scholarly journals Cretaceous and Cenozoic dinoflagellate cysts and other palynomorphs from the western and eastern margins of the Labrador–Baffin Seaway

2016 ◽  
Vol 36 ◽  
pp. 1-143 ◽  
Author(s):  
Robert A. Fensome ◽  
Henrik Nøhr-Hansen ◽  
Graham L. Williams
Keyword(s):  
New Combination ◽  
Labrador Sea ◽  
New Genera ◽  
The West ◽  
Palynological Analysis ◽  
Baffin Bay ◽  
Davis Strait ◽  
History Of ◽  
Greenland Margin ◽  
Plant Microfossil

New palynological analysis of samples from 13 offshore wells on the Canadian Margin and six wells on the West Greenland Margin has led to a new event biostratigraphic framework for Cretaceous–Cenozoic strata of the Labrador Sea – Davis Strait – Baffin Bay (Labrador–Baffin Seaway) region. This framework is based on about 150 dinoflagellate cyst taxa and 30 acritarch, algal, fungal and plant microfossil (mostly miospore) taxa. In the systematics we include three new genera of dinocysts (Scalenodinium, Simplicidinium and Taurodinium), 16 new species of dinocysts (Chiropteridium gilbertii, Chytroeisphaeridia hadra, Cleistosphaeridium elegantulum, Cleistosphaeridium palmatum, Dapsilidinium pseudoinsertum, Deflandrea borealis, Evittosphaerula? foraminosa, Ginginodinium? flexidentatum, Hystrichosphaeridium quadratum, Hystrichostrogylon digitus, Impletosphaeridium apodastum, Scalenodinium scalenum, Surculosphaeridium convocatum, Talladinium pellis, Taurodinium granulatum and Trithyrodinium? conservatum), four emendations of dinocyst genera (Alterbidinium, Chatangiella, Chiropteridium and Surculosphaeridium), six new combinations for dinocyst species (Alterbidinium biaperturum, Deflandrea majae, Kleithriasphaeridium mantellii, Simplicidinium insolitum, Spongodinium grossum, Spongodinium obscurum), one new acritarch species (Fromea quadrangularis), one new miospore species (Baculatisporites crenulatus) and one new combination for miospores (Tiliaepollenites crassipites). Most of the taxa included provide age information, almost exclusively last occurrences (range ‘tops’), but some are useful mainly for environmental interpretations. Collectively, they provide a powerful tool for helping to establish the geological history of the Labrador–Baffin Seaway.  

Cretaceous-Palaeogene sub-basaltic and intrabasaltic sediments of the Kangerdlugssuaq area, Central East Greenland

1981 ◽  
Vol 118 (4) ◽  
pp. 337-354 ◽  
Author(s):  
A. C. Higgins ◽  
N. J. Soper
Keyword(s):  
Labrador Sea ◽  
Organic Detritus ◽  
Eruption Rate ◽  
East Greenland ◽  
Baffin Bay ◽  
Sequence Of Events ◽  
Basement Rocks ◽  
Shelf Sea ◽  
History Of ◽  
Greenland Margin

SummaryCretaceous-Palaeogene sediments of the Kangerdlugssuaq area on the continental margin of Central East Greenland were deposited in an embayment of an extensive pre-NE Atlantic shelf sea. Pre-Sparnacian sediments are thin (150 m), incomplete and of siliciclastic type, formed in shallow marine waters. Sparnacian times saw the onset of vigorous basaltic vulcanicity, marking the initial rifting episode between Greenland and Eurasia. Uplift immediately prior to the vulcanicity is evidenced by an unconformity at the base of the Sparnacian, above which basement-derived arkosic sandstones and conglomerates are followed by about 1.5 km of coarse volcaniclastics, basaltic flows of dominantly picritic composition, pro-grading hyaloclastite wedges and thin siltstones with abundant organic detritus. Very rapid subsidence accompanied this early phase of vulcanicity, maintaining the top of the pile close to sea level and allowing the deposition of a further kilometre of waterlain tuffs in the embayment. Sedimentation extended northwards and eastwards on to basement rocks at this period, with the formation of a non-marine sequence which includes coals.The overlying plateau tholeiites overlap the earlier volcanics; their depositional area was extremely extensive along the East Greenland margin and bears no relationship to the Kangerdlugssuaq sedimentary embayment, although their thickest development, 4 km or more, was attained in that region. Eruption rate of the pile exceeded subsidence for a period and it is dominantly subaerial.This sequence of events is compared with the similar history of sedimentation and basaltic vulcanicity on the west coast of Greenland, and it is inferred that just as the East Greenland sequence records the initiation of spreading between Greenland and Rockall-Faeroe at anomaly 24−25 time, so that of West Greenland marks the propagation of the Labrador Sea spreading axis through the Davis Strait into Baffin Bay at anomaly 26−27 time.

