CHARACTERIZING LAYERED GABBRO WITHIN THE ENGELS DEPOSIT AT THE LIGHTS CREEK STOCK, PLUMAS COUNTY, CALIFORNIA

2019 ◽  
Author(s):  
Mario G. Velazquez ◽  
◽  
Hannah M. Aird ◽  
Hannah M. Aird
Keyword(s):  
Layered Gabbro

Petrology and Structure of Layered Gabbro Pleasant Bay, Maine

1963 ◽  
Vol 71 (2) ◽  
pp. 215-237
Author(s):  
Marion E. Bickford
Keyword(s):  
Layered Gabbro

Early basic magmatism in the evolution of Archaean high-grade gneiss terrains: an example from the Lewisian of NW Scotland

1987 ◽  
Vol 51 (361) ◽  
pp. 345-355 ◽  
Author(s):  
H. R. Rollinson
Keyword(s):  
Trace Element ◽  
Source Region ◽  
High Grade ◽  
Ocean Ridges ◽  
Layered Gabbro ◽  
Basic Magmatism ◽  
Melting Regime ◽  
High Grade Metamorphism ◽  
Tonalitic Gneiss ◽  
Common Parent

AbstractAmphibolite blocks from an Archaean (2.9 Ga) trondhjemite-agmatite complex in the Lewisian at Gruinard Bay have a varied trace element and REE content. Whilst some of the variability is attributable to element mobility during high-grade metamorphism and subsequent trondhjemite magmatism, it is for the main part considered to be a primary feature of the amphibolites. The observed trace element and REE chemistry is best explained in terms of source region heterogeneity and suggests a melting regime comparable with that beneath certain types of mid-ocean ridge. There are geochemical similarities between the amphibolites and the Lewisian layered gabbro-ultramafic complexes, and the two may represent the derivative liquid and associated cumulates respectively from a common parent magma. Thus there is a parallel between the processes which generated some Archaean amphibolites and layered gabbro complexes and those operating beneath modern ocean ridges. Hornblendite and amphibolite pods enclosed within tonalitic gneiss, also found as blocks in the agmatite complex, are geochemically distinct from the main group of amphibolites and are probably of calc-alkaline parentage.

The Centre 3 layered gabbro intrusion, Ardnamurchan, NW Scotland

2007 ◽  
Vol 144 (6) ◽  
pp. 897-908 ◽  
Author(s):  
B. O'Driscoll
Keyword(s):  
Late Stage ◽  
Country Rock ◽  
The Other ◽  
Field Observations ◽  
Layered Gabbro ◽  
Modal Layering ◽  
Gabbro Intrusion

AbstractDetailed remapping of the Palaeogene Ardnamurchan Centre 3 gabbros, NW Scotland, suggests that this classic sequence of ring-intrusions forms a composite layered lopolith. The area mapped by previous studies as the Great Eucrite gabbro intrusion comprises 70% by area of Centre 3. Field observations suggest that most of the other smaller ring-intrusions of Centre 3 (interior to the Great Eucrite) constitute either distinct petrological facies of the same intrusion, or included country-rock or peridotite blocks. These observations, together with syn-magmatically deformed inward-dipping modal layering, are used here to support the interpretation that significant central sagging occurred in the intrusion at a late stage in its crystallization history.

The structure and intrusive mechanism of the Kap Edvard Holm layered gabbro complex, East Greenland

1969 ◽  
Vol 106 (1) ◽  
pp. 46-56 ◽  
Author(s):  
R. Elsdon
Keyword(s):  
Country Rock ◽  
Chemical Data ◽  
Layered Series ◽  
East Greenland ◽  
Layered Gabbro

SUMMARYThe complex can be divided into three units, here named the Lower, Middle and Upper Layered Series respectively, on the basis of petrochemical data and correction of the dips of the layering for the effects of post-consolidational flexuring. There are no chilled margins, and the contact with the country rock consists of granular basic and ultrabasic rocks, older than the cumulates of the layered series. The intrusive mechanism is considered in the light of field and chemical data.

Sign in / Sign up

Export Citation Format

Share Document