Observation and simulation of solid sedimentary flux: examples from northwest Africa
File(s)
Author(s)
Type
Journal Article
Abstract
The sedimentary archive preserved at passive margins provides important clues about the evolution of continental topography. For example, histories of African uplift, erosion, and deposition of clastic sedimentary rock provide information about mantle convection. Furthermore, relating histories of uplift and erosion from regions where sediment is generated to measurements of efflux is important for understanding basin evolution and the distribution of natural resources. We focus on constraining Mesozoic to Recent solid sedimentary flux to northwest Africa's passive margin, which today is fed by rivers draining dynamically supported topography. Histories of sedimentary flux are calculated by mapping stratigraphy using seismic reflection and well data courtesy of Tullow Oil Plc and TGS. Stratigraphic ages, conversion from two‐way time to depth and compaction, are parameterized using biostratigraphic and check‐shot records from exploration, International Ocean Discovery Program and Deep Sea Drilling Project wells. Results indicate that Late Cretaceous to Oligocene (∼100–23 Ma) sedimentary flux decreased gradually. A slight increase in Neogene sedimentary flux is observed, which is concomitant with a change from carbonate to clastic sedimentation. Pliocene to Recent (∼5–0 Ma) flux increased by an order of magnitude. This history of sedimentary flux and facies change is similar to histories observed at other African deltas. To constrain sources of sedimentary flux, 14,700 longitudinal river profiles were inverted to calculate a history of continental uplift. These results were used to parameterize a simple “source‐to‐sink” model of fluvial erosion and sedimentary efflux. Results suggest that increased clastic flux to Africa's deltas from ∼30 Ma was driven by denudation induced by dynamic support.
Date Issued
2019-11
Date Acceptance
2019-08-31
Citation
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences, 2019, 20 (11), pp.4613-4634
ISSN
1525-2027
Publisher
American Geophysical Union
Start Page
4613
End Page
4634
Journal / Book Title
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences
Volume
20
Issue
11
Copyright Statement
©2019. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Lodhia, B. H., Roberts, G. G., Fraser, A. J., Jarvis, J., Newton, R., & Cowan, R. J. ( 2019). Observation and simulation of solid sedimentary flux: Examples from northwest Africa. Geochemistry, Geophysics, Geosystems, 20, 4613– 4634, which has been published in final form at https://doi.org/10.1029/2019GC008262
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GC008262
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
source to sink
Africa
drainage patterns
inversion
dynamic support
reservoir prediction
BEDROCK INCISION MODELS
STREAM-POWER
WEST-AFRICA
RIVER INCISION
LANDSCAPE EVOLUTION
FLUVIAL EROSION
SOUTH-AFRICA
TIME SCALES
BASINS
STRATIGRAPHY
Geochemistry & Geophysics
04 Earth Sciences
02 Physical Sciences
Publication Status
Published
Date Publish Online
2019-10-01