Revision of the March Formation (Tremadocian) in Southeastern Ontario

1973 ◽  
Vol 10 (7) ◽  
pp. 1140-1155 ◽  
Author(s):  
Ivor J. Bond ◽  
Robert G. Greggs
Keyword(s):  
Sedimentary Environment ◽  
Lower Boundary ◽  
Lower Paleozoic ◽  
Type Area ◽  
Reference Sections ◽  
Conodont Fauna ◽  
Definition Of ◽  
Stratigraphic Succession ◽  
Reference Section ◽  
Upper Boundary

Reference sections are proposed for the revised March Formation (Tremadocian) along the MacDonald–Cartier Freeway a few miles west of Brockville, Ontario. The sequence of the March Formation delineated by these sections yields nearly a complete stratigraphic succession for this formation in southeastern Ontario. The lithology, thickness, and sedimentary environment are described, and the known conodont fauna is recorded.The establishment of a nearly complete reference section allows better understanding of the March as represented in the type area west of Ottawa, Ontario and permits more precise definition of the upper and lower contacts of the formation. The upper boundary of the March Formation as revised coincides with a probable Tremadoc–Arenig boundary: the lower boundary, also lithologically distinct coincides with the abrupt first appearance of conodonts in the Lower Paleozoic succession in southeastern Ontario.

scholarly journals ON THE POSITION OF THE BOUNDARY BETWEEN THE MOSCOVIAN AND KASIMOVIAN GLOBAL STAGES OF THE CARBONIFEROUS IN THE DONETS BASIN

2021 ◽  
Vol 14 (1) ◽  
pp. 63-71
Author(s):  
Tamara I. Nemyrovska
Keyword(s):  
Lower Boundary ◽  
Donets Basin ◽  
Present Position ◽  
Precise Position ◽  
Index Species ◽  
Potential Index ◽  
Type Area ◽  
Extinction Event ◽  
Moscow Basin ◽  
Definition Of

Detailed new data on paleontology and stratigraphy were obtained in the process of fulfilling the tasks of the International Carboniferous Subcommission on definition of the scopes of the Moscovian and Kasimovian global stages and the precise position of the boundary between them. The analysis of these data has shown that the position of this boundary in the type  area and in the other regions needs the revision. Recently the investigation of the conodonts from the Moscovian–Kasimovian boundary deposits in the Donets Basin revealed that the boundary between the Moscovian and Kasimovian stages in the official Ukrainian Carboniferous Stratigraphic Scheme does not correspond to this boundary in the type area of these stages in the  Moscow Basin. To correct this situation the lower boundary of the Kasimovian in the Ukrainian Scheme must be downgraded by two conodont zones — Swadelina subexcelsa and Sw. makhlinae. To update this boundary in the type area to fulfill the task of the Carboniferous Subcommission four conodont species were proposed as potential index-species for the definition of the boundary between the Moscovian and Kasimovian global stages. These conodont species are as follows Sw. subexcelsa,  Idiognathodus sagittalis, I. turbatus and I. heckeli. One of these species, which is selected, will be used as a marker of the  studied boundary. None of these species is officially selected as a marker. If Sw. subexcelsa will be selected, the position of  the Moscovian–Kasimovian boundary will remain at the present position. In this case this boundary in the Donets Basin has to be downgraded by two conodont zones. If one of three Idiognathodus will be selected, this boundary in the type area will be   upgraded by one and a half regional substage. In the Donets Basin it will be upgraded by less than a cycle. Keywords: Carboniferous, stratigraphy, conodonts, extinction event, index-­species. 

Polygnathids (Conodonta) around the Pragian/Emsian boundary from the Dacun-1 section (central Guangxi, South China)

2019 ◽  
Vol 93 (06) ◽  
pp. 1210-1220 ◽  
Author(s):  
Jian-Feng Lu ◽  
José Ignacio Valenzuela-Ríos ◽  
Jau-Chyn Liao ◽  
Yi Wang
Keyword(s):  
South China ◽  
Lower Boundary ◽  
South China Block ◽  
The South ◽  
Lowermost Part ◽  
Conodont Fauna ◽  
First Time ◽  
Upper Boundary

AbstractThe base of the Emsian, which is defined by the first appearance of the conodont Polygnathus kitabicus, has never been successfully demonstrated in the South China Block (including Guangxi and eastern Yunnan). As a result, we studied conodonts from the lowermost part of the Shizhou Member of the Yukiang Formation at the Dacun-1 section in the Liujing area, Guangxi. This new investigation has revealed a conodont fauna only consisting of Polygnathus pireneae, P. sokolovi, P. kitabicus, P. sp. and Pandorinellina exigua philipi, which can be assigned to the uppermost part of the pireneae Zone and the lowermost part of the kitabicus Zone in ascending order. The Pragian/Emsian boundary at the Dacun-1 section is located in the highest thick-bedded limestone bed that can be observed in the lowermost part of the Shizhou Member. Therefore, this is the first time that the lower boundary of the Emsian defined by the lowest occurrence of P. kitabicus is reported in the South China Block. However, the scarcity of suitable limestone samples for conodont analysis in the middle and upper parts of the Shizhou Member precludes definitive identification of the upper boundary of the kitabicus Zone in the Liujing area.