scholarly journals Evolution of Labrador Sea–Baffin Bay: Plate or Plume Processes?

2017 ◽  
Vol 44 (3) ◽  
pp. 91-102 ◽  
Author(s):  
Alexander Lewis Peace ◽  
Gillian R. Foulger ◽  
Christian Schiffer ◽  
Ken J.W. McCaffrey
Keyword(s):  
Ad Hoc ◽  
Labrador Sea ◽  
Continental Lithosphere ◽  
The West ◽  
Baffin Bay ◽  
Bay Area ◽  
Oceanic Spreading ◽  
Davis Strait ◽  
Orogenic Belts ◽  
Le Canada

Breakup between Greenland and Canada resulted in oceanic spreading in the Labrador Sea and Baffin Bay. These ocean basins are connected through the Davis Strait, a bathymetric high comprising primarily continental lithosphere, and the focus of the West Greenland Tertiary volcanic province. It has been suggested that a mantle plume facilitated this breakup and generated the associated magmatism. Plume-driven breakup predicts that the earliest, most extensive rifting, magmatism and initial seafloor spreading starts in the same locality, where the postulated plume impinged. Observations from the Labrador Sea–Baffin Bay area do not accord with these predictions. Thus, the plume hypothesis is not confirmed at this locality unless major ad hoc variants are accepted. A model that fits the observations better involves a thick continental lithospheric keel of orogenic origin beneath the Davis Strait that blocked the northward-propagating Labrador Sea rift resulting in locally enhanced magmatism. The Davis Strait lithosphere was thicker and more resilient to rifting because the adjacent Paleoproterozoic Nagssugtoqidian and Torngat orogenic belts contain structures unfavourably orientated with respect to the extensional stress field at the time.RÉSUMÉLa cassure entre le Groenland et le Canada a entraîné une expansion océanique de la mer du Labrador et de la baie de Baffin. Ces bassins océaniques sont reliés par le détroit de Davis, un haut bathymétrique constitué principalement de lithosphère continentale et de la province volcanique tertiaire de l'ouest du Groenland. Il a été suggéré qu'un panache du manteau a facilité cette cassure et généré le magmatisme associé. L’hypothèse d’une cassure produite par panache du manteau prédit que la première distension océanique, la plus importante, le magmatisme et l'expansion océanique initial se produisent là où le panache mantélique touche la croûte continentale. Or les observations dans la région de la mer du Labrador–baie de Baffin ne correspondent pas à ces prédictions. Et donc l'hypothèse du panache ne fonctionne pas dans cette région à moins que des facteurs ad hoc déterminants ne soient présents. Un modèle qui correspond mieux aux observations présuppose la présence d’une épaisse quille lithosphérique continentale d'origine orogénique sous le détroit de Davis qui aurait bloqué l’expansion océanique de la mer du Labrador vers le nord, ce qui aurait provoqué une augmentation du magmatisme localement. La lithosphère du détroit de Davis était plus épaisse et plus résistante à l’expansion océanique parce que les bandes orogéniques paléoprotérozoïques du Nagssugtoqidian et de Torngat renferment des structures défavorablement orientées par rapport au champ de contraintes d’extensions de l'époque.

