New demagnetization results of 286 palaeomagnetic specimens from 15 sites in Neoproterozoic–Lower... more New demagnetization results of 286 palaeomagnetic specimens from 15 sites in Neoproterozoic–Lower Paleozoic sequences of Ny Friesland–Nordaustlandet (the Caledonian Eastern Svalbard Terrane) are presented. New in situ 40 Ar/ 39 Ar ultraviolet mass spectrometry (Uv-MS) age determinations on amphibolites and mylonites from the Ny Friesland cluster in the 340–460 Ma interval correspond broadly to the Caledonian thermal event. Older ages are observed but are more scattered and probably reflect partial resetting or argon gain of Proterozoic micas. Palaeomagnetic, petrological and structural data confirm a west to east decrease in the degree of the Caledonian metamorphism and remagnetization across Hinlopenstretet, which is interpreted here to coincide with the limit of Caledonian east-directed overthrusting. No pre-Caledonian palaeomagnetic record was identified in investigated amphibolites and metacarbonates of Ny Friesland. Pre-folding pre-Caledonian, potentially Neoproterozoic (primar...
New demagnetization results of 286 palaeomagnetic specimens from 15 sites in Neoproterozoic–Lower... more New demagnetization results of 286 palaeomagnetic specimens from 15 sites in Neoproterozoic–Lower Paleozoic sequences of Ny Friesland–Nordaustlandet (the Caledonian Eastern Svalbard Terrane) are presented. New in situ 40 Ar/ 39 Ar ultraviolet mass spectrometry (Uv-MS) age determinations on amphibolites and mylonites from the Ny Friesland cluster in the 340–460 Ma interval correspond broadly to the Caledonian thermal event. Older ages are observed but are more scattered and probably reflect partial resetting or argon gain of Proterozoic micas. Palaeomagnetic, petrological and structural data confirm a west to east decrease in the degree of the Caledonian metamorphism and remagnetization across Hinlopenstretet, which is interpreted here to coincide with the limit of Caledonian east-directed overthrusting. No pre-Caledonian palaeomagnetic record was identified in investigated amphibolites and metacarbonates of Ny Friesland. Pre-folding pre-Caledonian, potentially Neoproterozoic (primar...
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Papers by Mariusz Burzyński