Revision of the tephrostratigraphy of the lower Sixtymile River area, Yukon Territory, Canada

2011 ◽  
Vol 48 (3) ◽  
pp. 695-701 ◽  
Author(s):  
J. A. Westgate ◽  
S. J. Preece ◽  
L. E. Jackson
Keyword(s):  
Glass Phase ◽  
Fission Track ◽  
Yukon Territory ◽  
The Other ◽  
Middle Pleistocene ◽  
Fine Grained ◽  
Tephra Beds ◽  
Age Determinations

Five distinctive tephra beds are preserved in fine-grained sediments on a prominent terrace strath along the lower Sixtymile River of the Yukon Territory. Commencing with the oldest unit, they are TA, SM3, Gold Run, Hollis 2, and Flat Creek tephra beds. The uppermost three tephra beds have rhyolitic compositions, the other two are bimodal with a much more basic glass phase. Three glass fission-track age determinations point to deposition during the early-Middle Pleistocene. We correct an error in an earlier study by clarifying that Flat Creek tephra is younger than Gold Run tephra, TA tephra is older.

Gold Run tephra: a Middle Pleistocene stratigraphic and paleoenvironmental marker across west-central Yukon Territory, Canada

2009 ◽  
Vol 46 (6) ◽  
pp. 465-478 ◽  
Author(s):  
J. A. Westgate ◽  
S. J. Preece ◽  
D. G. Froese ◽  
A. M. Telka ◽  
J. E. Storer ◽  
...  
Keyword(s):  
Magnetic Polarity ◽  
Yukon Territory ◽  
Middle Pleistocene ◽  
Long Distance ◽  
West Central ◽  
Shrub Tundra ◽  
Chemical Attributes ◽  
Brunhes Chron ◽  
Tephra Beds ◽  
Study Sites

Gold Run tephra has been found at Thistle Creek, Sixtymile River, and the Klondike goldfields of west-central Yukon, Canada. It is a hornblende-bearing rhyolitic tephra with thicknesses of up to 10 cm at each site, suggesting a widespread distribution across interior Alaska and the Yukon Territory, given the long distance to the nearest volcanic centre. Old Crow, Flat Creek, and TA tephra beds are stratigraphically associated with Gold Run tephra at our study sites and have distinctive compositions. Gold Run tephra is not accommodated by the current classification scheme for late Cenozoic distal tephra beds in Alaska and the Yukon Territory — a scheme based on the physical and chemical attributes — so that its provenance is unknown. An early-Middle Pleistocene age is supported by a glass fission-track age of 0.74 ± 0.06 Ma, a normal remanent magnetic polarity for the enclosing loess, and the presence of a late Irvingtonian faunal assemblage in the associated organic-rich silts at Thistle Creek. Hence, Gold Run tephra was deposited during the very early part of the Brunhes Chron, at which time a shrub tundra environment prevailed across west-central Yukon.

Fission-track ages of late Cenozoic distal tephra beds in the Yukon Territory and Alaska

1982 ◽  
Vol 19 (11) ◽  
pp. 2167-2178 ◽  
Author(s):  
Nancy D. Naeser ◽  
John A. Westgate ◽  
Owen L. Hughes ◽  
Troy L. Péwé
Keyword(s):  
Fission Track ◽  
Yukon Territory ◽  
Late Cenozoic ◽  
Geologic History ◽  
Detailed Characterization ◽  
Track Method ◽  
History Of ◽  
Characterization Studies ◽  
Fission Track Ages ◽  
Tephra Beds

Six distal tephra beds from the Yukon Territory and Alaska have been dated by the fission-track method. Zircon and glass ages were determined for the Fort Selkirk and Lost Chicken tephra beds, but only glass ages for the others.Assuming that no track fading has occurred in the glass, Old Crow and Dawson tephra beds are younger than 120 000 and 52 000 years BP, respectively. Mosquito Gulch tephra is 1.22 Ma old, Fort Selkirk tephra is about 1 Ma old, the Ester Ash Bed is 0.45 Ma old, and the best estimate of the age of Lost Chicken tephra is the range 1.7–2.6 Ma.It is evident from these results and from the known abundance of tephra beds within late Cenozoic deposits of the Yukon Territory and Alaska that application of the fission-track method to distal tephra, in conjunction with detailed characterization studies, offers great potential for elucidation of the late Cenozoic geologic history of Alaska and the Yukon Territory.

