Paleomagnetism of the Late Paleozoic granites of the Angara–Vitim batholith and the host rocks of the Baikal–Patom folded area: tectonic implications

Shatsillo, A. V.; Fedyukin, I. V.; Powerman, Vladislav

doi:10.1016/j.rgg.2014.06.006

Cited by 13 publications

(1 citation statement)

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“…(отделение крупных геоблоков, например Колымского) [Parfenov, Kuzmin, 2001], раскрытие Вилюйского палеорифта [Gurevich, 1984;Pavlov et al, 2008;Konstantinov et al, 2011] и формирование генеральных структур Байкальской складчатой области [Konstantinov, 1998;Kravchinsky et al, 2001;Shatsillo et al, 2014].…”

Section: обсуждение результатовunclassified

Petro- And Paleomagnetic Studies of Basalts of the Upper Devonian Appainskaya Suite (Western Yakutia)

Михайлович¹,

Дмитриевич²,

Зарифович³

et al. 2016

Geodin. tektonofiz.

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Introduction. One of the main tasks of paleomagnetic studies is to obtain a framework of reference poles for calculating the kinematic characteristics of lithospheric taxones as a basis for geodynamic reconstructions. Each paleomagnetic reference point must have a precise (±10 Ma) geochronological dating and a maximum paleomagnetic reliability index. A correct paleomagnetic pole (PMP) can be obtained from the data of geochronological and paleomagnetic studies conducted in one and the same geological object, such as a suite, an intrusive complex etc. In the Yakutian diamondiferous province (YDP), such objects include basalt nappes of the Upper Devonian Appainskaya suite, which stratigraphic position is undoubted (Fran, 385-375 Ma). Geological setting (in brief). In the eastern segments of the Siberian platform, a powerful cycle of tectonic and magmatic activity in the Middle Paleozoic produced transgressive and sheet intrusions, volcanic pipes, lava and tuff formations comprised of basites, as well as all the currently known industrial diamondiferous kimberlite bodies. Magmatic activity of basites was associated with formation of paleorift systems, including the largest one, Viluyi paleorift (Fig. 1). In the Middle Paleozoic, the geodynamic setting for magmatism and rifting was determined by the plume-lithosphere interaction. The rise of the plume's matter underneath the thinned lithosphere was accompanied by decompression melting and formation of basaltic magmas in large volumes. We have studied basalts of the Appainskaya suite which were sampled from the Ygyatta and Markha river valleys (Fig. 2). In the coastal outcrops at the Ygyatta river, two nappes are observed, a (stratigraphically) lower outcrop 17÷23/10 containing plagiophyre palagonite basalts (upper five meters are outcropped), and an upper outcrop 16/10 containing olivinophyric palagonite basalts (upper three meters are outcropped). In the coastal outcrops of the Markha river, from the Enerdek loop to the M. Dyukteli river (outcrop 16÷20/14), only plagiophyric basalts of the lower nappe are developed. At this location, the total capacity of the basalts can reach 35-40 m. In view of the fact that the basalts lie subhorizontally at angles up to 5° (outcrop 17/14, Fig. 3), oriented samples were taken in the modern system of coordinates. Formational features of the chemical composition typical of the Middle Paleozoic intrusive basites (higher contents of Ti, Fe and K) are less clear in derivatives of the effusive facies. By their chemical composition, the basalts are normal alkalinity rocks (the sum of alkali not higher than 3.05 %; SiO2=48.1-49.7 %; rather moderate content of TiO2=1.9-2.5 %) (Fig. 4 A, B). The amount of magnesia (Mg#) ranges from 46 to 56. The main carriers of natural remanent magnetization (NRM, In) are titanomagnetites that belong to titanomagnetite and hemo-ilmenite series (Fig. 4). Research. Our research was conducted in specialized laboratories using modern equipment and facilities of Geo-Scientific Research Enterprise (NIGP) PJSC AL...

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Section: обсуждение результатовunclassified