Strontium isotopic resolution of magma dynamics in a layered intrusion

Nature ◽  
1981 ◽  
Vol 294 (5837) ◽  
pp. 155-157 ◽  
Author(s):  
C. M. Gray ◽  
A. D. T. Goode
Keyword(s):  
Layered Intrusion ◽  
Magma Dynamics ◽  
Isotopic Resolution

scholarly journals Degenerate dispersive equations arising in the study of magma dynamics

Nonlinearity ◽  
2006 ◽  
Vol 20 (1) ◽  
pp. 21-49 ◽  
Author(s):  
G Simpson ◽  
M Spiegelman ◽  
M I Weinstein
Keyword(s):  
Dispersive Equations ◽  
Magma Dynamics

Seismic image of the basal portion of the Bjerkreim-Sokndal layered intrusion

Geology ◽  
1997 ◽  
Vol 25 (12) ◽  
pp. 1107 ◽  
Author(s):  
Sharon Deemer ◽  
Charles Hurich
Keyword(s):  
Layered Intrusion ◽  
Seismic Image ◽  
Basal Portion

scholarly journals Raman and CRDS isotopic resolution spectroscopy for biomedicine applications

2019 ◽  
Vol 1379 ◽  
pp. 012050
Author(s):  
Aleksandr Grishkanich ◽  
Yan Chubchenko ◽  
Marina Kustikova ◽  
Aleksandr Zhevlakov ◽  
Leonid Konopelko ◽  
...  
Keyword(s):  
Isotopic Resolution

scholarly journals Growth and Impact of a Mafic–Silicic Layered Intrusion in the Vinalhaven Intrusive Complex, Maine

2015 ◽  
Vol 56 (2) ◽  
pp. 273-298 ◽  
Author(s):  
Robert A. Wiebe ◽  
David P. Hawkins
Keyword(s):  
Layered Intrusion ◽  
Intrusive Complex

MULTIPLE SILLS OR A LAYERED INTRUSION? TIME TO DECIDE

2012 ◽  
Vol 115 (3) ◽  
pp. 283-290 ◽  
Author(s):  
R. G. CAWTHORN
Keyword(s):  
Layered Intrusion

Vertical igneous layering in the Ewarara layered intrusion, central Australia

1977 ◽  
Vol 114 (5) ◽  
pp. 365-374 ◽  
Author(s):  
A. D. T. Goode
Keyword(s):  
Layered Intrusion ◽  
Multiple Injection ◽  
Crystal Mush ◽  
Flow Differentiation ◽  
Central Australia ◽  
Ultramafic Cumulates ◽  
Inhomogeneous Crystal ◽  
Feeder Zone ◽  
Igneous Layering ◽  
Layered Sequence

SummaryThe Ewarara Intrusion of central Australia contains two vertical fine-banded horizons within a sequence of sub-horizontal ultramafic cumulates. The horizons are arranged in an en échelon pattern adjacent to a steep intrusional contact, and consist of an alternation of two layer types which correspond to the two major lithologies present in the horizontal sequence. The horizons are up to 5 m thick. A number of possible origins, including folding of originally horizontal cumulates, flow differentiation and multiple injection, do not satisfactorily explain the formation of the layering. The most likely origin appears to involve differential viscous flow along the steep contact of an inhomogeneous crystal mush derived from the horizontal layered sequence. This mobilization is related to fresh injections along a feeder zone trending 060µ, the only such zone recognized in the Giles Complex.

Naldrettite (Pd2Sb): A new find in Brazil and comparison with worldwide occurrences

2021 ◽  
Vol 59 (6) ◽  
pp. 1801-1820
Author(s):  
Giorgio Garuti ◽  
Federica Zaccarini
Keyword(s):  
Regional Metamorphism ◽  
Layered Intrusion ◽  
Hydrothermal Fluids ◽  
Maximum Temperature ◽  
Magma Intrusion ◽  
Type Composition ◽  
Before And After ◽  
Magmatic Stage ◽  
New Finding ◽  
Podiform Chromitites