Paleopathology: Exostoses of the Third Metacarpal in Pleistocene Horses from the Yukon Territory

1975 ◽  
Vol 12 (6) ◽  
pp. 1053-1058 ◽  
Author(s):  
L. P. E. Choquette ◽  
C. R. Harington ◽  
J. Archibald
Keyword(s):  
Late Pleistocene ◽  
Yukon Territory ◽  
The Other ◽  
Middle Pleistocene ◽  
The Third ◽  
Equus Asinus ◽  
Wild Ass

Two third metacarpals from extinct Yukon Pleistocene horses display pathological exostoses. One specimen is from the Yukon wild ass (Equus (Asinus) lambei) of probable late Pleistocene age; the other is from a large horse like Equus (Plesippus) verae, which may be of early middle Pleistocene age or somewhat later.

scholarly journals Neutron Imaging Using a Fine-Grained Nuclear Emulsion

2021 ◽  
Vol 7 (1) ◽  
pp. 4
Author(s):  
Katsuya Hirota ◽  
Tomoko Ariga ◽  
Masahiro Hino ◽  
Go Ichikawa ◽  
Shinsuke Kawasaki ◽  
...  
Keyword(s):  
Image Analysis ◽  
High Resolution ◽  
Neutron Detector ◽  
Nuclear Emulsion ◽  
Neutron Imaging ◽  
The Other ◽  
Crystal Oscillator ◽  
Fine Grained ◽  
Cold Neutrons ◽  
Track Analysis

A neutron detector using a fine-grained nuclear emulsion has a sub-micron spatial resolution and thus has potential to be applied as high-resolution neutron imaging. In this paper, we present two approaches to applying the emulsion detectors for neutron imaging. One is using a track analysis to derive the reaction points for high resolution. From an image obtained with a 9 μm pitch Gd grating with cold neutrons, periodic peak with a standard deviation of 1.3 μm was observed. The other is an approach without a track analysis for high-density irradiation. An internal structure of a crystal oscillator chip, with a scale of approximately 30 μm, was able to be observed after an image analysis.

scholarly journals Global-Local Enhancement Network for NMF-Aware Sign Language Recognition

2021 ◽  
Vol 17 (3) ◽  
pp. 1-19
Author(s):  
Hezhen Hu ◽  
Wengang Zhou ◽  
Junfu Pu ◽  
Houqiang Li
Keyword(s):  
Sign Language ◽  
Daily Life ◽  
The Other ◽  
Challenging Problem ◽  
Language Recognition ◽  
Local Enhancement ◽  
Sign Language Recognition ◽  
Vocabulary Size ◽  
Hand Gestures ◽  
Fine Grained

Sign language recognition (SLR) is a challenging problem, involving complex manual features (i.e., hand gestures) and fine-grained non-manual features (NMFs) (i.e., facial expression, mouth shapes, etc .). Although manual features are dominant, non-manual features also play an important role in the expression of a sign word. Specifically, many sign words convey different meanings due to non-manual features, even though they share the same hand gestures. This ambiguity introduces great challenges in the recognition of sign words. To tackle the above issue, we propose a simple yet effective architecture called Global-Local Enhancement Network (GLE-Net), including two mutually promoted streams toward different crucial aspects of SLR. Of the two streams, one captures the global contextual relationship, while the other stream captures the discriminative fine-grained cues. Moreover, due to the lack of datasets explicitly focusing on this kind of feature, we introduce the first non-manual-feature-aware isolated Chinese sign language dataset (NMFs-CSL) with a total vocabulary size of 1,067 sign words in daily life. Extensive experiments on NMFs-CSL and SLR500 datasets demonstrate the effectiveness of our method.

scholarly journals Prehistorical Obsidian Sources in the Island of Lipari (Aeolian Islands)

2020 ◽  
Vol 6 (1) ◽  
pp. 393-402
Author(s):  
Maria Clara Martinelli ◽  
Mauro Coltelli ◽  
Marco Manni ◽  
Letizia Bonizzoni ◽  
Alessandra Guglielmetti ◽  
...  
Keyword(s):  
Fission Track ◽  
Scientific Research ◽  
Raw Material ◽  
Neolithic Period ◽  
Study Analysis ◽  
Geological Samples ◽  
Aeolian Islands ◽  
Methodological Aspects ◽  
And Diffusion ◽  
Age Determinations

