Inverted topography in the southeastern part of the Western Desert of Egypt

Zaki, Abdallah S.; Giegengack, Robert

doi:10.1016/j.jafrearsci.2016.05.020

Cited by 48 publications

(6 citation statements)

References 11 publications

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“…Combining these data with ground-truth investigation has revealed recurrent cut-and-fill features, including inverted paleotopography evidenced by inverted fluvial channels that parallel those documented for Utah, Egypt, Australia, and China (see refs. 33 and 34 for reviews) and even Mars ( 35 , 36 ) ( Fig. 1 and SI Appendix , Figs.…”

Section: Resultsmentioning

confidence: 99%

Integrative geochronology calibrates the Middle and Late Stone Ages of Ethiopia’s Afar Rift

Niespolo

WoldeGabriel

Renne

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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The Halibee member of the Upper Dawaitoli Formation of Ethiopia’s Middle Awash study area features a wealth of Middle and Later Stone Age (MSA and LSA) paleoanthropological resources in a succession of Pleistocene sediments. We introduce these artifacts and fossils, and determine their chronostratigraphic placement via a combination of established radioisotopic methods and a recently developed dating method applied to ostrich eggshell (OES). We apply the recently developed 230Th/U burial dating of OES to bridge the temporal gap between radiocarbon (14C) and 40Ar/39Ar ages for the MSA and provide 14C ages to constrain the younger LSA archaeology and fauna to ∼24 to 21.4 ka. Paired 14C and 230Th/U burial ages of OES agree at ∼31 ka for an older LSA locality, validating the newer method, and in turn supporting its application to stratigraphically underlying MSA occurrences previously constrained only by a maximum 40Ar/39Ar age. Associated fauna, flora, and Homo sapiens fossils are thereby now fixed between 106 ± 20 ka and 96.4 ± 1.6 ka (all errors 2σ). Additional 40Ar/39 results on an underlying tuff refine its age to 158.1 ± 11.0 ka, providing a more precise minimum age for MSA lithic artifacts, fauna, and H. sapiens fossils recovered ∼9 m below it. These results demonstrate how chronological control can be obtained in tectonically active and stratigraphically complex settings to precisely calibrate crucial evidence of technological, environmental, and evolutionary changes during the African Middle and Late Pleistocene.

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Section: Resultsmentioning

confidence: 99%

Integrative geochronology calibrates the Middle and Late Stone Ages of Ethiopia’s Afar Rift

Niespolo

WoldeGabriel

Renne

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…Examples of comparable features in mountainous areas are stepped topography (Wahrhaftig, 1965), terrace development (Ritter, 1967), and inverted river channels in the Sierra Nevada of California (Busby et al, 2016; Giegengack, 1968; Lindgren, 1911; Whitney, 1880). Additional examples have been reported in Africa (Butt & Bristow, 2013; Giegengack & Zaki, 2017; Giegengack, 1968; Zaki & Giegengack, 2016; Zaki et al, 2018); Australia (Kemp & Rhodes, 2010); Europe (Cuevas et al, 2010; Friend et al, 1981); and North America (Williams et al, 2007). Inverted channels have been important in the study of past climate, in relation to paleo‐drainage systems (Williams et al, 2007; Williams et al, 2009; Zaki et al, 2020).…”

Section: Introductionmentioning

confidence: 94%

Earthen ridges in coastal sand dunes of the Caribbean coast, Venezuela: Anthropogenic or natural?

et al. 2020

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Earthen ridges that occur in the active Los Médanos de Coro dune fields of the Venezuelan Caribbean coast have been attributed either to anthropogenic or natural origins. Anthropogenic explanations have focused on their location, geometry, structure, and compaction, in the context of archaeological sites and artifacts throughout the dunes, to suggest an origin as causeways built by the extinct Caquetío people and/or their pre‐Hispanic ancestors. To assess this topic, geomorphic, physicochemical, and elemental analyses were carried out on the ridges and interdunal beaches and playas. The configuration, elevation, and composition of the ridges, along with three bulk sediment 14C dates that range 1900–3000 year BP, are here found to be most compatible with a natural origin as exhumed paleochannels. Past human occupants may, however, have used the features as causeways.

