scholarly journals Birth and death of oceanic basins: geodynamic processes from rifting to continental collision in Mediterranean and circum-Mediterranean orogens

2018 ◽  
Vol 155 (2) ◽  
pp. 229-232 ◽  
Author(s):  
G. CAPPONI ◽  
A. FESTA ◽  
G. REBAY
Keyword(s):  
Tectonic Evolution ◽  
Continental Collision ◽  
Geodynamic Evolution ◽  
Different Types ◽  
Geodynamic Processes ◽  
Orogenic Belts

The study of the evolution of ocean basins from birth to death is crucial for the understanding of the geodynamic evolution of orogenic systems. Exhumed ophiolite-bearing orogenic belts represent significant fossil analogues of different types of modern oceanic basins, allowing detailed multiscale and multidisciplinary investigations. Such investigations are highly important to our understanding of the ancient and modern geodynamic processes connected to the different stages of complete tectonic evolution, from rifting to subduction, collision and exhumation.

Granulite-gneiss (high grade) belts: geodynamic view

2018 ◽  
pp. 13-22
Author(s):  
N. A. Bozhko
Keyword(s):  
Tectonic Evolution ◽  
Continental Collision ◽  
Complex Interaction ◽  
High Grade ◽  
Plate Tectonic ◽  
The Earth ◽  
Granulite Metamorphism ◽  
Different Types ◽  
Endogenous Activity ◽  
The Relationship

On the basis of analysis and generalization of modern data the features of the structure and tectonic evolution of granulite-gneiss (high-grade) belts of the Earth are considered. Their continental collisional tectonic nature, polycyclic and inherited character of development, expressed in repeated manifestations in the same belt of several stages of granulite metamorphism, separated by intervals of several hundred million years, are confirmed. Granulite-gneiss belts are permanent mobility structures that maintain endogenous activity in all stages of their existence, including intraplate environments. The relationship between high-grade belts and supercontinental cyclicity is revealed, which is expressed in the spatial coincidence of the majority of them to the outskirts of the young oceans that arose during the breakup of Pangea; in the control of assembly and breakup of ancient supercontinents along granulite belts; in correlation of manifestations of different types of granulite metamorphism in these belts with the stages of the supercontinent cycle. In the evolution of these belts there is a complex interaction of plate-tectonic and mantle-plume mechanisms, which is expressed in the combination of continental collision and underplating processes. The possibility of using granulite-gneiss belts in paleotectonic analysis along with other indicators of geodynamic settings is shown.

Magmatic record of continuous Neo-Tethyan subduction after initial India-Asia collision in the central part of southern Tibet

2020 ◽  
Author(s):  
Feng Huang ◽  
Tyrone O. Rooney ◽  
Ji-Feng Xu ◽  
Yun-Chuan Zeng
Keyword(s):  
Mantle Wedge ◽  
Leading Edge ◽  
Continental Collision ◽  
Southern Tibet ◽  
Mafic Rocks ◽  
Lhasa Terrane ◽  
Slab Breakoff ◽  
Geodynamic Processes ◽  
Generation Mechanisms ◽  
Transitional Phase

The Lhasa Terrane in southern Tibet is the leading edge of the Tibet-Himalaya Orogen and represents a fragmentary record of terminal oceanic subduction. Thus, it is an ideal region for studying magmatism and geodynamic processes that occurred during the transition from oceanic subduction to continental collision and/or oceanic slab breakoff. Here we examine a suite of early Cenozoic mafic rocks (ca. 57 Ma) within the central part of Lhasa Terrane, southern Tibet, which erupted during a transitional phase between the onset of India-Asia continental collision and Neo-Tethyan slab breakoff. These rocks display a geochemical affinity with magmas produced by fluid-fluxed melting of the mantle wedge within a subduction zone environment. The whole-rock element and Sr-Nd isotope compositions of these mafic rocks are similar to those of Cretaceous subduction-related magmatism in southern Tibet, demonstrating the sustained influence of the Neo-Tethys Ocean slab on the mantle wedge during the onset of the collision of India and Asia. The results of our geochemical forward modeling constrain the conditions of melt generation at depths of 1.3−1.5 GPa with significant fluid additions from the Neo-Tethyan slab. These results provide the first petrological and geochemical evidence that slab flux-related magmatism continued despite the commencement of continental collision. While existing studies have suggested that magmas were derived from melting of the Neo-Tethyan slab during this period, our new results suggest that additional magma generation mechanisms were active during this transitional phase.

