scholarly journals Stratigraphic and Structural Framework of Upper Middle Ordovician Rocks in the Head Lake-Burleigh Falls Area of South-Central Ontario

2007 ◽  
Vol 47 (3) ◽  
pp. 253-268 ◽  
Author(s):  
Bruce V. Sanford
Keyword(s):  
Structural Deformation ◽  
Early Cambrian ◽  
Middle Ordovician ◽  
North American Continent ◽  
The North ◽  
Tectonic Events ◽  
Structural Framework ◽  
South Central ◽  
Field Investigations ◽  
Block Faulting

ABSTRACT Field investigations in the Head Lake-Burleigh Falls area of south-central Ontario, that focused mainly on the Covey Hill(?), Shadow Lake, Gull River and Coboconk formations along the Paleozoic escarpment, provided clear evidence of faulting. Observed and inferred structural deformation, coupled with faciès changes within the Shadow Lake and lower Gull River, point to a succession of basement movements during the Phanerozoic. These range from Hadrynian-Early Cambrian, through Middle Ordovician to post-late Middle Ordovician times. Some of the earlier movements (Hadrynian-Early Cambrian to late Middle Ordovician) appear to be coincident with, and probably related to, plate tectonic events and the associated Taconian orogeny that were in progress along the southeastern margins of the North American continent. Post-Middle Ordovician block faulting, on the other hand, may have been triggered by any number of epeirogenic events related to late stage Taconian, Acadian or Alleghanian orogenies in Late Ordovician to Carboniferous times, or possibly to rifting associated with continental break-up and initiation of seafloor spreading processes in the early Mesozoic. Manuscrit révisé accepté le 5 août 1993

scholarly journals 3D reconstruction of syn-tectonic strata in a salt-related orogen: learnings from the Llert syncline (South-central Pyrenees)

2020 ◽  
Vol 18 ◽  
pp. 1-19
Author(s):  
Adrià Ramos ◽  
Berta Lopez-Mir ◽  
Elisabeth P. Wilson ◽  
Pablo Granado ◽  
Josep Anton Muñoz
Keyword(s):  
3D Reconstruction ◽  
Field Research ◽  
Rift System ◽  
Passive Margins ◽  
Fold System ◽  
The North ◽  
Structural Framework ◽  
South Central ◽  
Insight Into ◽  
Central Pyrenees

The Llert syncline is located in the South-central Pyrenees, between the eastern termination of the EW-trending Cotiella Basin and the north-western limb of the NS-trending Turbón-Serrado fold system. The Cotiella Basin is an inverted upper Coniacian-lower Santonian salt-floored post-rift extensional basin developed along the northern Iberian rift system. The Turbón-Serrado fold system consists of upper Santonian – Maastrichtian contractional salt-cored anticlines developed along an inverted transfer zone of the Pyrenean rift system. Based on field research, this paper presents a 3D reconstruction of the Llert syncline in order to further constrain the transition between these oblique salt-related structures. Our results suggest that the evolution of the Llert syncline was mainly controlled by tectonic shortening related to the tectonic inversion of the Cotiella Basin synchronously to the growth of the Turbón-Serrado detachment anticline, and by the pre-compressional structural framework of the Pyrenean rift system. Our contribution provides new insight into the geometric and kinematic relationships of structures developed during the inversion of passive margins involving salt.

