Sedimentology and Facies Distribution in the Lower Triassic Vardebukta Formation on Oscar II Land, Svalbard
MetadataVis full innførsel
This thesis concerns the Lower Triassic Vardebukta Formation at Oscar II Land. The field data collected from the Triassic exposure on Selmanset, Bertilryggen and Ramfjelldalen, north of Isfjorden, during fieldwork in 2017 has been used for sedimentological facies analysis and identification of facies associations, in order to improve the understanding of the Lower Triassic Vardebukta, in the heavily tectonized area of Oscar II Land. Oscar II Land has been considered as an important region when it comes to demonstrating the contractional Tertiary tectonic, since an almost 50 km wide intensely deformed zone of Late Paleozoic and Mesozoic strata is exposed. As a consequence of the early Cenozoic folding, the stratigraphy seen at Selmaneset and Ramfjellet are steeply dipping to 90 degrees, and the general quality of the outcrop on these locations are variable. 11 facies and 7 facies associations are interpreted based on the sedimentary analysis from the outcrops and the logs. This is followed by a description of the logs from the different locations, based on the facies and facies associations. Based on presented results, an upwards coarsening trend has been seen at Selmaneset, grading from offshore deposits to upper shoreface and barrier bar deposits. This is similar to the coarsening up trend seen at Festningen. However, a significantly difference in the thickness has been seen between Selmaneset and Festningen. The complex tectonics may have resulted in several repetitions at Selmaneset, resulting in a thick succession, compared to neighbouring areas. A deepening trend has been seen from Selmaneset to Bertilryggen, which has been interpreted to be distal offshore transition deposits, followed by a deepening to offshore deposits. This interpretation is supported by the the eastward deepening trend seen in the findings across Spitsbergen. However, in order to get a better understanding of the depositional environment, further studies of the structural geology of Oscar II Land will be important.