Cretaceous paleomagnetic directions in different volcanics in Chukotka (NE Russia)

2021 ◽  
Author(s):  
Ivan Lebedev ◽  
Elizaveta Bobrovnikova ◽  
Artem Moiseev ◽  
Bagdasarian Tatiana
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Field Studies ◽  
Published Data ◽  
Geological Data ◽  
Fold Belt ◽  
Paleomagnetic Pole ◽  
The Pacific ◽  
Chukotka Volcanic Belt ◽  
Ne Russia

<p>The Cretaceous Okhotsk-Chukotka volcanic belt (OChVB) is one of the largest provinces of continental marginal magmatism with length more than 3000 km along the Pacific edge of Asia. In the field studies of 2019 and 2020 we sampled 21 sections in the northern part of the OChVB and 3 sections from basement of OChVB. These sections are represented by basalts and andesites; their tuffs, ignibrites and other volcanic rocks are much less common. The age of these volcanics is estimated based on U-Pb and Ar-Ar published data and our new Ar-Ar dates.</p><p>Based on the obtained data, a new paleomagnetic pole for the Chukotka part of the OChVB was calculated. The latitude of this paleomagnetic pole differs from the expected one when compared with that calculated for Chukotka from published data from Besse and Courtillot, 2003; Torsvik et al., 2012. These results are inconsistent with most of the existing geological data. Only a few works admit younger displacements in the southern part of the Verkhoyansk fold belt or in modern diffuse boundary of the Eurasian and North American plates. Moreover, we compare our OChVB pole with results from basaltic complexes from the basement, which has been likely remagnetized when OChVB was formed.</p><p>Acknowledgements: study of cretaceous volcanics is supported by RSF grant № 19-47-04110 and jurassic by RSF grant №18-77-10073.</p>

The Cretaceous Okhotsk–Chukotka Volcanic Belt (NE Russia): Geology, geochronology, magma output rates, and implications on the genesis of silicic LIPs

2012 ◽  
Vol 221-222 ◽  
pp. 14-32 ◽  
Author(s):  
P.L. Tikhomirov ◽  
E.A. Kalinina ◽  
T. Moriguti ◽  
A. Makishima ◽  
K. Kobayashi ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Chukotka Volcanic Belt ◽  
Ne Russia

New paleomagnetic data for Ochotsk-Chukotka volcanic belt

2020 ◽  
Author(s):  
Ivan Lebedev ◽  
Olesya Usanova ◽  
Tanya Fadeeva ◽  
Florian Lhuillier ◽  
Baha Eid ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Field Work ◽  
Magnetic Fabric ◽  
Time Interval ◽  
The North ◽  
Secular Variations ◽  
North Eastern ◽  
Chukotka Volcanic Belt ◽  
Normal Polarity

<p class="db9fe9049761426654245bb2dd862eecMsoNormal"><span lang="EN-US">The Okhotsk-Chukotka volcanic belt (OChVB),  located in the north-eastern part of Russia, is a unique volcanic structure, which has been formed over a wide time interval from Aptian (K1) to Cenomanian (K2) [Tihomirov, 2018]. Age of its formation nearly coincides with the occurrence of the Cretaceous geomagnetic superchron of normal polarity. Thus, the volcanic formations of the OChVB represent a promising object to study the characteristics of the geomagnetic field during the Cretaceous superchron (direction, paleointensity, secular variations) needed to test various models explaining superchrons’s existence .</span></p> <p class="db9fe9049761426654245bb2dd862eecMsoNormal"><span lang="EN-US">During the reconnaissance field work of the summer 2019 we have sampled volcanic rocks in 9 sections each includes from 8 to 30 sites corresponding either to lava flow or to tuff layers.</span></p> <p class="db9fe9049761426654245bb2dd862eecMsoNormal"><span lang="EN-US">Up to date we have carried out AF demagnetization, petromagnetic and AMS studies. Demagnetisations studies demonstrate that the rocks contain paleomagnetic record of the ancient (primary?) magnetization of good to excellent quality. Petromagnetic experiments indicate that the main magnetic mineral in majority of studied volcanics is titanomagnetite with pseudo-single domain grain size. We use the magnetic fabric derived from AMS studies to test either the modern attitude (slight dipping up to 10-15˚) of studied rocks is due to primary paleorelief or the rocks have experienced some tectonic deformations.</span></p>

