Evaluating crustal contamination in continental basalts: the isotopic composition of the Picture Gorge Basalt of the Columbia River Basalt Group

Brandon, A. D.; Hooper, P. R.; Goleš, Gordon G.; Lambert, R. St J.

doi:10.1007/bf00321750

Cited by 68 publications

(57 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9; Brandon et al 1993;Hooper and Hawkesworth 1993). Indeed, the shapes of the patterns of the CGB, which show an enrichment of strongly incompatible trace elements and a negative Nb-Ta anomaly accompanied by high positive ε Nd and low 87 Sr/ 86 Sr values, can readily be explained by melting of a depleted mantle source with a superimposed subduction-related enrichment (Hooper and Hawkesworth 1993).…”

Section: Miocene Rocksmentioning

confidence: 94%

See 1 more Smart Citation

The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?

et al. 2008

View full text Add to dashboard Cite

The Tertiary (Paleogene and Neogene) geological record in south-central Canadian Cordillera is dominated by the 350-400 km wide, lower Eocene volcanic arc and the overlying Miocene-Recent back-arc lavas that are separated by a hiatus in magmatic activity between 48 and 24 Ma. In the Black Dome area (-240 km north of Vancouver), the Eocene volcanic rocks are mainly continental margin calc-alkaline andesite and dacite, resulting from the melting of a juvenile mafic source at the base of the crust. In contrast, the Miocene volcanic rocks resemble continental flood basalts. Both Eocene and Miocene rocks from the Black Dome volcanic complex have high positive ε Nd values (+7.2 to +7.4 and +6.4 to +7.6, respectively) and low initial Sr isotopic ratios (0.702 516 -0.703 528 and 0.703 376 -0.703 392, respectively) comparable to modern oceanic basalts. The onset of the hiatus in magmatism at 48 Ma coincides with capture of the Kula Plate by the Pacific Plate resulting in a change in convergence direction with the North American Plate from orthogonal to margin-parallel. The margin-parallel motion is inferred to have removed a 50-100 km sliver of the Eocene forearc that formed the boundary between the Pacific and subducted Kula Plate. Reinitiation of arc magmatism at 24 Ma is related to subduction of the Farallon and associated plates and it superimposed back-arc tholeiitic magmatism on top of the Eocene arc. Résumé : La géologie du Tertiaire dans le centre-sud de la Cordillère canadienne est dominée par un arc volcanique (Éocène inférieur) d'une longueur de 350-400 km et les laves d'arrière-arc (Miocène-Récent) qui le recouvre; les laves et l'arc sont séparés par un hiatus d'activité magmatique qui a eu lieu entre 48 et 24 Ma. Dans le secteur de Black Dome (-240 km au nord de Vancouver), les roches volcaniques éocènes sont principalement des andésites calco-alcalines et des dacites de bordure continentale qui proviennent de la fusion d'une source mafique juvénile à la base de la croûte. Par contre, les roches volcaniques datant du Miocène ressemblent à des basaltes de plateaux continentaux. Les roches du complexe volcanique Black Dome datant de l'Éocène et du Miocène ont des valeurs ε Nd positives élevées (respectivement +7,2 à +7,4 et +6,4 à +7,6) et de faibles rapports isotopiques Sr initiaux (respectivement 0,702 516 -0,703 528 et 0,703 376 -0,703 392), comparables aux basaltes océaniques modernes. Le début de l'hiatus dans le magmatisme il y a 48 Ma coïncide avec la capture de la plaque de Kula par la plaque du Pacifique, ce qui a conduit à un changement de la direction de convergence avec la plaque nord-américaine d'orthogonale à parallèle à la bordure. Le mouvement parallèle à la bordure aurait enlevé une bande de 50-100 km de l'avant-arc éocène qui formait la limite entre la plaque du Pacifique et la plaque subductée de Kula. La réinitiation du magmatisme d'arc il y a 24 Ma est reliée à la subduction de la plaque de Farallon et d'autres plaques apparentées et elle a superposé le magmatisme tholéiitique d'arrière-arc...