Chapter 24 Carboniferous–Neogene tectonic evolution of the Fennoscandian transition zone, southern Sweden

2020 ◽  
Vol 50 (1) ◽  
pp. 603-620 ◽  
Author(s):  
Mikael Erlström
Keyword(s):  
Transition Zone ◽  
Tectonic Evolution ◽  
Early Permian ◽  
Southern Sweden ◽  
Shallow Marine ◽  
The North ◽  
Tectonic Events ◽  
Southwestern Margin ◽  
Depositional Setting ◽  
Block Faulting

AbstractThe Fennoscandian transition zone, including the Sorgenfrei–Tornquist Zone, constitutes the weakened and faulted bedrock between a craton, including the ancient continent Baltica to the north, and the boundary between Baltica and Avalonia along the Trans-European Fault Zone to the south. Early Permian subsidence in this transition zone resulted in the development of various basins and the initiation of a more or less continuous Permian–Paleogene depositional cycle. In southwestern Sweden, magmatic activity associated with transtensional deformation along the Sorgenfrei–Tornquist Zone prevailed during the Late Carboniferous–Permian. However, the transition zone is dominated by a Mesozoic sedimentary rock succession displaying both hiatuses and great lateral variability in composition and thickness, which can be related to several tectonic events including the progressive break-up of Pangaea. Much of the deposition took place in continental, coastal and shallow-marine settings. Early–Middle Jurassic block faulting and basanitic or melanephelinitic volcanism, as well as Late Cretaceous tectonic inversion along the Sorgenfrei–Tornquist Zone, related to a changeover to a predominantly compressive tectonic regime coeval with the Alpine orogeny, significantly influenced the depositional setting. Subsequent Paleogene–Neogene regional uplift of the southwestern margin of Baltica resulted in significant erosion of the bedrock.

scholarly journals The Sirius Passet Fauna, an Early Cambrian Lagerstätte from North Greenland

1992 ◽  
Vol 6 ◽  
pp. 233-233
Author(s):  
John S. Peel ◽  
Simon Conway Morris ◽  
Jon R. Ineson
Keyword(s):  
Carbonate Platform ◽  
The Arctic ◽  
Early Cambrian ◽  
Burgess Shale ◽  
Generic Level ◽  
Northern Margin ◽  
North American Continent ◽  
The North ◽  
Platform Carbonates ◽  
North Greenland

The Sirius Passet Fauna of North Greenland is one of the oldest Cambrian lagerstätten from the North American continent. It is known from a single locality in Peary Land (83°N, 40°W), on the shores of the Arctic Ocean, where outer shelf mudstones from the lower part of the Buen Formation (Early Cambrian) yield a rich assemblage of mainly poorly skeletised organisms with preserved soft parts. The steeply-dipping fossiliferous mudstones occur in close proximity to horizontally-bedded platform carbonates of the underlying Portfjeld Formation (Early Cambrian) in a structurally complex terrane. The boundary between the fossiliferous mudstones and the platform carbonates apparently defines the original northern margin of the carbonate platform and is not, as previously suggested, a structural feature, although some minor tectonic modification can not be excluded. Thus, the fossiliferous mudstones were apparently deposited in a transitional slope setting basinward of the shelf edge.As currently known, the Sirius Passet Fauna comprises about 40 species, based on a collection of almost 5,000 slabs collected during brief visits to the isolated locality in 1989 and 1991. Arthropods dominate, with bivalved bradoriids and the trilobite Buenellus higginsi Blaker, 1988 being the numerically most abundant taxa. Weakly skeletised Naraoia-like and Sidneyia-like arthropods often preserve limbs and gills, as do bivalved arthropods similar to Waptia. Choia is the most common of several sponges. Worms include both priapulids and polychaetes, with a large palaeoscolecidan being conspicuous.Fully articulated specimens of halkieriid worms, clad in an armour of hundreds of individual sclerites, are most notable amongst several problematic taxa. Rare specimens of possible onychophorans are also present, while brachiopods, hyoliths and other shelly fossils are rare or absent.The Sirius Passet Fauna seems to show little taxonomic similarity to the Middle Cambrian Burgess Shale of western Canada or the Chengjiang Fauna from the Lower Cambrian of China at the generic level. Together with the latter fauna, however, it confirms both the general picture of Cambrian life presented by the Burgess Shale, and the existence of this great diversity of weakly skeletised arthropods already in the Early Cambrian.

