Trace-Element and Sr-Nd Isotopic Geochemistry of the PGE-Bearing Hongge Layered Intrusion, Southwestern China

2003 ◽  
Vol 45 (4) ◽  
pp. 371-382 ◽  
Author(s):  
H. Zhong ◽  
Y. Yao ◽  
S. F. Hu ◽  
X. H. Zhou ◽  
B. G. Liu ◽  
...  
Keyword(s):  
Trace Element ◽  
Layered Intrusion ◽  
Southwestern China ◽  
Isotopic Geochemistry

Trace-element and Sr–Nd isotopic geochemistry of the PGE-bearing Xinjie layered intrusion in SW China

2004 ◽  
Vol 203 (3-4) ◽  
pp. 237-252 ◽  
Author(s):  
Hong Zhong ◽  
Yong Yao ◽  
Stephen A. Prevec ◽  
Allan H. Wilson ◽  
Morris J. Viljoen ◽  
...  
Keyword(s):  
Trace Element ◽  
Layered Intrusion ◽  
Sw China ◽  
Isotopic Geochemistry

XVII.—The Major Ultrabasic and Basic Intrusions of St Kilda, Outer Hebrides

1967 ◽  
Vol 66 (17) ◽  
pp. 419-444 ◽  
Author(s):  
R. R. Harding
Keyword(s):  
Trace Element ◽  
Major Element ◽  
Layered Intrusion ◽  
Fine Grained ◽  
Outer Hebrides ◽  
Crystal Accumulation

AbstractThe structures and mineralogy of the Tertiary ultrabasic and basic intrusions are described. The ultrabasic rocks are thought to be remnants of a layered intrusion which once extended from Hirta to Boreray, and which probably formed by crystal accumulation. The eucrites may represent higher levels of this intrusion. A 350 feet-thick, fine-grained margin is described from the East Glen Bay Gabbro. The metamorphism of the ultrabasic and eucritic rocks, and the formation of the Glacan Mor Complex, probably occurred in a basic environment, before intrusion of the first acid rocks on St. Kilda. Five major-element and twenty-two trace-element analyses are presented.

Age and Geochemical Studies of the Snyder Breccia, Coastal Labrador

1975 ◽  
Vol 12 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Jackson M. Barton Jr. ◽  
Erika S. Barton
Keyword(s):  
Trace Element ◽  
North Atlantic ◽  
Layered Intrusion ◽  
Basement Complex ◽  
Fine Grained ◽  
The North ◽  
Isotopic Analyses ◽  
The Matrix ◽  
The North Atlantic ◽  
Geochemical Studies

The Snyder breccia is composed of angular to subrounded xenoliths of migmatites and amphibolites in a very fine grained matrix. It is apparently intrusive into the metasediments of the Snyder Group exposed at Snyder Bay, Labrador. The Snyder Group unconformably overlies a migmatitic and amphibolitic basement complex and is intruded by the Kiglapait layered intrusion. K–Ar ages indicate that the basement complex is Archean in age (> 2600 m.y. old) and that the Kiglapait layered intrusion was emplaced prior to 1280 m.y. ago. Major and trace element analyses of the matrix of the Snyder breccia indicate that while it was originally of tonalitic composition, later it locally underwent alteration characterized by loss of sodium and strontium and gain of potassium, rubidium and barium. Rb–Sr isotopic analyses show that this alteration occurred about 1842 m.y. ago, most probably contemporaneously with emplacement of the breccia. The Snyder Group thus was deposited sometime between 2600 and 1842 m.y. ago and may be correlative with other Aphebian successions preserved on the North Atlantic Archean craton.

Nature des sources des composants andesitiques des Gres du Champsaur et des Gres de Taveyannaz; implications dans l'evolution des Alpes occidentales au Paleogene

2001 ◽  
Vol 172 (4) ◽  
pp. 487-501 ◽  
Author(s):  
Maud Boyet ◽  
Henriette Lapierre ◽  
Marc Tardy ◽  
Delphine Bosch ◽  
Rene Maury
Keyword(s):  
Trace Element ◽  
Western Alps ◽  
Northern Italy ◽  
Calc Alkaline ◽  
Magmatic Source ◽  
Isotopic Compositions ◽  
Alpine Zone ◽  
Internal Zone ◽  
Isotopic Geochemistry

Abstract Paleogene magmatism is widespread in the western Alps and its origin is still a matter of debate. It consists of calc-alkaline and shoshonitic suites with mainly granodioritic intrusions in the Internal Zone (northern Italy), andesitic volcanism in the Delphino-Helvetic Zone (French-Swiss domain) and the Esterellite intrusions in Provence. In the External Alpine Zone, the Taveyannaz Sandstones and the Champsaur Sandstones preserve andesitic pebbles and mineral fragments dated at 32 Ma. On the basis of trace-element and isotopic geochemistry (Sr, Nd, Pb and O) of mineral separates (amphibole, pyroxene and plagioclase) and andesitic clasts, we characterise the nature of magmatic source(s) and compare the isotopic compositions of the andesites with those of well known Paleogene igneous suites.

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