Late Early Devonian Dacryoconarid Tentaculites, Northern Yukon Territory

1972 ◽  
Vol 9 (3) ◽  
pp. 297-318 ◽  
Author(s):  
Rolf Ludvigsen
Keyword(s):  
New Species ◽  
Environmental Factors ◽  
Yukon Territory ◽  
Early Devonian ◽  
The Road ◽  
Blackstone River

The late Early Devonian succession in northern Yukon Territory contains a well-preserved dacryoconarid tentaculite fauna dominated by Turkestanella acuaria (Richter) in the upper part of the Road River Formation and T. acuaria and Nowakia parabarrandei Churkin and Carter in the overlying Michelle Formation. Based on the dacryoconarid tentaculite fauna the bulk of the Michelle Formation in the Ogilvie to Hart Rivers area is dated as late Pragian (early Emsian), and based on the graptolite and dacryoconarid tentaculite fauna the uppermost Road River Formation in the Blackstone River area is dated as Pragian (early Emsian or late Siegenian or both). The appearance of species of Nowakia in northern Yukon considerably earlier than in Bohemia is documented. It is concluded that some genera of the Dacryoconarida were influenced in their occurrence by environmental factors. New species described are Turkestanella minuta, Viriatellina michellensis, Guerichina lenini, Styliolina blackstonensis, and Metastyliolina conica.

Description and correlation of Late Ordovician conodonts from the D. ornatus and P. pacificus graptolite zones, Road River Group, northern Yukon Territory

1987 ◽  
Vol 24 (7) ◽  
pp. 1450-1464 ◽  
Author(s):  
Alexander D. McCracken
Keyword(s):  
New Species ◽  
New Genus ◽  
Late Ordovician ◽  
Yukon Territory ◽  
Upper Ordovician ◽  
The Road ◽  
Anticosti Island ◽  
Blackstone River ◽  
A New Species

Upper Ordovician carbonate beds within clastic strata of the Road River Group, northern Yukon Territory, have yielded 403 conodont elements representing 25 species; 19 of these are illustrated. Genera present are Amorphognathus, Belodina, Besselodus, Drepanoistodus, Eocarniodus?, Gamachignathus, Icriodella, Noixodontus, Oulodus, Panderodus s.l., Paroistodus?, Plectodina, Protopanderodus, Pseudobelodina s.l., Scabbardella, Strachanognathus, and Walliserodus. The apparatus of new genus A new species A includes a symmetrical and bifurrowed rastrate element.Sparse conodont faunas from Rock River occur in strata below a level bearing graptolites of the D. ornatus Zone and between this zone and the succeeding P. pacificus Zone. These conodonts have a range of "Trentonian" –Gamachian (upper Caradoc –Hirnantian).The fauna from Blackstone River is from a single bed that is 3 m below the G. persculptus Zone? and 13.7 m above the P. pacificus Zone. Although stratigraphically closer to the former, this fauna may be equivalent to a level within the P. pacificus Zone; the conodonts suggest correlation with the late Richmondian Fauna 12 and the lower G. ensifer Zone of Anticosti Island, Quebec. A similar fauna (G. ensifer Zone) occurs in one horizon within the P. pacificus Zone at upper Peel River. One metre above this is the informal D. cf. D. mirus graptolite biohorizon (P. pacificus Zone).The Blackstone and Peel faunas equate to a level within the Ordovician Anceps bands C and D of the Ordovician–Silurian boundary stratotype at Dob's Linn, Scotland. The interval of Fauna 13 and the Gamachian Stage may correspond to Anceps Band E and the C.? extraordinarius Band (and contiguous strata) at Dob's Linn. The base of the G. ensifer Zone and the higher base of the Gamachian are probably late Rawtheyan.

New early Devonian gastropods from the families Crassimarginatidae (new family) and Scoliostomatidae (new family), Royal Creek Area, Yukon Territory, Canada

2002 ◽  
Vol 76 (2) ◽  
pp. 246-255 ◽  
Author(s):  
Jiří Frýda ◽  
Robert B. Blodgett ◽  
Alfred C. Lenz
Keyword(s):  
New Species ◽  
New Genus ◽  
Yukon Territory ◽  
New Genera ◽  
Morphological Comparison ◽  
The Czech Republic ◽  
Early Devonian ◽  
The Road ◽  
New Family ◽  
The Family

