Western Kamchatka-Koryak continental-margin volcanogenic belt: Age, composition, and sources

2011 ◽  
Vol 49 (8) ◽  
pp. 768-792 ◽  
Author(s):  
P. I. Fedorov ◽  
D. V. Kovalenko ◽  
O. A. Ageeva
Keyword(s):  
Continental Margin ◽  
Age Composition ◽  
Western Kamchatka ◽  
Volcanogenic Belt

scholarly journals GRANITOIDS OF THE ALTAKHTA COMPLEX IN THE EASTERN PART OF THE BUREYA CONTINENTAL MASSIF OF THE CENTRAL ASIAN FOLD BELT: AGE, GEOCHEMICAL FEATURES AND GEODYNAMIC INTERPRETATIONS

2021 ◽  
Vol 40 (4) ◽  
pp. 51-71
Author(s):  
V.А. Guryanov ◽  
◽  
Е.V. Nigai ◽  
Yu.Yu. Yurchenko ◽  
M.V. Arkhipov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Continental Margin ◽  
Late Triassic ◽  
Geodynamic Setting ◽  
Central Asian Fold Belt ◽  
Fold Belt ◽  
Age Composition ◽  
Central Asian ◽  
Formation Conditions ◽  
Two Phases

New data are reported on the age, composition and formation conditions of the Late Triassic granitoids of minor intrusions from the eastern part of the Bureya continental massif of the Central Asian fold belt, and their geodynamic interpretation is given. U-Pb geochronological studies on zircons indicate that the age of rocks of the Altakhta syenite-leucogranite complex is in the 235–224 Ma range, which intrusion proceeding in two phases. The formation of magmatites is associated with the first phase (235.3 ± 2.9–230 Ma), which by their geochemical features are similar to А1-type intraplate granitoids and by REE concentrations to subduction- and collision-related granitoids. Geochemical characteristics of А2-type and А2 + I & S-type granites (226–224 Ma) suggest their formation in a syncollisional setting. The evolution of the chemical composition of the Altakhta granitoids indicates a change in the geodynamic setting type, when the opposing (orthogonal) movement of the plates at the convergent boundary (subduction) changed to their sliding past each other (transform continental margin).

Late Cretaceous Kholokhovchan floral assemblage of the Okhotsk-Chukotka volcanogenic belt (North-Eastern Asia)

Palaeobotany ◽  
2013 ◽  
Vol 4 ◽  
pp. 116-147 ◽  
Author(s):  
S. V. Shczepetov ◽  
A. B. Herman
Keyword(s):  
Late Cretaceous ◽  
Eastern Asia ◽  
Plant Fossils ◽  
Volcanogenic Belt ◽  
North Eastern ◽  
Volcanogenic Deposits ◽  
Floral Assemblage ◽  
Eastern Russia ◽  
Comprehensive Study

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.

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

Palaeobotany ◽  
2016 ◽  
Vol 7 ◽  
pp. 80-95 ◽  
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.

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

Palaeobotany ◽  
2014 ◽  
Vol 5 ◽  
pp. 73-93 ◽  
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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