Geochemical similarity of Cambrian alkaline and subalkaline magmatism (Kuznetsk Alatau orogen, Siberia): a new data synthesis
This is a synthesis of recent geochemical evidence from Cambrian granitic, gabbro-monzonitic, and few small gabbro-foidolitic intrusions in the Early Paleozoic Kuznetsk Alatau orogen (western Central Asian Orogenic Belt, Siberia). Their origin is attributed to late- and post-orogenic regional magmat...
| Published in: | Геосферные исследования № 3. С. 27-39 |
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| Main Author: | |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Online Access: | http://vital.lib.tsu.ru/vital/access/manager/Repository/koha:000901691 Перейти в каталог НБ ТГУ |
| Summary: | This is a synthesis of recent geochemical evidence from Cambrian granitic, gabbro-monzonitic, and few small gabbro-foidolitic intrusions in the Early Paleozoic Kuznetsk Alatau orogen (western Central Asian Orogenic Belt, Siberia). Their origin is attributed to late- and post-orogenic regional magmatism which produced different rock types sharing basic similarity in isotope systematics and trace-element compositions. The εNd(t) values of ~2 to 8.7 in main igneous lithologies record the extent of interaction between depleted and enriched mantle. Concurrent increase of initial 87Sr/86Sr (0.7039-0.7058) ratios and δ18О values (6.5-13 ‰) in rocks and minerals, as well as 207Pb enrichment (207Pb/204Pb(t) = 15.5-15.7), indicate crustal contamination of mantle melts. Trace-element patterns in the rocks correspond to a mixed IAB + OIB source. The alkaline and subalkaline rocks of the Kuznetsk Alatau area share trace element and isotopic similarity and apparently emplaced almost synchronously late during a regional-scale tectonic event. The synthesized data show that Cambrian magmatism in the area involved mixed mantle and continental crust melt components and acted in a complex tectonic setting of the former active margin of the Paleo-Asian Ocean impacted by a mantle plume. |
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| Bibliography: | Библиогр.: с. 36-39 |
| ISSN: | 2542-1379 |