Geochemistry of mafic dikes in the Adirondack mountains: implications for late Proterozoic continental rifting

Coish, R. A.; Sinton, Christopher W.

doi:10.1007/bf00344084

Cited by 60 publications

(57 citation statements)

References 60 publications

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“…metagabbros from nw sardinia 153 (6639-11 727), (comparable with the values of 7000-11 000 found by Coish and Sinton (1992) for mildly alkaline dykes in the Adirondacks), very low Th/La (0.05-0.09), Th/Nb (0.06-0.10) and Nb/U (mostly >50), and positive rather than negative anomalies for Nb and Ta. An enriched asthenospheric source is suggested by the low La/Nb values ( 1.1), in agreement with the hypothesis of Fitton et al (1988) who considered that the basalts of the Basin and Range Province (La/Nb < 1.5 in the OIB range) are of asthenospheric origin and that the basalts from the Sierran Province with La/Nb > 1.5 are from a lithospheric source.…”

Section: Evidence Of An Enriched Asthenospheric Mantle Source For Alksupporting

confidence: 73%

“…All the above authors attributed the high values of both ratios to a fluid or melt contribution on the part of previously subducted material to the subcontinental mantle. The high TiO 2 content (2.18-3.54 wt%) and the high Ti/Y and Ti/Zr values (498-883 and 59-140, respectively) are comparable to those found by Coish and Sinton (1992) in the mildly alkaline Adirondack dykes, for which those authors proposed an enriched asthenospheric source instead of a subcontinental mantle contaminated by subduction-related fluid or melts. In contrast, an enriched subcontinental mantle source was claimed by Pegram (1990) for Mesozoic Appalachian tholeiites, completely different from the mildly alkaline rocks of the Adirondacks (Coish and Sinton 1992) and Nurra (this paper).…”

Section: Evidence Of An Enriched Asthenospheric Mantle Source For Alksupporting

confidence: 71%

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Pre‐Variscan metagabbro from NW Sardinia, Italy: evidence of an enriched asthenospheric mantle source for continental alkali basalts

et al. 2003

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Small metagabbro bodies are enclosed in the metasedimentary sequence of NW Sardinia. The metagabbro represents the last magmatic episode before the continent-continent collision which built up the Variscan chain of north Sardinia.\ud The metagabbro are composed up of variable proportions of plagioclase and pyroxene igneous relics and metamorphic minerals. Major and trace element data, i.e high TiO2, P2O5 and low K, Rb content, as well as LREE, Nb, Ta enrichment, suggest an alkaline affinity for the gabbro and emplacement in a within-plate tectonic setting. The gabbro was derived from an island alkali basalt-like asthenospheric mantle source enriched with incompatible elements and uncontaminated by crustal or subducted materials. Non-modal modelling indicated a 5-7% partial melting of the asthenospheric mantle. \u

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Section: Evidence Of An Enriched Asthenospheric Mantle Source For Alksupporting

confidence: 73%

Section: Evidence Of An Enriched Asthenospheric Mantle Source For Alksupporting

confidence: 71%

Pre‐Variscan metagabbro from NW Sardinia, Italy: evidence of an enriched asthenospheric mantle source for continental alkali basalts

et al. 2003

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“…Previous work in our laboratory applied inductively coupled argon plasma (ICAP) analysis (Coish & Sinton, 1992) to reveal the iron content of human saliva. We defined salivary iron concentrations as ranging from 0n1 to 1n0 µM (unpublished observations), and therefore included these concentrations in our in vitro studies.…”

Section: Discussionmentioning

confidence: 99%

“…For expression studies, ferric citrate was added to the iron-depleted medium described above at concentrations ranging from 0n01 to 10 µM. Absolute metal ion concentrations were confirmed on a Thermo Jarell Ash Inductively Coupled Argon Plasma (ICAP 61) analyser (Coish & Sinton, 1992) that had been previously standardized with a metal solution containing 1000 p.p.m. iron, magnesium and manganese.…”

