Basement Fracturing and Weathering On- and Offshore Norway – Genesis, Age, and Landscape Development

Tuesday, 16 December 2014
Roelant van der Lelij1, Jochen Knies1,2, Johan Faust1, Thomas Scheiber1, Marco Broenner1, Ola Fredin1,3, Axel Mueller1 and Giulio Viola1,4, (1)Geological Survey of Norway, Trondheim, Norway, (2)UiT The Arctic University of Norway, CAGE-Centre for Arctic Gas Hydrate, Environment, and Climate, Dept. of Geology, Tromso, Norway, (3)Norwegian University of Science and Technology, Department of Geography, Trondheim, Norway, (4)Norwegian University of Science and Technology, Department of Geology and Mineral Resources, Trondheim, Norway
Saprolite remnants onshore Scandinavia have been investigated only sporadically. The nature and age of the deeply weathered material thus remains only loosely constrained. The type and degree of weathering of in situ weathered soils are indicative of the environmental conditions during their formation. When external forcing changes, properties related to previous weathering conditions are usually preserved, for example in clay mineral assemblages. By constraining the age and rate of weathering onshore and by isotopically dating selected faults determined to be intimately linked to weathered basement blocks, the influence of climate development, brittle deformation and landscape processes on weathering can be quantified. The "BASE" project aims to establish a temporal and conceptual framework for brittle tectonics, weathering patterns and landscape evolution affecting the basement onshore and offshore Norway. We will study the formation of saprolite in pre-Quaternary times, the influence of deep weathering on landscape development and establish a conceptual structural template of the evolution of the brittle deformational features that are exposed on onshore (weathered) basement blocks. Moreover, saprolitic material may have been eroded and preserved along the Norwegian continental margin during Cenozoic times. By studying both the onshore remnants and offshore erosional products deposited during periods of extreme changes of climate and tectonic boundary conditions (e..g Miocene-Pliocene), new inferences on the timing and controlling mechanisms of denudation, and on the relevance of deep weathering on Late Cenozoic global cooling can be drawn.