Paleomagnetism of the Mesozoic Coast Parallel Dolerite Dikes of West Greenland

Paleomagnetic measurements on 61 drill cores from eight sites of the Coast Parallel dikes of west Greenland (Fiskenaesset area) have yielded a pole position at 169°E, 54°N, α95 = 5.9°. When these data are combined with those from the Nunarsuit-Tornarssuk area (Ketelaar 1963) the pole is 168°E, 56°N, α95 = 6°. Reversely magnetized dikes are present in both areas.The Coast Parallel dike pole lies close to the Triassic pole position for North America if corrected for Bullard's fit. The dikes were therefore intruded prior to the Mesozoic separation of Greenland and North America.

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Holocene shore-lines and glacial stages in Greenland - an attempt at correlation

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v41.7281 ◽

1972 ◽

Vol 41 ◽

pp. 1-39

Author(s):

A Weidick

Keyword(s):

North America ◽

Current Literature ◽

Younger Dryas ◽

Low Pressure ◽

East Greenland ◽

West Greenland ◽

History Of ◽

Climatic Optimum ◽

North Greenland

Post-Wisconsinian uplift of West, North and East Greenland has been estimated on the basis of information in current literature and compared to the data collected by the author in central West Greenland. For West and North Greenland the dated uplift allows an estimate to be made of the age of former shore-lines, which in turn have been used to date the stages of the extent of the Inland lce. The results have been compared with published information on the age of glacial stages in East Greenland. The estimated ages of the ice margin stages imply a history of deglaciation in West (and North?) Greenland comparable to that of North America. In both areas the major deglaciation took place after the Younger Dryas and a marked halt took place in Boreal times. It is possibie that the history of East Greenland is more closely related to that of Scandinavia where a widespread deglaciation took place prior to the Younger Dryas. The deglaciation of North Greenland was interrupted by a marked readvance or readvances during the climatic optimum. It is possible that the northward shift of the low pressure centres during this period led to an increased accumulation on the northern part of the Inland lce.

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Ice conditions offshore West Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v159.8206 ◽

1993 ◽

Vol 159 ◽

pp. 43-47

Author(s):

H.H Thomsen

Keyword(s):

North America ◽

Working Conditions ◽

Environmental Studies ◽

The Political ◽

West Greenland ◽

Ice Conditions ◽

Special Information

An offshore West Greenland licensing found was formally approved by the Danish Minister of Energy on 26 March 1992, and announced in industry journals in the following months. To give interested companies an opportunity to familiarise themselves with the political framework, licensing terms, geology of the licensing area and general working conditions in Greenland, presentations were held in Europe and North America (Christiansen et al., this report. In addition GGU prepared a special information package 'Offshore West Greenland – Exploration Information 1992' for the licensing round. One of the enclosures in this package is a brief review of ice conditions offshore West Greenland with particular reference to the licensing area (Thomsen, 1992; Fig. 1). The licensing round failed to attract any applications, but ice conditions offshore West Greenland remain of prime interest to any group planning geophysical or environmental studies in the area. For this reason a summary of the report enclosed in the information package is given here.

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Extent of Grenvillian remanence components in rocks of the Southern Province

Canadian Journal of Earth Sciences ◽

10.1139/e82-059 ◽

1982 ◽

Vol 19 (4) ◽

pp. 698-708 ◽

Cited By ~ 10

Author(s):

M. Stupavsky ◽

D. T. A. Symons

Keyword(s):