Section: Media Preparationmentioning

confidence: 99%

Expression of Streptococcus mutans fimA is iron-responsive and regulated by a DtxR homologue

et al. 2001

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Iron uptake, transport and storage in Streptococcus mutans, the principal causative agent of human dental cavities, is unexplored despite early reports in the literature which predict a role for this trace metal in cariogenesis. Experiments in the authors' laboratory revealed several iron-responsive proteins in S. mutans, one of which reacted with a polyclonal antiserum directed against the FimA fimbrial adhesin from Streptococcus parasanguis on Western blots. The results of Western blot and Northern hybridization experiments support an inverse relationship between iron availability and S. mutans fimA expression, and metal ion uptake experiments implicate FimA in S. mutans 55 Fe transport. Cloning of the S. mutans fimA homologue facilitated the construction of a fimA knockout mutant which grew poorly in an ironlimiting medium relative to the wild-type progenitor strain, lending further support to a role for FimA in S. mutans iron transport. The authors also identified and cloned a dtxR-like gene (dlg) located downstream of fimA on the S. mutans chromosome, and noted increased fimA expression in a S. mutans dlg knockout mutant relative to wild-type on RNA spot blots and Western blots. The uptake of 55 Fe, which was also significantly increased in this mutant, was compromised in a fimA/dlg double knockout. These findings are consistent with a role for Dlg in the iron-mediated regulation of fimA, and possibly other S. mutans iron transporters. Finally, the cariogenic potential of the fimA and dlg knockout mutants was not significantly different from that of the wild-type progenitor in a germ-free rat model.

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“…Determinationofthe source of the magma composition is highly difficultbecause there are several mantle components (DMM, HIMU, EM1, EM2).Some authors (Coish and Sinton, 1992)have used La/Ta and La/Nb ratios to distinguish lithospheric (La/Ta > 22; La/Nb > 1.5) fromasthenospheric sources which would be characterized by La/Ta < 22; La/Nb < 1.5. The Bayon rocks are characterized by ratios (La/Ta = 36-80; La/Nb=3-5).…”

Section: Source and Tectonic Settingmentioning

confidence: 99%

Geochemistry of the Bayonplutonic Complex – Western Cameroon

Belnoun¹,

Tchouankoue²,

Itiga³

et al. 2013

Glo Jnl Geo Sci

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The BayonNeoproterozoic plutonic complex located in Western Cameroon intrudes gneisses of Paleo to Neo Proterozoic age. The complex is composed of gabbro, monzogabbro and monzonites frequently crosscut by trachytic and granitic veins. /Lu N = 14 -27) with none or negligible Eu anomalies. The monzonite shows also moderate fractionatedpatterns (La N /Lu N = 20 -27) with fairly positive Eu anomalies. All the studied rocks show flat HREE features. The primitive mantle-normalized element patterns are almost homogeneous with negative anomalie in Ta, Nb, Th, P and Ti. Sm/Nd-wr-Cpx-Pl ages of the complex are 580 ± 13 Ma; 553 ± 32 Ma for the monzogabbro and 547 ± 26 Ma for the monzonite. The Nd/Sr isotopic compositions show that the Bayon plutonic rocks were generated by partial melting of subcontinental lithospheric mantle. The depleted mantle Nd model age TD M of 1.6 -1.7 Ga indicates that the studied rocks originated by partial melting of Mesoproterozoic mantle.

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Geochemistry of mafic dikes in the Adirondack mountains: implications for late Proterozoic continental rifting

Cited by 60 publications

References 60 publications

Pre‐Variscan metagabbro from NW Sardinia, Italy: evidence of an enriched asthenospheric mantle source for continental alkali basalts

Pre‐Variscan metagabbro from NW Sardinia, Italy: evidence of an enriched asthenospheric mantle source for continental alkali basalts

Expression of Streptococcus mutans fimA is iron-responsive and regulated by a DtxR homologue

Geochemistry of the Bayonplutonic Complex – Western Cameroon

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