Linking an Early Triassic delta to antecedent topography: Source-to-sink study of the southwestern Barents Sea margin

Abstract

Present-day catchments adjacent to sedimentary basins may preserve geomorphic elements that have been active through long intervals of time. Relicts of ancient catchments in present-day landscapes may be investigated using mass-balance models and can give important information about upland landscape evolution and reservoir distribution in adjacent basins. However, such methods are in their infancy and are often difficult to apply in deep-time settings due to later landscape modification.The southern Barents Sea margin of N Norway and NW Russia is ideal for investigating source-to-sink models, because it has been subject to minor tectonic activity since the Carboniferous, and large parts have eluded significant Quaternary glacial erosion. A zone close to the present-day coast has likely acted as the boundary between basin and catchments since the Carboniferous. Around the Permian-Triassic transition, a large delta system started to prograde from the same area as the present-day largest river in the area, the Tana River, which has long been interpreted to show features indicating that it was developed prior to present-day topography. We performed a source-to-sink study of this ancient system in order to investigate potential linkages between present-day geomorphology and ancient deposits.We investigated the sediment load of the ancient delta using well, core, twodimensional and three-dimensional seismic data, and digital elevation models to investigate the geomorphology of the onshore catchment and surrounding areas. Our results imply that the present-day GSA Bulletin; January/February 2018; v. 130 Tana catchment was formed close to the Permian-Triassic transition, and that the Triassic delta system has much better reservoir properties compared to the rest of Triassic basin infill. This implies that landscapes may indeed preserve catchment geometries for extended periods of time, and it demonstrates that source-to-sink techniques can be instrumental in predicting the extent and quality of subsurface reservoirs.

Progradation Rates Measured at Modern River Outlets: A First‐Order Constraint on the Pace of Deltaic Deposition

“…To achieve this goal, we use Landsat‐derived satellite images to identify plan view changes in the subaerial morphology of 331 modern deltas, from which we can quantify localized progradation rates that occur adjacent to the fluvial entry points at the deltaic shorelines. These rates are compared with parameters in the Milliman and Farnsworth () data set, a well‐documented compilation of climate, catchment, and fluvial discharge parameters, many of which are feasible to constrain in ancient systems (Eide et al, ; Helland‐Hansen et al, ; Sømme et al, ), as well as additional parameters quantifying properties of the depositional sink such as water depth extracted from General Bathymetric Chart of the Oceans (GEBCO) bathymetric data (Jakobsson et al, ) and wave energy extracted from Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO+)‐derived data products (AVISO+, ). We take advantage of the Google Earth Engine (Gorelick et al, ) to create our rate compilation.…”

Using climate to relate water discharge and area in modern and ancient catchments

“…Such studies may be undertaken in order to: predict or estimate parameters of sedimentary transport networks, which are inaccessible to study due to erosion or burial (Martinsen et al ., ); understand the propagation and fidelity of environmental signals through time (Paola et al ., ; Romans et al ., ); and characterize the evolution of past landscapes (e.g. Sømme et al ., ; Bhattacharya et al ., ; Eide et al ., in press).…”

“…Depending on the available data set and the questions asked, some of these parameters may be measured, estimated or modelled, while some parameters are kept as variables (e.g. Allen et al ., ; Sømme et al ., ; Eide et al ., in press).…”

Clinoform development and topset evolution in a mud‐rich delta – the Middle Triassic Kobbe Formation, Norwegian Barents Sea

“…Where reservoir‐scale sandstone deposits are encountered they are usually of poorer quality than the sandstone of the Goliat Field (Tsikalas et al ., ). This is primarily due to how the more fine‐grained, immature and mud‐rich nature of sediments are sourced from the south‐east (Bergan & Knarud, ; Mørk, ; Eide et al ., ).…”

“…The best reservoir properties are instead found along the southern margin of the basin (i.e. the Goliat Field) and are attributed to a more mature provenance area in the Norwegian Caledonides to the south (Bergan & Knarud, ; Mørk, ; Ryseth, ; Fleming et al ., ; Eide et al ., ). How far the southerly derived sedimentary systems extend into the basin and how the depositional system has evolved in response to variations in autogenic and allogenic forcing factors is not known, but the reservoir properties of the Kobbe Formation are likely to be governed by the influx and extent of mature sediment from the south in combination with reservoir preserving factors in more central parts of the basin which counter the effects of burial that varied across the basin (Baig et al ., ).…”