scholarly journals Diamicton facies in the vicinity of Duhlata cave, Bosnek karst region, Southwestern Bulgaria

2021 ◽  
Vol 82 (3) ◽  
pp. 105-108
Author(s):  
Athanas Chatalov ◽  
Dilyana Hristova
Keyword(s):  
Debris Flows ◽  
Source Area ◽  
Lower Triassic ◽  
Upper Triassic ◽  
Karst Region ◽  
Flood Events ◽  
Red Beds ◽  
Karst Caves ◽  
Rock Types ◽  
Extreme Flood

Karst caverns in the Upper Triassic dolostones of the Rusinovdel Formation are filled with allochthonous clastics (brecciaconglomerates with maximum boulder size) and locally with speleothems (flowstones). Deposition of the former (diamicton facies) by debris flows resulted from extreme flood events along the upper reaches of Struma river. The polymict material reflects erosion of various rock types in the source area but is dominated by resedimented Lower Triassic red beds. The diamictons are more or less similar to the few known examples from Quaternary karst caves.

scholarly journals Ectomycorrhiza resilience and recovery to extreme flood events in Tuber aestivum and Quercus robur

Mycorrhiza ◽  
2021 ◽  
Author(s):  
P. W. Thomas
Keyword(s):  
Climate Change ◽  
Seedling Growth ◽  
Quercus Robur ◽  
Root Systems ◽  
Fruiting Bodies ◽  
Flood Events ◽  
Tuber Aestivum ◽  
Soil Zone ◽  
Extreme Flood ◽  
The Impact

AbstractVery little is known about the impact of flooding and ground saturation on ectomycorrhizal fungi (EcM) and increasing flood events are expected with predicted climate change. To explore this, seedlings inoculated with the EcM species Tuber aestivum were exposed to a range of flood durations. Oak seedlings inoculated with T. aestivum were submerged for between 7 and 65 days. After a minimum of 114-day recovery, seedling growth measurements were recorded, and root systems were destructively sampled to measure the number of existing mycorrhizae in different zones. Number of mycorrhizae did not display correlation with seedling growth measurements. Seven days of submersion resulted in a significant reduction in mycorrhizae numbers and numbers reduced most drastically in the upper zones. Increases in duration of submersion further impacted mycorrhizae numbers in the lowest soil zone only. T. aestivum mycorrhizae can survive flood durations of at least 65 days. After flooding, mycorrhizae occur in higher numbers in the lowest soil zone, suggesting a mix of resilience and recovery. The results will aid in furthering our understanding of EcM but also may aid in conservation initiatives as well as providing insight for those whose livelihoods revolve around the collection of EcM fruiting bodies or cropping of the plant partners.

Stratigraphic correlation of the Permian-Triassic red beds constrained by detrital zircon geochronology: Moscow basin, East European platform

2021 ◽  
Author(s):  
Alvina Chistyakova ◽  
Roman Veselovskiy
Keyword(s):  
Detrital Zircon ◽  
East European Platform ◽  
Lower Triassic ◽  
Detrital Zircons ◽  
Upper Permian ◽  
Stratigraphic Correlation ◽  
Red Beds ◽  
East European ◽  
Moscow Basin ◽  
Stratigraphic Position

<p>There's no doubt that nowadays detrital zircon U-Pb geochronology is actually required method of sedimentary basins analysis. Furthermore, this approach may have a lot of applications, such as a stratigraphic correlation. Here we present the first results of U–Pb LA–ICP–MS dating of detrital zircon from the Permian-Triassic red beds located within the Moscow Basin of the East European platform. Two outcrops have been studied: the Zhukov Ravine P/T boundary reference section and the Nedubrovo strata with uncertain stratigraphic position (uppermost Permian or lower Triassic?).</p><p>U–Pb ages of detrital zircon grains have been obtained for two samples – the Upper Permian and Lower Triassic age, which were taken in the proximity to the Permian–Triassic boundary in the Zhukov Ravine. Corresponding age distributions show contrasting provenance of the studied sedimentary rocks, pointing out that principal change in source of clastic material occurred on the Paleozoic-Mesozoic boundary. It means that detrital zircon U–Pb geochronology can be used as an additional independent tool for stratigraphic correlation of the Permian-Triassic red beds, at least within the Moscow Basin. We demonstrate this in the case of the Nedubrovo section with debated (Permian or Triassic?) stratigraphic position: the obtained data on detrital zircons persuasively suggests Early Triassic age of the Nedubrovo strata.</p><p>This study is supported by the Russian Foundation for Basic Research (project no. 18-05-00593).</p>

