Baltica during the Ediacaran and Cambrian : A paleomagnetic study of Hailuoto sediments in Finland

We present a new Late Neoproterozoic paleomagnetic pole for Baltica from an inclined 272 m deep oriented sedimentary drill core in Hailuoto, Western Finland. The depositional age of the Hailuoto sediments is poorly constrained at 570-600 Ma. Three components of magnetization were isolated with therm...

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Bibliographic Details
Published in:Precambrian Research
Main Authors: Klein, R., Salminen, Johanna, Mertanen, S.
Other Authors: Department of Physics, Division of Geophysics and Astronomy (-2017)
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier Scientific Publ. Co 2021
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Online Access:http://hdl.handle.net/10138/329808
Description
Summary:We present a new Late Neoproterozoic paleomagnetic pole for Baltica from an inclined 272 m deep oriented sedimentary drill core in Hailuoto, Western Finland. The depositional age of the Hailuoto sediments is poorly constrained at 570-600 Ma. Three components of magnetization were isolated with thermal and alternating field (AF) demagnetization treatments. The ChRM (characteristic remanence magnetization) component is a high coercivity/unblocking temperature dual polarity component that passes a reversal test. The combined observed ChRM component of the Hailuoto sediments (D = 334.2 degrees; I = 44.4 degrees; alpha(95) = 7 2; k = 16.5) yields a paleomagnetic pole of Plat = 48.7 degrees N and Plon = 241.1 degrees E with A95 = 8.1 degrees. The inclination corrected direction (f = 0.6) of D = 334.4 degrees; I = 57.7 degrees; alpha(95) = 5.8 degrees; k = 25.2 yields a paleomagnetic pole of Plat = 60.5 degrees N and Plon = 247.9 degrees E with A95 = 7.6 degrees. As it is a dual-polarity ChRM carried by both magnetite and hematite, with no resemblance to younger events, we interpret it as a primary component. A paleolatitude for Hailuoto of 383 was calculated from the ChRM. Two secondary components were identified. The first is a low coercivity/blocking temperature component with a remanent magnetization of D = 239.0 degrees; I = 67.3 degrees; alpha(95) = 8.7 degrees (N = 13 samples), which we interpret as drilling-induced remanent magnetization (DIRM). The second secondary component has a remanent magnetization of D = 49.4 degrees; I = 34.9 degrees; alpha(95) = 8.6 degrees (N = 5 samples) and is commonly seen in Fennoscandian formations. The ChRM Hailuoto pole adds to the scattered Ediacaran paleomagnetic data of Baltica and indicate large distances between other late Neoproterozoic and early Cambrian paleomagnetic poles. We present reconstructions of Baltica and Laurentia between 616 and 550 Ma which move Baltica from high latitudes (615 Ma), over the polar region, to low latitudes (550 Ma), and Laurentia from low ...