THE EVOLUTION OF GLACIAL LAKES IN THE WINOOSKI RIVER VALLEY, VERMONT

2018 ◽  
Author(s):  
Stephen F. Wright ◽  
Keyword(s):  
2004 ◽  
Vol 41 (7) ◽  
pp. 881-895 ◽  
Author(s):  
Brent C Ward ◽  
Bruce Thomson

Sediments in lower Chehalis valley span middle Wisconsin (Olympia nonglacial interval) to Holocene time. Sediments are divided into six units with chronological control provided by 14 new radiocarbon ages. Fluvial gravel spans the transition from the late Olympia nonglacial interval to the early Fraser Glaciation. Glaciolacustrine sedimentation represents the first definitive glacial activity in the valley and indicates that Vashon ice in the Fraser Lowland blocked the mouth of the Chehalis valley at ca. 18–17 ka BP. Ice then flowed down the Chehalis valley. The Chehalis valley deglaciated while ice persisted in the Fraser Lowland, forming another lake. After this lake drained, terraces and fans formed. This style of glaciation–deglaciation is typical of many watersheds peripheral to the Fraser Lowland in that local valley ice was slightly out of phase with ice in the lowland. This resulted in glacial lakes forming during both advance and retreat phases. However, in contrast to watersheds in the northwestern Fraser Lowland, no definitive evidence of a Coquitlam ice advance was found within the Chehalis valley. Although glaciers in the area were likely active and advancing, data from the Chehalis valley indicates that they were not as extensive as previously thought. Since ice source areas in the northeastern Fraser Lowland are in the leeward area of the Coast Mountains, it is suggested that lower precipitation resulted in limited glacier activity there during the Coquitlam Stade.


2002 ◽  
Vol 54 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Philip J. Holme ◽  
Stephen R. Hicock ◽  
Lionel E. Jackson

Abstract Surficial geology mapping of the Beaver Mines area, distribution of Canadian Shield erratics, stratigraphy of Quaternary sediments exposed along the Castle River valley and its tributaries and correlation with southwestern Alberta geochronology, indicate that Cordilleran and Laurentide ice were in contact in the lower Castle River valley during the Late Wisconsinan Substage. During this time two Cordilleran glacial advances are recognised in the lower reaches of the valley, its tributaries and the western Interior Plains: 1) an earlier advance (M1), during which ice thickness averaged between 320 - 350 m thick in the Beaver Mines area, and 2) a later readvance (M2). A single Laurentide advance (C2) into the Beaver Mines area was contemporaneous with retreat of Cordilleran ice from the M2 maximum position, resulting in coalescence of the two ice masses. This followed a C1 advance that is recognised outside the area. During montane advances, glaciers were topographically-controlled and efficiently eroded their substrates. Deglaciation was characterised by ice retreat, stagnation of detached ice masses, and damming of glacial lakes by retreating Laurentide ice.


1997 ◽  
Vol 16 (1) ◽  
pp. 133-134
Author(s):  
Joanne M. Westphal
Keyword(s):  

2016 ◽  
Vol 27 (3-4) ◽  
pp. 47-54
Author(s):  
K. K. Holoborodko ◽  
V. O. Makhina ◽  
K. S. Buchnieva ◽  
O. E. Pakhomov

