cladophlebis inaequipinnulata, Birisia sp., Ginkgo ex gr. adiantoides, G. ex gr. sibirica, Sequoia, Metasequoia, Menispermites, Dalembia and Trochodendroides. The common genera of the Aleeki and Chaun floras are Coniopteris, Asplenium, Arctopteris, Cladophlebis, Ginkgo, Sphenobaiera, Heilungia, Phoenicopsis, Picea, Sequoia, Metasequoia, Menispermites, Dalembia and Trochodendroides. Besides that the Aleeki flora contains some species, which were believed as endemic of the Chaun flora: Tchaunia lobifolia, Cladophlebis grandis and Araucarites subacutensis. The Aleeki and Chaun floras are now considered as contemporaneous regional floras, which were distributed in the northern part of the Okhotsk-Chukotka volcanogenic belt.

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The late cretaceous flora from volcanogenic deposits of Northern Priokhotie (The Okhotsk-Chukotka volcanogenic belt)

Palaeobotany ◽

10.31111/palaeobotany/2011.2.100 ◽

2011 ◽

Vol 2 ◽

pp. 100-113 ◽

Cited By ~ 5

Author(s):

L. B. Golovneva ◽

S. V. Shczepetov

Keyword(s):

Late Cretaceous ◽

Fine Grained ◽

Lacustrine Deposits ◽

Volcanogenic Belt ◽

Volcanogenic Deposits ◽

Systematic Composition

The Karamken floristic assemblage occurs from basal layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at Khasyn River near Karamken settlement. The Karamken assemblage is composed of 6 taxa: Heilungia sp., Phoenicopsis ex gr. angustifolia Heer, Sphenobaiera sp., Metasequoia sp., Taxodium amguemensis (Efimova) Golovn., Trochodendroides sp. This flora is distinct from more ancient Arman flora and younger Ola flora. According to systematic composition the Karamken floristic assemblage is similar to the Chaun flora of Central Chukotka (the Coniacian), to the Aleeki flora from the Villigha and Toomahni Rivers interfluve (the Coniacian) and to the floristic assemblage from the Leurvaam (?) Formation of Eastern Chukotka (Efimova, 1966). On this basis the age of the Karamken flora is estimated as the Coniacian. Association of the remains of Metasequoia, Taxodium amguemensis, Phoenicopsis and large leaves of Sphenobaiera is repeated in different localities in different part of the OCVB. These remains are usually connected with fine-grained volcanogenic-terrigenous paludal-lacustrine deposits.

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