Paleomagnetic study of the late Neoproterozoic Bull Arm and Crown Hill formations (Musgravetown Group) of eastern Newfoundland: implications for Avalonia and West Gondwana paleogeography1This article is one of a series of papers published in CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology.

2012 ◽  
Vol 49 (1) ◽  
pp. 308-327 ◽  
Author(s):  
Sergei A. Pisarevsky ◽  
Phil J.A. McCausland ◽  
Joseph P. Hodych ◽  
Sean J. O’Brien ◽  
Jennifer A. Tait ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Paleomagnetic Data ◽  
Special Issue ◽  
West Gondwana ◽  
Paleomagnetic Study ◽  
Late Neoproterozoic ◽  
Moderate Scale

A paleomagnetic study of subaerial volcanic rocks and associated siltstones of the Ediacaran Bull Arm Formation in the Avalon Zone of Newfoundland revealed a stable bipolar, hematite-borne primary remanence supported by positive conglomerate, contact, and fold tests. Mean remanence directions in two distal areas (Bonavista and Argentia) are similar, indicating a low paleolatitude position of Avalonia at ∼570 Ma. Redbeds of the overlying ∼550 Ma Crown Hill Formation also carry a primary bipolar hematite-borne remanence with moderate inclination, indicating that Avalonia remained at low to medium paleolatitudes through the end of the Ediacaran. Combining our results with previously published paleomagnetic data of Avalonia suggests moderate-scale drift of Avalonia through low southern paleolatitudes through the latter half of the Ediacaran, providing a paleogeographic context for the development of the first complex metazoan life.

scholarly journals Paleomagnetism of the Amazonian Craton and its role in paleocontinents

2016 ◽  
Vol 46 (2) ◽  
pp. 275-299 ◽  
Author(s):  
Manoel Souza D'Agrella-Filho ◽  
Franklin Bispo-Santos ◽  
Ricardo Ivan Ferreira Trindade ◽  
Paul Yves Jean Antonio
Keyword(s):  
West African ◽  
The Other ◽  
Paleomagnetic Data ◽  
Clockwise Rotation ◽  
Oblique Collision ◽  
West Gondwana ◽  
Amazonian Craton ◽  
Rodinia Supercontinent ◽  
Paleomagnetic Poles ◽  
Late Neoproterozoic

ABSTRACT: In the last decade, the participation of the Amazonian Craton on Precambrian supercontinents has been clarified thanks to a wealth of new paleomagnetic data. Paleo to Mesoproterozoic paleomagnetic data favored that the Amazonian Craton joined the Columbia supercontinent at 1780 Ma ago, in a scenario that resembled the South AMerica and BAltica (SAMBA) configuration. Then, the mismatch of paleomagnetic poles within the Craton implied that either dextral transcurrent movements occurred between Guiana and Brazil-Central Shield after 1400 Ma or internal rotation movements of the Amazonia-West African block took place between 1780 and 1400 Ma. The presently available late-Mesoproterozoic paleomagnetic data are compatible with two different scenarios for the Amazonian Craton in the Rodinia supercontinent. The first one involves an oblique collision of the Amazonian Craton with Laurentia at 1200 Ma ago, starting at the present-day Texas location, followed by transcurrent movements, until the final collision of the Amazonian Craton with Baltica at ca. 1000 Ma. The second one requires drifting of the Amazonian Craton and Baltica away from the other components of Columbia after 1260 Ma, followed by clockwise rotation and collision of these blocks with Laurentia along Grenvillian Belt at 1000 Ma. Finally, although the time Amazonian Craton collided with the Central African block is yet very disputed, the few late Neoproterozoic/Cambrian paleomagnetic poles available for the Amazonian Craton, Laurentia and other West Gondwana blocks suggest that the Clymene Ocean separating these blocks has only closed at late Ediacaran to Cambrian times, after the Amazonian Craton rifted apart from Laurentia at ca. 570 Ma.