Floodplain valley of the Dnieper river midstream is a unique natural complex, having a great bìogeographical, ecological, environmental, historical and recreational values. In 1990, the Natural reserve «Dniprovsko-Orilsky» was established within the area. The Natural reserve «Dniprovsko-Orilsky» is environmentally protected site within the Dnipropetrovsk region, Dnipropetrovsk oblast, Ukraine. This reserve occupies part of the Dnieper river valley and marshy and reedy banks of Protovch river (existing bed of Oril river). It was created by Regulation of the Council of Ministers of the USSR of 15 September 1990, No. 262, based on common zoological and ornitological Nature reserves «Taromskì plavni» and «Obukhovskie zaplavy». On the territory of the Natural reserve «Dniprovsko-Orilsky», they were registered 32 Lepidoptera species listed in the List of Threatened Species at different categories (5 species in IUCN Red List ; 18 in Red Data Book of Ukraine; 7 in European Red List of plants and animals endangered on a global scale; 31 in Red Book of Dnipropetrovsk oblast). The main scientific materials were author’s collections from area of research and materials of entomological funds, Department of Zoology and Ecology, Oles Honchar Dnipropetrovsk National University (mostly Memorial Collection of V. O. Barsov). Field surveys covered all the ecosystems basic on size and degree of protection. The author’s researches have conducted over the past decade during annual expeditions to the Reserve. Taxonomic structure of the complex is quite diverse, and represented by all the major families of higher millers and rhopalocera, having protectedstatus. In relation to taxonomy, this complex formed by representatives of five superfamilies (Zyganoidea, Noctuoidea, Bombycoidea, Hesperioidea, Papilionoidea) from 11 families (Zygaenidae, Saturniidae, Sphingidae, Noctuidae Arctiidae Hesperiidae, Papilionidae, Pieridae, Nymphalidae, Satyridae, Lycaenidae). High taxonomic diversity can be explained by unique geographical location of the reserve in azonal conditions of the Dnieper river valley. Such location allows to enter different zoogeographic Lepidoptera groups on the reserve territory. Zoogeographic analysis of species protected within the reserve territory selected 7 basic groups. It was found that most of the globally rare species have Mediterranean origin (39 %); species of Palearctic origin are in second place (22 %); Western Palearctic and Ponto-Kazakh types of areas are same of number of species, and come third (11 %); and others come 17 % (European, Euro-Siberian, and Holarctic). This fauna component is specific due to presence of so-called «northern» species that make up 40 % (representatives of Palearctic, Western Palearctic, Euro-Siberian, European and Holarctic groups). Their existence within the reserve territory is only possible due to development of boreal valley ecosystems. High taxonomic diversity can be explained by unique geographical location of the reserve in azonal conditions of the Dnieper river valley. Such location allows to enter different zoogeographic Lepidoptera groups on the reserve territory. Zoogeographic analysis of species protected within the reserve territory selected 7 basic groups. It was found that most of the globally rare species have Mediterranean origin (39 %); species of Palearctic origin are in second place (22 %); Western Palearctic and Ponto-Kazakh types of areas are same of number of species, and come third (11 %); and others come 17 % (European, Euro-Siberian, and Holarctic). This fauna component is specific due to presence of so-called «northern» species that make up 40 % (representatives of Palearctic, Western Palearctic, Euro-Siberian, European and Holarctic groups). Their existence within the reserve territory is only possible due to development of boreal valley ecosystems.


2018 ◽  
Vol 12 (5-6) ◽  
pp. 50-57 ◽  
Author(s):  
I. S. Voskresensky ◽  
A. A. Suchilin ◽  
L. A. Ushakova ◽  
V. M. Shaforostov ◽  
A. L. Entin ◽  
...  

To use unmanned aerial vehicles (UAVs) for obtaining digital elevation models (DEM) and digital terrain models (DTM) is currently actively practiced in scientific and practical purposes. This technology has many advantages: efficiency, ease of use, and the possibility of application on relatively small area. This allows us to perform qualitative and quantitative studies of the progress of dangerous relief-forming processes and to assess their consequences quickly. In this paper, we describe the process of obtaining a digital elevation model (DEM) of the relief of the slope located on the bank of the Protva River (Satino training site of the Faculty of Geography, Lomonosov Moscow State University). To obtain the digital elevation model, we created a temporary geodetic network. The coordinates of the points were measured by the satellite positioning method using a highprecision mobile complex. The aerial survey was carried out using an unmanned aerial vehicle from a low altitude (about 40–45 m). The processing of survey materials was performed via automatic photogrammetry (Structure-from-Motion method), and the digital elevation model of the landslide surface on the Protva River valley section was created. Remote sensing was supplemented by studying archival materials of aerial photography, as well as field survey conducted immediately after the landslide. The total amount of research results made it possible to establish the causes and character of the landslide process on the study site. According to the geomorphological conditions of formation, the landslide refers to a variety of landslideslides, which are formed when water is saturated with loose deposits. The landslide body was formed with the "collapse" of the blocks of turf and deluvial loams and their "destruction" as they shifted and accumulated at the foot of the slope.


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