Petrology of Serra Geral (Paran�) continental flood basalts, southern Brazil: crustal contamination, source material, and South Atlantic magmatism

1985 ◽  
Vol 91 (1) ◽  
pp. 54-65 ◽  
Author(s):  
R. V. Fodor ◽  
Cricket Corwin ◽  
Ari Roisenberg
Keyword(s):  
Crustal Contamination ◽  
South Atlantic ◽  
Source Material ◽  
Southern Brazil ◽  
Contamination Source ◽  
Flood Basalts ◽  
Continental Flood Basalts

The Michael Gabbro and other Mesoproterozoic lithospheric probes in southern and central Labrador

1997 ◽  
Vol 34 (12) ◽  
pp. 1566-1580 ◽  
Author(s):  
Ronald F. Emslie ◽  
Michael A. Hamilton ◽  
Charles F. Gower
Keyword(s):  
Crustal Contamination ◽  
Isotopic Signature ◽  
Geochemical Data ◽  
Magmatic Activity ◽  
Flood Basalts ◽  
Grenville Province ◽  
Continental Flood Basalts ◽  
The North ◽  
Basement Rocks ◽  
Northwestern Margin

The Michael Gabbro (1426 Ma) and the Shabogamo Gabbro (1459 Ma) represent two large diabase intrusive episodes that affected the northwestern margin of the northeastern Grenville Province. Both have sustained variable effects of subsequent Grenvillian metamorphism. Other broadly contemporaneous magmatic activity in the region includes the formation of Elsonian anorthosite–granitoid complexes (1.46–1.29 Ga) that intruded Churchill Province and Nain Province rocks to the north, the Harp dykes (1.27 Ga), and Mealy dykes (~1.25 Ga). Petrologic and geochemical data show that the Michael Gabbro and Shabogamo Gabbro are similar, with the latter displaying more cumulate rock characteristics, and the former having compositions closer to those of rapidly cooled magma. Both have compositions comparable to those of other continental diabases and to some continental flood basalts. Sr and Nd initial isotopic compositions of Michael Gabbro (εNd(1426 Ma) = −4.7 to −6.0, ISr(1426 Ma) = 0.7032–0.7044) and Shabogamo Gabbro (εNd(1459 Ma) = −4.0 to −5.5, ISr(1459 Ma) = 0.7020–0.7060) are alike and overlap, suggesting similar sources and processes of development. Comparisons with other nearly contemporary mafic suites in central and southern Labrador show that only the Mealy dykes have a distinctly more radiogenic isotopic signature. Paradoxically, other mafic suites that intrude older basement rocks north of the Grenville Front have less enriched Nd signatures than do those that intrude younger basement rocks south of the front. The argument is made that the subcontinental lithospheric mantle, and not crustal contamination, played the most influential role in evolution of the magmas.

Regional variations within the Paraná flood basalts (southern Brazil): Evidence for subcontinental mantle heterogeneity and crustal contamination

1989 ◽  
Vol 75 (1-2) ◽  
pp. 103-122 ◽  
Author(s):  
E.M. Piccirillo ◽  
L. Civetta ◽  
R. Petrini ◽  
A. Longinelli ◽  
G. Bellieni ◽  
...  
Keyword(s):  
Crustal Contamination ◽  
Mantle Heterogeneity ◽  
Southern Brazil ◽  
Flood Basalts ◽  
Regional Variations

scholarly journals Lead isotope constraints on the mantle sources involved in the genesis of Mesozoic high-Ti tholeiite dykes (Urubici type) from the São Francisco Craton (Southern Espinhaço, Brazil)

2016 ◽  
Vol 46 (suppl 1) ◽  
pp. 105-122 ◽  
Author(s):  
Leila Soares Marques ◽  
Eduardo Reis Viana Rocha-Júnior ◽  
Marly Babinski ◽  
Karine Zuccolan Carvas ◽  
Liliane Aparecida Petronilho ◽  
...  
Keyword(s):  
Mantle Source ◽  
Crustal Contamination ◽  
Experimental Tests ◽  
Pb Isotope ◽  
Flood Basalts ◽  
Nd Isotope ◽  
Continental Flood Basalts ◽  
Rock Fragments ◽  
Mantle Sources ◽  
First Results

ABSTRACT: The first results of Pb isotope compositions of the high-Ti Mesozoic dykes of the Southern Espinhaço are presented. The results do not show large variations and are significantly more radiogenic than the Pb isotope compositions of the high-Ti tholeiites from the Paraná Continental Flood Basalts. The data combined with published geochemical and Sr-Nd isotope results rule out crustal contamination processes in the genesis of the dykes, requiring magma generation in metasomatized subcontinental lithospheric mantle with the involvement of HIMU-type and carbonatite components. The magmas may have been also derived from a mantle source containing ~4 - 5% of pyroxenite and ~1% of carbonatite melts, agreeing with published Os isotope compositions of high-Ti rocks from the Paraná Continental Flood Basalts. These metasomatizing agents could be responsible for mantle source refertilization, as was also proposed in the literature to explain the characteristics of xenoliths of the Goiás Alkaline Province, which also occurs in the border of the São Francisco Craton. Additionally, to evaluate the risks of Pb contamination during sample preparation for analysis, several experimental tests were accomplished, which indicate the need of sawed surface removal and a careful washing of small-sized rock fragments before powdering, especially for rocks with [Pb] < 7 µg/g.

scholarly journals Continental Flood Basalts and Mantle Plumes: a Case Study of the Northern Ethiopian Plateau

2009 ◽  
Vol 50 (7) ◽  
pp. 1377-1403 ◽  
Author(s):  
L. Beccaluva ◽  
G. Bianchini ◽  
C. Natali ◽  
F. Siena
Keyword(s):  
Mantle Plumes ◽  
Flood Basalts ◽  
Continental Flood Basalts ◽  
Ethiopian Plateau

Peperite formed by lava flows over sediments: An example from the central Paraná Continental Flood Basalts, Brazil

2007 ◽  
Vol 159 (4) ◽  
pp. 343-354 ◽  
Author(s):  
Breno L. Waichel ◽  
Evandro F. de Lima ◽  
Carlos A. Sommer ◽  
Romulo Lubachesky
Keyword(s):  
Lava Flows ◽  
Flood Basalts ◽  
Continental Flood Basalts
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