scholarly journals Regional Stratigraphic Framework of Surficial Sediments and Bedrock Beneath Lake Ontario

2007 ◽  
Vol 47 (3) ◽  
pp. 337-352 ◽  
Author(s):  
D. R. Hutchinson ◽  
C.F. Michael Lewis ◽  
G. E. Hund
Keyword(s):  
Single Channel ◽  
Lake Ontario ◽  
Water Levels ◽  
Lake Area ◽  
Surficial Sediments ◽  
Upper Great Lakes ◽  
Bedrock Surface ◽  
High Level ◽  
Seismic Reflection Profiles ◽  
Seismic Reflections

ABSTRACT Approximately 2550 km of single-channel high-resolution seismic reflection profiles have been interpreted and calibrated with lithological and geochronological information from four representative piston cores and one grab sample to provide a regional stratigraphie framework for the subbottom deposits of Lake Ontario. Five units overlying Paleozoic bedrock were identified and mapped. These are classified as informal units and represent, from oldest to youngest: (A) subglacial till (?) deposited by the Port Huron ice at the end of the Wisconsin glaciation; (B) an ice-marginal (?) unit confined to the western part of the lake that was probably deposited during retreat of the Port Huron ice shortly after 13 ka; (C) a regionally extensive unit of laminated glacio-lacustrine clay that accumulated until about 11 ka; (D) a weakly laminated to more massive lake clay deposited during a period of reduced water supply and rising water levels after the drawdown of the high-level glacial lakes (Iroquois and successors); and (E) modern lake clay less than 10 m thick that began accumulating around 6-8 ka with the subsequent return of upper Great Lakes drainage through the Ontario basin. Seismic reflections also define the configuration of the bedrock surface and pre-glacial stream valleys incised in the bedrock surface. Several anomalous bottom and subbottom features in the surficial sediments are mapped, such as discontinuous and offset reflections, furrows, gas pockets, and areas of large subbottom relief. None of these features appear to be spatially correlative with the diffuse seismicity that characterizes the lake area or with deeper structures such as Paleozoic bedrock faults or crustal-penetrating faults in the Precambrian basement.

The geological structure and distribution of Paleozoic rocks on the Avalon Platform, offshore Newfoundland

1987 ◽  
Vol 24 (7) ◽  
pp. 1412-1420 ◽  
Author(s):  
P. W. Durling ◽  
J. S. Bell ◽  
G. B. J. Fader
Keyword(s):  
Seismic Reflection ◽  
Single Channel ◽  
Geological Structure ◽  
Structural Mapping ◽  
Grand Banks ◽  
Seismic Reflection Profiles ◽  
Paleozoic Rocks ◽  
Seismic Reflections ◽  
Avalon Peninsula ◽  
Overthrust Belt

Single-channel seismic reflection profiles obtained across the Avalon Platform, offshore Avalon Peninsula, Newfoundland, have been studied for seismic reflections and interpreted in conjunction with lithologic and biostratigraphic data. Formline structural mapping revealed a 4000 m thick Ordovician–Silurian marine shale sequence that is gently folded about north-northwest–south-southeast axes and is unconformably overlain by a synclinal outlier of Devonian(?) redbeds approximately 700 m thick.The Avalon Platform on the Grand Banks may represent a mildly deformed Acadian terrane, which is contiguous with onshore Avalonian sequences, or it may be part of a foreland zone adjacent to an overthrust belt, or both.

A Confrontation between Two Doctrines: The Birth of Struggle for Hegemony in Hebrew Children's Literature during the 1930s and 1940s

2008 ◽  
Vol 1 (2) ◽  
pp. 139-155 ◽  
Author(s):  
YAEL DARR
Keyword(s):  
Children's Literature ◽  
Educational System ◽  
Single Channel ◽  
Children’S Literature ◽  
The Political ◽  
Literary Creation ◽  
History Of ◽  
High Level ◽  
First Time ◽  
Literary Quality

This article describes a crucial and fundamental stage in the transformation of Hebrew children's literature, during the late 1930s and 1940s, from a single channel of expression to a multi-layered polyphony of models and voices. It claims that for the first time in the history of Hebrew children's literature there took place a doctrinal confrontation between two groups of taste-makers. The article outlines the pedagogical and ideological designs of traditionalist Zionist educators, and suggests how these were challenged by a group of prominent writers of adult poetry, members of the Modernist movement. These writers, it is argued, advocated autonomous literary creation, and insisted on a high level of literary quality. Their intervention not only dramatically changed the repertoire of Hebrew children's literature, but also the rules of literary discourse. The article suggests that, through the Modernists’ polemical efforts, Hebrew children's literature was able to free itself from its position as an apparatus controlled by the political-educational system and to become a dynamic and multi-layered field.

