干旱区生态环境知识资源中心(Arid): Large-Scale Tectonic Forcing of the African Landscape

Arid

DOI	10.1029/2021JF006345
	Large-Scale Tectonic Forcing of the African Landscape
	O'Malley, C. P. B.; White, N. J.; Stephenson, S. N.; Roberts, G. G.
通讯作者	O'Malley, CPB ; White, NJ (corresponding author)，Univ Cambridge, Dept Earth Sci, Bullard Labs, Cambridge, England. ; O'Malley, CPB (corresponding author)，Imperial Coll London, Dept Earth Sci & Engn, London, England.
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
ISSN	2169-9003
EISSN	2169-9011
出版年	2021
卷号	126 期号:12
英文摘要	Successful inverse modeling of observed longitudinal river profiles suggests that fluvial landscapes are responsive to continent-wide tectonic forcing. However, inversion algorithms make simplifying assumptions about landscape erodibility and drainage planform stability that require careful justification. For example, precipitation rate and drainage catchment area are usually assumed to be invariant. Here, we exploit a closed-loop modeling strategy by inverting drainage networks generated by dynamic landscape simulations in order to investigate the validity of these assumptions. First, we invert 4,018 African river profiles to determine an uplift history that is independently calibrated, and subsequently validated, using separate suites of geologic observations. Second, we use this tectonic forcing to drive landscape simulations that permit divide migration, interfluvial erosion and changes in catchment size. These simulations reproduce large-scale features of the African landscape, including growth of deltaic deposits. Third, the influence of variable precipitation is investigated by carrying out a series of increasingly severe tests. Inverse modeling of drainage inventories extracted from simulated landscapes can largely recover tectonic forcing. Our closed-loop modeling strategy suggests that large-scale tectonic forcing plays the primary role in landscape evolution. One corollary of the integrative solution of the stream-power equation is that precipitation rate becomes influential only if it varies on time scales longer than similar to 1 Ma. We conclude that calibrated inverse modeling of river profiles is a fruitful method for investigating landscape evolution and for testing source-to-sink models. Plain Language Summary There is excellent geologic evidence that large portions of the African landscape were lifted up above sea level over the last 30 million years by upward flow of hot mantle rocks beneath the tectonic plate. The strongest evidence comes from marine deposits which contain fossil fish and sea snakes that are now perched at elevations of hundreds of meters in the middle of the North African desert. Mantle processes gave rise to an egg-carton pattern of gigantic swells and depressions that characterizes much of the continent. As the landscape evolved, it was sculpted and eroded by the action of massive rivers such as the Niger, the Nile and the Congo. Height along the length of each of these rivers varies and appears to preserve a memory of landscape growth. In that sense, rivers appear to act as tape recorders of tectonic processes such as mantle flow. Here, we use computer simulations of an evolving landscape to test the idea that rivers contain mantle memories. These simulations, which include complexities such as variable rainfall, allow rivers to develop naturally as landscapes grow. Our results suggest that the African landscape and its drainage patterns contain valuable information about deep Earth processes. Key Points Continent-wide inventories of longitudinal river profiles preserve recoverable signals of regional uplift Tectonically forced landscape simulations enable testing of inverse modeling strategies Closed-loop modeling suggests that fluvial landscapes are dominated by tectonic forcing
英文关键词	Africa river profile neogene landscape evolution sedimentary flux drainage
类型	Article
语种	英语
开放获取类型	Bronze
收录类别	SCI-E
WOS记录号	WOS:000757163400002
WOS关键词	CRETACEOUS-TERTIARY BOUNDARY ; GRAIN-SIZE DISTRIBUTIONS ; SURFACE-WAVE TOMOGRAPHY ; APATITE FISSION-TRACK ; STREAM POWER EQUATION ; SOUTH-AFRICA ; CONTINENTAL-MARGIN ; WEST-AFRICAN ; HYDROLOGICAL CHANGES ; SEDIMENT TRANSPORT
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/375699
作者单位	[O'Malley, C. P. B.; White, N. J.; Stephenson, S. N.] Univ Cambridge, Dept Earth Sci, Bullard Labs, Cambridge, England; [O'Malley, C. P. B.; Roberts, G. G.] Imperial Coll London, Dept Earth Sci & Engn, London, England; [Stephenson, S. N.] Univ Oxford, Dept Earth Sci, Oxford, England
推荐引用方式 GB/T 7714	O'Malley, C. P. B.,White, N. J.,Stephenson, S. N.,et al. Large-Scale Tectonic Forcing of the African Landscape[J],2021,126(12).
APA	O'Malley, C. P. B.,White, N. J.,Stephenson, S. N.,&Roberts, G. G..(2021).Large-Scale Tectonic Forcing of the African Landscape.JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE,126(12).
MLA	O'Malley, C. P. B.,et al."Large-Scale Tectonic Forcing of the African Landscape".JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE 126.12(2021).