ABSTRACT Naldrettite (Pd2Sb) is a PGM discovered in 2005 in Mesamax Northwest deposit, Ungava region, Quebec, Canada. Before and after its approval, PGM with the naldrettite type composition have been reported from a number of localities worldwide. Most frequently, naldrettite has been documented in magmatic Ni–Cu–PGE sulfide deposits, hydrothermal veins in porphyry coppers of the Cu–Au type, and PGE deposits of Alaskan-type zoned intrusions. Naldrettite has been occasionally found in metasomatic Sb–As sulfide ore, metamorphic Ni–oxide ore, and podiform chromitites, although these occurrences have not been fully constrained by solid chemical analyses or paragenetic reconstruction. In this paper we report the first discovery of naldrettite in Brazil. This new finding occurs in a chromitite sample collected in the Luanga Complex, a Neo-archaean layered intrusion in the Carajás Mineral Province. Paragenetic association with alteration assemblages (ferrianchromite, Fe-hydroxides, chlorite) suggests precipitation of naldrettite from metamorphic hydrothermal fluids. The average composition of the Luanga sample (Pd1.76Pt0.24)Σ2.00(Sb0.57As0.43)Σ1.00 shows major substitution of Pt and As. These elements were derived from the breakdown of primary sperrylite, and were incorporated in naldrettite deposited by percolating fluids, at temperature below 350 °C (maximum temperature registered by the crystallization of associated chlorite). An overview of documented occurrences indicates that naldrettite can form in a variety of igneous rocks (ultramafic, mafic, felsic), even involving minimal concentrations of Pd and Sb. Crystallization of naldrettite generally occurs in the post-magmatic stage due to the activity of hydrothermal fluids containing volatile species Sb, As, Bi, Te, and Pd due to its higher mobility compared with the other PGE. A major issue concerns the origin of fluids that can be: (1) “residual”, after the main crystallization of the host magma, (2) “metamorphic”, during regional metamorphism or serpentinization, and (3) “metasomatic”, emanating from an exotic magma intrusion. The combination of two or three of these factors is the most likely process observed in the naldrettite-bearing complexes.

Coupled substitutions in PGE-enriched cobaltite: new evidence from the Rio Jacaré layered complex, Bahia state, Brazil

2015 ◽  
Vol 79 (5) ◽  
pp. 1185-1193 ◽  
Author(s):  
Andrei Y. Barkov ◽  
Yana Fedortchouk ◽  
Robert A. Campbell ◽  
Tapio A.A. Halkoaho
Keyword(s):  
Layered Intrusion ◽  
Fluid Phase ◽  
Primary Phase ◽  
Sulfur Fugacity ◽  
Type Molecule ◽  
Substitution Mechanism ◽  
Compositional Variability ◽  
New Evidence ◽  
Layered Complex ◽  
Grain Core

AbstractMicrocrystals of platinum-group element (PGE)-bearing cobaltite occur in the Gulcari A deposit of vanadiferous titanomagnetite in the lower zone of the Rio Jacaré mafic-ultramafic layered intrusion, Brazil. Aggregates of cobaltite and sperrylite are cluster-like and developed generally along the boundary of Fe-Ti oxide grains with deuteric silicates. Our observations of cryptic zoning, compositional variability and interelement correlations are based on 37 analytical points (wavelength-dispersion spectrometry mode) of cobaltite, and indicate that Ir and Rh behave uniformly with Ni and antipathetically with Co which, in turn, correlates directly with S content. Iridium, Rh and Ni apparently substitute for Co in the As-enriched grain core, and the substitution mechanism invokes solid solution with a cattierite-type molecule: (Ni + Ir + Rh) + (AsS) = Co + (S2). The PGE-bearing cobaltite probably crystallized as a primary phase at 500 to 300°C, from microvolumes of a late fluid phase. The observed enrichment in S and decrease in the As:S ratio at the cobaltite grain margins is a reflection of the increase in sulfur fugacity (fS2) with decrease in temperature of crystallization.

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.

Petrology and Ni-Cu-Cr-PGE Mineralization of the Largest Mafic Pluton in Europe: The Early Proterozoic Burakovsky Layered Intrusion, Karelia, Russia

1995 ◽  
Vol 37 (6) ◽  
pp. 509-525 ◽  
Author(s):  
Evgenii V. Sharkov ◽  
O. A. Bogatikov ◽  
Tanya L. Grokhovskaya ◽  
A. V. Chistyakov ◽  
Vyacheslav A. Ganin ◽  
...  
Keyword(s):  
Layered Intrusion ◽  
Early Proterozoic ◽  
Pge Mineralization
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