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

• 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
• Subjects: Ediacaran; Paleomagnetism; Paleogeography; Baltica; Laurentia; Hailuoto sediments; TRUE POLAR WANDER; INDUCED REMANENT MAGNETIZATION; NORTH-AMERICA; WESTERN NEWFOUNDLAND; VENDIAN SEDIMENTS; EARTHS OBLIQUITY; LOWER ORDOVICIAN; SNOWBALL EARTH; IAPETUS OCEAN; SOUTH URALS; 1171 Geosciences; Fennoscandian; Newfoundland
• Online Access: http://hdl.handle.net/10138/329808

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 ...