scholarly journals ON DIVERSITY OF CONFIGURATIONS GENERATED BY EXCITABLE CELLULAR AUTOMATA WITH DYNAMICAL EXCITATION INTERVALS

2012 ◽  
Vol 23 (12) ◽  
pp. 1250085 ◽  
Author(s):  
ANDREW ADAMATZKY
Keyword(s):  
Cellular Automata ◽  
Lower Boundary ◽  
Morphological Diversity ◽  
Excitable Media ◽  
Stationary Waves ◽  
Future Studies ◽  
Time Dynamics ◽  
Wide Range ◽  
Localized Excitations ◽  
Upper Boundary

Excitable cellular automata with dynamical excitation interval exhibit a wide range of space-time dynamics based on an interplay between propagating excitation patterns which modify excitability of the automaton cells. Such interactions leads to formation of standing domains of excitation, stationary waves and localized excitations. We analyzed morphological and generative diversities of the functions studied and characterized the functions with highest values of the diversities. Amongst other intriguing discoveries we found that upper boundary of excitation interval more significantly affects morphological diversity of configurations generated than lower boundary of the interval does and there is no match between functions which produce configurations of excitation with highest morphological diversity and configurations of interval boundaries with highest morphological diversity. Potential directions of future studies of excitable media with dynamically changing excitability may focus on relations of the automaton model with living excitable media, e.g. neural tissue and muscles, novel materials with memristive properties and networks of conductive polymers.

scholarly journals A 3-D RBF-FD solver for modeling the atmospheric global electric circuit with topography (GEC-RBFFD v1.0)

2015 ◽  
Vol 8 (10) ◽  
pp. 3007-3020 ◽  
Author(s):  
V. Bayona ◽  
N. Flyer ◽  
G. M. Lucas ◽  
A. J. G. Baumgaertner
Keyword(s):  
Numerical Model ◽  
Differential Operators ◽  
Lower Boundary ◽  
Elliptic Partial Differential Equation ◽  
Electric Circuit ◽  
Global Electric Circuit ◽  
Mesh Free ◽  
Conductivity Profile ◽  
The Right ◽  
Upper Boundary

Abstract. A numerical model based on radial basis function-generated finite differences (RBF-FD) is developed for simulating the global electric circuit (GEC) within the Earth's atmosphere, represented by a 3-D variable coefficient linear elliptic partial differential equation (PDE) in a spherically shaped volume with the lower boundary being the Earth's topography and the upper boundary a sphere at 60 km. To our knowledge, this is (1) the first numerical model of the GEC to combine the Earth's topography with directly approximating the differential operators in 3-D space and, related to this, (2) the first RBF-FD method to use irregular 3-D stencils for discretization to handle the topography. It benefits from the mesh-free nature of RBF-FD, which is especially suitable for modeling high-dimensional problems with irregular boundaries. The RBF-FD elliptic solver proposed here makes no limiting assumptions on the spatial variability of the coefficients in the PDE (i.e., the conductivity profile), the right hand side forcing term of the PDE (i.e., distribution of current sources) or the geometry of the lower boundary.

The agnostoid arthropod Lotagnostus Whitehouse, 1936 (late Cambrian; Furongian) from Avalonian Cape Breton Island (Nova Scotia, Canada) and its significance for international correlation

2016 ◽  
Vol 154 (5) ◽  
pp. 1001-1021 ◽  
Author(s):  
STEPHEN R. WESTROP ◽  
ED LANDING
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Debris Flow ◽  
Type Species ◽  
Cape Breton Island ◽  
Late Cambrian ◽  
Cape Breton ◽  
Type Area ◽  
Stratigraphic Succession

AbstractNew and archival collections from the Chelsey Drive Group of the Avalon terrane of Cape Breton Island, Nova Scotia, Canada, yield late Cambrian trilobites and agnostoid arthropods with full convexity that contrast with compacted, often deformed material from shale and slate typical of Avalonian Britain. Four species of the agnostoid Lotagnostus form a stratigraphic succession in the upper Furongian (Ctenopyge tumida–Parabolina lobata zones). Two species, L. ponepunctus (Matthew, 1901) and L. germanus (Matthew, 1901) are previously named; L. salteri and L. matthewi are new. Lotagnostus trisectus (Salter, 1864), the type species of the genus, is restricted to compacted material from its type area in Malvern, England. Lotagnostus americanus (Billings, 1860) has been proposed as a globally appropriate index for the base of ‘Stage 10’ of the Cambrian. All four species from Avalonian Canada are differentiated clearly from L. americanus in its type area in Laurentian North America (i.e., from debris flow blocks in Taconian Quebec). In our view, putative occurrences of L. americanus from other Cambrian continents record very different species. Lotagnostus americanus cannot be recognized worldwide, and other taxa should be sought to define the base of Stage 10, such as the conodont Eoconodontus notchhpeakensis.

