A chronology of alluvial fan response to Late Quaternary sea level and climate change, Crete

Pope, Richard J.; Candy, Ian; Skourtsos, Emmanuel

doi:10.1016/j.yqres.2016.06.003

Cited by 27 publications

(44 citation statements)

References 54 publications

(135 reference statements)

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“…We surveyed LW retention and reach‐scale parameters in 37 reaches of steep, nonperennial streams with well‐developed alluvial banks suggesting a regular surface flow regime within 13 catchments to cover a variety of channel and valley configurations and the composition of riparian vegetation in the Lefka Ori Mountains and their foothills (western Crete, Greece; Figure ). The majority of the region is underlain by crystalline Mesozoic limestone, which turns into the karstic hydrological regime of local aquifers (Pope et al, ; Skourtsos et al, ). Local precipitation displays a highly seasonal distribution, with more than 90% of the average annual precipitation falling between October and March (Koutroulis et al, ; Perry, ).…”

Section: Study Areamentioning

confidence: 99%

Drivers of Low Instream Large Wood Retention and Imprints of Wood Mobility in Mountain Nonperennial Streams of a Mediterranean Semiarid Environment

Galia

Horáček

Macurová

et al. 2019

Water Resources Research

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The majority of research on instream large wood (LW) focuses on perennial streams in temperate zones, and much less is known about wood distribution and its driving factors in other environments, such as semiarid bioclimatic regions. In this study, we sought to predict LW retention by assessing reach‐scale variables to infer the influence of external factors on the presence of LW in 37 independent reaches of ephemeral and intermittent streams draining a mountain range in a Mediterranean semiarid environment (Lefka Ori Mountains, Crete, Greece). In addition, we focused on LW pieces that had been mobilized by fluvial transport to find links between wood mobility and the external reach‐scale characteristics of this environment. Markedly low average LW frequency (6.5 LW/100 m) and volume (9.06 m3/ha) were observed in the studied reaches in comparison with streams draining other bioclimatic regions. Only one complex general linear model was found to predict LW volume (including valley confinement and basal area of coniferous trees), and five explanatory variables (elevation as a proxy of annual precipitation, valley type, valley confinement index, basal area of coniferous trees, and basal area of all trees) were significant in separated models predicting LW volume. Only two variables (valley floor width and the basal area of broadleaf trees) were significant in separated models for prediction of LW frequency. The mobilized LW in the studied streams tends to be stored as individual, dispersed pieces rather than in jams, likely due to overall low LW abundance which effectively prevents clustering of wood.

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Section: Study Areamentioning

confidence: 99%

Drivers of Low Instream Large Wood Retention and Imprints of Wood Mobility in Mountain Nonperennial Streams of a Mediterranean Semiarid Environment

Galia

Horáček

Macurová

et al. 2019

Water Resources Research

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“…Climate in the eastern Mediterranean is generally drier during glacial or stadial intervals relative to the present day, whereas interstadials are thought to be analogous to today's climate (e.g., Tzedakis, 2009). Sediment production is inferred to be higher during much of the late Quaternary relative to the modern production, especially during climatic transitions that force variations in hillslope vegetation communities, as evidenced by available geochronology for large alluvial fans along the south coast (e.g., Pope et al, 2008Pope et al, , 2016Wegmann, 2008;Gallen et al, 2014). Most of the rivers draining the Asteroúsia and Díkti mountains are ephemeral.…”

