Palaeomagnetic results from the Middle Carboniferous rocks of the Hornsund region, southern Spitsbergen: preliminary report

• Main Authors: Krzysztof Michalski, Marek Lewandowski
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Key words; Arctic; Spitsbergen; Palaeozoic; palaeomagnetism; palaeogeography; tectonics; Hornsund; Hyrnefjellet; Svalbard; Tilting
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.600.4828; http://www.polar.pan.pl/ppr25/ppr25-169.pdf

ABSTRACT: Palaeomagnetic investigation of the Upper Carboniferous clastic Hyrnefjellet Formation from opposite limbs of the Hyrnefjellet Anticline in southern Spitsbergen (Sval− bard Archipelago) uncovered two components of NRM. Direction C1 (D = 224.6°; I = –27.9°; = 22.40; 95 % = 5.6°) is of prefolding origin and most probably of near−primary origin. High Tb spectra above 575°C indicate hematite as the carrier of C1. Acquisition of the C1 component may be related to an early diagenetic crystallization of hematite, not excluding a detrital origin of the NRM. A paleopole calculated for the C1 component ( = 23.3°N; = 147.7°E) falls into the Late Devonian–Early Carboniferous sector of APWP for Baltica. This result suggests that Svalbard remained in the present day orientation with respect to Baltica since the Carboniferous time. A second component with intermediate unblocking temperatures, determined in the Hyrnefjellet Formation deposits, is labelled C2. Its mean ori− entation for in situ position is D = 11.2°; I = 69.2 ° ( = 44.05; 95 % = 6.3°), thus being similar to Late Mesozoic directions for Baltica. After 100 % tectonic correction for tilting of anticline limbs and axis, the C2 component orientation is D = 265.7°; I = 59.7°, thus being distant from any directions for Baltica. Detailed analysis suggest that the C2 component is most probably of synfolding origin, and it was formed during the Tertiary Alpine Tectonic Event.