The New Data on Biostratigraphy of the Basic Geological Section of the Continental  Cenozoic Deposits of Aktau Mountains  (South-East Kazakhstan, Ili Basin)

Nigmatova, Saida; Bayshashov, Bulat; Zhamangara, Aizhan; Lucas, S.; Bayadilov, Kalyk; Kasymkhankyzy, Alma; orcid,

doi:10.32014/2018.2518-170x.21

Cited by 3 publications

(3 citation statements)

References 3 publications

(3 reference statements)

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“…Cenozoic stratigraphy of the Aktau succession. 1: after Lucas et al (1997) and Nigmatova et al (2018). 2: This study after Bodina (1961).…”

Section: Laser Ablation U-pb Datingmentioning

confidence: 99%

“…The Aktau succession consists of more than 1,000 m of basinal Cenozoic sediments (Figure 2), which are continuously exposed along the northern limb of the south verging anticline. An overview of the Cenozoic (bio)stratigraphy of the Aktau succession is given in Nigmatova et al (2018) and summarized in Figure 2. From ~320 to 740 m, middle to upper Miocene formations (abbreviated Fm) comprise reddish‐brownish mudstones with thin‐sheeted sandstones and gypcretes (Bastau Fm), multicolored marls, mudstones, and gypcretes (Koktal Fm) and greyish marls and limestones with reddish‐brownish gypsiferous mudstones (Kokterek Fm; Bazhanov & Kostenko, 1961; Bodina, 1961; Voigt et al, 2017).…”

Section: Geographical Geological and Climatological Settingmentioning

confidence: 99%

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Long‐Period Astronomical Forcing of Westerlies' Strength in Central Asia During Miocene Climate Cooling

Frisch

Voigt

Verestek

et al. 2019

Paleoceanog and Paleoclimatol

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The continental expression of global cooling during the Miocene Climate Transition in Central Asia is poorly documented, as the tectonically active setting complicates the correlation of Neogene regional and global climatic developments. This study presents new geochemical data (CaSO 4 content, carbonate δ 13 C and δ 18 O) from the endorheic alluvial-lacustrine Aktau succession (Ili Basin, southeast Kazakhstan) combined with findings from the previously published facies evolution. Time series analysis revealed long-eccentricity forcing of the paleohydrology throughout the entire succession, split into several facies-dependent segments. Orbital tuning, constrained by new laser ablation U-Pb dates and a preexisting magnetostratigraphy, places the succession in a 5.0 Ma long interval in the middle to late Miocene (15.6 to 10.6 Ma). The long-term water accumulation in the Ili Basin followed the timing of the Miocene Climate Transition, suggesting increased precipitation in the catchment area in response to climate cooling and stronger westerly winds. This was paced by minima of the 2.4 Ma eccentricity cycle, which favored the establishment of a discharge playa (~14.3 Ma) and a perennial lake (12.6 to 11.8 Ma). Furthermore, low obliquity amplitudes (nodes) caused a transient weakening of the westerlies at~13.7 to 13.5 Ma and at~12.7 Ma, resulting in negative hydrological budgets and salinization. Flooding of the windward Ili Basin coeval with aridification in the leeward basins suggests that the Tian Shan was a climate boundary already in the middle Miocene. Our results emphasize the impact of climate fluctuations on the westerlies' strength and thus on Central Asian hydrology. Plain Language Summary The global climate changed from an exceptional warm to a colder state in the middle Miocene epoch, representing a milestone in the evolution of today's climate. This study focuses on the, so far fragmentary, understanding of the Central Asian climate response to this global climate transition by investigating deposits of a former (salt) lake in the Ili Basin, southeast Kazakhstan. Regular sediment alternations represent cycles of low and high water level, overprinted by a long-term lake expansion. Time series analysis of climate sensitive geochemical and environmental parameters, together with the determination of absolute rock ages, enabled the identification of sedimentary cycles (405 ka and 1.2 Ma long), which are equivalent to climate influencing variations of the Earth's orbit and tilt angle. We conclude that water level maxima are linked to periods of low seasonal climate differences reoccurring every 405 ka. The lake expansion is caused by more precipitation due to strengthened westerly winds, in response to global cooling. Westerly winds were transiently weakened during periods of low variability of the Earth's tilt angle, promoting high evaporation and salinization. Our results emphasize the impact of climate change on the westerlies' strength and thus on Central Asian moisture supply.

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“…Cenozoic stratigraphy of the Aktau succession. 1: after Lucas et al (1997) and Nigmatova et al (2018). 2: This study after Bodina (1961).…”

Section: Laser Ablation U-pb Datingmentioning

confidence: 99%

Section: Geographical Geological and Climatological Settingmentioning

confidence: 99%

Long‐Period Astronomical Forcing of Westerlies' Strength in Central Asia During Miocene Climate Cooling

Frisch

Voigt

Verestek

et al. 2019

Paleoceanog and Paleoclimatol

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“…In our research, the word ak (white) as part of oronyms was used to describe the lithological specific nature of orographic objects, the color of rocks such as limestone and chalk. Some toponyms directly or indirectly define the composition of rocks, names with the word ak are found in other areas of Kazakhstan in the form of complex names Aktau (South-Eastern Kazakhstan) [17], Akshoky, Aktas, where veins of limestone, gypsum, marl, white marble, monoquartzite, barite and quartz occur. Such toponyms include the names of the fields Aktasty and Akzhar in Aktobe region.…”

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confidence: 99%

TOPONYMS OF CRETACEOUS DEPOSITS IN WESTERN KAZAKHSTAN TERRITORY (in the context of Aktobe region)

ABDULLINA¹,

Sergeyeva²,

Kuat³

et al. 2021

News of NAN RK. SGTS

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The article deals with the occurrence of Cretaceous deposits in the territory of Aktobe region and geographical ground of their reflection in local toponyms. Aktobe region is characterized by the complexity of the terrain in West Kazakhstan. Terrain features are influenced by its geological structure and terrain-forming factors. The map presents a selection of toponyms including the words ak, bor, saz, kum, shagyl which correspond to the formations of lower Cretaceous and upper Cretaceous deposits widespread in the western part of the region. The percent of oronyms, hydronyms and oikonyms in the toponyms of 141 names selected in the study area was analyzed with subsequent representation on the diagram. The analysis of the names of Aktolagay, Akshatau, Belogorka, Aktau, Akzhar, etc., indicating the reflection in toponyms of such physical properties of rocks as composition, color and the rate of their frequency is carried out, the results are presented in a table. The map shows the position of geographical features corresponding to the outcropping Cretaceous beds and photos of the area are provided.

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Rock magnetic signature of a Miocene playa cycle in Central Asia and environmental implications

Verestek

Appel

Frisch

et al. 2019

Int J Earth Sci (Geol Rundsch)

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The New Data on Biostratigraphy of the Basic Geological Section of the Continental Cenozoic Deposits of Aktau Mountains (South-East Kazakhstan, Ili Basin)

Cited by 3 publications

References 3 publications

Long‐Period Astronomical Forcing of Westerlies' Strength in Central Asia During Miocene Climate Cooling

Long‐Period Astronomical Forcing of Westerlies' Strength in Central Asia During Miocene Climate Cooling

TOPONYMS OF CRETACEOUS DEPOSITS IN WESTERN KAZAKHSTAN TERRITORY (in the context of Aktobe region)

Rock magnetic signature of a Miocene playa cycle in Central Asia and environmental implications

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