Two new distinctive families, Crassimarginatidae and Scoliostomatidae, each characterized by unusual gerontic apertural morphotypes, are established on the basis of study of the richly diverse Lower Devonian gastropod fauna of the Road River Formation in the Royal Creek area, Yukon Territory. The Early Devonian genus Crassimarginata Jhaveri, 1969, is transferred from the family Palaeotrochidae and placed, together with the new genus Yukonoconcha, into the new family Crassimarginatidae, which is characterized by a pupiform shell with an explanate outer apertural lip in the gerontic growth stage. The new family Scoliostomatidae unites Devonian gastropod genera (Scoliostoma Braun, 1838; Brilonella Kayser, 1873; Anarconcha Horný, 1964; Eoscoliostoma new genus; Mitchellia Koninck, 1877; and Pseudomitchellia new genus), which are characterized by a distinctive, free, twisted (both outwards and backwards) gerontic final half whorl. More detailed morphological comparison of members of this family has allowed their division into two new subfamilies: the Scoliostomatinae and Mitchelliinae. New genera include Yukonoconcha, Eoscoliostoma, and Pseudomitchellia. The former two genera are represented each by a single new species from Yukon Territory, Yukonoconcha pedderi and Eoscoliostoma norrisi. The latter genus is represented by two species, the type Pseudomitchellia bohemica (Perner) from the Koněprusy Limestone (Pragian) of the Czech Republic and Pseudomitchellia macqueeni new species from Yukon Territory.

Middle and Late Ordovician conodont faunas and biostratigraphy of graptolitic strata of the Road River Group, northern Yukon Territory

1987 ◽  
Vol 24 (4) ◽  
pp. 643-653 ◽  
Author(s):  
Alexander D. McCracken ◽  
Alfred C. Lenz
Keyword(s):  
Northwest Territories ◽  
Cold Water ◽  
Late Ordovician ◽  
Yukon Territory ◽  
Warm Water ◽  
Rare Occurrence ◽  
Carbonate Facies ◽  
The Road ◽  
Fine Grained ◽  
Blackstone River

Ordovician conodont faunas from the fine-grained clastic Road River Group in northern Yukon Territory contain a mixture of species from both warm- and cold-water regions. This group in southwestern Northwest Territories also has mixed faunas, whereas conodonts from the carbonate facies are more characteristic of the warm-water regions.Six conodont associations and biozones are identified from the Yukon. Some, such as the early Llanvirn "Cordylodus" horridus – Spinodus spinatus association, contain reworked elements. The Pygodus serra Zone (middle–late Llanvirn) is within the upper P. tentaculatus Zone and well below the G. euglyphus Zone. Genera include Ansella, Periodon, Protopanderodus, Pygodus, and Walliserodus.At Peel River, conodonts are within the P. pacificus Zone. The Blackstone River conodonts occur above the P. pacificus Zone and below the G. persculptus Zone (?) and include Oulodus rohneri, Plectodina florida, and Noixodontus. Amorphognathus ordovicicus, Gamachignathus ensifer, O. ulrichi, and Plectodina tenuis occur in both faunas. These represent Fauna 12, found in late Richmondian strata, rather than the Gamachian Fauna 13 and are assigned to the G. ensifer Zone; both occurrences of G. ensifer are biohorizons. The C.? extraordinarius and G. persculptus zones are not recognized at Peel and Rock rivers and Tetlit Creek.The Ozarkodina n. sp. A – Icriodella sp. B association occurs at Pat Lake between the G. persculptus Zone (?) and the underlying P. pacificus Zone. The Ozarkodina have a Silurian aspect but must be regarded as Ordovician.The Ordovician–Silurian boundary in the Road River Group of the Yukon is best defined using graptolites because of the rare occurrence of conodonts.

New porcellioidean gastropods from early Devonian of Royal Creek area, Yukon Territory, Canada, with notes on their early phylogeny

2008 ◽  
Vol 82 (3) ◽  
pp. 595-603 ◽  
Author(s):  
Jiří Frýda ◽  
Robert B. Blodgett ◽  
Alfred C. Lenz ◽  
Štěpán Manda
Keyword(s):  
Lower Devonian ◽  
Yukon Territory ◽  
Shell Morphology ◽  
Western Canada ◽  
Evolutionary Trend ◽  
Early Devonian ◽  
Old World ◽  
The Road ◽  
Classical Models

This paper presents a description of new gastropods belonging to the superfamily Porcellioidea (Vetigastropoda) from the richly diverse Lower Devonian gastropod fauna of the Road River Formation in the Royal Creek area, Yukon Territory. This fauna belongs to Western Canada Province of the Old World Realm. The Pragian speciesPorcellia(Porcellia)yukonensisn. sp. andPorcellia(Paraporcellia) sp. represent the oldest presently known members of subgeneraPorcellia(Porcellia) andPorcellia(Paraporcellia). Their simple shell ornamentation fits well with an earlier described evolutionary trend in shell morphology of the Porcellinae. Late Pragian to early EmsianPerryconcha pulchran. gen. and n. sp. is the first member of the Porcellioidea bearing a row of tremata on adult teleoconch whorls. The occurrence of this shell feature in the Porcellioidea is additional evidence that the evolution of the apertural slit was much more complicated than has been proposed in classical models of Paleozoic gastropod evolution.

