Sedimentary rocks from the Grønsennknippa area, located in Vestre Slidre in Valdres, have been studied by field investigations, remote sensing and laboratory techniques. The tectonostratigraphic setting has been briefly investigated primarily by remote sensing using available open-source data, supported by field investigations. The depositional environment has been interpreted from sedimentary field data and observations, supported by petrographical, geochemical and mineralogical analyses including thin section, XRD, XRF, SEM, EMP and heavy mineral separation. Possible fossil palynomorphs and organic matter have been extracted by standard palynological processing techniques.
The Neoproterozoic Valdres Group at Grønsennknippa is composed of coarse clastic sedimentary rocks deposited in fluvial/alluvial environment. The studied succession is dominated by bodies of massive pebbly conglomerates with well rounded clasts, alternating with sandstone beds. Various sandstone facies are overlying the alternating conglomerate and sandstone units, only interrupted by one conglomerate and one diamictite unit. The latter is possibly correlative to the tillite deposit recognized from the Valdres Group at Mellane. Mineralogical composition and field observations indicate relatively short transport distance and fairly texturally immature sediments. The composition is affected by later metamorphism, overprinting the original mineralogy. Four lithofacies are recognized from the studied succession, further subdivided into 12 facies. These have been assigned to five facies associations reflecting various depositional settings within fluvial/alluvial conditions. The fossil assemblage is described morphologically under the main group of acritarchs. The aim was not to correlate the assemblage with well-described fossiliferous strata, but to indicate that similar assemblages are encountered from other strata of similar age. The assemblage is dominated by sphaeromorph and herkomorph acritarchs, in addition to organic remains of unknown origin.
Alluvial/fluvial formations of the Hedmark Basin were compared to the Valdres Group at Grønsennknippa, and revealed comparable depositional environment and stratigraphic development. Correlation with previously described sections of the Valdres Group at Mellane showed that the Grønsennknippa succession exhibit more immature mineralogical and textural signature, being composed of more feldspar minerals and dominated by coarse grained detritus.