Paleomagnetism of 2.44 Ga mafic dykes in Russian Karelia, eastern Fennoscandian Shield — implications for continental reconstructions

Magnetic signatures related to orogenic gold mineralization, Central Lapland Greenstone Belt, Finland

“…2200-2000 Ma), probably due to fluid circulation. In most samples the characteristic remanence direction (ChRM) is similar to the direction typically obtained from Svecofennian age rocks, ca.1900-1800 Ma (Mertanen et al, 1999). The palaeomagnetic poles, calculated from the ChRM, form a coherent group (Fig.…”

“…1900-1800 Ma) caused a strong magnetic overprinting on the Precambrian basement rocks in the eastern Fennoskandian shield (Mertanen et al, 1999). Komatiitic, ultramafic rocks tend to be originally highly magnetic due to their primary, mainly coarse-grained magnetite, and carry both high induced and remanent magnetizations.…”

7.2 Huronian-Age Glaciation

“…may also be indicated by widespread deposition of mature Sumian quartzites, which imply a high degree of chemical weathering. Warm and humid climatic conditions appear to be corroborated by an apparent sub-equatorial position of the region at 07-27 (palaeomagnetic data obtained from the 2440 Ma mafic dykes, Mertanen et al 1999).…”

Secular variation of the Late Archean–Early Proterozoic geodynamo

“…Squares (M) show estimates derived from the Matachewan dikes (this work). Circles show estimates based on paleomagnetic data from the Karelia (K) [Mertanen et al, 1999] and Pilbara (P) [Strik et al, 2003] cratons. Confidence intervals shown for M, K and P are 1s and were calculated using a N-1 jackknife [Efron, 1982].…”