A basaltic-ferrobasaltic granulite association, Oonagalabi gneiss complex, Central Australia: magmatic variation in an Early Proterozoic rift

1986 ◽  
Vol 93 (3) ◽  
pp. 381-394 ◽  
Author(s):  
Warwick J. Sivell
Keyword(s):  
Early Proterozoic ◽  
Gneiss Complex ◽  
Central Australia

Isotopic evidence for the extent of early Proterozoic basement in Scotland and northwest Ireland

1991 ◽  
Vol 128 (4) ◽  
pp. 385-388 ◽  
Author(s):  
A. P. Dickin ◽  
D. R. Bowes
Keyword(s):  
Nd Isotope ◽  
Early Proterozoic ◽  
Isotopic Evidence ◽  
Gneiss Complex ◽  
Proterozoic Basement ◽  
Western Ireland ◽  
Isotope Systematics

AbstractTightly clustered Sm–Nd model ages, with an average of 1.96±0.02Ga, for the gneiss complex of Inishtrahull indicate coeval development with the earlyProterozoic gneiss terrane of Islay. The extent of this terrane, largely beneath the Dalradian Supergroup, is argued to be 100×600 km, from northeast Scotland to western Ireland. This is based on the distribution of dated basement in conjunction with Pb, Sr and Nd isotope systematics and inherited zircons in Caledonian granites of the region.

scholarly journals Gneiss complex of the Skærfjorden region (76°-78°N), North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 35-51
Author(s):  
J.M Hull ◽  
J.D Friderichsen ◽  
J.A Gilotti ◽  
N Henriksen ◽  
A.K Higgins ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Crystalline Rocks ◽  
East Greenland ◽  
Early Proterozoic ◽  
North East ◽  
Gneiss Complex ◽  
Intrusive Rocks ◽  
Caledonian Orogeny ◽  
Subduction Zone Magmatism

The crystalline rocks of the Skærfjorden region are dominated by grey migmatitic orthogneisses with smaller bodies of ultramafic, mafic and metasedimentary lithologies. Archaean rocks (c. 3.0 Ga) have been documented, but crustal additions were predominantly Early Proterozoic (2.0–1.75 Ga) in age, reflecting subduction zone magmatism. FolIowing Early Proterozoic orogenesis and migmatisation, granitic sheets (c. 1.7 Ga) and dolerite dykes were intruded. These intrusive rocks were subsequently deformed and metamorphosed in the Caledonian orogeny (c. 400 Ma). The Skærfjorden region is located in the Caledonian hinterland, where orogen parallel stretching and extension followed an early nappe stage.

Precambrian (Aphebian) microfossils from Belcher Islands, Hudson Bay

1969 ◽  
Vol 6 (5) ◽  
pp. 1137-1144 ◽  
Author(s):  
H. J. Hofmann ◽  
G. D. Jackson
Keyword(s):  
Hudson Bay ◽  
Early Proterozoic ◽  
Late Proterozoic ◽  
Central Australia ◽  
First Time ◽  
Proterozoic Age

A small assemblage of primitive microscopic fossils is here reported for the first time from the lower part of the Belcher Group in Hudson Bay. The microbiota includes chains and clumps of bacteria, and filamentous and spheroidal structures of probable algal or fungal affinities. In addition, a variety of isolated and clustered spheroids and other structures of probable biologic origin is present. The structures are more than 1600 m.y. old, and occur in a black chert associated with thick dolomite beds considered to be of Aphebian (Early Proterozoic) age. Morphologically comparable Precambrian microfossils occur in the Gunflint Formation (Early Proterozoic, Ontario) and the Bitter Springs Formation (Late Proterozoic, central Australia).

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