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling
Keyword(s):  
Water Level ◽  
Bronze Age ◽  
Environmental Changes ◽  
High Water ◽  
Alluvial Fan ◽  
Water Levels ◽  
Lake Area ◽  
Dune Field ◽  
The North ◽  
Sand Drift

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

Impact of Oligotrophication, Temperature, and Water Levels on Walleye Habitat in the Bay of Quinte, Lake Ontario

2004 ◽  
Vol 133 (4) ◽  
pp. 868-879 ◽  
Author(s):  
C. Chu ◽  
C. K. Minns ◽  
J. E. Moore ◽  
E. S. Millard
Keyword(s):  
Lake Ontario ◽  
Water Levels

Rare earth element concentrations in Quaternary volcanic rocks of southwestern British Columbia

1984 ◽  
Vol 21 (6) ◽  
pp. 731-736 ◽  
Author(s):  
Nathan L. Green ◽  
Paul Henderson
Keyword(s):  
British Columbia ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Lake Area ◽  
Calc Alkaline ◽  
Lower Light ◽  
The Individual ◽  
High Level ◽  
Ree Patterns

A suite of hy-normative hawaiites, ne-normative mugearite, and calc-alkaline andesitic rocks from the Garibaldi Lake area exhibits fractionated, slightly concave-upward REE patterns (CeN/YbN = 4.5–15), heavy REE contents about 5–10 times the chondritic abundances, and no Eu anomalies. It is unlikely that the REE patterns provide information concerning partial melting conditions beneath southwestern British Columbia because they have probably been modified substantially by upper crustal processes including crustal contamination and (or) crystal fractionation. The REE contents of the Garibaldi Lake lavas are not incompatible with previous interpretations that (1) the hawaiites have undergone considerable fractionation of olivine, plagioclase, and clinopyroxene; and (2) the individual andesitic suites were derived from separate batches of chemically distinct magma that evolved along different high-level crystallization trends. In general, however, the andesites are characterized by lower light REE contents than the basaltic andesites. These differences in LREE abundances may reflect different amounts of LREE-rich accessory phases, such as apatite, sphene, or allanite, assimilated from the underlying quartz diorites.

scholarly journals Identification of optimum segment in single channel EEG biometric system

2021 ◽  
Vol 23 (3) ◽  
pp. 1847
Author(s):  
Muhammad Afif Hendrawan ◽  
Pramana Yoga Saputra ◽  
Cahya Rahmad
Keyword(s):  
Single Channel ◽  
Support Vector ◽  
Discrete Wavelet ◽  
Eeg Signal ◽  
Alpha Band ◽  
Biometric System ◽  
Linear Discriminant ◽  
Power Spectral ◽  
Eyes Open ◽  
High Level

Nowadays, biometric modalities have gained popularity in security systems. Nevertheless, the conventional commercial-grade biometric system addresses some issues. The biggest problem is that they can be imposed by artificial biometrics. The electroencephalogram (EEG) is a possible solution. It is nearly impossible to replicate because it is dependent on human mental activity. Several studies have already demonstrated a high level of accuracy. However, it requires a large number of sensors and time to collect the signal. This study proposed a biometric system using single-channel EEG recorded during resting eyes open (EO) conditions. A total of 45 EEG signals from 9 subjects were collected. The EEG signal was segmented into 5 second lengths. The alpha band was used in this study. Discrete wavelet transform (DWT) with Daubechies type 4 (db4) was employed to extract the alpha band. Power spectral density (PSD) was extracted from each segment as the main feature. Linear discriminant analysis (LDA) and support vector machine (SVM) were used to classify the EEG signal. The proposed method achieved 86% accuracy using LDA only from the third segment. Therefore, this study showed that it is possible to utilize single-channel EEG during a resting EO state in a biometric system.

Acoustic interpretation of Quaternary sedimentation and erosion on the channelled upper Laurentian Fan, Atlantic margin of Canada

1982 ◽  
Vol 19 (10) ◽  
pp. 1974-1984 ◽  
Author(s):  
David J. W. Piper ◽  
William R. Normark
Keyword(s):  
Single Channel ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Survey Area ◽  
Overbank Sediments ◽  
Abandoned Channel ◽  
Acoustic Facies ◽  
Seismic Reflection Profiles ◽  
Atlantic Margin ◽  
To Receive

About 1000 km of single-channel seismic-reflection profiles from a 50 km × 100 km area on the upper Laurentian Fan shows no evidence of the large slumps interpreted by previous workers in this area. Our detailed profile grid indicates that slump-like masses are commonly in depositional continuity with definite autochthonous sediments, and surfaces previously interpreted as slide planes are either facies changes or the result of valley-wall erosion. Only a few small slump blocks of relatively consolidated sediment are found on the uppermost fan. Acoustic-facies distribution shows a single Early (?) Pleistocene fan valley crossing the northeast part of the survey area with thick overbank sediments to the southwest. In the middle (?) Pleistocene this valley became incised. Its upper reaches then ceased to receive sediment, and a new valley was cut extending southward from the upper slope and intercepting the lower reaches of the old fan valley. This channel diversion was probably related either to the glacial excavation of the Laurentian Channel or to a major slump scar that formed east of the survey area. Most of the old abandoned channel was plugged by overbank deposits from the new master channel. Two other valleys farther west also developed at this time or somewhat earlier. In Late Pleistocene time, all three valleys were incised and more than 1 km of sedimentary material was stripped from much of the uppermost part of the fan, probably as a result of headward erosion of submarine canyons and general thalweg lowering.

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