Mantle source heterogeneity of the Early Jurassic basalt of eastern North America

J.g  Shellnutt, Jaroslav Dostal, Meng-Wan Yeh

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

One of the defining characteristics of the basaltic rocks from the Early Jurassic Eastern North America (ENA) sub-province of the Central Atlantic Magmatic Province (CAMP) is the systematic compositional variation from South to North. Moreover, the tectono-thermal regime of the CAMP is debated as it demonstrates geological and structural characteristics (size, radial dyke pattern) that are commonly associated with mantle plume-derived mafic continental large igneous provinces but is considered to be unrelated to a plume. Mantle potential temperature (TP) estimates of the northern-most CAMP flood basalts (North Mountain basalt, Fundy Basin) indicate that they were likely produced under a thermal regime (TP ≈ 1450 °C) that is closer to ambient mantle (TP ≈ 1400 °C) conditions and are indistinguishable from other regions of the ENA sub-province (TPsouth = 1320–1490 °C, TPnorth = 1390–1480 °C). The regional mantle potential temperatures are consistent along the 3000-km-long ENA sub-province suggesting that the CAMP was unlikely to be generated by a mantle plume. Furthermore, the mantle potential temperature calculation using the rocks from the Northern Appalachians favors an Fe-rich mantle (FeOt = 8.6 wt %) source, whereas the rocks from the South Appalachians favor a less Fe-rich (FeOt = 8.3 wt %) source. The results indicate that the spatial-compositional variation of the ENA basaltic rocks is likely related to differing amounts of melting of mantle sources that reflect the uniqueness of their regional accreted terranes (Carolinia and West Avalonia) and their post-accretion, pre-rift structural histories.

Original languageEnglish
Pages (from-to)1033-1058
Number of pages26
JournalInternational Journal of Earth Sciences
Volume107
Issue number3
DOIs
Publication statusPublished - 2018 Apr 1

Fingerprint

mantle source
Jurassic
basalt
mantle
potential temperature
thermal regime
mantle plume
rock
Avalonia
large igneous province
flood basalt
North America
province
dike
terrane
spatial variation
plume
melting
accretion
mountain

Keywords

  • Central Atlantic Magmatic Province
  • Early Jurassic
  • Mantle potential temperature
  • North Mountain basalt
  • Northern Appalachians

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

Cite this

Mantle source heterogeneity of the Early Jurassic basalt of eastern North America. /  Shellnutt, J.g; Dostal, Jaroslav; Yeh, Meng-Wan.

In: International Journal of Earth Sciences, Vol. 107, No. 3, 01.04.2018, p. 1033-1058.

Research output: Contribution to journalArticle

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