Moderate overthickening of thinned sialic crust and the origin of granitic magmatism and regional metamorphism in low-P-high-T terranes

Geology ◽  
1989 ◽  
Vol 17 (6) ◽  
pp. 520 ◽  
Author(s):  
Peter H. Thompson
Keyword(s):  
Regional Metamorphism ◽  
Sialic Crust ◽  
Granitic Magmatism

U–Pb geochronometry in the Horseranch Range, northern Omineca Belt, British Columbia, Canada

1994 ◽  
Vol 31 (2) ◽  
pp. 341-350
Author(s):  
Heather E. Plint ◽  
Randall R. Parrish
Keyword(s):  
British Columbia ◽  
Regional Metamorphism ◽  
Granitic Rocks ◽  
Precambrian Basement ◽  
North Central ◽  
Magmatic Rocks ◽  
Granitic Magmatism ◽  
Common Observation ◽  
Western Side ◽  
Dextral Strike Slip

A U–Pb geochronometric study of granitic rocks in the Horseranch Range in the northern Omineca Belt, north-central British Columbia, was carried out to determine the age of deformation, metamorphism, and magmatism and to determine if Precambrian basement is exposed in the range.Our results document Eocene (48–54 Ma) and late Early Cretaceous (113 Ma) granitic magmatism, limit the regional schistosity development to 113 Ma and older, and constrain the peak of syn- to posttectonic regional metamorphism to about 113 Ma. There is no direct evidence for Jurassic metamorphism, although our data do not preclude it. Dextral, oblique-slip mylonitization along the western side of the range is, in part, of Eocene age and related to transtensional tectonics synchronous with movement along regional, dextral strike-slip faults. No Precambrian basement was identified. However, U–Pb data indicate Early Proterozoic inheritance in some of the granitic rocks, a common observation in magmatic rocks of the Omineca Belt.

scholarly journals Shrimp and conventional U-Pb age, Sm-Nd isotopic characteristics and tectonic significance of the K-rich Itapuranga suite in Goiás, Central Brazil

2003 ◽  
Vol 75 (1) ◽  
pp. 97-108 ◽  
Author(s):  
MÁRCIO M. PIMENTEL ◽  
ELTON L. DANTAS ◽  
REINHARDT A. FUCK ◽  
RICHARD A. ARMSTRONG
Keyword(s):  
Magma Mixing ◽  
Regional Metamorphism ◽  
Quartz Syenite ◽  
Sialic Crust ◽  
Central Brazil ◽  
Tectonic Significance ◽  
Mafic Magmas ◽  
End Members ◽  
T Values ◽  
Tectonic Origin

The Itapuranga alkali granite and Uruana quartz syenite are large K-rich EW-elongated intrusions, in the central part of the Neoproterozoic Brasília Belt, central Brazil. They are associated with Pireneus lineaments, which cut the regional NNW-SSE structures of the southern part of the belt. SHRIMP and conventional U-Pb data for the Itapuranga and Uruana intrusions indicate crystallization ages of 624 ± 10 Ma and 618 ± 4 Ma, respectively. Three zircon cores from the Itapuranga granite yielded U-Pb ages between 1.79 and 1.49 Ga. Sm-Nd T DM ages for both intrusions are 1.44 Ga and epsilonNd(T) values are -5.1 and -5.7, suggesting the input of material derived from older (Paleo- to Mesoproterozoic) sialic crust in the origin of the parental magmas. Magma mixing structures indicate co-existence of mafic and felsic end-members. The felsic end-member of the intrusions is dominantly represented by crust-derived melts, formed in response to the invasion of Paleo/Mesoproterozoic sialic crust by alkali-rich mafic magmas at ca. 620 Ma. These intrusions are roughly contemporaneous with, or perhaps slightly younger than, the peak of regional metamorphism in the southern Brasília Belt. Their emplacement along the Pireneus lineament suggest a syn-tectonic origin for them, most probably in transtensional settings along these faults.

New age data on the low-temperature regional metamorphism of Mt. Medvednica (Croatia)

2006 ◽  
Vol 49 (3) ◽  
pp. 207-221 ◽  
Author(s):  
Katalin Judik ◽  
Kadosa Balogh ◽  
Darko Tibljaš ◽  
Péter Árkai
Keyword(s):  
Low Temperature ◽  
Regional Metamorphism ◽  
New Age

Alkaline granitic magmatism of the Western Transbaikalia: Petrogenetic and geodynamic implications from U-Pb isotopic–geochronological data

Lithos ◽  
2021 ◽  
Vol 390-391 ◽  
pp. 106098
Author(s):  
A.A. Tsygankov ◽  
V.B. Khubanov ◽  
O.V. Udoratina ◽  
M.A. Coble ◽  
G.N. Burmakina
Keyword(s):  
Geochronological Data ◽  
Western Transbaikalia ◽  
Granitic Magmatism

Fluid and enthalpy production during regional metamorphism

1989 ◽  
Vol 102 (3) ◽  
pp. 347-366 ◽  
Author(s):  
James A. D. Connolly ◽  
Alan B. Thompson
Keyword(s):  
Regional Metamorphism

The Granitization Process and its Limitations as Exemplified in Certain Parts of New South Wales

1952 ◽  
Vol 89 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Germaine A. Joplin
Keyword(s):  
Wave Front ◽  
New South ◽  
Regional Metamorphism ◽  
New South Wales ◽  
Compressional Wave ◽  
Thermal Metamorphism ◽  
South Wales ◽  
Strong Compression

AbstractIn an attempt to dissect the granitization process in an area of regional metamorphism, it is suggested that granite is forcibly injected during strong compression, that the compressional wave passes upwards and outwards in advance of the magma, and that several changes take place before its arrival. Six stages in this process are recognized in the Cooma and Albury districts of N.S.W.: (1) Regional Metamorphism, (2) Superimposed Thermal Metamorphism, (3) Permeation without Magmatic Addition, (4) Addition from an Attenuated Magma, (5) Formation of a Potassic Wave-Front, and (6) Injection of the Magma as Concordant Intrusions. The conditions favouring granitization are discussed and the question of basic fronts is considered.

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