scholarly journals Theoretical Gravity Anomalies of Glaciers Having Parabolic Cross-Sections

1964 ◽  
Vol 5 (38) ◽  
pp. 255-257 ◽  
Author(s):  
Charles E. Corbató
Keyword(s):  
Cross Sections ◽  
Lower Boundary ◽  
Gravity Anomalies ◽  
Vertical Axis ◽  
Two Dimensional ◽  
Axis Of Symmetry ◽  
Upper Boundary

AbstractEquations and a graph are presented for calculating gravity anomalies on a two-dimensional glacier model having a horizontal upper boundary and a lower boundary which is a parabola with a vertical axis of symmetry.

Artinskian conodonts from the Dingjiazhai Formation of the Baoshan Block, west Yunnan, southwest China

2002 ◽  
Vol 76 (4) ◽  
pp. 741-750 ◽  
Author(s):  
Katsumi Ueno ◽  
Yoshihiro Mizuno ◽  
Xiangdong Wang ◽  
Shilong Mei
Keyword(s):  
Southern Hemisphere ◽  
Southwest China ◽  
Warm Water ◽  
Early Permian ◽  
Northern Margin ◽  
Stratigraphic Unit ◽  
Current Definition ◽  
Conodont Fauna ◽  
Definition Of ◽  
First Time

Permian conodonts were recovered for the first time from the Dingjiazhai Formation, a well-known diamictite-bearing stratigraphic unit in the Gondwana-derived Baoshan Block in West Yunnan, Southwest China. The conodont fauna occurs in limestone units within the upper part of the formation and consists of Sweetognathus bucaramangus (Rabe), S. whitei (Rhodes), Mesogondolella bisselli (Clark and Behnken), and an unidentified ramiform element. Based on the known stratigraphic distribution of 5. bucaramangus (Rabe), the fauna is referable to the upper Sweetognathus whitei-Mesogondolella bisselli Zone, and thus is dated as middle Artinskian according to the current definition of the stage. The Dingjiazhai Formation is overlain paraconformably by the Woniusi Formation, which is represented mostly by basalts and basaltic volcaniclastics related to rifting volcanism during the separation of the Baoshan Block from Gondwanaland. The present discovery of conodonts from the upper part of the Dingjiazhai Formation reveals that the glaciogene diamictites in the Dingjiazhai Formation are older than middle Artinskian, and the inception of rifting volcanism of the Baoshan Block is later than middle Artinskian.Occurrence of an essentially warm water element, Sweetognathus bucaramangus (Rabe), in the Dingjiazhai conodont assemblage notwithstanding, the entire fossil faunas including brachiopods and fusulinoideans from the limestone units of the formation can be best interpreted as a middle latitudinal, non-tropical, and still substantially Gondwana-influenced assemblage developed at the northern margin of Gondwanaland just after deglaciation in the southern hemisphere during Early Permian time. This time could be regarded as the beginning of the Cimmerian Region, which had mixed or transitional paleobiogeographic characteristics between the Paleoequatorial Tethyan and cool/cold Gondwanan realms, and which became well developed during Middle Permian time.

An ammonite zonation for the Toarcian (Lower Jurassic) of the North American Cordillera

1994 ◽  
Vol 31 (6) ◽  
pp. 919-942 ◽  
Author(s):  
Giselle K. Jakobs ◽  
Paul L. Smith ◽  
Howard W. Tipper
Keyword(s):  
New Species ◽  
North America ◽  
North American ◽  
Lower Boundary ◽  
Lower Jurassic ◽  
North American Cordillera ◽  
Queen Charlotte Islands ◽  
The North ◽  
Reference Sections ◽  
A New Species

This is the second in a series of papers intended to establish a Lower Jurassic ammonite zonation that takes into account the biostratigraphic and biogeographic peculiarities of the North American succession. In North America the lower boundary of the Toarcian is drawn at the first appearance of Dactylioceras above the last occurrence of Amaltheus and Fanninoceras. The lower Toarcian is represented by the Kanense Zone; the middle Toarcian by the Planulata and Crassicosta zones; and the upper Toarcian by the Hillebrandti and Yakounensis zones. Section 5 on the Yakoun River in the Queen Charlotte Islands is designated the stratotype for the Planulata, Crassicosta, and Hillebrandti zones; section 3 on the Yakoun River is designated the stratotype for the Yakounensis Zone; an ideal stratotype for the Kanense Zone is not presently known. Reference sections further illustrating the faunal associations that characterize the zones are designated in eastern Oregon (Snowshoe Formation) and northern British Columbia (Spatsizi Group). The Dactylioceratidae, Harpoceratinae, and Hildoceratinae provide the most important zonal indicators for the lower Toarcian; Dactylioceratidae, Phymatoceratinae, and Bouleiceratinae for the middle Toarcian; and Phymatoceratinae, Grammoceratinae, and Hammatoceratinae for the upper Toarcian. Phymatoceras hillebrandti is described as a new species.

