Paleomagnetic studies of rapakivi complexes in the Fennoscandian Shield : Implications for the origin of Proterozoic massif-type anorthosite magmatism
| Autor: | Bjarne Almqvist, Satu Mertanen, Mohsen Oveisy Moakhar, Sten-åke Elming, Johanna Salminen, Chong Wang |
|---|---|
| Přispěvatelé: | Doctoral Programme in Geosciences, Department of Geosciences and Geography, University of Helsinki, Doctoral Programme in Geosciences, University of Helsinki, Department of Geosciences and Geography |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
1171 Geosciences
Paleomagnetism 010504 meteorology & atmospheric sciences education 010502 geochemistry & geophysics Superswell Baltica 01 natural sciences Supercontinent Paleontology Anorthosite Geochemistry and Petrology 0105 earth and related environmental sciences geography geography.geographical_feature_category Geofysik Proterozoic Geology Massif Rapakivi Nuna supercontinent Geophysics Magmatism Massif anorthosites Geologi |
| Popis: | Paleomagnetic studies have been performed on five rapakivi related complexes in Sweden and Finland. Poles of varying quality have been defined and the majority of the similar to 1640-1497 Ma poles are clustering on low latitudinal positions. By combining data from similar to 1500 Ma intrusions a new high-quality pole (Plat: 13 degrees N; Plon: 190 degrees E; A(95): 11 degrees, K: 14) for Baltica has been defined. Tectonic reconstructions, on the basis of the new data and previously published high-quality data, indicate that Baltica experienced stable low latitude to equatorial positions during 1640-1470 Ma, temporally coinciding with globally pronounced rapakivi-anorthosite magmatism. Our study argues against single hotspot source for similar to 1640-1620 Ma, similar to 1590-1520 Ma, and 1470-1410 Ma rapakivianorthosites, but supports a model of large-scale superswell under a stationary low-latitude position of supercontinent Nuna for the origin of rapakivi-anorthosite magmatism. However, a possibility for convergent tectonism as the origin cannot be ruled out. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|