Envelope Curves for Extreme Flood Events

1982 ◽  
Vol 108 (10) ◽  
pp. 1208-1212
Author(s):  
John R. Crippen
Keyword(s):  
Flood Events ◽  
Extreme Flood

scholarly journals An 1-D Integrated Hydro-Mechanical Model to Unravel Different Hydrological Triggering Processes of Debris Flows

2018 ◽  
Author(s):  
Theo W.J. van Asch ◽  
Bin Yu ◽  
Wei Hu
Keyword(s):  
Mechanical Model ◽  
Debris Flows ◽  
Overland Flow ◽  
Model Simulation ◽  
Slope Angle ◽  
Great Influence ◽  
Source Area ◽  
Material Model ◽  
Flume Experiments ◽  
Bed Material

Many studies, which try to analyze the meteorological threshold conditions for debris flows ignore the type of initiation. This paper focuses on the differences in hydrological triggering processes of debris flows in channel beds of the source areas. The different triggering processes were studied in the laboratory and by model simulation on the field scale. The laboratory experiments were carried out in a flume, 8 m long and a width of 0.3 m. An integrated hydro-mechanical model was developed, describing Hortonian and Saturation overland flow, through flow, maximum sediment transport and failure of bed material. The model was tested on the processes observed in the flume. The flume experiments show a sequence of hydrological processes triggering debris flows, namely erosion and transport by intensive overland flow and by infiltrating water causing failure of channel bed material. Model simulations carried out on a schematic hypothetical source area of a catchment show that the type and sequence of these triggering processes are determined by slope angle and the hydraulic conductivity of the bed material. It was also clearly demonstrated that the type of initiation process and the geometrical and hydro-mechanical parameters may have a great influence on rainfall intensity-duration threshold curves, indicating the start of debris flows.

scholarly journals Contributions of historical hydrogeomorphology to determine floodable areas from extreme flood events

Huellas ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 11-26
Author(s):  
Volonte Antonela ◽  
◽  
Veronica Gil ◽  
◽  
◽  
...  
Keyword(s):  
Flood Events ◽  
Extreme Flood

Extreme flood events favour floodplain mollusc diversity

Hydrobiologia ◽  
2008 ◽  
Vol 621 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Christiane Ilg ◽  
Francis Foeckler ◽  
Oskar Deichner ◽  
Klaus Henle
Keyword(s):  
Flood Events ◽  
Extreme Flood

Regional Determination of Historical Heavy Rain for Reconstruction of Extreme Flood Events

In Extremis ◽  
2010 ◽  
pp. 90-102
Author(s):  
Paul Dostal ◽  
Florian Imbery ◽  
Katrin Bürger ◽  
Jochen Seidel
Keyword(s):  
Heavy Rain ◽  
Flood Events ◽  
Extreme Flood ◽  
Regional Determination

scholarly journals Brief communication: The curious case of the large wood-laden flow event in the Pocuro stream (Chile)

2017 ◽  
Vol 17 (11) ◽  
pp. 2053-2058 ◽  
Author(s):  
Diego Ravazzolo ◽  
Luca Mao ◽  
Bruno Mazzorana ◽  
Virginia Ruiz-Villanueva
Keyword(s):  
Initial Phase ◽  
Large Wood ◽  
Flood Events ◽  
Additional Source ◽  
Good Opportunity ◽  
Mountain Environments ◽  
Direct Observations ◽  
Extreme Flood ◽  
Large Wood Transport ◽  
Wood Transport

Abstract. Large wood transported during extreme flood events can represent a relevant additional source of hazards that should be taken into account in mountain environments. However, direct observations and monitoring of large-wood transport during floods are difficult and scarce. Here we present a video of a flood characterised by multiple phases of large-wood transport, including an initial phase of wood-laden flow rarely described in the literature. Estimations of flow velocity and transported wood volume provide a good opportunity to develop models of large-wood-congested transport.

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