Supplementary files for: Mudstone diagenesis and sandstone provenance in an Upper Jurassic – Lower Cretaceous evolving half-graben system, Wollaston Forland, North-East Greenland

The influence of rifting on the composition of Kimmeridgian to Barremian mudstones from northern Wollaston Forland in North-East Greenland is investigated by petrographic and mineralogical analysis, in addition to U-Pb zircon provenance analysis of nearby sandstones. The mudstone composition is found to vary systematically as a function of both the timing of the rifting progression and the position in the half-graben depositional system. Pyrite primarily precipitated in the early rift to rift climax phases. Euhedral pyrite overgrowths on framboids formed only during the rift climax phase (Lindemans Bugt Formation). Dolomite is the dominant carbonate cement, except for the sediments deposited in the early waning rift phase (Palnatokes Bjerg Formation) where calcite is dominant, and in the late waning rift phase (Stratumbjerg Formation) where siderite dominates. A diagenetic process scheme is established to summarize the main diagenetic reactions, of which the highest-temperature reactions with precipitation of illite, quartz, ankerite and barite signify sediment burial depths of >2 km prior to exhumation. Uplift-induced fracturing mainly occurred in the early rift to rift acceleration succession (Bernbjerg Formation). Mudstones in the proximal part of the half-graben (Rødryggen-1 core) include more detrital kaolinite than the distal mudstones (Brorson Halvø-1 core), which contain more mixed-layer illite/smectite and illite. Vermiculite was deposited only in the proximal part of the basin where it is found in the rift climax and waning rift successions. Chlorite was deposited both proximally and distally during the waning rift phase, though the supply began earlier in the distal part. Fine-grained sediment in the distal part of the half-graben was therefore probably supplied by axial transport from Palaeoproterozoic crystalline rocks and Meso- to Neoproterozoic metamorphic rocks located to the north and north-west.