AbstractThis research project concerns the study, analysis and dating of obsidian flows on the island of Lipari, in relation to the population of the Aeolian Islands, during the Neolithic period.The collection, processing and diffusion of Lipari obsidian characterise the Neolithic population of Lipari and the entire Mediterranean. By improving the knowledge of supply methods in the territory, it will be possible to formulate hypotheses on the chronology of the sources, the ways of collecting the raw material and on the mobility of the Neolithic communities in the Aeolian Islands. The scientific research is divided into two main topics: the first concerns the analytical and methodological aspects of archaeological and geological studies of Lipari obsidian; the second, the formation of obsidian at Lipari, their sources and lithological characteristics. Throughout the duration of this study we will perform new age determinations of Neolithic obsidian artefacts and geological samples, directly with the method of fission track, and indirectly dating paleo soils using the radiocarbon method.

scholarly journals I.—Microscopic Structure of Irish Granites. No. 2. Granite of Aillemore, Co. Mayo

1874 ◽  
Vol 1 (1) ◽  
pp. 1-2
Author(s):  
Edward Hull
Keyword(s):  
The Other ◽  
Microscopic Structure ◽  
South Side ◽  
North West ◽  
Fine Grained ◽  
Lower Silurian ◽  
The North ◽  
Geological Map ◽  
Vertical Walls ◽  
Dark Green

This granite forms an isolated mass, rising into two eminences a few miles south of Louisburg, called Corvock Brack (1287 feet) and Knockaskeheen (1288 feet). It is a greyish granite—generally fine—grained—consisting of quartz, two felspars,—one orthoclase, the other triclinic, probably oligoclase—and dark green mica. In some places there are patches in which the felspar assumes the appearance of “graphic granite.” Numerous boulders of this granite are strewn over the district to the north-west, and on the south side of Knockaskeheen; the rock is traversed by regular joints ranging N. 10 W., along which it splits off into nearly vertical walls. The position of the granite is shown on Griffith's Geological Map of Ireland, and it is surrounded by schistose beds, generally metamorphosed, and probably of Lower Silurian age. The granite itself is of older date than the Upper Llandovery beds, which lie to the southward.

Conditional Belief and the Ramsey Test

2002 ◽  
Vol 51 ◽  
pp. 215-232
Author(s):  
Scott Sturgeon
Keyword(s):  
Everyday Life ◽  
Common Sense ◽  
The Other ◽  
Coarse Grained ◽  
Degrees Of Belief ◽  
Conditional Belief ◽  
Ramsey Test ◽  
Fine Grained

Consider the frameS believes that—.Fill it with a conditional, sayIf you eat an Apple, you'll drink a Coke.what makes the result true? More generally, what facts are marked by instances ofS believes (A→C)?In a sense the answer is obious: beliefs are so marked. Yet that bromide leads directly to competing schools of thought. And the reason is simple.Common-sense thinks of belief two ways. Sometimes it sees it as a three-part affair. When so viewed either you believe, disbelieve, or suspend judgment. This take on belief is coarse-grained. It says belief has three flavours: acceptance, rejection, neither. But it's not the only way common-sense thinks of belief. Sometimes it's more subtle: ‘How strong is your faith?’ can be apposite between believers. That signals an important fact. Ordinary practice also treats belief as a fine-grained affair. It speaks of levels of confidence. It admits degrees of belief. It contains a fine-grained take as well. There are two ways belief is seen in everyday life. One is coarse-grained. The other is fine-grained.

Nodular and other Keratophyres at St. Nicolas, Quebec

1971 ◽  
Vol 8 (1) ◽  
pp. 116-131
Author(s):  
F. Fitz Osborne ◽  
Paul Laroche
Keyword(s):  
The Other ◽  
Magmatic Origin ◽  
Fine Grained ◽  
Checker Board

Sills in Cambrian sandstone at two localities provide complementary evidence for the magmatic origin of keratophyres near St. Nicolas. The thickest sill has one facies whose solids at the time it was half or somewhat more crystallized had the composition of a hornblende laugenite. The rest magma at this stage gave rise to stellate and trachytoid keratophyre characterized by chlorite and checker-board albite with some quartz. At the other locality magma approximately of the composition of the stellate keratophyre was emplaced as sills up to 4 ft (1.2 m) thick and gave rise to medium-grained keratophyre with, along the selvages or within the sills, a fine-grained variety with chlorite and nodules, up to 1 in. (2.5 cm) diameter, of plagioclase. Illite or its precursor was secreted from the sills and was replaced by a network of veins with cores of quartz and spheroids of plagioclase, of chlorite, and of carbonate.

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