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GEOREF RECORD

Mineralogical evolution of the Paleogene formations in the Kyzyltokoy Basin, Kyrgyzstan; implications for the formation of glauconite

Tursunai Bektemirova, Apas Bakirov, Hu Ruizhong, He Hongping, Cai Yuanfeng, Tan Wei and Chen Aiqing
Mineralogical evolution of the Paleogene formations in the Kyzyltokoy Basin, Kyrgyzstan; implications for the formation of glauconite
Clays and Clay Minerals (February 2018) 66 (1): 43-60

Abstract

Although several hypotheses for the formation of glauconite have been proposed, the sedimentary environment and mechanism of glauconitization are still poorly understood. In this contribution, the mineralogy and chemical compositions of sediments from Paleogene formations (Fms) in the Kyzyltokoy basin (Kyrgyzstan) were examined to better understand glauconitization processes. The samples were analyzed using microscopic petrography, X-ray diffraction (XRD), electron probe microanalysis (EPMA), and X-ray fluorescence (XRF). Interlayered diatomite-argillaceous rocks were newly identified within the diatomites of the Isfara Fm. Glauconite from the Kyzyltokoy basin displayed two stages of maturity: 1) early stage (nascent) glauconite grains composed of approximately 3.5% K (sub 2) O and approximately 8%FeOT; 2) late-stage (highly evolved) glauconite grains composed of 7-9% K (sub 2) O and approximately 27% FeOT. The early stage glauconite grains in the Hanabad Fm green clay (green clay is clay with a greenish color) indicate interruptions in glauconitization processes, whereas the (highly) evolved glauconite grains show a completed glauconitization process along the contact between the Hanabad and Sumsar Fms. Hematite was detected in the red clay (clay with reddish color) of the Sumsar Fm and probably formed by glauconite disintegration. Accordingly, the Paleogene Fms depositional conditions were of three types: 1) beginning of glauconitization with interruptions, 2) completion of glauconitization, and 3) glauconite disintegration. Glauconitization in the Kyzyltokoy basin, thus, likely occurred via a combination of dissolution, precipitation, and recrystallization processes.


ISSN: 0009-8604
EISSN: 1552-8367
Coden: CLCMAB
Serial Title: Clays and Clay Minerals
Serial Volume: 66
Serial Issue: 1
Title: Mineralogical evolution of the Paleogene formations in the Kyzyltokoy Basin, Kyrgyzstan; implications for the formation of glauconite
Affiliation: Chinese Academy of Sciences, Institute of Geochemistry, Guiyang, China
Pages: 43-60
Published: 201802
Text Language: English
Publisher: Clay Minerals Society, Chantilly, VA, United States
References: 46
Accession Number: 2018-068165
Categories: Geochemistry of rocks, soils, and sedimentsSedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 4 tables, geol. sketch map
N41°22'60" - N41°22'60", E71°19'60" - E71°19'60"
Secondary Affiliation: University of Chinese Academy of Sciences, CHN, ChinaKyrgyz National Academy of Science, Institute of Geology, KGZ, KyrgyzstanNanjing University, CHN, China
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Abstract, Copyright, Clay Minerals Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201837
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