scholarly journals Lower Palaeozoic Franklinian Basin of North Greenland

1991 ◽  
Vol 160 ◽  
pp. 71-139
Author(s):  
A.K Higgins ◽  
J.R Ineson ◽  
J.S Peel ◽  
F Surlyk ◽  
M Sønderholm
Keyword(s):  
Carbonate Platform ◽  
Early Carboniferous ◽  
Normal Faults ◽  
Early Cambrian ◽  
Middle Ordovician ◽  
The North ◽  
Water Trough ◽  
Lower Palaeozoic ◽  
Orogenic Uplift ◽  
North Greenland

The Franklinian Basin extends from the Canadian Arctic Islands to eastern North Greenland, a distance of approximately 2000 km. In the North Greenland segment about 8 km of Lower Palaeozoic strata are well exposed and permit the recognition of 7 stages in the evolution of the basin. With the exception of the first stage of basin initiation, which occurred dose to the Precambrian-Cambrian boundary, each stage is differentiated into a southern shelf and slope, and a northern deep-water trough. The position of the boundary between the shelf and trough was probably controlled by deep seated normal faults and, with time, the basin expanded southwards leading to a final foundering of the shelf areas during the Silurian. The 7 stages in the evolution of the Franklinian Basin in North Greenland are: 1, Late Proterozoic? - Early Cambrian shelf (basin initiation); 2, Early Cambrian carbonate platform and incipient trough; 3, Early Cambrian siliciclastic shelf and turbidite trough; 4, Late Early Cambrian - Middle Ordovician carbonate shelf and starved trough; 5, Middle Ordovician - Early Silurian aggradational carbonate platform, starved slope and trough; 6, Early Silurian ramp and rimmed shelf, and turbidite trough; 7, Early - Late Silurian drowning of the platform. Basin evolution and sedimentation patterns in the eastem part of the Franklinian Basin were strongly influenced by the dosure of the lapetus Ocean and Caledonian orogenic uplift in eastern North Greenland. The Franklinian Basin in North Greenland was finally closed in Devonian - Early Carboniferous times, resulting in strong deformation of the northern part of the Franklinian trough sequence during the Ellesmerian Orogeny.

scholarly journals Carbonate debris flows in the Cambrian of south-west Peary Land, eastern North Greenland

1980 ◽  
Vol 99 ◽  
pp. 43-49
Author(s):  
J.R Ineson
Keyword(s):  
Debris Flows ◽  
Early Cambrian ◽  
The South ◽  
The West ◽  
Middle Ordovician ◽  
The North ◽  
Late Cambrian ◽  
North Side ◽  
South West ◽  
North Greenland

In south-western Peary Land a thick carbonate dominated sequence of Early to Late Cambrian Age conformably overlies the Early Cambrian Buen Formation, and is overlain, unconformably, by the Wandel Valley Formation of Early-Middle Ordovician age (Peel, 1979; Palmer & Peel, 1979). This sequence is subdivided into the Brønlund Fjord Group and the overlying Tavsens Iskappe Group (Peel, 1979; Ineson & Peel, this report). The Brønlund Fjord Group characteristically forms resistant bluffs along the north side of Wansel Dal from J. P. Koch Fjord in the west to Independence Fjord (fig. 20) in the east. The Tavsens Iskappe Group is confined to western areas by the south-easterly overstep of the Wandel Valley Formation.

scholarly journals The small shelly fossil Mongolitubulus from the Lower Cambrian of central North Greenland

1988 ◽  
Vol 137 ◽  
pp. 55-60
Author(s):  
J.S Peel ◽  
M.R Blaker
Keyword(s):  
North American ◽  
Lower Cambrian ◽  
First Record ◽  
Early Cambrian ◽  
American Continent ◽  
North American Continent ◽  
The North ◽  
North Greenland

The problematic small shelly fossil Mongolitubulus Missarzhevsky, 1977 is reported from the Henson Gletscher Formation of late Early Cambrian age (Bonnia-Olenellus Zone) in southem Freuchen Land, central North Greenland. Mongolitubulus is described from strata of similar Early Cambrian age (Botomian) in Mongolia and Kazakhstan, and is also reported from Antarctica. The Greenland Mongolitubulus is the first record of the genus from the North American continent.

