“…The volumes of sediments deposited in the Bear Island Trough Mouth Fan as a result of the Cenozoic erosion in the Barents Sea shelf comprise approximately 70 % glacial and 30 % pre-glacial sediments [4]. In the study area very high glacial erosion was balanced by high glacial deposition of the reworked sediments.…”
Section: Pleistocene Contribution To Net Erosionmentioning
The Pleistocene sedimentary conditions and the glacial contribution to net erosion were determined for the outer Bear Island Trough by using a Monte Carlo-type method. The approach uses ages for glacial/interglacial periods that were based on the regional ice-sheet volume curve. The results indicate that the western Barents Sea was glaciated during four marine isotope stages: MIS 16 (635.6-624.7 ka), MIS 12 (438.7-428.0 ka), MIS 6 (138.6-134.6 ka) and MIS 2 (19.3-16.0 ka) for a total duration of 29 ka. The first glacial event (before 440 ka, MIS 16) resulted in homogeneous erosion over the study area (with an erosion rate of 24.2 ± 8.5 mm/a). After 440 ka, a change in sedimentary conditions resulted in inhomogeneous erosion rates over the study area from -12.6 ± 1.6 (i.e. net deposition) to 1.6 ± 1.8 mm/a (i.e. net erosion). The most likely values of average deposition rates during interglacial periods were modelled as 0.12 ± 0.1 mm/a. In the outer Bear Island Trough the net erosion was found to be mainly the effect of tectonic uplift and subsequent erosion prior to the glacial ages. The results show that in most parts of the study area the Pleistocene glacial contribution to the total net erosion was small: the most likely glacial contribution in the eastern part of the area reaches 100 m, which is about 9 % of the total net erosion, while in the westernmost part the glaciations did not contribute to the net erosion.
“…The volumes of sediments deposited in the Bear Island Trough Mouth Fan as a result of the Cenozoic erosion in the Barents Sea shelf comprise approximately 70 % glacial and 30 % pre-glacial sediments [4]. In the study area very high glacial erosion was balanced by high glacial deposition of the reworked sediments.…”
Section: Pleistocene Contribution To Net Erosionmentioning
The Pleistocene sedimentary conditions and the glacial contribution to net erosion were determined for the outer Bear Island Trough by using a Monte Carlo-type method. The approach uses ages for glacial/interglacial periods that were based on the regional ice-sheet volume curve. The results indicate that the western Barents Sea was glaciated during four marine isotope stages: MIS 16 (635.6-624.7 ka), MIS 12 (438.7-428.0 ka), MIS 6 (138.6-134.6 ka) and MIS 2 (19.3-16.0 ka) for a total duration of 29 ka. The first glacial event (before 440 ka, MIS 16) resulted in homogeneous erosion over the study area (with an erosion rate of 24.2 ± 8.5 mm/a). After 440 ka, a change in sedimentary conditions resulted in inhomogeneous erosion rates over the study area from -12.6 ± 1.6 (i.e. net deposition) to 1.6 ± 1.8 mm/a (i.e. net erosion). The most likely values of average deposition rates during interglacial periods were modelled as 0.12 ± 0.1 mm/a. In the outer Bear Island Trough the net erosion was found to be mainly the effect of tectonic uplift and subsequent erosion prior to the glacial ages. The results show that in most parts of the study area the Pleistocene glacial contribution to the total net erosion was small: the most likely glacial contribution in the eastern part of the area reaches 100 m, which is about 9 % of the total net erosion, while in the westernmost part the glaciations did not contribute to the net erosion.
“…During the Cenozoic, the southern Barents Sea Basin and Fennoscandia were mainly in a state of uplift and erosion (Henriksen et al, 2011b;Laberg et al, 2012;Baig et al, 2016). The total erosion along the southern Barents Sea is estimated at ~1200 m, and approximately half of this is estimated to be due glacial erosion during the last 2.7 m.y.…”
Section: Linking a Triassic Delta To Present-day Catchmentsmentioning
confidence: 99%
“…The total erosion along the southern Barents Sea is estimated at ~1200 m, and approximately half of this is estimated to be due glacial erosion during the last 2.7 m.y. (Laberg et al, 2012;Baig et al, 2016). The erosion onshore in northern Fennoscandia is uncertain.…”
Section: Linking a Triassic Delta To Present-day Catchmentsmentioning
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.
“…The sediments deposited in the Barents Sea region are affected by several phases of uplift and net erosion because of opening stages of the Atlantic and Arctic oceans and also glacial erosion during the Plio-Pleistocene period (Faleide et al, 1993;Dore and Lundin, 1996;Henriksen et al, 2011). The amount of exhumation is varied between 400 and 3000 m in different parts of the greater Barents Sea (Ohm et al, 2008;Henriksen et al, 2011;Baig et al, 2016). Henriksen et al (2011) and Baig et al (2016) estimate 1300 m of exhumation for the Jurassic sediments at well 7125/1-1.…”
Section: Geologic Frameworkmentioning
confidence: 99%
“…The amount of exhumation is varied between 400 and 3000 m in different parts of the greater Barents Sea (Ohm et al, 2008;Henriksen et al, 2011;Baig et al, 2016). Henriksen et al (2011) and Baig et al (2016) estimate 1300 m of exhumation for the Jurassic sediments at well 7125/1-1.…”
This study investigates the seismic velocity anisotropy of two organic-rich shales from the Norwegian Continental Shelf. The tested organic-rich shale samples were from the Upper Jurassic Draupne and Hekkingen formations collected from two wells (16/ 8-3S and 7125/1-1) drilled in the central North Sea and western Barents Sea, respectively. The two tested shales are different in organic matter richness and thermal maturation, and they have experienced different burial histories. The shale core plugs were tested in a triaxial cell under controlled pore pressure. Seismic velocities (V P and V S ) were measured along different orientations with respect to layering to identify the complete tensor of the rock elastic moduli, and to investigate the velocity anisotropy as a function of increasing effective stress. The measured velocity values exhibit strong anisotropy for the two tested organic-rich shales. The anisotropy for both shales is strongest for V S . Seismic velocities follow an increasing trend as the effective stress increases. The anisotropy decreases somewhat with increasing consolidation, probably due to the closing of preexisting fractures and microcracks. The reduction of anisotropy is more evident for the P-wave because it decreases from 0.32 to 0.25 for the Draupne sample and from 0.28 to 0.24 for the Hekkingen sample when the vertical effective stress increases from 26 to 50 MPa. In general, the Hekkingen sample indicates slightly higher velocity values than the Draupne sample due to more compaction and lower porosity. In spite of major differences between the two shale formations in terms of organic matter content, maturity and burial history, they indicate almost the same degree of velocity anisotropy. The outcomes of this study can contribute to better imaging of organic-rich Draupne and Hekkingen shales by constraining the rock-physics properties.
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