Hydrological History of the West Baray, Angkor, revealed through Palynological Analysis of Sediments from the West Mebon

2005 ◽  
Vol 92 (1) ◽  
pp. 497-521 ◽  
Author(s):  
Dan Penny ◽  
Christophe Pottier ◽  
Matti Kummu ◽  
Roland Fletcher ◽  
Ugo Zoppi ◽  
...  
Keyword(s):  
The West ◽  
Palynological Analysis ◽  
History Of

scholarly journals Full-fit reconstruction of the Labrador Sea and Baffin Bay

2013 ◽  
Vol 5 (2) ◽  
pp. 917-962 ◽  
Author(s):  
M. Hosseinpour ◽  
R. D. Müller ◽  
S. E. Williams ◽  
J. M. Whittaker
Keyword(s):  
North America ◽  
Continental Crust ◽  
Seafloor Spreading ◽  
Labrador Sea ◽  
Gravity Inversion ◽  
Seismic Profiles ◽  
Baffin Bay ◽  
Davis Strait ◽  
Break Up ◽  
Magnetic Lineations

Abstract. Reconstructing the opening of the Labrador Sea and Baffin Bay between Greenland and North America remains controversial. Recent seismic data suggest that magnetic lineations along the margins of the Labrador Sea, originally interpreted as seafloor spreading anomalies, may lie within the crust of the continent–ocean transition. These data also suggest a more seaward extent of continental crust within the Greenland margin near the Davis Strait than assumed in previous full-fit reconstructions. Our study focuses on reconstructing the full-fit configuration of Greenland and North America using an approach that considers continental deformation in a quantitative manner. We use gravity inversion to map crustal thickness across the conjugate margins, and assimilate observations from available seismic profiles and potential field data to constrain the likely extent of different crustal types. We derive end-member continental margin restorations following alternative interpretations of published seismic profiles. The boundaries between continental and oceanic crust (COB) are restored to their pre-stretching locations along small circle motion paths across the region of Cretaceous extension. Restored COBs are fitted quantitatively to compute alternative total-fit reconstructions. A preferred full-fit model is chosen based on the strongest compatibility with geological and geophysical data. Our preferred model suggests that (i) the COB lies oceanward of magnetic lineations interpreted as magnetic anomaly 31 (70 Ma) in the Labrador Sea, (ii) all previously identified magnetic lineations landward of anomaly 27 reflect intrusions into continental crust, and (iii) the Ungava fault zone in Davis Strait acted as a leaky transform fault during rifting. This robust plate reconstruction reduces gaps and overlaps in the Davis Strait and suggests that there is no need for alternative models proposed for reconstructions of this area including additional plate boundaries in North America or Greenland. Our favored model implies that break up and formation of continent–ocean transition (COT) first started in the southern Labrador Sea and Davis Strait around 88 Ma and then propagated north and southwards up to onset of real seafloor spreading at 63 Ma in the Labrador Sea. In the Baffin Bay, continental stretching lasted longer and actual break up and seafloor spreading started around 61 Ma (Chron 26).

scholarly journals Faults and fractures in central West Greenland: onshore expression of continental break-up and sea-floor spreading in the Labrador – Baffin Bay Sea

2006 ◽  
Vol 11 ◽  
pp. 185-204 ◽  
Author(s):  
Robert W. Wilson ◽  
Knud Erik S. Klint ◽  
Jeroen A.M. Van Gool ◽  
Kenneth J.W. McCaffrey ◽  
Robert E. Holdsworth ◽  
...  
Keyword(s):  
Dominant Role ◽  
Field Studies ◽  
Labrador Sea ◽  
Tectonic Structures ◽  
Two Phase ◽  
Baffin Bay ◽  
Fault Systems ◽  
Davis Strait ◽  
Regional Tectonic ◽  
Sea Floor Spreading