Early Devonian brachiopods from Satun Province, southern Thailand

1999 ◽  
Vol 73 (5) ◽  
pp. 850-859 ◽  
Author(s):  
A. J. Boucot ◽  
L. R. M. Cocks ◽  
P. R. Racheboeuf
Keyword(s):  
New Species ◽  
New Genus ◽  
New Genus And Species ◽  
Benthic Assemblages ◽  
Early Devonian ◽  
Old World ◽  
Southern Thailand ◽  
Biogeographical Region

Twelve brachiopod taxa are described from the Early Devonian (probable early Emsian) Pa Samed Formation of southern Thailand, including the new genus and species Quasiprosserella samedensis (Ambocoeliidae?) and the new species Plectodonta forteyi, Caplinoplia thailandensis, and Clorinda wongwanichi. They are the first undoubted Devonian brachiopods from Thailand. They represent the deeper-water Benthic Assemblages BA4-5, and, although clearly indicative of the Old World Realm, cannot be assigned to a particular biogeographical region. A new undescribed fauna from the contemporary Zebingyi Formation of Burma (Myanmar) is also noted.

The sequence and correlation of Early Ordovician (Arenig) graptolite faunas in the Richardson Trough and Misty Creek Embayment, Yukon Territory and District of Mackenzie, Canada

2006 ◽  
Vol 43 (12) ◽  
pp. 1791-1820 ◽  
Author(s):  
D E Jackson ◽  
A C Lenz
Keyword(s):  
Northwest Territories ◽  
Deep Water ◽  
Yukon Territory ◽  
Early Ordovician ◽  
The Road ◽  
Bedded Chert ◽  
First Occurrence ◽  
Mackenzie Mountains ◽  
First Time

Four graptolite biozones are recorded from the Arenig portion of the Road River Group in the Richardson and Mackenzie mountains in the Yukon and Northwest Territories. In ascending order, these zones are Tetragraptus approximatus, Pendeograptus fruticosus, Didymograptus bifidus, and Parisograptus caduceus australis (new). The Castlemainian stage may be represented by nongraptolitic massive bedded chert. The Arenig–Llanvirn boundary is drawn below the first occurrence of Undulograptus austrodentatus. Fifty-four graptolite taxa are present, and 16 of these species and subspecies are recorded for the first time in this deep-water biotope, namely, Didymograptus? cf. adamantinus, D. asperus, D. dilatans, D. cf. kurcki, D. validus communis, Holmograptus aff. leptograptoides, H. sp. A, Isograptus? sp. nov. A, I. ? dilemma, Keblograptus geminus, Pseudisograptus manubriatus harrisi, Ps. m. koi, Ps. m. janus, Ps. cf. tau, Xiphograptus lofuensis, and Zygograptus cf. abnormis.

scholarly journals Graptolite dynamics in Silurian and Devonian time

1987 ◽  
Vol 35 ◽  
pp. 149-159
Author(s):  
T. N. Koren'
Keyword(s):  
Environmental Factors ◽  
Sea Level ◽  
Comparative Studies ◽  
Climate Changes ◽  
Environmental Changes ◽  
Time Intervals ◽  
Early Devonian ◽  
Carbonate Sedimentation ◽  
Reference Sections ◽  
Devonian Age

On the basis of biostratigraphic data known at present some preliminary attempts are made to evaluate graptolite dynamics, that is changes in graptolite diversity in time and space within pelagic fades of Si­lurian and Early Devonian age. For the comparative studies of diversity fluctuations versus some major environmental changes a standard graptolite zonation is used. Several critical and more or less well stu­died stratigraphical intervals are chosen; among them the Ordovician/Silurian, Sheinwoodian/Gorstian and Gorstian/Ludfordian boundary beds. For each level the most complete reference sections are analy­zed. Special attention is given to the graptolite extinction, specification and radiation events within these time intervals. They might have been partly connected with or influenced by the environmental factors as a result of eustatic sea-level and climate changes, alteration of anoxic conditions, migration of carbonate sedimentation in pelagic direction, and other globally detectable events. The graptolite evolution during the time of monograptid existence can be subdivided into three phases using the comparison of the ampli­tude of the extinction-origination events and repeatability of the synphasic cycles.

