The Lausitz graywackes, Saxo-Thuringia, Germany—Witness to the Cadomian orogeny

2007 ◽  
Author(s):  
Helga Kemnitz
Keyword(s):  
Cadomian Orogeny

Precise U–Pb zircon ages from Alderney, Channel Islands: growing evidence for discrete Neoproterozoic magmatic episodes in northern Cadomia

2001 ◽  
Vol 138 (6) ◽  
pp. 719-726 ◽  
Author(s):  
R. S. D'LEMOS ◽  
B. V. MILLER ◽  
S. D. SAMSON
Keyword(s):  
Small Groups ◽  
Quartz Diorite ◽  
Channel Islands ◽  
Igneous Complex ◽  
Plutonic Complex ◽  
Northern Channel Islands ◽  
Cadomian Orogeny ◽  
Late Neoproterozoic ◽  
Magmatic Event ◽  
Deformational Event

The northernmost exposures of rocks formed during the Late Neoproterozoic Cadomian orogeny in the Channel Islands–northern France region occur on Alderney. The island mainly comprises foliated quartz diorite, once considered to be 2 Ga, pre-Cadomian basement, and an undeformed basic to intermediate plutonic complex. A precise age of 610±2 Ma, based on U–Pb analyses of single and small groups of zircons, for the foliated Fort Tourgis quartz diorite demonstrates that the oldest rocks were emplaced and deformed during a Cadomian magmatic event. The age is virtually identical to ages from similar, foliated syntectonic quartz diorite bodies on the islands of Guernsey and Sark and at La Hague (north Normandy), indicating that this magmatic and deformational event was regional in extent. Discordant zircon xenocrysts define an upper intercept age of c. 2 Ga indicating the presence of Palaeoproterozoic basement at depth. Single zircons from the undeformed Bibette Head granodiorite give a precise U–Pb age of 572±1 Ma. This age is closely similar to that for the emplacement of the Northern Igneous Complex of Guernsey. The emerging data indicate that Cadomian magmatism in the northern Channel Islands region was not a protracted continuum, but occurred during two distinct, short-lived events separated by c. 30–40 my.

Geochemistry and U–Pb zircon geochronology of metagranites in Istranca (Strandja) Zone, NW Pontides, Turkey: Implications for the geodynamic evolution of Cadomian orogeny

2014 ◽  
Vol 26 (2) ◽  
pp. 755-771 ◽  
Author(s):  
Sabah Yilmaz Şahin ◽  
Namık Aysal ◽  
Yıldırım Güngör ◽  
Irena Peytcheva ◽  
Franz Neubauer
Keyword(s):  
Zircon Geochronology ◽  
Geodynamic Evolution ◽  
Cadomian Orogeny

The Cadomian orogeny in the North Armorican Massif: a brief review

1990 ◽  
Vol 51 (1) ◽  
pp. 3-12 ◽  
Author(s):  
R. S. D’Lemos ◽  
R. A. Strachan ◽  
C. G. Topley
Keyword(s):  
The North ◽  
Cadomian Orogeny ◽  
Armorican Massif

The Cadomian orogeny

1991 ◽  
Vol 13 (6) ◽  
pp. 739-740
Author(s):  
Nicholas Rast
Keyword(s):  
Cadomian Orogeny

Le Brioverien. Esquisse des caracteres stratigraphiques, metamorphiques, structuraux et paleographiques de l'Antecambrien recent dans le Massif armoricain

1962 ◽  
Vol S7-IV (3) ◽  
pp. 413-430 ◽  
Author(s):  
Jean Cogne
Keyword(s):  
Middle Part ◽  
Basement Rock ◽  
Areal Extent ◽  
Short Period ◽  
Granitic Intrusion ◽  
Cadomian Orogeny ◽  
Armorican Massif ◽  
Basic Rocks ◽  
Feldspathic Sandstone

Abstract The stratigraphic characteristics of the Brioverian from Normandy to the Vendee reflect a complete geosynclinal cycle younger than the Pentevrian (Precambrian) but completed before the Cambrian transgression. The Brioverian is the basement rock of the Armorican massif, and thus has the largest areal extent of any Precambrian formation in France. The lower part consists of epimetamorphic basic rocks (ophiolites). The middle part is feldspathic sandstone, phtanite, quartzite, and phyllitic shale. After a short period of emergence, the upper beds were deposited, consisting of the Saint Germain-le-Gaillard rhyolite, the Granville tillite complex, and shale and sandstone at the top. Cadomian folding and granitic intrusion occurred, forming the Cadomian chain prior to Cambrian transgression, and thereby affecting the structure of the Armorican massif. The Brioverian clearly was a folded and partially granitized sole before the dawn of the Paleozoic, but the exact dates of the deposition of the Brioverian and of the Cadomian orogeny are still hypothetical.

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