Paleomagnetism of the Lawrenceton Formation volcanic rocks, Silurian Botwood Group, Change Islands, Newfoundland

1989 ◽  
Vol 26 (2) ◽  
pp. 296-304 ◽  
Author(s):  
Julie E. Gales ◽  
Ben A. van der Pluijm ◽  
Rob Van der Voo
Keyword(s):  
North American ◽  
Volcanic Rocks ◽  
Mobile Belt ◽  
Structural Mapping ◽  
Polar Wander ◽  
The North ◽  
Apparent Polar Wander Path ◽  
Paleomagnetic Study ◽  
North American Craton

Paleomagnetic sampling of the Lawrenceton Formation of the Silurian Botwood Group in northeastern Newfoundland was combined with detailed structural mapping of the area in order to determine the deformation history and make adequate structural corrections to the paleomagnetic data.Structural analysis indicates that the Lawrenceton Formation experienced at least two folding events: (i) a regional northeast–southwest-trending, Siluro-Devonian folding episode that produced a well-developed axial-plane cleavage; and (ii) an episode of local north-trending folding. Bedding – regional cleavage relationships indicate that the latter event is older than the regional folding.Thermal demagnetization of the Lawrenceton Formation yielded univectorial southerly and shallow directions (in situ). A fold test on an early mesoscale fold indicates that the magnetization of the Botwood postdates this folding event. However, our results, combined with an earlier paleomagnetic study of nearby Lawrenceton Formation rocks, demonstrate that the magnetization predates the regional folding. Therefore, we conclude that the magnetization occurred subsequent to the local folding but prior to the period of regional folding.While a tectonic origin for local folding cannot be entirely excluded, the subaerial nature of these volcanics, the isolated occurrence of these folds, and the absence of similar north-trending folds in other areas of eastern Notre Dame Bay suggest a syndepositional origin. Consequently, the magnetization may be nearly primary. Our study yields a characteristic direction of D = 175°, I = +43°, with a paleopole (16°N, 131 °E) that plots near the mid-Silurian track of the North American apparent polar wander path. This result is consistent with an early origin for the magnetization and supports the notion that the Central Mobile Belt of Newfoundland was adjacent to the North American craton, in its present-day position, since the Silurian.

The late Neoproterozoic Frog Lake hornblende gabbro pluton, Avalon Terrane of Nova Scotia: evidence for the origins of appinites

2010 ◽  
Vol 47 (2) ◽  
pp. 103-120 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David J.W. Piper ◽  
Basilios Tsikouras
Keyword(s):  
Nova Scotia ◽  
Country Rock ◽  
Volcanic Rocks ◽  
Mafic Magma ◽  
Single Type ◽  
Structural Level ◽  
Element Abundances ◽  
Hornblende Gabbro ◽  
Late Neoproterozoic ◽  
Low K

The late Neoproterozoic Frog Lake pluton, in the Avalon terrane of the Cobequid Highlands, Nova Scotia, consists predominantly of hornblende gabbro. It shows petrographic similarities to water-rich mafic intrusions known as appinites that are present in some collisional orogens. This study aims to further understanding of the origin of appinitic intrusions. In the field, the main hornblende gabbro was intruded between screens of metasedimentary country rock that is of upper greenschist metamorphic grade. The contacts appear to have been pathways for magma of gabbroic, tonalitic–granodioritic, and granitic composition that carried enclaves of gabbroic lithologies. Some of these magmas had a high volatile content, resulting in abundance of hydrous mineral phases, pegmatites, and diffuse felsic segregations. These varied rocks in the contact zones experienced progressive shear resulting in syn-magmatic deformation. Low-Ti hornblende gabbros have trace-element abundances similar to subduction-related low-K mafic rocks, including some enrichment in large-ion lithophile elements and marked relative depletion in Nb and Y. High-Ti hornblende gabbros and pyroxene–mica gabbro show more alkaline characteristics, with higher amounts of Nb, Y, P2O5, and high-field-strength elements. Tonalite and granite veins are geochemically similar to volcanic-arc granite. Comparison with appinites in the literature suggests that the Frog Lake pluton represents a deeper structural level than most appinites. The Frog Lake appinites were part of the feeder system to back-arc volcanic rocks of the Jeffers Group. Comparison with other appinites also leads to the conclusion that there is not a single type of “appinitic magma”: different appinitic plutons range in composition from low-K calc-alkaline to shoshonitic. The essential characteristic is a water-rich mafic magma. Appinites occur in settings undergoing crustal-scale strike-slip shear, where the faults allow rapid rise of mafic magma to shallow crustal levels.

scholarly journals Mid–Late Neoproterozoic rift-related volcanic rocks in China: Geological records of rifting and break-up of Rodinia

2012 ◽  
Vol 3 (4) ◽  
pp. 375-399 ◽  
Author(s):  
Linqi Xia ◽  
Zuchun Xia ◽  
Xueyi Xu ◽  
Xiangmin Li ◽  
Zhongping Ma
Keyword(s):  
Volcanic Rocks ◽  
Break Up ◽  
Late Neoproterozoic

