Petrology and Tectonic Setting of Dyke Swarms Emplaced in the Upper Jurassic Qorveh Granitoid Complex (Majidabad and Kangareh), Kurdistan Province, Iran

2018 ◽  
pp. 439-458
Author(s):  
Ashraf Torkian
Keyword(s):  
Tectonic Setting ◽  
Upper Jurassic ◽  
Dyke Swarms ◽  
Granitoid Complex

The 2405 Ma and 2310 Ma Mafic Dyke Swarms in the Karelian Craton: Age, Chemical and Sr-Nd Isotope Composition, and Tectonic Setting

2016 ◽  
Vol 90 (s1) ◽  
pp. 123-123
Author(s):  
A.V. Stepanova ◽  
E.B. Salnikova ◽  
A.V. Samsonov ◽  
Yu.O. Larionova ◽  
S.V. Egorova ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Tectonic Setting ◽  
Mafic Dyke ◽  
Karelian Craton ◽  
Nd Isotope ◽  
Dyke Swarms ◽  
Nd Isotope Composition

Tectonic setting and origin of the Proterozoic rapakivi granites of southeastern Fennoscandia

1992 ◽  
Vol 83 (1-2) ◽  
pp. 165-171 ◽  
Author(s):  
Ilmari Haapala ◽  
O. Tapani Rämö
Keyword(s):  
Tectonic Setting ◽  
Parental Magma ◽  
Transitional Zone ◽  
Isotopic Evolution ◽  
Domal Structure ◽  
Deep Seismic Soundings ◽  
Mafic Magmas ◽  
Thin Crust ◽  
High Level ◽  
Dyke Swarms

ABSTRACTThe 1·65–1·54 Ga rapakivi granites of southeastern Fennoscandia represent the silicic members of a bimodal magmatic association in which the mafic members are tholeiitic diabase dykes and minor gabbroic-anorthositic bodies. They are metaluminous to slightly peraluminous A-type granites and occur as high-level batholiths and stocks in an E-W-trending belt extending from Soviet Karelia to southwestern Finland. The Soviet Karelian granites were emplaced into the contact zone between Archaean craton and Svecofennian juvenile 1·9Ga-old crust, while the Finnish granites were intruded into the Svecofennian crust. Deep seismic soundings show that the rapakivi granites and the contemporaneous, mainly WNW or NW-trending diabase dyke swarms are situated in a zone of relatively thin crust. Below the Wiborg Batholith there exists a domal structure in the lithosphere in which a transitional zone (mafic underplate) occurs between the crust and the mantle.The Nd isotopic evolution of the rapakivi granites (εNd(T) −3·1—−0·2) corresponds to the evolution of the 1·9Ga-old Svecofennian crust, as do their Pb isotopic compositions. This implies that the Finnish granites represent anatectic melts of the Svecofennian crust. In contrast, the Soviet Karelian granites show isotopic composition indicative of substantial incorporation of Archaean lower crust material. Petrochemical modelling of one of the Finnish batholiths shows that its parental magma could have been generated by c. 20% melting of a granodioritic source and that fractional crystallisation was important during the subsequent evolution of this magma.The rapakivi granites are redefined as A-type granites that show the rapakivi texture at least in larger batholiths. The field, geochemical, and seismic data indicate that the classical Finnish rapakivi granites were generated in an anorogenic extensional regime by partial melting of the lower/middle crust. The melting, and possibly also the extensional tectonics, were related to upwellings of hot mantle material which led to intrusion of mafic magmas at the base and into the crust.

Magnetic fabric constraint on tectonic setting of Paleoproterozoic dyke swarms in the North China Craton, China

2019 ◽  
Vol 329 ◽  
pp. 247-261 ◽  
Author(s):  
Yonggang Yan ◽  
Liwei Chen ◽  
Baochun Huang ◽  
Zhiyu Yi ◽  
Jie Zhao
Keyword(s):  
North China Craton ◽  
North China ◽  
Tectonic Setting ◽  
Magnetic Fabric ◽  
The North ◽  
Dyke Swarms

Geochemistry and tectonic setting of the Golabad granitoid complex (SW Nain, Iran)

2018 ◽  
Vol 139 ◽  
pp. 120-132
Author(s):  
Mahin Mansouri Esfahani ◽  
Mahmoud Khalili ◽  
Zahra Alaminia
Keyword(s):  
Tectonic Setting ◽  
Granitoid Complex

The tectonic significance of some basic dyke swarms in the Canadian Superior Province with special reference to the geochemistry and paleomagnetism of the Mistassini swarm, Quebec, Canada