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“…Sediment deposited in these rivers now stands as ridges in the landscape (e.g., Giegengack & Zaki, 2017 ). Most of these paleorivers were developed on consolidated sedimentary quartzite, the “Nubia Formation”, deposited during the late Cretaceous time (Said & Issawi, 1964 ; Zaki & Giegengack, 2016 ). The Nubia Formation consists of detrital quartzite, derived mainly from the African Shield (Giegengack & Zaki, 2017 ).…”

Section: Regional Settingmentioning

confidence: 99%

“…A snapshot of this record is well‐preserved in southern Egypt, where ancient riverbeds and fans survive as inverted topography in the modern landscape. These landforms occur over an ∼38,000 km 2 region on the western and eastern sides of Lake Nasser (Figure 2 ; Zaki & Giegengack, 2016 ; Giegengack & Zaki, 2017 ). These landforms are well‐preserved in inverted topography, taking different forms, including fine‐branched ridges, single‐thread ridges, and sedimentary fans (bearing inverted channel forms).…”

Section: Introductionmentioning

confidence: 99%

Fluvial Depositional Systems of the African Humid Period: An Analog for an Early, Wet Mars in the Eastern Sahara

et al. 2022

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A widely hypothesized but complex transition from widespread fluvial activity to predominantly aeolian processes is inferred on Mars based on remote sensing data observations of ancient landforms. However, the lack of analysis of in situ martian fluvial deposits hinders our understanding of the flow regime nature and sustainability of the martian fluvial activity and the hunt for ancient life. Studying analogs from arid zones on Earth is fundamental to quantitatively understanding geomorphic processes and climate drivers that might have dominated during early Mars. Here we investigate the formation and preservation of fluvial depositional systems in the eastern Sahara, where the largest arid region on Earth hosts important repositories of past climatic changes. The fluvial systems are composed of well-preserved single-thread sinuous to branching ridges and fan-shaped deposits interpreted as deltas. The systems' configuration and sedimentary content suggest that ephemeral rivers carved these landforms by sequential intermittent episodes of erosion and deposition active for 10-100s years over ∼10,000 years during the late Quaternary. Subsequently, these landforms were sculpted by a marginal role of rainfall and aeolian processes with minimum erosion rates of 1.1 ± 0.2 mm/yr, supplying ∼96 ± 24 × 10 10 m 3 of disaggregated sediment to adjacent aeolian dunes. Our results imply that similar martian fluvial systems preserving single-thread, short distance source-to-sink courses may have formed due to transient drainage networks active over short durations. Altogether, this study adds to the growing recognition of the complexity of interpreting climate history from orbital images of landforms.Plain Language Summary Mars is currently a dry and cold desert, but rivers preserved in inverted topography suggest that water once flowed during its early history. However, how sustained and how frequently these rivers flowed remains uncertain. Here we study ancient fluvial systems (rivers and deltas) from the eastern Sahara that formed during the late Quaternary, in much wetter conditions than those prevailing today in this desert and which bear striking analogies to martian systems. We find that rivers and deltas, now preserved as ridges, record short distance source-to-sink high-energy systems formed due to heavy rainfall events. Our observations and measurements of the meandering systems within the deltaic features suggest that such wet conditions might have spanned tens to a few hundred years over a total duration of ∼10,000 years. Since the wet conditions ceased, arid conditions prevailed, and the aeolian processes resumed, sculpting ridges out of ancient channels. Our results imply that martian fluvial systems may have been associated with similar local and heavy runoff conditions that lasted 10-100s years over thousands of years, possibly sufficient to support habitability. A shift toward arid environments led to the sculpting of fluvial ridges and the widespread formation of dunes across the modern martian landscape.

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Inverted topography in the southeastern part of the Western Desert of Egypt

Cited by 48 publications

References 11 publications

Integrative geochronology calibrates the Middle and Late Stone Ages of Ethiopia’s Afar Rift

Integrative geochronology calibrates the Middle and Late Stone Ages of Ethiopia’s Afar Rift

Earthen ridges in coastal sand dunes of the Caribbean coast, Venezuela: Anthropogenic or natural?

Fluvial Depositional Systems of the African Humid Period: An Analog for an Early, Wet Mars in the Eastern Sahara

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