Subsurface Identification of a Palaeozoic Carbonate System in the Barents Sea: Build-Up Distribution, Geometry and Development
Arnout Colpaert, David Hunt, Florian Miquelis, Sandra Brocheray, Brita Graham-Wall, Gaynor Patton, Anthony Avu, 2010. "Subsurface Identification of a Palaeozoic Carbonate System in the Barents Sea: Build-Up Distribution, Geometry and Development", Seismic Imaging of Depositional and Geomorphic Systems, Lesli J. Wood, Toni T. Simo, Norman C. Rosen
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The Norwegian Barents Sea is used as a subsurface laboratory for improving our workflows to retrieve and quantify geomorphic information from seismic data over ancient carbonate systems. Here, we present a novel volume-based seismic interpretation work flow for improved imaging of carbonate features as, for example, subtle build-up complexes and karst. Frequency decomposition followed by RGB-blending is one of the most powerful tools in this work flow for extracting highly detailed information from seismic. A number of seismic surveys in the Norwegian Barents Sea have been revisited and interpreted with this work flow, revealing information on the Upper Paleozoic carbonate systems that otherwise would have remained hidden from interpreter. The newly retrieved seismic geomorphic data is paramount for suggesting new carbonate build-up growth models for the spectacular polygonal build-ups observed on seismic as widespread build-up complexes expanding over thousands of square kilometers. Systematic quantitative shape analyses provide insights on the geometry and self-organization of the polygonal build-ups. Growth is mainly controlled by the paleo-environmental position on the platform, stable slope, or on active fault blocks, reflecting variations in available accommodation space. Two separate phases of polygonal build-up development having distinct geomorphic expression are recognized through time: (1) Subtle features from the volume-based interpretation reveal low-relief Palaeoaplysina—phylloid algae polygonal-elongated ridge systems formed from the warm-water carbonate factory controlling the deposition during the Gipsdalen Group. These subtle systems compete with deposition of more basinal evaporites for space on low angle ramp systems.(2) A second set of polygonal build-ups are recognized in the cooler water carbonate interval of the Bjarmeland Group. These high relief Bryozoan-Tnbiphytes mound complexes have been recognized in previous studies, but our novel seismic geomorphic analysis allows unraveling the internal growth pattern of these spectacular complexes at a seismic scale. Starting as individual nuclei, these mounds amalgamate quickly into ridges that start to form polygonal networks. Subsequently, different cycles of aggradation followed by progradation are recognized in the buildups. Geomorphic quantification proves that basinal settings are dominated by aggradation, whereas slope and platform settings are prone to more progradational development of these polygons.