Abstract
Palaeomagnetic studies were carried out on Silurian sedimentary rocks of Estonia. The studied sequence (126 samples from 4 localities) is composed of Silurian lime- and dolostones of Llandovery and Wenlock age (444-423 Ma). Rock magnetic data revealed magnetite, (titano)hematite, and pyrrhotite as the main carriers of remanent magnetization. We found that different secondary magnetizations characterize rocks at different localities, whereas similarities exist between the localities. The virtual poles fall near the Silurian-Early Devonian and Late Palaeozoic segment of the Baltica's APWP. The heritage of these components is related to either syndepositional or early diagenetic changes, and to chemical remagnetization due to late diagenetic processes and/or regional events that affected Baltica during the Late Palaeozoic.
Highlights
Estonia is located on the southern slope of the Fennoscandian Shield where the Ediacaran to Devonian terrigenous and carbonate sediments cover the ~1.88 Ma Svecofennian crystalline basement
Magnetization of carbonate rocks is low with the intensities of the natural remanent magnetization (NRM) between 0.02 and 0.48 mA m–1 and magnetic susceptibilities between –40 × 10–6 and 54 × 10–6 SI
Silurian carbonates of Estonia revealed different components of magnetization
Summary
Estonia is located on the southern slope of the Fennoscandian Shield where the Ediacaran to Devonian terrigenous and carbonate sediments cover the ~1.88 Ma Svecofennian crystalline basement. The absence of Late Phanerozoic rocks suitable for isotope dating makes the palaeomagnetic method the only reliable technique for search of ages of secondary processes previously identified by lithological and mineralogical studies of fracture and pore fillings of the existing sequence (Pichugin et al 1976; Puura et al 1996, 1999). In central Estonia, the Silurian samples from the Rõstla quarry yielded secondary remagnetizations, pointing to Late Devonian– Mississipian and Cretaceous ages (Plado et al 2008). Rocks of the Juuru to Jaagarahu Baltoscandian regional stages (Llandovery and Wenlock) were sampled in four quarries of western and central Estonia, in order to find out approximate ages of remagnetizations and to correlate these to geological processes causing postdepositional transformations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