scholarly journals Flexible pavement rehabilitation with continuously reinforced concrete slab with HFRP bars - mechanistic analysis

2019 ◽  
Vol 262 ◽  
pp. 05019
Author(s):  
Magdalena Złotowska ◽  
Roman Nagórski ◽  
Piotr Radziszewski ◽  
Michał Sarnowski ◽  
Paweł Tutka
Keyword(s):  
Fatigue Life ◽  
Environmental Factors ◽  
Negative Impact ◽  
Concrete Slab ◽  
Mechanistic Model ◽  
Continuous Reinforcement ◽  
Reinforced Concrete Slab ◽  
Pavement Rehabilitation ◽  
The Road ◽  
Road Pavement

Asphalt road pavements are subject to damage under the influence of loads from the traffic of vehicles and of the environmental factors. One of the ways to strengthen damaged flexible pavements is to apply a cement concrete overlay with continuous reinforcement. The purpose of this paper is to analyze the road structure with concrete overlay with continuous reinforcement HFRP composite bars, which is laid on the existing cracked asphalt layers of a typical flexible road of KR3 traffic category. In HFRP bars some of the basalt fibers have been replaced with carbon fibers with the addition of resin binders. This do the possibility of making concrete slabs with increased resistance for environmental aggression, with good mechanical properties, which is especially important in the case of road constructions. An analysis of fatigue life of the strengthened asphalt pavement with a concrete slab with continuous reinforcement of HFRP bars was carried out, implementing the mechanistic model of the pavement structure. The stress analysis in the structure under the action of static loading was determined by the Finite Element Method using the Abaqus/Standard program. The maximum value of stress caused by temperature gradient in the concrete slab was calculated from the Westergaard’s formula for infinite slab. It has been shown that strengthening the analyzed road pavement with a continuous reinforcement is a technology that ensures an increase in fatigue life and reinforcement with HFRP bars further increases durability due to the negative impact of environmental factors.

Chitinozoa from the Early Devonian (Lochkovian–Pragian) Garra Limestone, central New South Wales, Australia

1993 ◽  
Vol 67 (5) ◽  
pp. 738-758 ◽  
Author(s):  
Theresa Winchester-Seeto
Keyword(s):  
New Species ◽  
New South ◽  
New South Wales ◽  
Northern Africa ◽  
Early Devonian ◽  
South Wales ◽  
Two New Species

Chitinozoa have been recovered from three sections within the Garra Limestone in central New South Wales, Australia. A total of 31 species are identified and two new species, Angochitina hypenetes and Bursachitina mawsonae, are described. Three stratigraphically distinct assemblages from the late Lochkovian to the early Pragian are distinguished and compared with faunas of a similar age from Europe and northern Africa.

Evaluation and Analysis of Factors Affecting Road Traffic Accidents in Tripoli-Libya

2018 ◽  
Vol 38 ◽  
pp. 124-132
Author(s):  
Faris Ahmed Abdulfatah Elturki ◽  
Shaban Ismael Albrka Ali
Keyword(s):  
Environmental Factors ◽  
Human Factors ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Influential Factor ◽  
Road Traffic Accidents ◽  
Permanent Disability ◽  
High Exposure ◽  
Transportation Demand ◽  
The Road

Incessant of transportation demand growth in developing countries in latest years has led to several traffic issues in city areas, among the most challenging ones are vehicular emission, traffic congestion, and accidents. The growth of transportation demand has great influences, and very unfortunate impact on the society regarding crashes, death, and injuries from road accidents have reached epidemic proportions worldwide. The variation increased in speeds and vehicle density resulted in high exposure to accidents which lead loss of life and permanent disability, injury, and damage to property. This paper classified and investigate the most critical factors affect road traffic accidents (RTAs) in Tripoli the capital city of Libya. Four main categories were chosen to build the questionnaire, namely; human factors, road factors, vehicle factors and environmental factors. Moreover, a quantitative method was used to collect the data from the field, 400 respondents include; drivers, pedestrian and passengers were the sample size of the questionnaire and relative importance index (RII) were used for classification of one group and among all groups. The results show that more than 84%of respondents considered the over speeding as the most significant factor cusses of RTAs among all groups, while 81% considered the disobedience to driving code such as children who are playing with the car on the road as the most influential factor in human factors group. Also, nearly 74% of respondents seeing that poor brakes or brake failure factor has a high and considerable impact on the RTAs among the vehicle factors. Regarding the road factors group, 79% of the respondents ranked poor or no street lighting factor as one of the most effective factors on RTAs in road factors and third effecting factor concerning all factors, on the other hand, the environmental factors have the slights impacts compared with other factors.

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