Biostratigraphic, paleogeographic, and tectonic implications of Late Ordovician conodonts from the Grog Brook Group, northwestern New Brunswick

1983 ◽  
Vol 20 (4) ◽  
pp. 651-671 ◽  
Author(s):  
Godfrey S. Nowlan
Keyword(s):  
New Brunswick ◽  
North Atlantic ◽  
Debris Flows ◽  
Late Ordovician ◽  
Thrust Faulting ◽  
The North ◽  
Atlantic Province ◽  
Unusual Distribution ◽  
Alternative Hypotheses ◽  
Structural High

Diverse conodont faunas recovered from the Grog Brook Group in northwestern New Brunswick indicate a Late Ordovician, probably Gamachian, age. The conodonts are of mixed provincial affinity including components of the North Atlantic Province (e.g., Hamarodus, Icriodella, Periodon, and Protopanderodus) and taxa representing shallow (e.g., Rhipidognathus) to deeper water environments (e.g., Phragmodus) in the Midcontinent Province. Elements of Amorphognathus ordovicicus Branson and Mehl numerically dominate the faunas that together with sparse representatives of Gamachignathus ensifer McCracken, Nowlan and Barnes suggest a latest Ordovician age. The beds from which the conodont faunas have been recovered are interpreted as distal debris flows that originated at the basin margin and brought Midcontinent Province conodonts down the slope to mix with indigenous North Atlantic Province faunas. The faunas are correlative with those from the Matapedia Group (previously thought to overlie the Grog Brook Group) and their occurrence suggests at least partial lateral equivalence of the two units.The conodonts recovered are only slightly thermally altered. Two alternative hypotheses are proposed to explain the juxtaposition of relatively unaltered conodonts of the Grog Brook Group and highly altered forms from the Matapedia Group. The first suggests that thrust faulting took place in the Late Ordovician – Early Silurian and that this process and later normal faulting account for the unusual distribution of conodont colour alteration. The second possibility is that the strata of the Grog Brook Group in the section examined were deposited on a structural high and overlain by little or no sediment of the Matapedia Group; however, such a structural high must have had access to a source of Midcontinent Province conodonts. Acadian thrusting then brought higher grade Matapedia Group strata into contact with this part of the Grog Brook Group.

scholarly journals Bioestratigrafía y provincialismo de conodontes del tramo medio-superior de la Formación San Juan en el cerro Viejo de Huaco, Precordillera, Argentina

2018 ◽  
Vol 45 (2) ◽  
pp. 274 ◽  
Author(s):  
Matías J. Mango ◽  
Guillermo L. Albanesi
Keyword(s):  
North Atlantic ◽  
Species Level ◽  
San Juan ◽  
Insufficient Information ◽  
Entire Interval ◽  
Middle Ordovician ◽  
The North ◽  
Atlantic Province ◽  
The North Atlantic ◽  
Color Alteration

The present study deals with the conodont biostratigraphy from the middle and upper parts of the San Juan Formation (Lower-Middle Ordovician) exposed at the Los Gatos creek section, west of the cerro Viejo de Huaco, Central Precordillera of San Juan Province. The numerous conodonts recovered, corresponding to 55 species, allow to recognize a series of biozones in the studied section. The biostratigraphic analysis carried out herein allows determining associations of conodonts assignable to the Oepikodus evae, Oepikodus intermedius, Baltoniodus triangularis-Tripodus laevis and Lenodus variabilis zones that correspond to the middle Floian to lower Darriwilian. The Baltoniodus navis and Microzarkodina parva zones were not identified due to insufficient information provided by this stratigraphic section. In general, the levels corresponding to the Baltoniodus triangularis-Tripodus laevis Zone contain more conodonts, than the records of other localities from Precordillera. These specimens are well preserved with a color alteration index (CAI) of 2-2.5, indicating overburden paleotemperatures ranging from 60° and 155° C. The large presence of fragmented conodonts, with recrystallized surfaces and crystal overgrowth, could indicate the effect of distinctive diagenetic fossil processes on the bearer limestone. The analysis of the diversity and abundance of genera and species of conodonts by chronostratigraphic intervals presents a great percentage of cosmopolitan taxa, 18% and 38% in common, at species level, only with the North-American Midcontinent Province (NAMP), and with a small percentage with the North-Atlantic Province (NAP) and the Precordillera, which allows to approximate a greater paleobiogeographic affinity of the conodonts recovered with those of the NAMP than those of the NAP for the entire interval studied. On the other hand, the Precordillera is verified as a province with its own characteristics as identified by several authors.

A probable glacio-marine deposit of Late Ordovician—Early Silurian age from the north central Newfoundland Appalachian Belt

1974 ◽  
Vol 111 (6) ◽  
pp. 549-564 ◽  
Author(s):  
A. M. McCann ◽  
M. J. Kennedy
Keyword(s):  
North Atlantic ◽  
Late Ordovician ◽  
Mobile Belt ◽  
North Atlantic Region ◽  
Upper Ordovician ◽  
Atlantic Region ◽  
North Central ◽  
Marine Deposits ◽  
Lower Silurian ◽  
The North

SummaryConglomerate beds occur in an Upper Ordovician—Lower Silurian clastic sequence on the northeastern side of the Newfoundland Central Paleozoic Mobile Belt. They contain scattered pebbles and cobbles dispersed in a finely laminated sandstone and siltstone matrix. Laminations are generally 5–20 mm thick and the clasts 10–300 mm across. The laminations are locally disrupted by the clasts. These laminations have subsequently been tectonically flattened into augen around the clasts and locally disrupted by boudinage. It is concluded that these conglomerate beds represent icerafted glacio-marine deposits interbedded with turbidites which were probably deposited in a locally restricted marine environment. The deposits are interpreted on the basis of scattered fossil localities as being of Late Ordovician–Early Silurian age. They are compared with deposits of similar age elsewhere in the North Atlantic region.