Section: Tectonic Geomorphology Of South-central Cretementioning

confidence: 99%

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

2017

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Abstract. Topography is a reflection of the tectonic and geodynamic processes that act to uplift the Earth's surface and the erosional processes that work to return it to base level. Numerous studies have shown that topography is a sensitive recorder of tectonic signals. A quasi-physical understanding of the relationship between river incision and rock uplift has made the analysis of fluvial topography a popular technique for deciphering relative, and some argue absolute, histories of rock uplift. Here we present results from a study of the fluvial topography from south-central Crete, demonstrating that river longitudinal profiles indeed record the relative history of uplift, but several other processes make it difficult to recover quantitative uplift histories. Prior research demonstrates that the south-central coastline of Crete is bound by a large ( ∼ 100 km long) E-W striking composite normal fault system. Marine terraces reveal that it is uplifting between 0.1 and 1.0 mm yr −1 . These studies suggest that two normal fault systems, the offshore Ptolemy and onshore South-Central Crete faults, linked together in the recent geologic past (ca. 0.4-1 My BP). Fault mechanics predict that when adjacent faults link into a single fault the uplift rate in footwalls of the linkage zone will increase rapidly. We use this natural experiment to assess the response of river profiles to a temporal jump in uplift rate and to assess the applicability of the stream power incision model to this setting. Using river profile analysis we show that rivers in south-central Crete record the relative uplift history of fault growth and linkage as theory predicts that they should. Calibration of the commonly used stream power incision model shows that the slope exponent, n, is ∼ 0.5, contrary to most studies that find n ≥ 1. Analysis of fluvial knickpoints shows that migration distances are not proportional to upstream contributing drainage area, as predicted by the stream power incision model. Maps of the transformed stream distance variable, χ, indicate that drainage basin instability, drainage divide migration, and river capture events complicate river profile analysis in south-central Crete. Waterfalls are observed in southern Crete and appear to operate under less efficient and different incision mechanics than assumed by the stream power incision model. Drainage area exchange and waterfall formation are argued to obscure linkages between empirically derived metrics and quasi-physical descriptions of river incision, making it difficult to quantitatively interpret rock uplift histories from river profiles in this setting. Karst hydrology, break down of assumed drainage area discharge scaling, and chemical weathering might also contribute to the failure of the stream power incision model to adequately predict the behavior of the fluvial system in south-central Crete.

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Section: Climatic and Geomorphic Settingmentioning

confidence: 99%

Response to review by Dr. Sarah Boulton

Gallen¹

2016

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Topography is a reflection of the tectonic and geodynamic processes that act to uplift the Earth's surface and the erosional processes that work to return it to base level. Numerous studies have shown that topography is a sensitive recorder of tectonic signals. A quasi-physical understanding of the relationship between river incision and rock uplift has made the analysis of fluvial topography a popular technique for deciphering relative, and some argue absolute, histories of rock uplift. Here we present results from a study of the fluvial topography from south-central Crete, demonstrating that river longitudinal profiles indeed record the relative history of uplift, but several other processes make it difficult to recover quantitative uplift histories. Prior research demonstrates that the south-central coastline of Crete is bound by a large ( ∼ 100 km long) E-W striking composite normal fault system. Marine terraces reveal that it is uplifting between 0.1 and 1.0 mm yr −1 . These studies suggest that two normal fault systems, the offshore Ptolemy and onshore South-Central Crete faults, linked together in the recent geologic past (ca. 0.4-1 My BP). Fault mechanics predict that when adjacent faults link into a single fault the uplift rate in footwalls of the linkage zone will increase rapidly. We use this natural experiment to assess the response of river profiles to a temporal jump in uplift rate and to assess the applicability of the stream power incision model to this setting. Using river profile analysis we show that rivers in south-central Crete record the relative uplift history of fault growth and linkage as theory predicts that they should. Calibration of the commonly used stream power incision model shows that the slope exponent, n, is ∼ 0.5, contrary to most studies that find n ≥ 1. Analysis of fluvial knickpoints shows that migration distances are not proportional to upstream contributing drainage area, as predicted by the stream power incision model. Maps of the transformed stream distance variable, χ, indicate that drainage basin instability, drainage divide migration, and river capture events complicate river profile analysis in south-central Crete. Waterfalls are observed in southern Crete and appear to operate under less efficient and different incision mechanics than assumed by the stream power incision model. Drainage area exchange and waterfall formation are argued to obscure linkages between empirically derived metrics and quasi-physical descriptions of river incision, making it difficult to quantitatively interpret rock uplift histories from river profiles in this setting. Karst hydrology, break down of assumed drainage area discharge scaling, and chemical weathering might also contribute to the failure of the stream power incision model to adequately predict the behavior of the fluvial system in south-central Crete.

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A chronology of alluvial fan response to Late Quaternary sea level and climate change, Crete

Cited by 27 publications

References 54 publications

Drivers of Low Instream Large Wood Retention and Imprints of Wood Mobility in Mountain Nonperennial Streams of a Mediterranean Semiarid Environment

Drivers of Low Instream Large Wood Retention and Imprints of Wood Mobility in Mountain Nonperennial Streams of a Mediterranean Semiarid Environment

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

Response to review by Dr. Sarah Boulton

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