2016 •
Palaeomagnetism of Middle Ordovician Carbonate Sequence, Vaivara Sinimaed Area, Northeast Estonia, Baltica
Authors:
Jüri Plado, Ulla Preeden, Argo Jõeleht, Lauri J. Pesonen, Satu Mertanen
Abstract:
The hill range of Vaivara Sinimaed in northeast Estonia consists of several narrow east-to northeast-trending glaciotectonic fold structures. The folds include tilted (dips 4-75 degrees) Middle Ordovician (early Darriwilian) layered carbonate strata that were studied by mineralogical, palaeomagnetic, and rock magnetic methods in order to specify the post-sedimentational history of the area and to obtain a better control over the palaeogeographic position of Baltica during the Ordovician. Mineralogical studies revealed that (titano) magnetite, h (...)
The hill range of Vaivara Sinimaed in northeast Estonia consists of several narrow east-to northeast-trending glaciotectonic fold structures. The folds include tilted (dips 4-75 degrees) Middle Ordovician (early Darriwilian) layered carbonate strata that were studied by mineralogical, palaeomagnetic, and rock magnetic methods in order to specify the post-sedimentational history of the area and to obtain a better control over the palaeogeographic position of Baltica during the Ordovician. Mineralogical studies revealed that (titano) magnetite, hematite, and goethite are carriers of magnetization. Based on data from 5 sites that positively passed a DC tilt test, a south-easterly downward directed component A (D-ref = 154.6 degrees +/- 15.3 degrees, I-ref = 60.9 degrees +/- 9.7 degrees) was identified. The component is carried by (titano) magnetite, dates to the Middle Ordovician (Plat = 17.9 degrees, Plon = 47.3 degrees, K = 46.7, A95 = 11.3 degrees), and places Baltica at mid-southerly latitudes. Observations suggest that in sites that do not pass the tilt test, the glaciotectonic event has caused some rotation of blocks around their vertical axis. Peer reviewed (Read More)
Jüri Plado, Ulla Preeden, Argo JÕeleht, Lauri J. Pesonen, Satu Mertanen
Acta Geophysica ·
2016
Paleontology |
Geochemistry |
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