Postglacial stratigraphy and sea-level change in southwestern New Brunswick

1987 ◽  
Vol 24 (2) ◽  
pp. 354-364 ◽  
Author(s):  
C. A. Honig ◽  
D. B. Scott
Keyword(s):  
New Brunswick ◽  
Sea Level ◽  
North Atlantic ◽  
Sea Level Change ◽  
Carbon 14 ◽  
Marine Deposits ◽  
Level Change ◽  
The North ◽  
Transition Points ◽  
Marine Areas

Cores from small basins in southwestern New Brunswick, above present sea level but below the former marine limit, were examined for microfaunal changes indicating a transition from marine to freshwater conditions. Carbon 14 dates of those transition points add to and strengthen a previous sea-level curve from the area. The oldest date places sea level at about 75 m above present at 16 000 years BP. Dates from the lower lakes (+ 10 m) appear to be anomalously old, and it is suggested that after 12 000 years BP erosion became a factor in marine areas. This erosion may be related to the overall breakup of ice in the North Atlantic and may explain why few dates younger than 12 000 years BP are found in raised marine deposits of New Brunswick and Maine.

Upper Ordovician conodont biostratigraphy and the age of the Collingwood Member, southern Ontario, Canada1Earth Science Sector (ESS) Contribution 20100302.

2011 ◽  
Vol 48 (11) ◽  
pp. 1497-1522 ◽  
Author(s):  
Shunxin Zhang ◽  
Glen A. Tarrant ◽  
Christopher R. Barnes
Keyword(s):  
North Atlantic ◽  
Carbonate Platform ◽  
Upper Ordovician ◽  
Hydrocarbon Source Rock ◽  
Southern Ontario ◽  
Blue Mountain ◽  
The North ◽  
Atlantic Province ◽  
Taconic Orogeny ◽  
A New Species

The Upper Ordovician stratigraphy in southern Ontario represents the clastic foredeep associated with the Appalachian Taconic Orogeny transitioning northwest into coeval carbonate platform facies. Ten measured and sampled sections in both the Collingwood area and on Manitoulin Island, Lake Huron, provide two relatively complete composite sections (277 and 95 m, respectively) through the marine part of the sequence. A total of 100 2 kg samples collected for a conodont biostratigraphic study yielded 77 215 well-preserved specimens. Taxonomic study of the fauna, illustrated herein, identified 34 species representing 22 genera and three taxa in open nomenclature. Taxonomic revisions are made to five species of Pseudobelodina and one of Rhipidognathus ; a new species, Pseudobelodina microdentata , is established. The fauna primarily represents the Midcontinent Province with incursions from the North Atlantic Province primarily in the Collingwood area. Four conodont zones are recognized that help refine the ages for the Upper Ordovician upper Lindsay (Collingwood Member), Blue Mountain, Georgian Bay, and Queenston formations. In particular, the Collingwood Member of the Lindsay Formation, a regionally distributed organic-rich shale of hydrocarbon source rock potential, is demonstrated to lie within the Amorphognathus ordovicicus Zone of North Atlantic Province and the Oulodus robustus Zone of Midcontinent Province and to be early Richmondian age.

The Currents of the North Atlantic

1892 ◽  
Vol 34 (872supp) ◽  
pp. 13940-13941
Author(s):  
Richard Beynon
Keyword(s):  
North Atlantic ◽  
The North ◽  
The North Atlantic

NATO adaptation to current challenges and mechanisms of Ukraine’s cooperation with the North Atlantic Treaty Organization

2019 ◽  
pp. 73-81
Author(s):  
Oleh Poshedin
Keyword(s):  
North Atlantic ◽  
Task Force ◽  
Response Force ◽  
Cyber Attack ◽  
Adaptation Measures ◽  
Joint Force ◽  
Security Environment ◽  
The North ◽  
The North Atlantic ◽  
Area Of Influence

The purpose of the article is to describe the changes NATO undergoing in response to the challenges of our time. Today NATO, as a key element of European and Euro-Atlantic security, is adapting to changes in the modern security environment by increasing its readiness and ability to respond to any threat. Adaptation measures include the components required to ensure that the Alliance can fully address the security challenges it might face. Responsiveness NATO Response Force enhanced by developing force packages that are able to move rapidly and respond to potential challenges and threats. As part of it, was established a Very High Readiness Joint Task Force, a new Allied joint force that deploy within a few days to respond to challenges that arise, particularly at the periphery of NATO’s territory. NATO emphasizes, that cyber defence is part of NATO’s core task of collective defence. A decision as to when a cyber attack would lead to the invocation of Article 5 would be taken by the North Atlantic Council on a case-by-case basis. Cooperation with NATO already contributes to the implementation of national security and defense in state policy. At the same time, taking into account that all decision-making in NATO based on consensus, Ukraine’s membership in the Alliance quite vague perspective. In such circumstances, in Ukraine you often can hear the idea of announcement of a neutral status. It is worth reminding that non-aligned status did not save Ukraine from Russian aggression. Neutral status will not accomplish it either. All talks about neutrality and the impossibility of Ukraine joining NATO are nothing but manipulations, as well as recognition of the Ukrainian territory as Russian Federation area of influence (this country seeks to sabotage the Euro-Atlantic movement of Ukraine). Think about it, Moldova’s Neutrality is enshrined in the country’s Constitution since 1994. However, this did not help Moldova to restore its territorial integrity and to force Russia to withdraw its troops and armaments from Transnistria.

Sign in / Sign up

Export Citation Format

Share Document