Construction of the Pacific Margin Of Gondwana During The Pannotios Cycle

2013 ◽  
pp. 77-87 ◽  
Author(s):  
Edmund Stump
Keyword(s):  
The Pacific ◽  
Pacific Margin

Cold seeps and benthic habitat on the Pacific margin of Canada

2011 ◽  
Vol 31 (2) ◽  
pp. S85-S92 ◽  
Author(s):  
J. Vaughn Barrie ◽  
Sarah Cook ◽  
Kim W. Conway
Keyword(s):  
Benthic Habitat ◽  
Cold Seeps ◽  
The Pacific ◽  
Pacific Margin

MESOZOIC TECTONICS OF THE OTWAY BASIN REGION: THE LEGACY OF GONDWANA AND THE ACTVE PACIFIC MARGIN—A REVIEW AND ONGOING RESEARCH

1995 ◽  
Vol 35 (1) ◽  
pp. 467 ◽  
Author(s):  
K.A. Hill ◽  
D.M. Finlayson ◽  
K.C. Hill ◽  
G.T. Cooper
Keyword(s):  
Ongoing Research ◽  
Ridge Subduction ◽  
The North ◽  
Southern Margin ◽  
The Pacific ◽  
Half Graben ◽  
Pacific Margin ◽  
Mantle Processes ◽  
Break Up ◽  
Basin Region

Mesozoic extension along Australia's southern margin and the evolution and architecture of the Otway Basin were probably controlled by three factors: 1) changes in global plate movements driven by mantle processes; 2) the structural grain of Palaeozoic basement; and, 3) changes in subduction along Gondwana's Pacific margin. Major plate realignments controlled the Jurassic onset of rifting, the mid-Cretaceous break-up and the Eocene onset of rapid spreading in the Southern Ocean.The initial southern margin rift site was influenced by the northern limit of Pacific margin (extensional) Jurassic dolerites and the rifting may have terminated dolerite emplacement. Changed conditions of Pacific margin subduction (e.g. ridge subduction) in the Aptian may have placed the Australia-Antarctic plates into minor compression, abating Neocomian southern margin rifting. It also produced vast amounts of volcanolithic sediment from the Pacific margin arc that was funnelled down the rift graben, causing additional regional subsidence due to loading. Albian orogenic collapse of the Pacific margin, related to collision with the Phoenix Plate, influenced mid-Cretaceous breakup propagating south of Tasmania and into the Tasman Sea.Major offsets of the spreading axis during breakup, at the Tasman and Spencer Fracture zones, were most likely controlled by the location of Palaeozoic terrane boundaries. The Tasman Fracture System was reactivated during break-up, with considerable uplift and denudation of the Bass failed rift to the east, which controlled Otway Basin facies distribution. Palaeozoic structures also had a significant effect in determining the half graben orientations within a general N-S extensional regime during early Cretaceous rifting. The late Cretaceous second stage of rifting, seaward of the Tartwaup, Timboon and Sorell fault zones, left a stable failed rift margin to the north, but the attenuated lithosphere of the Otway-Sorell microplate to the south records repeated extension that led to continental separation and may be part of an Antarctic upper plate.

scholarly journals Mesozoic tectonic evolution of the South Orkney Microcontinent, Scotia arc, Antarctica

1997 ◽  
Vol 134 (3) ◽  
pp. 383-401 ◽  
Author(s):  
R. A. J. TROUW ◽  
C. W. PASSCHIER ◽  
L. S. A. SIMÕES ◽  
R. R. ANDREIS ◽  
C. M. VALERIANO
Keyword(s):  
Upper Jurassic ◽  
Accretionary Wedge ◽  
The South ◽  
Orkney Islands ◽  
The Pacific ◽  
Exposed Part ◽  
Pacific Margin ◽  
Scotia Arc ◽  
Extensional Faulting ◽  
Five Phases

The South Orkney Islands are the exposed part of a continental fragment on the southern limb of the Scotia arc. The islands are to a large extent composed of metapelites and metagreywackes of probable Triassic sedimentary age. Deformation related to an accretionary wedge setting, with associated metamorphism from anchizone to the greenschist facies, are of Jurassic age (176–200 Ma). On Powell Island, in the centre of the archipelago, five phases of deformation are recognized. The first three, associated with the main metamorphism, are tentatively correlated with early Jurassic subduction along the Pacific margin of Gondwana. D4 is a phase of middle to late Jurassic crustal extension associated with uplift. This extension phase may be related to opening of the Rocas Verdes basin in southern Chile, associated with the breakup of Gondwanaland. Upper Jurassic conglomerates cover the metamorphic rocks unconformably. D5 is a phase of brittle extensional faulting probably associated with Cenozoic opening of the Powell basin west of the archipelago, and with development of the Scotia arc.

