Fluviatile deposits and morphology of alluvial surfaces as indicators of Quaternary environmental changes in the southern Negev, Israel

Grossman, Sari; Gerson, Ran

doi:10.1144/gsl.sp.1987.035.01.03

Cited by 11 publications

(11 citation statements)

References 11 publications

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“…Therefore, they followed others and assumed that the Pleistocene-Holo cene transition in the Eilat area was, respectively, a change from a wetter to a drier (and/or warmer) climate (Bull and Schick, 1979, p. 154). This assumption was also the basis of other studies, such as those by Gerson (1982) and Grossman and Gerson (1987), who analyzed hyperarid Negev Desert landforms. Bull and Schick (1979) emphasized that the time, type, or magnitude of this climate change could not be easily quantifi ed.…”

Section: Paleoclimate Of the Southern Negevmentioning

confidence: 67%

Late Quaternary weathering, erosion, and deposition in Nahal Yael, Israel: An "impact of climatic change on an arid watershed"?

Enzel¹,

Amit²,

Grodek³

et al. 2012

Geological Society of America Bulletin

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In their seminal paper in 1979, Bull andSchick proposed a conceptual model for the geomorphic response to Pleistocene to Holocene climate change, based on the hyperarid Nahal Yael watershed in the southern Negev Desert. In this model, the change from semiarid late Pleistocene to hyperarid early Holo cene climates reduced vegetation cover, increased the yield of sediment from slopes, and accelerated aggradation of terraces and alluvial fans. The model is now over 30 yr old, and during this time, chronologic, paleoenvironmental, and hydrogeomorphic research has advanced. Here, we reevaluate the model using data acquired in Nahal Yael over the 30 yr since the original model was proposed. Recent studies indicate that the late Pleistocene climate was hyperarid, and a transition from semiarid to hyperarid climates did not occur. The revised chronology reveals a major 35-20 ka episode of accelerated late Pleistocene sediment production on slopes (with lower rates probably already at ca. 50 ka) due to increased frequency of wetting-drying cycles caused by frequent extreme storms and fl oods between 35 and 27 ka. Without lag time, these sediments were transported and aggraded in depositional landscape components (fl uvial terraces and alluvial fans). This intensifi ed sediment production and delivery phase is unrelated to the Pleistocene-Holocene transition. The depositional landforms were rapidly incised between 20 and 18 ka. Since and/or soon after this Last Glacial Maximum (LGM) incision, most material leaving the basin originated from sediments stored in depositional landforms and was not produced from bedrock.Using these new data, we propose a revision to the Bull and Schick model in this hyperarid environment. Our revision suggests that the model should include the frequent storms and fl oods responsible for a late Pleistocene pulse of intense weathering due to numerous cycles of wetting and drying on slopes and coeval sediment transport to fl uvial terraces and alluvial fans. We also discuss the common use and pitfalls of using the Bull and Schick conceptual model to explain observations in diverse arid environments, usually without suffi cient data on basin-specifi c stratigraphic, chronologic, paleoenvironmental, and paleoclimatic information.

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Section: Paleoclimate Of the Southern Negevmentioning

confidence: 67%

Late Quaternary weathering, erosion, and deposition in Nahal Yael, Israel: An "impact of climatic change on an arid watershed"?

Enzel¹,

Amit²,

Grodek³

et al. 2012

Geological Society of America Bulletin

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“…These surfaces were classified based on their relative elevation, their morphological facies and their color tone, which is mainly indicative of the degree of development of desert pavement and varnish. Three main classes are generally distinguished in the region (e.g., Grossman and Gerson, 1987) and can indeed be identified on the images (Fig. 2).…”

Section: Geomorphic Settingmentioning

confidence: 84%

“…The Dead Sea area has long been recognized as a particularly appropriate area to investigate the geomorphic impact of Late Quaternary climate change (e.g., Grossman and Gerson, 1987;Bull, 1991). The Dead Sea rift has formed a lacustrine closed basin (e.g., Garfunkel et al, 1981).…”

Section: Introductionmentioning

confidence: 99%

Alluvial deposition and lake-level fluctuations forced by Late Quaternary climate change: the Dead Sea case example

Klinger

Avouac

Bourlès

et al. 2003

Sedimentary Geology

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“…In this respect, the deposits differ from those of the western scarp valleys of the Areva, 200 km to the south of the Dead Sea, where debris flows make up part of the Pleistocene river terraces (Grossman & Gerson 1987).…”

mentioning

confidence: 89%

Climatic versus tectonic controls of fan sequences: lessons from the Dead Sea, Israel

Frostick

Reid

1989

JGS

108

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Tectonic activity is commonly held responsible for abrupt coarsening of alluvial fan sequences and the role of climate is often relegated. The Pleistocene fans of the Dead Sea rift indicate clearly the problems of differentiating the sedimentary signatures of climatic and tectonic adjustments in a closed lake basin. Exposures are excellent. The rivers are currently incising in response to the low lake levels of the Holocene, producing cliffs >50m high. These reveal an interdigitation of lake deposits (dominantly fine grained carbonates) and the coarse river gravels which characterize the fan deposits. The bounds of each facies are sharp: river sediments are superimposed on lake sediments with little evidence of either reworking or loading; in turn, aragonite crusts are draped over alluvial gravels indicating the sudden return of still-water conditions. Neither can be explained by gradual adjustment of the hinterland river system after tectonic shock. Instead, it is clear that the coarse alluvium was deposited by discrete high magnitude floods that occurred only sporadically because of the infrequent nature of rainfall in this arid environment. In interpreting basin development in ancient settings, it is always tempting to assume that coarse deposits are indicative of tectonism. However, the Dead Sea fans demonstrate that climate is just as likely to be responsible for the conglomerates in a sedimentary sequence.

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Fluviatile deposits and morphology of alluvial surfaces as indicators of Quaternary environmental changes in the southern Negev, Israel

Cited by 11 publications

References 11 publications

Late Quaternary weathering, erosion, and deposition in Nahal Yael, Israel: An "impact of climatic change on an arid watershed"?

Late Quaternary weathering, erosion, and deposition in Nahal Yael, Israel: An "impact of climatic change on an arid watershed"?

Alluvial deposition and lake-level fluctuations forced by Late Quaternary climate change: the Dead Sea case example

Climatic versus tectonic controls of fan sequences: lessons from the Dead Sea, Israel

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