Early Precambrian Metaaleuropelites: REE–Th Systematics as a Key to Reconstruction of Sources for Their Fine-Grained Aluminosiliciclastics
| Autor: | V. N. Podkovyrov, A. V. Maslov |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
geography
geography.geographical_feature_category 010505 oceanography Proterozoic Akilia Archean Metamorphic rock Geochemistry Greenstone belt 010502 geochemistry & geophysics 01 natural sciences Volcanic rock Precambrian Geochemistry and Petrology Economic Geology Baltic Shield Geology 0105 earth and related environmental sciences |
| Zdroj: | Lithology and Mineral Resources. 56:212-235 |
| ISSN: | 1608-3229 0024-4902 |
| DOI: | 10.1134/s0024490221030056 |
| Popis: | The article analyzes the position of individual and average data points of the Archean and Early Proterozoic metaaleuropelites (Isua and Akilia associations, West Greenland; Beit Bridge Complex, Limpopo Province, South Africa; Moodies, Mozaan, and Pretoria groups, Barberton Mountain Land, South Africa; Kola Group, Baltic Shield, Russia; Nurmes paragneisses, Eastern Finland; Onot greenstone belt, southeastern Sayan region, Russia; Rampur Group, Lesser Himalayas, India; Kan metamorphic complex, eastern Sayan region, Russia; Ladoga Group, northern Ladoga region, Russia; Yenisei metamorphic complex, Russia; and others) in the (La/Yb)N–Eu/Eu* and (La/Yb)N–Th diagrams with classification fields constructed from data on the content of REE and Th in the fine grained clastic/aleuropelitic sediments near the estuary of different-category modern rivers, according to (Bayon et al., 2015). It has been shown that the vast majority of data points of metaaleuropelites are localized in fields 1 (particulates of major rivers in the world), 2 (particulates of rivers draining sedimentary substrates) and 4 (particulates of rivers flowing through volcanic rock terrains), as well as the zone overlapping fields 1–3 (particulates of rivers feeding on erosion products of the magmatic/metamorphic terrains). Data points of all examined objects with an age of more than 2.8 Ga in the (La/Yb)N–Eu/Eu* diagram are concentrated mainly in field 4. If all our assumptions are correct, these observations suggest the following conclusion: until the above-indicated time, large rivers and, most likely, rivers draining mainly sedimentary rocks did not exist, and processes of the recycling of fine-grained aluminosiliciclastics were reduced. |
| Databáze: | OpenAIRE |
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