1986 ◽  
Vol 23 (2) ◽  
pp. 238-253 ◽  
Author(s):  
W. F. Fahrig ◽  
K. W. Christie ◽  
E. H. Chown ◽  
D. Janes ◽  
N. Machado
Keyword(s):  
Genetic Relationship ◽  
Early Stage ◽  
Tectonic Setting ◽  
Superior Province ◽  
Plate Boundaries ◽  
Basic Dyke ◽  
Tectonic Significance ◽  
Fold Belts ◽  
Opening And Closing ◽  
Dyke Swarms

The Mistassini dykes extend northwest from the Mistassini embayment and comprise both tholeiitic and komatiitic suites. They are probably > 2000 Ma old and yield two major paleomagnetic components. One of these, with a pole at 131°W, 13°S, is thought to be an overprint related to the Elsonian Disturbance 1400–1500 Ma ago. A very steeply down (and reversed) component may be primary and has a pole at 080°W, 50°N.These spacial, chemical, and age relationships between the Mistassini, Molson, Marathon, and Payne River dyke swarms and the Aphebian supracrustal fold belts on the perimeter of the Superior Province suggest a genetic relationship between the dyke swarms and the fold belts. The supracrustal belts are evidence of the opening and closing of oceans, and the dyke swarms are evidence of early-stage failed arms related to these openings. More rarely (for example, the Payne River dykes), early-stage dyke swarms are developed and preserved parallel to the edges of newly developed spreading plate boundaries. Presumably if a spreading episode stops, the dykes themselves may remain as the only evidence of that event. Probably all the world's great continental dyke swarms have the above-described tectonic setting, and the number and extent of dyke swarms during a geological epoch may be a measure of the number and vigour of spreading events.

Global Mesozoic and Cenozoic Rift Systems: Constrain on the Tectonic Setting of Mafic Dyke Swarms

2016 ◽  
Vol 90 (s1) ◽  
pp. 169-170
Author(s):  
Huatian ZHANG ◽  
Jianghai LIU ◽  
Zhonglan LIU
Keyword(s):  
Tectonic Setting ◽  
Mafic Dyke ◽  
Dyke Swarms

Geochemistry of the mafic dykes in parts of the Singhbhum granitoid complex: petrogenesis and tectonic setting

2010 ◽  
Vol 4 (5-6) ◽  
pp. 933-943 ◽  
Author(s):  
Akhtar R. Mir ◽  
Shabber H. Alvi ◽  
V. Balaram
Keyword(s):  
Tectonic Setting ◽  
Mafic Dykes ◽  
Granitoid Complex

Detrital zircon constraints on the tectonic evolution of the Gravina belt, southeastern Alaska

1998 ◽  
Vol 35 (3) ◽  
pp. 253-268 ◽  
Author(s):  
Paul A Kapp ◽  
George E Gehrels
Keyword(s):  
Detrital Zircon ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Upper Jurassic ◽  
Ocean Basin ◽  
Detrital Zircons ◽  
Plate Motion ◽  
The West ◽  
Gravina Belt ◽  
Cordilleran Margin

Upper Jurassic - Lower Cretaceous marine clastic strata and mafic to intermediate volcanic rocks of the Gravina belt are part of a complex suture zone separating the Alexander and Wrangellia terranes on the west from the Yukon-Tanana and Stikine terranes to the east. U-Pb ages have been determined on 118 single detrital zircon grains from Gravina strata in an effort to determine the tectonic setting of the Gravina belt and the paleoposition of outboard terranes prior to their Late Cretaceous juxtaposition against inboard terranes. Samples from five stratigraphic units yield ages of 105-120 (n = 5), 140-165 (n = 56), 310-380 (n = 17), 400-450 (n = 19), 520-560 (n = 5), 920-1310 (n = 5), and 1755-1955 Ma (n = 5). The 105-120 and 140-165 Ma grains were shed primarily from arc-related plutons that lie outboard of the Gravina belt. The lack of 120-140 Ma ages coincides with a lull in magmatism in the outboard arc and in the western United States, which suggests that Gravina strata accumulated during major changes in plate motion along the Cordilleran margin. The 400-560 Ma zircons were derived from rocks of the Alexander terrane which also lie to the west. In contrast, the 310-380 and >900 Ma grains were apparently shed from inboard regions. Likely sources include the Yukon-Tanana and Stikine terranes in the northern Cordillera and assemblages in the northern California region which contain igneous rocks and detrital zircons of the appropriate ages. Our data accordingly support models in which the Gravina basin formed in narrow rift or transtensional basins, whereas the outboard Alexander and Wrangellia terranes were located along the California - Oregon - Washington - British Columbia - Alaska margin. Our data are less supportive of models in which the Gravina strata and underlying Alexander and Wrangellia terranes were separated from western North America by a large ocean basin, or were located along the coast of Mexico.

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