Cenozoic deposits of the underwater Akademicheskii Ridge in Lake Baikal

Kashik, S. A.; Lomonosova, T. K.

doi:10.1134/s0024490206040018

Cited by 4 publications

(7 citation statements)

References 7 publications

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“…В отложениях скв. BDP-96 и BDP-98 значения этого показателя заметно снижаются в верхней части разреза [Kashik, Lomonosova, 2006]. При переходе от отложений танхойской свиты к отложениям аносовской свиты в Баргузинской впадине было отмечено также резкое возрастание окисленности железа (Fe 2 O 3 /FeO) [Rasskazov et al, 2016].…”

Section: общая характеристика разрезаunclassified

Identifying Upper Miocene – Lower Pliocene Lacustrine Sediments in Dry Tunka Basin of the Baikal Rift Zone

Хассан¹,

Рассказов²,

Chuvashova³

et al. 2020

Geodin. tektonofiz.

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We present results of lithogeochemical, diatomic and palynological studies of sediments from the Tunka-13 well that was drilled in the southeastern part of dry Tunka basin in the Baikal rift zone. At the base of the section, there is an eroded basaltic flow of 16-15 Ma. From lithogeochemical signatures, we identify nine sedimentary units. The seven lower ones (interval 7.2-86.5 m) belong to the Tankhoi formation, the eighth (interval 2.7-6.6 m) to the Anosov formation, the ninth (interval <2.4 m) to the sandy stratum. We determined local sources of clastic material of basaltic and silicic compositions for units 1 and 2, respectively, and remote sources of silicic compositions for the overlaying units. The section shows a change from alluvial facies (units 1-3) through avandelta (unit 4) and lacustrine ones (units 5-7), again to alluvial facies (unit 8) and then to lacustrine-eolian ones (unit 9). Spore and pollen spectra from sediments of units 1-7 are divided into three palynozones (PZ), reflecting the vegetation change in the Late Miocene -Early Pliocene: PZ-1 -coniferous and deciduous forests with a small participation of thermophilic broadleaved species in moderately warm, humid climatic conditions; PZ-2 -enhancing the role of hemlock and more diverse thermophilic deciduous rocks in more humid and warm conditions; PZ-3 -a gradual reduction in the number of hemlock and other dark coniferous species, removing broadleaved species by birch and alder, growing grassy communities in wetlands due to climate cooling. We identified layers of lacustrine facies by occurrence of fossil diatoms that are absent in the layers of the alluvial and avandelta facies. In lacustrine sediments, we distinguish four diatom zones: DZ-1 denotes a relatively deep Late Miocene paleolake, marked by planktonic species, DZ-2, DZ-3 and DZ-4 -a shallow Early Pliocene lake with a developed littoral zone and short transgression. The Late-Miocene paleolake transgression, indicated by changing facies, is associated with structural reorganization, accompanied by volcanic extinction in the Tunka valley about 9-8 Ma, and the Early Pliocene short transgression with a new reorganization, reflected in volcanic rejuvenation about 4.0 Ma.

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Section: общая характеристика разрезаunclassified

Identifying Upper Miocene – Lower Pliocene Lacustrine Sediments in Dry Tunka Basin of the Baikal Rift Zone

Хассан¹,

Рассказов²,

Chuvashova³

et al. 2020

Geodin. tektonofiz.

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“…Скважины BDP-96-1.2 и BDP-98, пройденные на Академическом хребте, вскрыли в глубинном интервале 600 м две осадочные толщи: нижнюю, сформированную за счет привноса материала из Баргузинской впадины, и верхнюю, отлагавшуюся при привносе материала из Верхнеангарской впадины. Смена питающих провинций, произошедшая во временном интервале 7.65-7.09 млн лет назад [Kashik, Lomonosova, 2006], совпадала по времени с активностью вулканического центра Намару. По имеющимся данным о строении разрезов Танхойского третичного поля какие-либо следствия этой перестройки не выявлены.…”

Section: палинокомплексыunclassified

“…На оз. Байкал выполнен большой объем литологических и биостратиграфических работ по программе «Байкал-бурение» [Khursevich et al, 2001[Khursevich et al, , 2005Kashik, Lomonosova, 2006;Kuz'min et al, 2009;и др. ].…”

unclassified

“…Pal'shin), 17 -ocherous, with different particle sizes; 18-20 -basement rocks: 18 -gneiss and schist of Khangarul series PR 1 hu, 19 -granite, granite gneiss of Khamardaban complex γPR 1 h, 20 -granite, granosyenites, granodiorites of Barguzin complex γεPZ 1-2 b; 21 -weathering crust: а -residual, б -redeposited; 22-26 -organic fossils: 22 -bones of vertebrates, 23 -fish, 24 -molluscs: а -anysomiaria, б -gastropods, 25 -leaf flora, 26 -diatoms, spores and pollen; 27 -in profiles, numbers in circles refer to lithologically different beds and units of terrigenic rocks; 28 -faults: а -confirmed, б -assumed; 29 -boundaries: а -unconformity, б -normal stratigraphic contact, в -inside the straton; 30 -well and its number. на структурную перестройку во второй половине позднего миоцена около 7-8 млн лет назад [Kashik, Lomonosova, 2006].…”

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confidence: 99%

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Sediments in the Tertiary Tankhoi field, South Baikal basin: stratigraphy, correlation and structural transformations in the Baikal region

Рассказов¹,

Лямина²,

Лузина³

et al. 2014

Geodyn. Tectonophys.

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Biostratigraphic and lithofacial studies of sediments in the Tankhoi Tertiary field, which evolution reflects transformations of the terrain in the Baikal region at the Oligocene-Miocene, Early-Middle Miocene, Miocene-Pliocene and Early-Late Pliocene transitions. The main part of the field is composed of clastic molassoids formed during 'early orogen' stage in the coastal part of an extensive paleobasin with a slow water current and in shallow lakes of the Mishikha-Klyuevka and Osinovka river paleobasins that formed, respectively, at the Oligocene-Miocene and Early-Middle Miocene boundaries. In the Miocene, as suggested by analyses of malacofauna and diatoms, South Baikal was a major, quite deep paleolake. These water bodies were related in the Miocene as evidenced by the partial similarity of diatom species found in South Baikal and the Tunka valley, as well as the presence of similar endemic fauna species in the sediments. Accumulated coarse, mainly proluvial-alluvial deposits are indicators of the tectonic activity that resulted in a dramatic 'late orogen' increase of contrasting features of the regional terrain. P a l e o g e o d y n a m i c s

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“…According to their data, the formation of Pleistocene-Holocene complex "A" is associated with the Angara development phase of Baikal, and its thickness is about 200 meters. The lithological investigations of core material from boreholes BDP-96-1; 2 and BDP-98 which exposed seismocomplex "A", showed that the matter composition of Pleistocene deposits is highly uniform (Kashik and Lomonosova, 2006;Kashik and Akulov, 2008). They are typical, horizontally occurring thin-layered polymictic graywackes that are represented by an alternation of aleurite clays and aleurite clay silts.…”

Section: The Matter Composition Of Bottom Sedimentsmentioning

confidence: 99%