NEW AMMONOID RECORDS AND GAMMA-SPECTROMETRY IN THE STRATOTYPE OF THE BELEUTIAN REGIONAL SUBSTAGE (CENTRAL KAZAKHSTAN)

БЕЛЕУТІ ӨҢІРЛІК ДЕҢГЕЙІНІҢ СТРАТОТИПІНДЕГІ АММОНИТТЕРДІҢ ЖАҢА ОЛЖАЛАРЫ ЖӘНЕ ГАММА-СПЕКТРОМЕТРИЯСЫ (ОРТАЛЫҚ ҚАЗАҚСТАН)
НОВЫЕ НАХОДКИ АММОНОИДEЙ И ГАММА-СПЕКТРОМЕТРИЯ В СТРАТОТИПЕ БЕЛЕУТИНСКОГО ГОРИЗОНТА (ЦЕНТРАЛЬНЫЙ КАЗАХСТАН)
Mustapayeva S. Nikolaeva S. Kabanov Р. Omarova G. Assambayeva A.
January-February 2026 National Academy of Sciences of the Republic of Kazakhstan

News of the National Academy of Sciences of the Republic of Kazakhstan, Series of Geology and Technical Sciences
2026 #2026 Issue 1 215 - 230 pp.

New ammonoid records from the stratotype of the Beleutian Regional Substage (Ulytau Region, Karsakbay District, Central Kazakhstan) confirm that the basal beds of the Beleutian Regional Substage can be assigned to the upper subzone of the Lower Serpukhovian Uralopronorites-Cravenoceras Genozone (E1b-c Zone of the European Carboniferous scale or Nm1b2 of the South Urals scale). This study is important for establishing the international GSSP boundary of the Serpukhovian and updating the regional Carboniferous scheme of Kazakhstan. The aim of this study is to resample the marker horizon near the base of the Beleutian Regional Substage containing Cravenoceras beleutense, Cravenoceras ulytauense, Neoglyphioceras litvinovichae, Sudeticeras karagandense, and Kazakhoceras hawkinsi does not correlate with the base of the Serpukhovian of the Global Scale or with the basal Pendleian of the European Scale, as the level of evolutionary development of Cravenoceras and Neoglyphioceras suggests a younger age. We resampled the marker horizon for ammonoids using a bed-by-bed method together with corals, crinoids and brachiopods. This method of precise sampling in association of spectral gamma ray study showed shallow-water settings with an input of siliciclastics from nearby land. Based on spectral gamma ray readings, the results show that the beds immediately below the marker horizon level could have been deposited in an oxygen-starved environment. Variance of U, Th, and K contents in the ammonoid-bearing beds can be attributed to variable siliciclastic supply in generally oxygenated settings. This study is important for practical substantiation of the base of the Serpukhovian in the Carboniferous regional scheme of Kazakhstan.

ammonoids , Beleutian Regional Substage , Carboniferous , Central Kazakhstan , gamma-spectrometry , Serpukhovian

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K.I. Satbayev University, Almaty, Kazakhstan
Yessenov University, Aktau, Kazakhstan
Natural History Museum, London, United Kingdom
Geological Survey of Canada, University of Calgary, Calgary, Canada
Satbayev University, Almaty, Kazakhstan

K.I. Satbayev University
Yessenov University
Natural History Museum
Geological Survey of Canada
Satbayev University

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