Multistage anatexis during tectonic evolution from oceanic subduction to continental collision: A review of the North Qaidam UHP Belt, NW China

2019 ◽  
Vol 191 ◽  
pp. 190-211 ◽  
Author(s):  
Shengyao Yu ◽  
Sanzhong Li ◽  
Jianxin Zhang ◽  
Yinbiao Peng ◽  
Ian Somerville ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Continental Collision ◽  
Nw China ◽  
The North ◽  
North Qaidam

Relationships between distributed and localized shear in the tectonic evolution of a Caledonian fold and thrust zone, northwest Ireland

1994 ◽  
Vol 131 (1) ◽  
pp. 123-136 ◽  
Author(s):  
G. I. Alsop
Keyword(s):  
Tectonic Evolution ◽  
Large Scale ◽  
Structural Investigation ◽  
Localized Deformation ◽  
Large Magnitude ◽  
Structural Anisotropy ◽  
Transport Direction ◽  
Thrust Zone ◽  
And Migration ◽  
Orogenic Belts

AbstractBroad zones of distributed shear operating through mid-crustal regions of orogenic belts may incorporate narrow horizons of intense localized deformation culminating in discrete, large magnitude displacements. The relative importance and relationship between distributed and localized shear are influenced by a variety of factors including lithological variation, pre-existing structural anisotropy, strain rate and migration of fluids. Rigorous structural analysis of lower amphibolite facies Dalradian metasediments in northwestern Ireland demonstrates that an early (D1) discrete ductile detachment was subsequently reactivated during distributed non-coaxial D2 deformation operating in a broad zone through the structural pile. Regional shear was directed towards the southeast and resulted in the generation and translation of kilometre-scale, isoclinal, recumbent sheath folds which close and face towards the transport direction. The D1 detachment is clearly folded around the hinges of these major folds, whilst on fold limbs it was reactivated and acted as a local décollement within the zone of distributed shear. Shear criteria along the detachment indicate a southeast-directed translation of the major folds, in sympathy with regional shear. A broad zone of D3 translation operating through the nappe pile resulted in coaxial refolding of large scale F2 folds by the D3 Ballybofey Nappe producing a complex fold interference pattern. Non-coaxial D3 deformation resulted in continued reactivation of local decollements, together with the initiation of east-southeast directed oblique thrusts and partial dismemberment of D2 folds. Detailed structural investigation allows concepts of distributed and localized shear to be evaluated and models of crustal deformation to be assessed.

40Ar/39Ar Incremental Release Ages of Biotite and Hornblende from Pre-Kenoran Gneisses between the Matagami-Chibougamau and Frotet-Troilus Greenstone Belts, Quebec

1974 ◽  
Vol 11 (11) ◽  
pp. 1586-1593 ◽  
Author(s):  
R. D. Dallmeyer
Keyword(s):  
High Temperature ◽  
Tectonic Evolution ◽  
Superior Province ◽  
High Grade ◽  
Continuous Increase ◽  
Thermal Event ◽  
Greenstone Belts ◽  
Orogenic Belts ◽  
Gas Fractions

Biotite and hornblende from high-grade, granitic gneisses exposed between the Matagami-Chibougamau and Frotet-Troilus greenstone belts in Quebec have been affected by Kenoran metamorphism. Biotites record total gas 40Ar/39Ar ages of 2308 ± 30 m.y. and 2338 ± 30 m.y. Incrementally released gas fractions yield similar plateau ages, suggesting that the biotites have been totally degassed as a result of the thermal event. The ages are interpreted as reflecting the time of post-metamorphic cooling when radiogenic 40Ar began to be retained within biotite. Hornblendes record total gas 40Ar/39Ar ages of 2517 ± 40 m.y. and 2610 ± 40 m.y. Incrementally released gas fractions show a wide deviation from the total gas ages, with a continuous increase in age from low to high temperature release fractions. This lack of correlation suggests that the hornblendes have been only partially degassed by Kenoran metamorphism. However, lack of a high-temperature release plateau indicates that original meramorphic crystallization was older than the ages recorded by the highest temperature release fractions (2599 ± 40 and 2801 ± 40 m.y.). Recognition of an older sialic terrain between these greenstone belts supports recent models proposed for the tectonic evolution of the supracrustal orogenic belts in the Superior Province.

Geodynamic processes and deformation in orogenic belts

1980 ◽  
Vol 63 (1-4) ◽  
pp. 261-273 ◽  
Author(s):  
John G. Dennis ◽  
Wolfgang R. Jacoby
Keyword(s):  
Geodynamic Processes ◽  
Orogenic Belts

Tectonic evolution of the Qinling orogen and adjacent orogenic belts

2016 ◽  
Vol 30 ◽  
pp. 1-5 ◽  
Author(s):  
Yunpeng Dong ◽  
Inna Safonova ◽  
Tao Wang
Keyword(s):  
Tectonic Evolution ◽  
Qinling Orogen ◽  
Orogenic Belts

scholarly journals Correlation of magmatic and tectonic events in the evolution of the West Chukotka ophiolites

2019 ◽  
Vol 486 (2) ◽  
pp. 202-207
Author(s):  
A. V. Ganelin ◽  
S. D. Sokolov
Keyword(s):  
Arctic Ocean ◽  
Tectonic Evolution ◽  
Late Jurassic ◽  
Early Carboniferous ◽  
The West ◽  
Tectonic Events ◽  
Geodynamic Processes

The article is an overview of the magmatic and geodynamic processes that formed Aluchin and Gromadnen-Vurguvem ophiolites in the territory of Western Chukotka. The ophiolites formed into a convergent system between the Siberian continent and the Proto-Arctic Ocean. In the tectonic evolution of this system, important milestones have been identified: the Early Carboniferous, the Later Triassic and the Late Jurassic.

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