Ketilidian structure and the rapakivi suite between Lindenow Fjord and Kap Farvel, South-East Greenland

2000 ◽  
pp. 50-59
Author(s):  
Brian Chadwick ◽  
Adam A. Garde ◽  
John Grocott ◽  
Ken J.W. McCaffrey ◽  
Mike A. Hamilton
Keyword(s):  
Coastal Region ◽  
Field Work ◽  
Natural Environment Research Council ◽  
East Greenland ◽  
The North ◽  
Tectonic Processes ◽  
Field Investigations ◽  
North Eastern ◽  
Bad Weather ◽  
North Eastern Part

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Chadwick, B., Garde, A. A., Grocott, J., McCaffrey, K. J., & Hamilton, M. A. (2000). Ketilidian structure and the rapakivi suite between Lindenow Fjord and Kap Farvel, South-East Greenland. Geology of Greenland Survey Bulletin, 186, 50-59. https://doi.org/10.34194/ggub.v186.5215 _______________ The southern tip of Greenland is underlain by the Palaeoproterozoic Ketilidian orogen (e.g. Chadwick & Garde 1996; Garde et al. 1998a). Field investigations in the summer of 1999 were focused on the structure of migmatites (metatexites) and garnetiferous granites (diatexites) of the Pelite Zone in the coastal region of South-East Greenland between Lindenow Fjord and Kap Farvel (Figs 1, 2). Here, we first address the tectonic evolution in the Pelite Zone in that region and its correlation with that in the Psammite Zone further north. Then, the structure and intrusive relationships of the rapakivi suite in the Pelite Zone are discussed, including particular reference to the interpretation of the controversial outcrop on Qernertoq (Figs 2, 8). Studies of the structure of the north-eastern part of the Julianehåb batholith around Qulleq were continued briefly from 1998 but are not addressed here (Fig. 1; Garde et al. 1999). The field study was keyed to an interpretation of the Ketilidian orogen as a whole, including controls of rates of thermal and tectonic processes in convergent settings. Earlier Survey field work (project SUPRASYD, 1992–1996) had as its principal target an evaluation of the economic potential of the orogen (Nielsen et al. 1993). Ensuing plate-tectonic studies were mainly funded in 1997–1998 by Danish research foundations and in 1999 by the Natural Environment Research Council, UK. The five-week programme in 1999 was seriously disrupted by bad weather, common in this part of Greenland, and our objectives were only just achieved. Telestation Prins Christian Sund was the base for our operations (Fig. 2), which were flown with a small helicopter (Hughes MD-500).

OREL SECURITY OFFICER BORIS GORDON AND THE «RED CHAPEL»

2020 ◽  
Vol 9 (3) ◽  
pp. 164-175
Author(s):  
A.Yu. SARAN ◽  
◽  
M.V. SOKOLOV ◽  
Keyword(s):  
Central Asia ◽  
Nazi Germany ◽  
Career Ladder ◽  
Security Officer ◽  
State Security ◽  
Successful Career ◽  
The North ◽  
South Central ◽  
Foreign Countries ◽  
Party Work

The purpose of the article is to study the biography of B.M. Gordon as a successful security officer in the 1920-s and 1930-s. He worked his way up the career ladder from a junior investigator to the head of regional divisions – territorial bodies of the VChK/GPU/OGPU/NKVD and the legal residency of the INO GUGB of NKVD in Germany. Having started his chekist service in the Orel province, he served in the South – Central Asia, in the North – in Arkhangelsk province,in the capital of the USSR, and in the capital of Nazi Germany – Berlin. Gordon fought with the white guards and evicted the dispossessed peasants, controlled the Soviet military and gathered information about the armies of foreign countries; he managed to work at both Soviet and party work. Finally, the energetic work and successful career led Boris Moiseyevich Gordon to his death, when in 1937, J.V. Stalin decided to destroy completely all the former operational leadership of the state security agencies, replacing it with new personnel.

