Petrology and tectonic significance of Mesozoic mafic dikes of the coastal New England igneous province, Massachusetts

Ross, Martin E.

doi:10.1130/spe268-p63

Cited by 5 publications

(14 citation statements)

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“…The province can also be extended farther south to include lamprophyres in Rhode Island described by Leavy and Hermes (1977) and Hermes et al (1984). The eastern Massachusetts dolerites are more alkalic than Eastern North American (ENA) dolerites to the west of the CNE province (Ross 1992).…”

Section: Discussionmentioning

confidence: 99%

“…The Mesozoic dykes in coastal Massachusetts are the southerly extension of the Coastal New England (CNE) province of McHone and Butler (1984) into southeastern New England with ages ranging from 190 Ma to 226 Ma (Ross 1990(Ross , 1992. They are interpreted to have formed in association with the early stage of rifting of Pangea to form the North Atlantic Ocean Basin (Ross and Reidel 1983;Ross 1985Ross , 1990.…”

Section: Discussionmentioning

confidence: 99%

“…The Mesozoic mafic dykes of eastern Massachusetts consist of tholeiitic olivine-dolerite, transitional-alkalic dolerite, nenormative alkaline dolerite, and at least three identified alkaline lamprophyres (Ross 1992). The Mesozoic dykes in coastal Massachusetts are the southerly extension of the Coastal New England (CNE) province of McHone and Butler (1984) into southeastern New England with ages ranging from 190 Ma to 226 Ma (Ross 1990(Ross , 1992.…”

Section: Discussionmentioning

confidence: 99%

“…The dyke intruded the Cambridge Argillite, as well as a 15 m-thick, easttrending altered dolerite dyke of unknown age (Ross 1992). Its contacts with both the Cambridge Argillite and the dolerite dyke are sharp and chilled (Fig.…”

Section: Geological Setting and Field Characteristicsmentioning

confidence: 99%

“…Southeastern New England has been intruded by at least five mafic dyke swarms that range in age from Proterozoic to Triassic (Ross 1990(Ross , 1992. Nearly all of the dykes are composed of dolerite but 3 lamprophyric dykes have been identified (Ross 1990) in Avalonia in eastern Massachusetts (Fig.…”

Section: Introductionmentioning

confidence: 99%

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An Early Triassic 40Ar/39Ar age for a camptonite dyke in Cambridge, Massachusetts

Ross¹

2010

atgeol

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A 2.4 m-thick megacryst-and xenolith-rich camptonite dyke briefly exposed during excavation of a subway station at Porter Square in Cambridge, Massachusetts, was sampled for petrological study and radiometric dating to constrain its age. The sample yielded a well-defined 40 Ar/ 39 Ar age of 246 ± 4 Ma using separates prepared from a ferro-kaersutite mega-phenocryst. This age is the oldest yet reported for a Coastal New England province lamprophyric dyke. The dyke likely reflects regional extension in Avalonia during the initial rifting stage of Pangea to form the North Atlantic Ocean basin. This new age further confirms that mantle upwelling began early in the Late Permian to Triassic as a precursor to the breakup of Pangea some 40 million years later. 39 Ar, il a été possible de déterminer avec relativement de précision un âge de 246 ± 4 Ma, grâce à des fractions obtenues par préparation d'un mégaphénocristal de ferro-kaersutite. Il s'agit de la plus ancienne datation établie pour un dyke lamprophyrique de la province géologique du littoral de la Nouvelle-Angleterre. Ce dyke rendrait vraisemblablement compte de l'extension régionale de l'Avalonien au cours du stade initial de distension de la masse continentale de Pangée, qui allait entraîner la création du bassin océanique de l'Atlantique Nord. Cette nouvelle datation vient confirmer une fois de plus que la remontée du manteau terrestre a débuté très tôt entre la fin du Permien et le Trias, cet événement géomorphologique annonçant le fractionnement ultérieur du continent de Pangée quelque 40 millions d'années plus tard. RÉSUMÉ[Traduit par la redaction]

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Geological Setting and Field Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Early Triassic 40Ar/39Ar age for a camptonite dyke in Cambridge, Massachusetts

Ross¹

2010

atgeol

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Supercontinental inheritance and its influence on supercontinental breakup: The Central Atlantic Magmatic Province and the breakup of Pangea

Whalen

Gazel

Vidito

et al. 2015

Geochem Geophys Geosyst

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The Central Atlantic Magmatic Province (CAMP) is the large igneous province (LIP) that coincides with the breakup of the supercontinent Pangea. Major and trace element data, Sr-Nd-Pb radiogenic isotopes, and high-precision olivine chemistry were collected on primitive CAMP dikes from Virginia (VA). These new samples were used in conjunction with a global CAMP data set to elucidate different mechanisms for supercontinent breakup and LIP formation. On the Eastern North American Margin, CAMP flows are found primarily in rift basins that can be divided into northern or southern groups based on differences in tectonic evolution, rifting history, and supercontinental inheritance. Geochemical signatures of CAMP suggest an upper mantle source modified by subduction processes. We propose that the greater number of accretionary events, or metasomatism by sediment melts as opposed to fluids on the northern versus the southern Laurentian margin during the formation of Pangea led to different subduction-related signatures in the mantle source of the northern versus southern CAMP lavas. CAMP samples have elevated Ni and low Ca in olivine phenocrysts indicating a significant pyroxenite component in the source, interpreted here as a result of subduction metasomatism. Different collisional styles during the Alleghanian orogeny in the North and South may have led to the diachroneity of the rifting of Pangea. Furthermore, due to a low angle of subduction, the Rheic Plate may have underplated the lithosphere then delaminated, triggering both the breakup of Pangea and the formation of CAMP.

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Evolution of a post-batholith dike swarm in central coastal Queensland, Australia: arc-front to backarc?

Allen

2000

Lithos

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Petrology and tectonic significance of Mesozoic mafic dikes of the coastal New England igneous province, Massachusetts

Cited by 5 publications

References 0 publications

An Early Triassic 40Ar/39Ar age for a camptonite dyke in Cambridge, Massachusetts

An Early Triassic 40Ar/39Ar age for a camptonite dyke in Cambridge, Massachusetts

Supercontinental inheritance and its influence on supercontinental breakup: The Central Atlantic Magmatic Province and the breakup of Pangea

Evolution of a post-batholith dike swarm in central coastal Queensland, Australia: arc-front to backarc?

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