Magnetic Field ◽

North America ◽

Thin Section ◽

Sedimentary Rocks ◽

Pole Position ◽

River Valley ◽

Field Reversal ◽

Paleomagnetic Study ◽

Northern Portion ◽

Sediment Matrix

Early Aphebian Gowganda sedimentary rocks and intruding Nipissing diabase sills were sampled for paleomagnetic study at 88 sites (~500 cores, ~1000 specimens) along two ~42 km long profiles extending north from the Grenville Front into the Cobalt Plate of the Southern Structural Province in the River Valley – Lake Temagami area of Ontario. After AF demagnetization a postfolding pre-Nipissing ~2200 Ma remanence was found in eight of the 37 Gowganda sediment sites that were > 2 km north of the front, giving a pole at 109°W, 63°N (dp = 10°, dm = 19°). The Nippissing diabase from > 2 km north of the front retains a stable antiparallel prefolding N1 remanence direction in 22 of 40 sites, giving a pole position of 85°W, 17°S (dp = 6°, dm = 10°). These "south and down" remanence directions found in the southern portion of the plate contrast with the antiparallel "north and up" directions found in the northern portion, thereby indicating the occurrence of either two nearly cogenetic Nipissing intrusive events or the sequential emplacement of the Nipissing during an Earth's magnetic field reversal across the plate. At two sites a Nipissing remagnetized remanence was found in Gowganda sediments with a pole of 115°W, 18°S. Also three "Nipissing" sites give a pole at 164°W, 3°N, which is close to the known pole for the later ~1.25 Ga Sudbury olivine diabase dikes. One site is adjacent to a large dike and two were found on thin-section examination to be olivine diabase. The eight sites in Gowganda sediment matrix and conglomerate clasts and in Nipissing diabase from within < 2 km from the front were found to have a postfolding metamorphic remanence with a Grenville orogenic pole at 45°W, 51°N (dp = 19°, dm = 21°). Finally, the results lead to a suggested revision in the APW path for the ~2300–~1650 Ma interval for North America.

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Paleomagnetism of drill cores from Labrador offshore wells

Canadian Journal of Earth Sciences ◽

10.1139/e82-194 ◽

1982 ◽

Vol 19 (11) ◽

pp. 2210-2214

Author(s):

Raymund R. Pätzold ◽

Ernst R. Deutsch

Keyword(s):

Thermal Treatment ◽

Early Cretaceous ◽

Pole Position ◽

Magnetic Intensity ◽

Thermal Demagnetization ◽

Initial Susceptibility ◽

Normal Polarity ◽

Short Core ◽

Basaltic Material ◽

Drill Cores

Values of the remanent magnetic intensity and inclination, initial susceptibility, and Koenigsberger ratios were obtained from basaltic material in four short core sections from three wells (Bjarni H81, two sections; Leif M48; Herjolf M92) drilled off Labrador. Published K–Ar dates are latest Jurassic to Early Cretaceous. Alternating-field (AF) demagnetization to 600 Oe (60 mT) and thermal demagnetization to 400 °C yielded stable, comparable remanent inclinations mostly of normal polarity for the Bjarni and Leif samples and revealed a change from reversed to normal polarity in the Bjarni well. Virtual pole position loci calculated from the paleoinclinations after AF and thermal treatment agree with published Early Cretaceous pole positions in the case of one Bjarni core, but the fit is poorer in the case of the second Bjarni core and the Leif core. These are the first paleomagnetic results from offshore Labrador.

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Palaeomagnetism of the Lower Carboniferous Billefjorden Group, Spitsbergen

Geological Magazine ◽

10.1017/s0016756800031824 ◽

1985 ◽

Vol 122 (4) ◽

pp. 383-388 ◽

Cited By ~ 14

Author(s):

D. R. Watts

Keyword(s):

North America ◽

Relative Motion ◽

Early Carboniferous ◽

Pole Position ◽

Russian Platform ◽

Lower Carboniferous ◽

Fine Grained ◽

Palaeomagnetic Data ◽

The Baltic

AbstractPalaeomagnetic data from mid to late Palaeozoic rocks are potentially valuable for testing models of the assembly of Spitsbergen and for determining the palaeo-position of parts of Spitsbergen relative to the major tectonic elements that comprised the Old Red Continent. Fine-grained red sandstones from the Tournaisian to Namurian Billefjorden Group, collected by members of Cambridge Spitsbergen expeditions, were subjected to stepwise chemical and thermal demagnetization. The characteristic magnetization is found in normal and reverse polarities and corresponds to a pole position at 23° S, 332 °E, dp = 5.7°, dm = 10.5°, which is near an early Carboniferous pole computed for the Baltic Shield-Russian Platform (Baltica). When compared to Laurentia (North America) in the context of the revised Mauch Chunk palaeomagnetic study, Spitsbergen falls a few degrees south of the Bullard reconstruction but the error of the determination of the palaeolatitude overlaps with this position. Therefore relative motion between any part of Spitsbergen and Laurentia and Baltica during the Carboniferous is not resolved.

