Table 11.1.

Outline stratigraphy of the Nordeste Volcanic System based on Fernandez (1980) showing dates of both Abdel-Monem et al. (1975) and Johnson et al. (1998)

SequenceLithologyThickness (m)Age (Ma)*Age (Ma)
Trachytes and TristanitesShort stubby flows and small plug-like intrusiveThin0.95 and 1.28
Upper BasaltsRelatively thin commonly aphyric alkali basalts and trachybasaltsc. 1501.860.78–0.82
Nordeste AnkaramitesTwo widespread thick flows of ankaramite and plagioclase ankaramitec. 200
Unconformity
Lower BasaltsConformable sequence of lavas ranging from ankaramite to alkali basalt to trachybasaltc. 10004.010.88
  • *K–Ar dates of Abdel-Monem et al. (1975).

  • Ar–Ar dates of Johnson et al. (1998).