scholarly journals Transnasal Humidified Rapid Insufflation Ventilatory Exchange With Nasopharyngeal Airway Facilitates Apneic Oxygenation: A Randomized Clinical Noninferiority Trial

2020 ◽  
Vol 7 ◽  
Author(s):  
Lingke Chen ◽  
Liu Yang ◽  
Weitian Tian ◽  
Xiao Zhang ◽  
Yanhua Zhao ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Lower Boundary ◽  
Clinical Trial Registration ◽  
Apneic Oxygenation ◽  
Nasopharyngeal Airway ◽  
Airway Opening ◽  
The Difference ◽  
To Receive ◽  
Noninferiority Margin ◽  
Upper Boundary

Background: Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) was used to extend the safe apnea time. However, THRIVE is only effective in patients with airway opening. Nasopharyngeal airway (NPA) is a simple device that can help to keep airway opening. This study aimed to investigate the noninferiority of NPA to jaw thrust for airway opening during anesthesia-induced apnea.Methods: This was a prospective randomized single-blinded noninferiority clinical trial on the use of THRIVE in patients with anesthesia-induced apnea. The participants were randomly allocated to receive NPA or jaw thrust. The primary outcomes were PaO2 and PaCO2 at 20 min after apnea, with noninferiority margin criteria of −6.67 and 0.67 kPa, respectively.Results: A total of 123 patients completed the trial: 61 in the NPA group and 62 in the jaw thrust group. PaO2 at 20 min after apnea was 42.9 ± 14.0 kPa in the NPA group and 42.7 ± 13.6 kPa in the jaw thrust group. The difference between these two means was 0.25 kPa (95% CI, −3.87 to 4.37 kPa). Since the lower boundary of the 95% CI was > −6.67 kPa, noninferiority was established because higher PO2 is better. PaCO2 at 20 min after apnea was 10.74 ± 1.09 kPa in the NPA group and 10.54 ± 1.18 kPa in the jaw thrust group. The difference between the two means was 0.19 kPa (95% CI, −0.14 to 0.53 kPa). Since the upper boundary of the 95% CI was <0.67 kPa, noninferiority was established because lower PCO2 is better. No patient had a SpO2 < 90% during apnea.Conclusion: When THRIVE was applied during anesthesia-induced apnea, NPA placement kept airway opening and was noninferior to jaw thrust in terms of its effects on PaO2 and PaCO2 at 20 min after apnea.Clinical Trial Registration:ClinicalTrials.gov (NCT03741998).

The effects of thermal conditions on the cell sizes of two-dimensional convection

1994 ◽  
Vol 281 ◽  
pp. 33-50 ◽  
Author(s):  
Masaki Ishiwatari ◽  
Shin-Ichi Takehiro ◽  
Yoshi-Yuki Hayashi
Keyword(s):  
Heat Flux ◽  
Lower Boundary ◽  
Thermal Conditions ◽  
Heat Fluxes ◽  
Internal Cooling ◽  
Two Dimensional ◽  
Numerical Integrations ◽  
The Difference ◽  
Convective Cells ◽  
Upper Boundary

The effects of thermal conditions on the patterns of two-dimensional Boussinesq convection are studied by numerical integration. The adopted thermal conditions are (i) the heat fluxes through both upper and lower boundaries are fixed, (ii) the same as (i) but with internal cooling, (iii) the temperature on the lower boundary and the heat flux through the upper boundary are fixed, (iv) the same as (iii) but with internal cooling, and (v) the temperatures on both upper and lower boundaries are fixed. The numerical integrations are performed with Ra = 104 and Pr = 1 over the region whose horizontal and vertical lengths are 8 and 1, respectively.The results confirm that convective cells with the larger horizontal sizes tend to form under the conditions where the temperature is not fixed on any boundaries. Regardless of the existence of internal cooling, one pair of cells spreading all over the region forms in the equilibrium states. On the other hand, three pairs of cells form and remain when the temperature on at least one boundary is fixed. The formation of single pairs of cells appearing under the fixed heat flux conditions shows different features with and without internal cooling. The difference emerges as the appearance of a phase change, whose existence can be suggested by the weak nonlinear equation derived by Chapman & Proctor (1980).

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