Cerro del Hierro, Spain: the largest exposed early Cambrian palaeokarst

2020 ◽  
pp. 1-14
Author(s):  
Eduardo Mayoral ◽  
María Eugenia Dies Álvarez ◽  
José Antonio Gámez Vintaned ◽  
Rodolfo Gozalo ◽  
Eladio Liñán ◽  
...  
Keyword(s):  
South America ◽  
Mediterranean Region ◽  
Early Cambrian ◽  
Karst Development ◽  
Global Context ◽  
Tectonic Events ◽  
Extensional Tectonic ◽  
Geomorphological Processes ◽  
The Uk ◽  
Regressive Events

Abstract We study the largest exposed example of an early Cambrian palaeokarst, associated with laterites and developed during rifting of the Ossa–Morena Zone. The lithostratigraphy, biostratigraphy, facies and the genesis reflect episodes of sea-level fall (Cerro del Hierro Regression) related to tectonic events and palaeoclimate. This palaeokarst can be primarily considered as the result of early Cambrian polyphase karstification in an extensional tectonic regime, later modified by Neogene–Quaternary geomorphological processes. The event may correlate with other regressive events of a similar age in Spain, Italy, United Kingdom, South America and Australia. This episode also has local names (e.g. Cerro del Hierro Regression in the Mediterranean region; Woodlands Regression in the UK). It is sometimes accompanied by additional karst development outside of Spain that is compared and interpreted in a global context.

scholarly journals Distribution, ecology and conservation of an endangered Andean hummingbird: the Violet-throated Metaltail (Metallura baroni)

2009 ◽  
Vol 19 (1) ◽  
pp. 63-76 ◽  
Author(s):  
BORIS A. TINOCO ◽  
PEDRO X. ASTUDILLO ◽  
STEVEN C. LATTA ◽  
CATHERINE H. GRAHAM
Keyword(s):  
Suitable Habitat ◽  
Species Occurrence ◽  
Entropy Model ◽  
Maxent Model ◽  
The North ◽  
The Andes ◽  
Guide Field ◽  
South Central ◽  
Detailed Assessment ◽  
Endangered Status

SummaryThe Violet-throated MetaltailMetallura baroniis a high altitude hummingbird endemic to south-central Ecuador currently considered globally ‘Endangered’. Here we present the first detailed assessment of its distribution, ecology and conservation. We first used a maximum entropy model (Maxent model) to create a predicted distribution for this species based on very limited species occurrence data. We used this model to guide field surveys for the species between April and October 2006. We found a positive relationship between model values and species presence, indicating that the model was a useful tool to predict species occurrence and guide exploration. In the sites where the metaltail was found we gathered data on its habitat requirements, food resources and behaviour. Our results indicate that Violet-throated Metaltail is restricted to the Western Cordillera of the Andes Mountains in Azuay and Cañar provinces of Ecuador, with an area of extent of less than 2,000 km2. Deep river canyons to the north and south, lack of suitable habitat, and potential interspecific competition in the east may limit the bird's distribution. The species occurred in three distinct habitats, includingPolylepiswoodland, the upper edge of the montane forest, and in shrubby paramo, but we found no difference in relative abundance among these habitats. The metaltail seems to tolerate moderate human intervention in its habitats as long as some native brushy cover is maintained. We found thatBrachyotumsp.,Berberissp., andBarnadesiasp. were important nectar resources. The ‘Endangered’ status of this species is supported due to its restricted distribution in fragmented habitats which are under increasing human pressures.

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