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Pingos at Nioghalvfjerdsfjorden, eastern North Greenland

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/ggub.v180.5101 ◽

1998 ◽

pp. 159-162 ◽

Cited By ~ 3

Author(s):

Ole Bennike

Keyword(s):

North America ◽

Open System ◽

Closed System ◽

Field Work ◽

Frozen Ground ◽

East Greenland ◽

Original Series ◽

West Greenland ◽

System Type ◽

North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bennike, O. (1998). Pingos at Nioghalvfjerdsfjorden, eastern North Greenland. Geology of Greenland Survey Bulletin, 180, 159-162. https://doi.org/10.34194/ggub.v180.5101 _______________ Pingos are isolated, conical mounds up to 50 m high with a core of ice covered by silt, sand or gravel. They are formed in regions where the ground is permanently frozen. Two types of pingo are distinguished, a closed-system and an open-system (Washburn 1979; Pissart 1988). The closed-system type is found on flat plains, whereas open-system pingos are found on valley floors. Open-system pingos grow by artesian pressure (Müller 1959; Washburn 1979). Water from higher altitudes migrates within or below the permanently frozen ground and becomes trapped within the permafrost and freezes to form a lens or core of ice. Active pingos have been reported from Svalbard, Russia, Alaska, Canada and Greenland (Washburn 1979), and fossil pingos from Pleistocene periglacial terrains have been reported from Europe and North America (De Gans 1988). In Greenland, most pingos have been reported from both East and West Greenland. In East Greenland pingos have been described from the area between 71°30′ and 74°30′N (Fig. 1). In West Greenland most pingos occur between 70° and 72°N. In addition, a pingo and some pingo-like forms have been described from North Greenland (Bennike 1983). All pingos in Greenland are located in valleys, usually on outwash plains. During field work in 1997 one fairly impressive pingo and several small pingos or pingo-like forms were observed at c. 79°30′N in eastern North Greenland. These are the northernmost pingos recorded from eastern Greenland, and the aim of this note is to document and describe these forms. The observations add to our knowledge about the distribution of pingos in Greenland, and a map showing the distribution of pingos in Greenland is presented as Fig. 1.

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Paleomagnetism of igneous rocks from the Belcher Islands, Northwest Territories, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e80-081 ◽

1980 ◽

Vol 17 (7) ◽

pp. 807-822 ◽

Cited By ~ 22

Author(s):

P. W. Schmidt

Keyword(s):

North America ◽

Northwest Territories ◽

Igneous Rock ◽

Pole Position ◽

Igneous Rocks ◽

Hudson Bay ◽

Plate Model ◽

Polar Wander ◽

Apparent Polar Wander Path ◽

Paleomagnetic Pole

Paleomagnetic results from igneous rock units on the Belcher Islands, Hudson Bay, are described. Fold tests for all units studied, as well as a contact test for the intrusive bodies, indicate that both primary (initial), and secondary (post-folding) magnetizations are present.The paleomagnetic pole position from primary directions of the oldest unit studied, the Eskimo volcanics, is situated at 40°S, 002°E (A95 = 12°) and is similar to that derived from equivalent volcanics on the mainland. The younger volcanic unit studied, the Flaherty volcanics, yielded a pole position from primary directions at 0°, 244°E (A95 = 7°). The Haig intrusions, associated with these younger volcanics, yields an almost identical pole position at 1°N, 247°E (A95 = 6°), being derived from directions which are shown to be not only pre–folding but also date from initial cooling. The Eskimo volcanics, which have been more deeply buried than the Flaherty (upper) volcanics, carry substantial components of secondary (post-folding) magnetization which yield a pole position at 19°N, 243°E (A95 = 15°), about 20° north of the pole positions derived from the youngest units.It is argued that the apparent polar wander path (APWP) constructed for the Belcher Islands is representative of the mainland Ungava Craton. Comparison with the equivalent APWP from elsewhere in North America shows that the two APWP's are at variance. Although a two-plate model could be advanced, perhaps a more conservative interpretation is to extend the existing North American APWP eastward to include the Belcher–Ungava APWP, that is, to favour a one-plate model.

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