scholarly journals Geochronology and thermochronology of Cretaceous plutons and metamorphic country rocks, Anyui-Chukotka fold belt, North East Arctic Russia

2009 ◽  
Vol 4 ◽  
pp. 157-175 ◽  
Author(s):  
E. L. Miller ◽  
S. M. Katkov ◽  
A. Strickland ◽  
J. Toro ◽  
V. V. Akinin ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
High Heat ◽  
White Mica ◽  
The Arctic ◽  
Second Phase ◽  
Quartz Veins ◽  
North East ◽  
Chukotka Volcanic Belt ◽  
Uplift And Erosion

Abstract. U-Pb isotopic dating of seven granitoid plutons and associated intrusions from the Bilibino region (Arctic Chukotka, Russia) was carried out using the SHRIMP-RG. The crystallization ages of these granitoids, which range from approximately 116.9±2.5 to 108.5±2.7 Ma, bracket two regionally significant deformational events. The plutons cut folds, steep foliations and thrust-related structures related to sub-horizontal shortening at lower greenschist facies conditions (D1), believed to be the result of the collision of the Arctic Alaska-Chukotka microplate with Eurasia along the South Anyui Zone (SAZ). Deformation began in the Late Jurassic, based on fossil ages of syn-orogenic clastic strata, and involves strata as young as early Cretaceous (Valanginian) north of Bilibino and as young as Hauterivian-Barremian, in the SAZ. The second phase of deformation (D2) is developed across a broad region around and to the east of the Lupveem batholith of the Alarmaut massif and is interpreted to be coeval with magmatism. D2 formed gently-dipping, high-strain foliations (S2). Growth of biotite, muscovite and actinolite define S2 adjacent to the batholith, while chlorite and white mica define S2 away from the batholith. Sillimanite (± andalusite) at the southeastern edge the Lupveem batholith represent the highest grade metamorphic minerals associated with D2. D2 is interpreted to have developed during regional extension and crustal thinning. Extension directions as measured by stretching lineations, quartz veins, boudinaged quartz veins is NE-SW to NW-SE. Mapped dikes associated with the plutons trend mostly NW-SE and indicate NE-SW directed extension. 40Ar/39Ar ages from S2 micas range from 109.3±1.2 to 103.0±1.8 Ma and are interpreted as post-crystallization cooling ages following a protracted period of magmatism and high heat flow. Regional uplift and erosion of many kilometers of cover produced a subdued erosional surface prior to the eruption of volcanic rocks of the Okhotsk-Chukotka volcanic belt (OCVB) whose basal units (~87 Ma) overlie this profound regional unconformity. A single fission track age on apatite from granite in the Alarmaut massif yielded an age of 90±11 Ma, in good agreement with this inference.

scholarly journals NAPPE STRUCTURE OF THE NORTH SPORADES (GREECE): ON THE GEOLOGICAL EVOLUTION OF ALONNISOS ISLAND

2004 ◽  
Vol 36 (4) ◽  
pp. 1636 ◽  
Author(s):  
V. Jacobshagen ◽  
D. Matarangas
Keyword(s):  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Field Studies ◽  
Geological Mapping ◽  
Published Data ◽  
The North ◽  
Geological Evolution ◽  
Geochemical Analyses ◽  
Pelagonian Zone ◽  
Rock Association