A Paleomagnetic Study of the Tectonic Deformation in Circum-Marmara Region, NW Anatolia, during the Late Cretaceous and Cenozoic Period

2020 ◽  
Author(s):  
Burak Semih Cabuk ◽  
Mualla Cengiz
Keyword(s):  
Upper Cretaceous ◽  
Rock Magnetism ◽  
Volcanic Rocks ◽  
High Coercivity ◽  
The Black Sea ◽  
Tectonic Deformation ◽  
Marmara Region ◽  
Magnetic Minerals ◽  
Single Plate ◽  
Paleomagnetic Study

<p>The Marmara region is located on the Alpine Himalayan orogenic belt which experienced a active tectonic deformation. The region consists of tectonic units such as the Istanbul Zone, the Strandja Zone and the Sakarya Continent. It is reported in the previous geological studies that the Istanbul Zone began to move southwards appart from the Moesia Platform with the effect of West Blacksea Fault in the west and West Crimea Fault in the east after the the opening of the Black Sea in the Cretaceous. It is known that the Intra Pontide suture is formed after the closure of the Intra-Pontide ocean during the Early Eocene due to the collision between İstanbulzone and the Sakarya continent which moved northwards. As a result of the continental collision, the region has completed its evolution under the influence of basin formation and the emplacement of North Anatolian Fault Zone from Miocene to the present.</p><p> </p><p>In this study, Upper Cretaceous-Oligocene sedimentary and volcanic rocks were sampled at 103 sites to investigate the tectonic deformation of the area. As a result of rock magnetism studies, it was shown that magnetic minerals in sedimentary and volcanic rocks are defined by titanium-rich titanomagnetite showing low coercivity, while in limestone samples, magnetization is defined by hematite showing high coercivity. As a result of anisotropy of magnetic susceptibility (AMS) measurements, it was observed that most of the samples show magnetic foliation and a deformation ellipsoid which is oblate. Paleomagnetic results show counterclockwise rotation of 19.9°±10.9° for the Sakarya continent, 27.4°±11.6°for the Pontides and 15.6°±11.8°for the Strandja Zone from Eocene to present. The results indicate that the region has completed the collision in Eocene and rotated counterclockwise as a large block. Deformation due to basin development or fault bounded block rotations which developed after Miocene could not been detected in this study. Miocene paleomagnetic data from previous studies in the study area are compatible with counterclockwise rotations in Upper Cretaceous-Oligocene which shows that different blocks emplaced in the study area moved together as a single plate during Eocene-Miocene time.</p>

scholarly journals Linzizong Volcanic Rocks in Linzhou of Tibet: A Volcanic Petrologic Assemblage in Continental Collision Environment

2008 ◽  
Vol 2 (4) ◽  
pp. 128
Author(s):  
Guochen Dong ◽  
Xuanxue Mo ◽  
Zhidan Zhao ◽  
Liang Wang ◽  
Su Zhao
Keyword(s):  
Volcanic Rocks ◽  
Continental Collision ◽  
Special Issue

Himalayan Journal of Sciences Vol.2(4) Special Issue 2004 pp. 128

scholarly journals New data on age of the Neoproterozoic volcanic rocks of Isakovka Terrain from the Sayan-Yenisei accretion belt (U-Pb, zircon)

2019 ◽  
Vol 488 (5) ◽  
pp. 521-525
Author(s):  
P. S. Kozlov ◽  
I. I. Likhanov ◽  
K. S. Ivanov ◽  
A. D. Nozhkin ◽  
S. V. Zinoviev
Keyword(s):  
Oil And Gas ◽  
Volcanic Rocks ◽  
Island Arc ◽  
Yenisei Ridge ◽  
Junction Zone ◽  
The West ◽  
Late Precambrian ◽  
Unconventional Oil And Gas ◽  
Late Neoproterozoic ◽  
First Time

The Late Neoproterozoic U-Pb age for zircon of island-arc metadacites (691 8.8 million years) and basalts (572 6.5 million years) of the Kiselikhinskaya Formation of the Kutukasskaya Group was established for the first time. The manifestation of basaltic volcanism is associated with rift-related processes. The studies clarify the Late Precambrian stratigraphy of the Yenisei Ridge and the features of the evolution of the Sayan-Yenisei accretionary belt at the Neoproterozoic stage of its history. Folded-thrust structures of the junction zone of the Yenisei Ridge with the West Siberian Plate may be favorable in relation to the search for unconventional oil and gas traps.

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