Response of Geochemical Characteristics on the Environmental Changes in the Holocene: Data on Bottom Sediments of Lake Maloe, Iturup Island
| Autor: | Pavel S Minyuk, V. Ya. Borkhodoev |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
chemistry.chemical_classification
geography geography.geographical_feature_category 020209 energy Trace element Geochemistry Detritus (geology) Weathering 02 engineering and technology Biogenic silica Sedimentary basin 010502 geochemistry & geophysics Marine regression 01 natural sciences Geophysics chemistry Geochemistry and Petrology Facies 0202 electrical engineering electronic engineering information engineering Organic matter Geology 0105 earth and related environmental sciences |
| Zdroj: | Geochemistry International. 59:422-434 |
| ISSN: | 1556-1968 0016-7029 |
| DOI: | 10.1134/s0016702921040054 |
| Popis: | Major and trace element distribution in the bottom sediments of Lake Maloe located on the Kuybyshev Isthmus, Iturup Island, was analyzed using the method of principal components. It was established that the geochemical characteristics of Lake Maloe sediments reflect a change from marine and lagoonal to fresh-water sedimentation environments. According to geochemical data, the erosion and weathering products of proximal rocks supplied detritus in the sedimentary basin. Marine facies (up to 6400 yr ago) are characterized by the increased contents of carbonates, the high salinity index Sr/Ba, and the low contents of nickel, biogenic silica, and organic matter. The element composition is clearly correlated with grain-size composition. The CIA index and Rb/Sr ratio indicate that the coarse-grained varieties, regardless of their genesis, are less chemically altered. They are enriched in detrital components, which comprise all elements, except for SiO2 and phosphorus. Marine regression at ca. 6400 yr ago was followed by lacustrine environment, which provided the predominant accumulation of biogenic silica and organic. The aeolian activity related to climatic cooling and marine regressions led to the formation of coarse-grained interlayers in silty sequence, which are clearly expressed by geochemical characteristics. The fresh-water facies show a distinct grain-size rhythmicity traced by Al2O3/(CaO + Na2O) ratio. |
| Databáze: | OpenAIRE |
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