On Alonnisos island detailed field studies were carried out concerning rock sequences and their boundaries, geochemical analyses of mafic volcanic rocks, and geological mapping of key areas in the southwestern and central parts of the island to the scale 1:10 000. In connection with already published data, our results led to a revision of the tectonic structure of the island and of its geological evolution. The deeper parts of Alonnisos are built up by Mesozoic rocks of the Pelagonian zone, locally with outliers of the Eohellenic nappe on top. Both units are covered by the well-known Mesoautochthonous sequence of Upper Cretaceous/Lower Tertiary age. These units are tectonically overlain by relics of the Palouki nappe, which consists of the probably Lower Cretaceous Palouki formation (once called "Palouki series"), followed by Upper Cretaceous marbles and by a metaflysch. This nappe was probably overthrust during the Eocebe (Mesohellenic) orogeny.Relics of the Palouki nappe can be followed from Alonnisos to Skopelos in the SW, over some small islands. As the rock association in its older parts point to a pelagic marine origin, we assume that the Palouki nappe had its origin in a relic of the Vardar ocean. Relations to other nappe ouliers, which hold a comparable position in the Sporades/Pelion region, are discussed.

scholarly journals Geochemistry and geochronology of cretaceous volcanism of Chauna region, Central Chukotka

2019 ◽  
Vol 64 (1) ◽  
pp. 20-42
Author(s):  
A. V. Ganelin ◽  
E. V. Vatrushkina ◽  
M. V. Luchitskaya
Keyword(s):  
River Basin ◽  
Early Cretaceous ◽  
Group Composition ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Sensu Stricto ◽  
Geochemical Data ◽  
Magmatic Stage ◽  
Chukotka Volcanic Belt ◽  
Cretaceous Volcanism

New geochronological and geochemical data on the age and composition of Cretaceous volcanism of Palyavaam River basin (Central Chukotka, Chauna region) are presented. First complex is composed of rhyolites, ignimbrites and felsic tuffs of Chauna Group of Okhotsk-Chukotka volcanic belt (OCVB). Second complex is represented by volcanic rocks of latite-shoshonite series of Early Cretaceous age, distinguished as Etchikun’ Formation. Its origin is still debatable. Some researchers refer deposits of Etchikun’ Formation to magmatic stage before OCVB activity. Other authors include in Chauna Group composition. Obtained data indicate heterogeneity of Etchikun’ Fomation volcanics and allow to divide them in two groups. Andesites of the first group (Etchikun’ Formation sensu stricto) have Early Cretaceous age and belong to magmatic stage before OCVB activity. Andesites of the second group correlate in age and composition with OCVB volcanic rocks. They occur at the base of Chauna Group and indicate homodromous character of volcanism evolution in the Central-Chukotka of Okhotsk-Chukotka volcanic belt.

Isotopic age of flora-bearing beds from the Amka Formation stratotype, Okhotsk-Chukotka volcanic belt

Palaeobotany ◽  
2016 ◽  
Vol 7 ◽  
pp. 38-46 ◽  
Author(s):  
V. V. Akinin ◽  
L. B. Golovneva ◽  
S. V. Shchepetov
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Isotopic Age ◽  
Weighted Mean ◽  
Shrimp Dating ◽  
Chukotka Volcanic Belt ◽  
Isotope Dating

U-Pb SHRIMP-dating of zircons from flora-bearing volcanic rocks of the Amka Formation stratotype (Ul'ya depression, Okhotsk-Chukotka volcanic belt) yield weighted mean 206Pb/238U age of 85.5 ±2 Ma (Santonian to Coniacian stage). This isotope dating is consistent with inferred Coniacian age of Ul’ya flora from the Amka Formation.

scholarly journals Age and paleomagnetism of the Okhotsk-Chukotka Volcanic Belt (OCVB) near Lake El'gygytgyn, Chukotka, Russia

