Solution‐collapse breccias of the Minkinfjellet and Wordiekammen Formations, Central Spitsbergen, Svalbard: a large gypsum palaeokarst system

Abstract

Large volumes of carbonate breccia occur in the late syn‐rift and early post‐rift deposits of the Billefjorden Trough, Central Spitsbergen. Breccias are developed throughout the Moscovian Minkinfjellet Formation and in basal parts of the Kazimovian Wordiekammen Formation. Breccias can be divided into two categories: (i) thick, cross‐cutting breccia‐bodies up to 200 m thick that are associated with breccia pipes and large V‐structures, and (ii) horizontal stratabound breccia beds interbedded with undeformed carbonate and siliciclastic rocks. The thick breccias occur in the central part of the basin, whereas the stratabound breccia beds have a much wider areal extent towards the basin margins. The breccias were formed by gravitational collapse into cavities formed by dissolution of gypsum and anhydrite beds in the Minkinfjellet Formation. Several dissolution fronts have been discovered, demonstrating the genetic relationship between dissolution of gypsum and brecciation. Textures and structures typical of collapse breccias such as inverse grading, a sharp flat base, breccia pipes (collapse dolines) and V‐structures (cave roof collapse) are also observed. The breccias are cemented by calcite cements of pre‐compaction, shallow burial origin. Primary fluid inclusions in the calcite are dominantly single phase containing fresh water (final melting points are ca 0 °C), suggesting that breccia diagenesis occurred in meteoric waters. Cathodoluminescence (CL) zoning of the cements shows a consistent pattern of three cement stages, but the abundance of each stage varies stratigraphically and laterally. δ18O values of breccia cements are more negative relative to marine limestones and meteoric cements developed in unbrecciated Minkinfjellet limestones. There is a clear relationship between δ18O values and the abundance of the different cement generations detected by CL. Paragenetically, later cements have lower δ18O values recording increased temperatures during their precipitation. Carbon isotope values of the cements are primarily rock‐buffered although a weak trend towards more negative values with increasing burial depth is observed. The timing of gypsum dissolution and brecciation was most likely related to major intervals of exposure of the carbonate platform during Gzhelian and/or Asselian/Sakmarian times. These intervals of exposure occurred shortly after deposition of the brecciated units and before deep burial of the sediments.

From detached to attached carbonate buildup complexes — 3D seismic data from the upper Palaeozoic, Finnmark Platform, southwestern Barents Sea

“…This subaerial exposure event is believed to be a regional event which on the inner Finnmark Platform is recorded by thin sandstone at the transition between the Gipsdalen and Bjarmeland groups . The collapse pipes and V-structures from the gypsum palaeo-karst system in Central Spitsbergen are of Moscovian-Kazimovian age (Eliassen and Talbot, 2005) and may serve as a possible analogue to karst formation in relation to evaporites.…”

Facies evolution and sequence chronostratigraphy of a “mid”-Cretaceous shallow-water carbonate succession of the Apulia Carbonate Platform from the northern Murge area (Apulia, southern Italy)

“…Ricchetti (1975) suggests that this type of dolomitic breccias might develop in hypersaline environments. The dolomitic breccias are then interpreted as solution-collapse breccias caused by the dissolution of evaporitic layers, interbedded with dolomite beds (e.g., Assereto and Kendall 1977;Eliassen and Talbot 2005). This interpretation cannot be fully supported in this paper since no direct or indirect evidence of the deposition of primary evaporitic layers has been found.…”

Depositional evolution of the Upper Carboniferous – Lower Permian Wordiekammen carbonate platform, Nordfjorden High, central Spitsbergen, Arctic Norway

“…In contrast, the more slowly subsiding crestal areas, the Nordfjorden and Ny Dallmann (1999). the east (Steel & Worsley, 1984;Johannesen & Steel, 1992;Eliassen & Talbot, 2003). Transgression of the High occurred during the Moscovian (Nilsson, 1988) and laterally extensive carbonate platforms of the Wordiekammen Formation were established as the siliciclasic source areas drowned (Steel & Worsley, 1984).…”

“…The most important is the N-Soriented Billefjorden Fault Zone which separates the Nordfjorden High from the better studied areas to the east (Holliday & Cutbill, 1972;Lønøy, 1995;Pickard et al, 1996;Samuelsberg & Pickard, 1999;Samuelsberg et al, 2000;Eliassen & Talbot, 2003;Blomeier et al, 2008Blomeier et al, 2011). This paper presents the first comprehensive study of the Wordiekammen carbonates on the Nordfjorden High.…”