show abstract

Section: Miocene Rocksmentioning

confidence: 94%

“…They resemble some Columbia River flood basalts (BCR-1 in Fig. 9, also Hooper and Hawkesworth 1993;Brandon et al 1993).…”

Section: Miocene Rocksmentioning

confidence: 96%

The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?

et al. 2008

View full text Add to dashboard Cite

show abstract

“…However, other geochemical evidences for crustal contamination are not clear. For example, the geochemical data (Table 1 and Zhou et al, 2000;Ge et al, 2000bGe et al, , 2001) of mafic-ultramafic rocks from Sibao group, totaling 37 samples, have never shown any correlation between differentiation indicator, Mg#, and some major and trace element ratios, such as K 2 O/TiO 2 , Rb/Sr, Ba/Zr, La/Sm and La/Yb (Brandon et al, 1993). Besides, any negative correlation in the Nb/Ta-La/Yb plot caused by crustal contamination (Münker, 1998) have never been found.…”

Section: Fig 3 Plot Of Zr/tio 2 -Nb/y For Mafic-ultramafic Rocks Frmentioning

confidence: 99%

Geochemistry of Meso- and Neoproterozoic mafic-ultramafic rocks from northern Guangxi, China: Arc or plume magmatism?

et al. 2004

View full text Add to dashboard Cite

Meso-and Neoproterozoic mafic-ultramafic rocks from northern Guangxi show mainly calc-alkaline features. The mafic rocks have (Nb/La) pm 1) = 0.13~0.51, (Th/La) pm = 0.85~3.3, Ti/Ti* 2) = 0.29~0.79 and show negative Nb and Ti anomalies in primitive mantle normalized diagrams. The Mesoproterozoic mafic rocks have lower ε Nd (T) than those of Neoproterozoic, -1.99 ~ -5.13 vs. -0.74 ~ 2.4, respectively. They plot in the field of volcanic arc basalt in tectonic discrimination diagrams and display geochemical signatures of island arc volcanics. The mafic-ultramafic rocks are thought to be the products of magmatism of convergent plate boundary rather than derived from mantle plume. Therefore, they can not be regarded as an indicator of breakup of Rodinia supercontinent.

show abstract

“…Further, the samples possess lower Al 2 O 3 /TiO 2 and Zr/Nb ratios than those estimated for the continental crust (4-9 vs. 24.1 and 5-8 vs.16.08, respectively; Rudnick and Gao, 2004). The ratios between the incompatible elements, K 2 O/TiO 2 , Rb/Sr, La/Sm, and La/Yb, do not increase with decreasing Mg#, and preclude the involvement of crustal-derived components in the source (Brandon et al, 1993). Besides the above geochemical evidence, field observations did not reveal any magmatic interaction of the host granitic country rock with the dikes.…”

Section: Assessing Crustal Contamination and Post-magmatic Alterationmentioning

confidence: 77%

Petrogenesis of mafic alkaline dikes from the ~2.18Ga Mahbubnagar Large Igneous Province, Eastern Dharwar Craton, India: Geochemical evidence for uncontaminated intracontinental mantle derived magmatism

Khanna

Sai

Zhao

et al. 2013

Lithos

View full text Add to dashboard Cite

Evaluating crustal contamination in continental basalts: the isotopic composition of the Picture Gorge Basalt of the Columbia River Basalt Group

Cited by 68 publications

References 59 publications

The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?

The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?

Geochemistry of Meso- and Neoproterozoic mafic-ultramafic rocks from northern Guangxi, China: Arc or plume magmatism?

Petrogenesis of mafic alkaline dikes from the ~2.18Ga Mahbubnagar Large Igneous Province, Eastern Dharwar Craton, India: Geochemical evidence for uncontaminated intracontinental mantle derived magmatism

Contact Info

Product

Resources

About