The complex Ungava fault zone lies in the Davis Strait and separates failed spreading centres in the Labrador Sea and Baffin Bay. This study focuses on coastal exposures east of the fault-bound Sisimiut basin, where the onshore expressions of these fault systems and the influence of pre-existing basement are examined. Regional lineament studies identify five main systems: N–S, NNE–SSW, ENE–WSW, ESE–WNW and NNW–SSE. Field studies reveal that strike-slip movements predominate, and are consistent with a ~NNE–SSW-oriented sinistral wrench system. Extensional faults trending N–S and ENE–WSW (basement-parallel), and compressional faults trending E–W, were also identified. The relative ages of these fault systems have been interpreted using cross-cutting relationships and by correlation with previously identified structures. A two-phase model for fault development fits the development of both the onshore fault systems observed in this study and regional tectonic structures offshore. The conclusions from this study show that the fault patterns and sense of movement on faults onshore reflect the stress fields that govern the opening of the Labrador Sea – Davis Strait – Baffin Bay seaway, and that the wrench couple on the Ungava transform system played a dominant role in the development of the onshore fault patterns.

The Sponge Family Guadalupiidae in the Texas Permian

2010 ◽  
Vol 84 (5) ◽  
pp. 821-847 ◽  
Author(s):  
Robert M. Finks
Keyword(s):  
Evolutionary History ◽  
Growth Patterns ◽  
New Genera ◽  
The West ◽  
Entire Family ◽  
Ecological Relationships ◽  
West Texas ◽  
The Family ◽  
History Of ◽  
Almost All

New and old species and genera of the family Guadalupiidae (spherulitic hypercalcified demosponges of the order Agelasida) are described or redescribed from the West Texas Permian. The entire family is reviewed and observations are made on the epibionts, growth patterns, functional morphology, ecological relationships, morphologic variability, modular structure, and evolutionary history of these largely reef-dwelling sponges. The stratigraphic distribution of species is also noted; many are limited and can define zones. The new genera Exovasa and Incisimura and the new species Guadalupia auricula, G. cupulosa, G. ramescens, G. microcamera, G. vasa, Cystothalamia megacysta, Lemonea simplex, Incisimura bella, and Exovasa cystauletoides are described. Almost all previously published taxa are redescribed and in some cases redefined. The Guadalupiidae are unique among hypercalcified sponges in having a modular thalamid layer (thalamidarium) covered on the exhalant surface by a non-modular stromatoporoid-like layer (trabecularium).

scholarly journals Volume, Freshwater, and Heat Fluxes through Davis Strait, 2004–05*

2011 ◽  
Vol 41 (3) ◽  
pp. 429-436 ◽  
Author(s):  
B. Curry ◽  
C. M. Lee ◽  
B. Petrie
Keyword(s):  
Heat Fluxes ◽  
First Year ◽  
Baffin Island ◽  
Fram Strait ◽  
The West ◽  
Baffin Bay ◽  
Freshwater Fluxes ◽  
Davis Strait ◽  
Island Shelf ◽  
Southward Transport

Abstract Davis Strait volume [−2.3 ± 0.7 Sv (1 Sv ≡ 106 m3 s−1); negative sign indicates southward transport], freshwater (−116 ± 41 mSv), and heat (20 ± 9 TW) fluxes estimated from objectively mapped 2004–05 moored array data do not differ significantly from values based on a 1987–90 array but are distributed differently across the strait. The 2004–05 array provided the first year-long measurements in the upper 100 m and over the shelves. The upper 100 m accounts for 39% (−0.9 Sv) of the net volume and 59% (−69 mSv) of the net freshwater fluxes. Shelf contributions are small: 0.4 Sv (volume), 15 mSv (freshwater), and 3 TW (heat) from the West Greenland shelf and −0.1 Sv, −7 mSv, and 1 TW from the Baffin Island shelf. Contemporaneous measurements of the Baffin Bay inflows and outflows indicate that volume and freshwater budgets balance to within 26% and 4%, respectively, of the net Davis Strait outflow. Davis Strait volume and freshwater fluxes nearly equal those from Fram Strait, indicating that both are significant Arctic freshwater pathways.

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