A late Miocene and early Pliocene upper slope-to-shelf sequence of calcareous fine sediment from the Pacific margin of New Zealand

1984 ◽  
Vol 15 (1) ◽  
pp. 331-342 ◽  
Author(s):  
P. F. Ballance ◽  
M. R. Gregory ◽  
G. W. Gibson ◽  
G. C. H. Chaproniere ◽  
A. P. Kadar ◽  
...  
Keyword(s):  
New Zealand ◽  
Late Miocene ◽  
Fine Sediment ◽  
Early Pliocene ◽  
The Pacific ◽  
Pacific Margin ◽  
Upper Slope

An introductory overview to the concept of displaced terranes

1983 ◽  
Vol 20 (6) ◽  
pp. 994-999 ◽  
Author(s):  
Zvi Ben-Avraham ◽  
Amos Nur
Keyword(s):  
Large Scale ◽  
Continental Margins ◽  
Oceanic Plateaus ◽  
Introductory Overview ◽  
The Pacific ◽  
History Of ◽  
Accreted Terranes ◽  
Pacific Margin ◽  
The Pacific Ocean ◽  
Oceanic Plates

On land much of the Pacific margin is composed of allochthonous terranes, which are of continental and noncontinental origins. In the oceans numerous oceanic rises, some of which are submerged continental fragments, are presently embedded in the oceanic plates. These oceanic rises are probably future accreted terranes. They thus represent one stage in the development of allochthonous terranes found in orogenic zones. Minerals found in these terranes were formed at locations that in the past could have been thousands of kilometres away. This is because some oceanic terranes were split into several parts that moved with their respective plates in different directions. Also, faulting at the continental margins caused large-scale concurrent and post-accretionary horizontal translations of hundreds of kilometres of the allochthonous terranes.Studying the allochthonous terranes may provide important information about the Paleozoic and early Mesozoic history of the Pacific Ocean, because most of the oceanic crust of this age has disappeared leaving only those allochthonous terranes that were once oceanic plateaus within this crust. Understanding the history of the Pacific basin plates and of the allochthonous terranes may lead to the discovery of minerals within the submerged oceanic plateaus.

Cenozoic magmatism of the Sierra Madre del Sur and tectonic truncation of the Pacific margin of southern Mexico

2018 ◽  
Vol 183 ◽  
pp. 85-114 ◽  
Author(s):  
D.J. Morán-Zenteno ◽  
B.M. Martiny ◽  
L. Solari ◽  
L. Mori ◽  
L. Luna-González ◽  
...  
Keyword(s):  
Southern Mexico ◽  
The Pacific ◽  
Sierra Madre ◽  
Sierra Madre Del Sur ◽  
Pacific Margin ◽  
Cenozoic Magmatism

Igneous history of the Andean Cordillera and Patagonian plateau around latitude 46°S

1981 ◽  
Vol 303 (1474) ◽  
pp. 105-149 ◽  
Keyword(s):  
Calc Alkaline ◽  
Alkali Basalts ◽  
Cinder Cones ◽  
Andean Cordillera ◽  
The Pacific ◽  
Igneous Activity ◽  
History Of ◽  
Pacific Margin ◽  
Rhyolite Volcanism ◽  
Back Arc

From the Middle Jurassic onwards persistent igneous activity in the southern Andes around 46 °S was controlled by easterly dipping subduction along the Pacific margin. Cogenetic plutonic rocks belonging to the Patagonian batholith, and calc-alkaline volcanics ranging from basaltic andesites to rhyolitic tuffs and ignimbrites are the principal products. Erosion of the primary volcanics has led at various times to the development of thick volcaniclastic sequences, for example in the Cretaceous-Lower Tertiary Divisadero formation. The Coyhaique region marks the northerly extension of a narrow back-arc basin in which the marine Neocomian successions accumulated. Volcaniclastics from the island arc, which presumably lay to the west, are intercalated with the sediments. Although the marine basin was short-lived a mildly extensional back-arc regime may have existed through much of Mesozoic-Recent times. Widespread basalt-rhyolite volcanism on the eastern side of the cordillera seems to have been associated with this tectonic environment. Remnants of the Patagonian basalt plateau at latitude 45-47 °S extend from the Argentine-Chile frontier to Lago Colhue Huapi. Four principal age and compositional groups have been distinguished in the lavas, (i) The oldest, which are about 80 Ma, occur in sections at Senguerr and Morro Negro. They are almost exclusively tholeiitic, but show some calc-alkaline affinities and resemble in other respects basalts from marginal basins, (ii) The second group (57-43 Ma) occur in the lower part of the Chile Chico section with a compositional spread from olivine tholeiites through alkali basalts to one occurrence of a basanite. (iii) The upper part of the main plateau sequence, where the flows are in the range 25-9 Ma, are dominantly of alkali basalt composition, (iv) Post-plateau flows from small cinder cones on the surface of the plateau range in age from ca. 4 Ma to 0.2 Ma or less. They are mostly highly undersaturated basanites, with occasional leucite basanites, enriched in incompatible elements. A few of the earlier tholeiites with calc-alkali traits may have been closely associated with subduction or marginal basin processes. The younger lavas are more alkalic intraplate types generated in the remote back-arc extensional zone.

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