2009 ◽  
Vol 4 ◽  
pp. 243-260 ◽  
Author(s):  
D. B. Stone ◽  
P. W. Layer ◽  
M. I. Raikevich
Keyword(s):  
Volcanic Belt ◽  
Pole Position ◽  
The Arctic ◽  
The South ◽  
Northeast Russia ◽  
The Pacific ◽  
Lake El’Gygytgyn ◽  
Ocean Region ◽  
Chukotka Volcanic Belt ◽  
Magnetic Vectors

Abstract. Paleomagnetic results from the upper two thirds of the whole section of the Okhotsk-Chukotka Volcanic Belt (OCVB) volcanics exposed in the area around Lake El'gygytgyn, Chukotka yield stable, consistent magnetic vectors and well-preserved reversed directions. The magnetostratigraphy and 40Ar/39Ar geochronologic data reported here indicate that the sampled OCVB volcanics were erupted between about 90 and 67 Ma, and show no significant change in the apparent pole position over that time. The OCVB extends from northeast China, across Northeast Russia to the Bering Straight. This belt is made up of both extrusive and intrusive rocks, with the extrusive rocks and their associated sediments being dominant. The whole belt important in interpreting the paleogeography of the region because it overlies many of the accreted terranes of Northeast Russia. Most importantly, it overlies parts of the Chukotka-Alaska block which is thought to have moved out of the Arctic Ocean region, as well as terranes accreted from the south. These latter terranes have been rafted northwards on the paleo-plates of the Pacific, implying that the present relative paleogeography of all of the terranes overlain by the OCVB were essentially in place by 67 Ma, and possibly as early as 90 Ma. However, comparing our paleomagnetic pole position for the OCVB with those for North America and Eurasia (a proxy for Siberia) shows a statistically significant displacement of the OCVB pole to the south west. This implies that not only the OCVB, but the underlying terranes of northeast Russia, experienced southerly displacement with respect to the Siberian and North American platforms since the Late Cretaceous.

The diachronous formation of the Enmyvaam and Amguema-Kanchalan volcanic fields in the Okhotsk-Chukotka volcanic belt (NE Russia): Evidence from isotopic data

2010 ◽  
Vol 434 (1) ◽  
pp. 1172-1178 ◽  
Author(s):  
V. G. Sakhno ◽  
V. F. Polin ◽  
V. V. Akinin ◽  
S. A. Sergeev ◽  
A. A. Alenicheva ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Isotopic Data ◽  
Volcanic Fields ◽  
Chukotka Volcanic Belt ◽  
Ne Russia

The Chingandzha flora of the Okhotsk-Chukotka volcanic belt

Palaeobotany ◽  
2019 ◽  
Vol 10 ◽  
pp. 13-179
Author(s):  
L. B. Golovneva
Keyword(s):  
River Basin ◽  
Volcanic Belt ◽  
Flowering Plants ◽  
Sedimentary Deposits ◽  
North East ◽  
The North ◽  
Magadan Region ◽  
Chukotka Volcanic Belt ◽  
Systematic Composition ◽  
Coastal Lowlands

The Chingandzha flora comes from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, North-East of Russia). The main localities of the Chingandzha flora are situated in the Omsukchan district of the Magadan Region: on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River). The Chingandzha flora includes 23 genera and 33 species. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created. The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The main genera are Arctop teris, Osmunda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Protophyllocladus, Pseudoprotophyllum, Trochodendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. The Chingandzha flora is distinct from other floras of the Okhotsk-Chukotka volcanic belt (OCVB) in predominance of flowering plants and in absence of the Early Cretaceous relicts such as Podozamites, Phoenicopsis and cycadophytes. According to its systematic composition and palaeoecological features, the Chingandzha flora is similar to the Coniacian Kaivayam and Tylpegyrgynay floras of the North-East of Russia, which were distributed at coastal lowlands east of the mountain ridges of the OCVB. Therefore, the age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Kaivayam phase of the flora evolution and to the Anadyr Province of the Siberian-Canadian floristic realm. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul’ya flora of the Ul’ya Depression.

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