First U–Pb geochronology on detrital zircons from Early-Middle Cambrian strata of the Torgau-Doberlug Syncline (eastern Germany) and palaeogeographic implications
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
LA-ICP-MS U–Pb data from detrital zircons of the Ediacaran to Cambrian siliciclastic sequence of the Torgau-Doberlug Syncline (TDS, Saxo-Thuringia, Germany) are reported for the first time. The majority of 203 analysed zircon grains is Proterozoic with minor amount of Archean and Palaeozoic grains. The U–Pb ages fall into three groups: 2.8–2.4 Ga (3%), Neoarchean to earliest Palaeoproterozoic; 2.3–1.6 Ga (46%), early to late Palaeoproterozoic; 1.0–0.5 Ga (47%), Neoproterozoic to Cambrian. This age distribution is typical for the West African Craton as the source area and for Cadomian orogenic events in northwestern Gondwana. The samples show an age gap between 1.6 and 1.0 Ga, which is characteristic for West African provenance and diagnostic in distinguishing this unit from East Avalonia and Baltica. The dataset shows clusters of Palaeoproterozoic ages at 2.2–1.7 Ga, that is typical for western Gondwana, which was affected by abundant magmatic intrusions (ca. 2.2–1.8 Ga) during the Eburnean orogeny (West African craton). Neoarchean zircon ages (3%) point to recycling of magmatic rocks formed during the Liberian and Leonian orogenies. Ediacaran to earliest Cambrian rocks of the TDS originated in an active margin regime of the Gondwanan shelf. The following early Palaeozoic overstep sequence was deposited within rift settings that reflects instability of the West-Gondwanan shelf and the separation of terranes from Ordovician onward. The results of this study demonstrate distinct northwestern African provenance of the Cambrian siliciclastics of the TDS. Due to Th–U ratios from concordant zircon analysis, igneous origin from felsic melts is concluded as the source of these grains.
Details
Originalsprache | Englisch |
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Seiten (von - bis) | 2445-2459 |
Seitenumfang | 15 |
Fachzeitschrift | International journal of earth sciences |
Jahrgang | 106 |
Ausgabenummer | 7 |
Publikationsstatus | Veröffentlicht - 1 Okt. 2017 |
Peer-Review-Status | Ja |
Extern publiziert | Ja |
Schlagworte
ASJC Scopus Sachgebiete
Schlagwörter
- Cambrian, Provenance, Saxo-Thuringia, Torgau-Doberlug Syncline, West African Craton, Zircon geochronology