TY - JOUR
T1 - Fluvial architecture in actively deforming salt basins
T2 - Chinle Formation, Paradox Basin, Utah
AU - Hartley, Adrian
AU - Evenstar, Laura
N1 - Publisher Copyright:
© 2017 The Authors. Basin Research © 2017 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Determining the response of fluvial systems to syn-sedimentary halokinesis is important for reconstructing the palaeogeography of salt basins, determining the history of salt movement and predicting development and architecture of sandstone bodies for subsurface fluid extraction. To assess both the influence of salt movement on fluvial system development and the use of lithostratigraphic correlation schemes in salt basins we have analysed the Triassic Chinle Formation in the Paradox Basin, Utah. Results indicate that sandstone body development proximal to salt bodies should be considered at two scales: intra- (local) and inter- (regional) mini-basin scale. At the intra-mini basin or local scale, conformable packages of up to 12 m deep meandering fluvial channel deposits and associated overbank deposits are developed, which may thin, pinch-out or become truncated towards salt highs. When traced down the axis of a mini-basin, individual stories extend for a few hundred metres, and form part of amalgamated channel-belt packages up to 60 m thick that can be traced for at least 25 km parallel to palaeoflow. Where salt movement outpaces sediment accumulation, progressive low angle unconformities are developed along the flanks of salt highs. Significantly, in mini-basins with high sand supply, sandstone bodies are present across salt highs where they show increased amalgamation, decrease in thickness due to truncation and no change in internal sandstone body character. At inter mini-basin or regional scale, spatial and temporal variations in accommodation space generated by differential salt movement strongly influence facies distributions and facies correlation lengths. Broad lithostratigraphic packages (5–50 m thick) can be correlated within mini-basins, but correlation of these units between adjacent mini-basins is problematic. Knowledge of fluvial system development at a regional scale is critical as, fluvial sediment distribution is focussed by topography generated by growing salt bodies, such that adjacent mini-basins can have significant differences in sandstone body thickness, distribution and lateral extent. The observations from the Chinle Formation indicate that lithostratigraphic-based correlation schemes can only be applied within mini-basins and cannot be used to correlate between adjacent mini-basins or across a salt mini-basin province. The key to predicting sandstone body development is an understanding of the timing of salt movement and reconstructing fluvial drainage system development.
AB - Determining the response of fluvial systems to syn-sedimentary halokinesis is important for reconstructing the palaeogeography of salt basins, determining the history of salt movement and predicting development and architecture of sandstone bodies for subsurface fluid extraction. To assess both the influence of salt movement on fluvial system development and the use of lithostratigraphic correlation schemes in salt basins we have analysed the Triassic Chinle Formation in the Paradox Basin, Utah. Results indicate that sandstone body development proximal to salt bodies should be considered at two scales: intra- (local) and inter- (regional) mini-basin scale. At the intra-mini basin or local scale, conformable packages of up to 12 m deep meandering fluvial channel deposits and associated overbank deposits are developed, which may thin, pinch-out or become truncated towards salt highs. When traced down the axis of a mini-basin, individual stories extend for a few hundred metres, and form part of amalgamated channel-belt packages up to 60 m thick that can be traced for at least 25 km parallel to palaeoflow. Where salt movement outpaces sediment accumulation, progressive low angle unconformities are developed along the flanks of salt highs. Significantly, in mini-basins with high sand supply, sandstone bodies are present across salt highs where they show increased amalgamation, decrease in thickness due to truncation and no change in internal sandstone body character. At inter mini-basin or regional scale, spatial and temporal variations in accommodation space generated by differential salt movement strongly influence facies distributions and facies correlation lengths. Broad lithostratigraphic packages (5–50 m thick) can be correlated within mini-basins, but correlation of these units between adjacent mini-basins is problematic. Knowledge of fluvial system development at a regional scale is critical as, fluvial sediment distribution is focussed by topography generated by growing salt bodies, such that adjacent mini-basins can have significant differences in sandstone body thickness, distribution and lateral extent. The observations from the Chinle Formation indicate that lithostratigraphic-based correlation schemes can only be applied within mini-basins and cannot be used to correlate between adjacent mini-basins or across a salt mini-basin province. The key to predicting sandstone body development is an understanding of the timing of salt movement and reconstructing fluvial drainage system development.
UR - http://www.scopus.com/inward/record.url?scp=85018885863&partnerID=8YFLogxK
U2 - 10.1111/bre.12247
DO - 10.1111/bre.12247
M3 - Article
AN - SCOPUS:85018885863
SN - 0950-091X
VL - 30
SP - 148
EP - 166
JO - Basin Research
JF - Basin Research
IS - 1
ER -