Multi-thread river channels: A perspective on changing European alpine river systems

2009 ◽  
Vol 71 (3) ◽  
pp. 253-265 ◽  
Author(s):  
Angela Gurnell ◽  
Nicola Surian ◽  
Luca Zanoni
2019 ◽  
Vol 33 (21) ◽  
pp. 2804-2823 ◽  
Author(s):  
Stefano Brighenti ◽  
Monica Tolotti ◽  
Maria Cristina Bruno ◽  
Michael Engel ◽  
Geraldene Wharton ◽  
...  

2014 ◽  
Vol 1 ◽  
pp. 6-31
Author(s):  
Nora Nieminski ◽  
Cari Johnson

Range Creek Canyon, located within the Book Cliffs of eastern Utah, contains some of the most abundant and well-preserved archaeological sites in North America. Its cliffs and landscapes provide a canvas for rock art panels and a foundation for granaries, ruins, and artifacts of the prehistoric Fremont Indians. In order to place these Range Creek sites within a geologic context, an illustrated geologic field guide was created for the general public. The guide focuses on the major bedrock formations that crop out in the canyon, as well as many indicators that facilitate geologic interpretation of these rocks. Outcrops of the Paleogene Flagstaff and Colton Formations (~58 to 48 million years old) in Range Creek Canyon were investigated in order to interpret their depositional environments. The lacustrine Flagstaff Limestone contains limestone beds and fossils of freshwater gastropods, oysters, and turtles indicative of lake environments. The unit coarsens upward with an increase of interbedded sandstone, which was deposited in and near ancient river channels. This trend suggests dynamic levels of the ancient lake, with overall encroachment of river systems near the contact with the Colton Formation. The fluvial Colton Formation is characterized by discontinuous, stacked beds of sandstone, representing a succession of migrating river channels and floodplain deposits. The Colton Formation exhibits a general upward trend of increased grain size and increased channel belt (continuous sandstone beds) frequency and lateral extent, implying a transition to higher energy river systems through time. These dynamic, ancient rivers may have been flowing generally northward into Eocene Lake Uinta, recorded in deposits of the Green River Formation north of Range Creek Canyon.


2015 ◽  
Vol 41 (3) ◽  
pp. 137-144
Author(s):  
Hakimeh Amanipoor

The mountain generation in Iran is because of continental collision between the Arabian and Eur-asia plate. Southwestern Iran shows active shorten that its evidences is deformation of crust and frequent earthquakes. At depth, active basement of the Zagros fold-thrust-belt in southwestern Iran, which are covered by folding of the Phanerozoic sediments, affected by some blind thrusted faults that have seismic nature. The Zagros fold-thrust-belt can be divided into 4 lithotectonic units including Sanandaj-Sirjan Zone (SSZ), Imbricate Zone (IZ), Zagros Fold Belt (ZFB), and Molasse Cover Sequence (MCS); this dividing and classification is based on geomorphology landscape, drainage pattern, rate of tectonics and stratigraphic records. Each tectonic unit characterized by especial abnormal forces in river systems. Active tectonics has the most important role to control the river systems by changing of channels incline. Change in the drainage pattern, channels cut, longitudinal profile, anomalous changes of sinuosity, changing of the side form and forming of terrace, change of river direction, compact meanders, cutting of meanders and geomorphology features of the rivers are responds to the active tectonics of region that are studied using remote sensing, DEM and field observations. These parameters are used to understand the vertical movement in the study area. Existing structures, especially growing anticlines and blind thrusted faults in the Zagros fold-thrust-belt, which cut the river channels and sometimes put them in parallel, are used in the study of their effect on the longitudinal and transverse tilt of morphological changes.


2014 ◽  
Vol 1 ◽  
pp. 6-31
Author(s):  
Nora M. Nieminski ◽  
Cari L. Johnson

Range Creek Canyon, located within the Book Cliffs of eastern Utah, contains some of the most abundant and well-preserved archaeological sites in North America. Its cliffs and landscapes provide a canvas for rock art panels and a foundation for granaries, ruins, and artifacts of the prehistoric Fremont Indians. In order to place these Range Creek sites within a geologic context, an illustrated geologic field guide was created for the general public. The guide focuses on the major bedrock formations that crop out in the canyon, as well as many indicators that facilitate geologic interpretation of these rocks. Outcrops of the Paleogene Flagstaff and Colton Formations (~58 to 48 million years old) in Range Creek Canyon were investigated in order to interpret their depositional environments. The lacustrine Flagstaff Limestone contains limestone beds and fossils of freshwater gastropods, oysters, and turtles indicative of lake environments. The unit coarsens upward with an increase of interbedded sandstone, which was deposited in and near ancient river channels. This trend suggests dynamic levels of the ancient lake, with overall encroachment of river systems near the contact with the Colton Formation. The fluvial Colton Formation is characterized by discontinuous, stacked beds of sandstone, representing a succession of migrating river channels and floodplain deposits. The Colton Formation exhibits a general upward trend of increased grain size and increased channel belt (continuous sandstone beds) frequency and lateral extent, implying a transition to higher energy river systems through time. These dynamic, ancient rivers may have been flowing generally northward into Eocene Lake Uinta, recorded in deposits of the Green River Formation north of Range Creek Canyon.


2007 ◽  
Vol 17 (6) ◽  
pp. 636-656 ◽  
Author(s):  
David M. Hannah ◽  
Lee E. Brown ◽  
Alexander M. Milner ◽  
Angela M. Gurnell ◽  
Glenn R. McGregor ◽  
...  
Keyword(s):  

2017 ◽  
Vol 43 ◽  
pp. 57-63 ◽  
Author(s):  
Monica Papini ◽  
Vladislav Ivov Ivanov ◽  
Davide Brambilla ◽  
Diego Arosio ◽  
Laura Longoni

Author(s):  
Gražina ŽIBIENĖ ◽  
Alvydas ŽIBAS ◽  
Goda BLAŽAITYTĖ

The construction of dams in rivers negatively affects ecosystems because dams violate the continuity of rivers, transform the biological and physical structure of the river channels, and the most importantly – alter the hydrological regime. The impact on the hydrology of the river can occur through reducing or increasing flows, altering seasonality of flows, changing the frequency, duration and timing of flow events, etc. In order to determine the extent of the mentioned changes, The Indicators of Hydrologic Alteration (IHA) software was used in this paper. The results showed that after the construction of Angiriai dam, such changes occurred in IHA Parameters group as: the water conditions of April month decreased by 31 %; 1-day, 3-days, 7-days and 30-days maximum flow decreased; the date of minimum flow occurred 21 days later; duration of high and low pulses and the frequency of low pulses decreased, but the frequency of high pulses increased, etc. The analysis of the Environmental Flow Components showed, that the essential differences were recorded in groups of the small and large floods, when, after the establishment of the Šušvė Reservoir, the large floods no longer took place and the probability of frequency of the small floods didn’t exceed 1 time per year.


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