| Title | Cretaceous to Eocene mixed turbidite-contourite systems offshore Nova Scotia (Canada): Spatial and temporal variability of down- and along-slope processes |
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| Author | Rodrigues, S; Deptuck, M E; Kendell, K L; Campbell, C ; Hernandez-Molina, F J |
| Source | Marine and Petroleum Geology vol. 138, 105572, 2022 p. 1-26, https://doi.org/10.1016/j.marpetgeo.2022.105572  Open Access |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210686 |
| Publisher | Elsevier |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Offshore region; Nova Scotia |
| NTS | 10 |
| Lat/Long WENS | -63.5000 -57.0000 45.0000 41.0000 |
| Subjects | marine geology; fossil fuels; deposition; depositional analyses; turbidites; contourites; seismic data; seismic surveys; seismic models; Lower Cretaceous; Upper Cretaceous |
| Illustrations | location maps; stratigraphic columns; seismic profiles; 3-D images; digital images |
| Program | Marine Geoscience for Marine Spatial Planning |
| Released | 2022 02 04 |
| Abstract | The identification of several Cretaceous to Paleogene mixed turbidite-contourite systems along the upper to middle continental slope of Nova Scotia provides a unique opportunity to investigate the
spatial and temporal variability of their morphological elements. The mixed systems were studied using 3D seismic reflection data and well-established chronostratigraphy from five exploration wells. Seismic interpretations and correlations suggest
four main evolutionary stages for the Late Jurassic - Paleogene sedimentary record, characterized by distinctive, diagnostic features at large (>1-10 km) to small (<100 m) scales: 1) initial turbidite systems developed between 160 and 125 Ma with
extensive tributary channel networks along the upper continental slope that fed submarine channels and channel-levees further down-slope; 2) onset and growth of mixed systems at 125-78 Ma, characterized by a seaward progradation and NE migration of
down-slope elongated mounded drifts and wide, U-shaped channels formed under potentially synchronous interactions between a SW-flowing bottom current and SE-directed turbidity flows; 3) shift of mixed systems at 78-50 Ma with SW migration of the
mounded drifts and submarine channels, associated with a potential switch of the bottom current direction at 78 Ma, from SW towards NE; and 4) burial stage post-50 Ma, characterized by several stages of hemipelagic deposition followed by gully
erosion at approximately 50, 40, and 35 Ma. The gradual transition from turbidite systems to fully developed mixed systems is associated with the tectonic and sedimentary background of the Nova Scotian margin during the Early to Late Cretaceous, as
well as the establishment of a Cretaceous to Eocene paleoceanographic circulation. Comparisons with other ancient and modern mixed systems reveal similar morphological features (e. g., mounded drifts and submarine channels) formed under synchronous
and asynchronous interactions between along- and down-slope processes. Their lateral distribution and vertical variability reflect a gradual change between the most influential process, from down-slope turbidity currents to along-slope bottom
currents. Secondary depositional features along the mounded drifts, such as N-S oriented sediment waves, result from along-slope sediment redistribution and remobilization near the seafloor. Mixed depositional systems form unconventional plays and
may become future targets for energy geosciences in a search for hydrocarbons or carbon capture and storage. |
| Summary | (Plain Language Summary, not published)
This paper presents the unique deposits that formed offshore Nova Scotia during the Late Cretaceous and Early Cenozoic due to the interaction of
along-slope and down-slope processes. The study has applications towards understanding and identifying reservoirs offshore for hydrocarbons and carbon storage. |
| GEOSCAN ID | 329683 |
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