Evolution of the neogene Gurghiu Mountains volcanic range (Eastern Carpathians, Romania), based on K-Ar geochronology

Ioan Seghedi, Alexandru Szakács, Norman J. Snelling, Zoltán Pécskay

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12 Citations (Scopus)

Abstract

K-Ar ages of rocks from the Gurghiu Mountains, the middle part of the longest volcanic chain in the Eastern Carpathians (Cǎlimani-Gurghiu-Harghita), indicate an interval of volcanic activity between 9.4-5.4 Ma. Magmatic activity migrated from North to South and built the following volcanic centres: Jirca (J), Fâncel-Lǎpuşna (FL), Bacta (B), Seaca-Tǎtarca (ST), Borzont (BZ), Şumuleu (S) and Ciumani-Fierǎstraie (CF). The timing of volcanic activity in each volcanic centre reflects the previously recognized overlapping age progression from North to South along the arc: J = 9.27.0 Ma; FL = 9.4-6.0 Ma; B = 7.5-7.0 Ma; ST = 7.3-5.4 Ma; BZ = 6.8 Ma; S = 6.8-6.2 Ma; CF = 7.1-6.3 Ma. Two peripheral small intrusive bodies have also been dated (Ditrǎu - 7.9 Ma and Corund - 7.4 Ma). The duration of volcanic activity of each centre is ca. 1 Ma, with a larger interval of 2.5 Ma for the Fâncel-Lǎpuşna volcano. Volcanic activity in the southernmost volcanic centres (ST; BZ; S; CF) between 7-6 Ma was contemporaneous. Certain volcanological problems are pointed out: (i) the voluminous debris-avalanche deposit assumed to belong to the Cǎlimani Mountains includes blocks of ca. 8 Ma up to the Gurghiu Valley and between 7.5-7.8 Ma south of the Gurghiu Valley (ii) the Fǎncel-Lǎpuşna caldera was generated around 6.9 Ma and involved a post-caldera uplift and/or erosion of the caldera floor and younger domes; and (iii) the model based on volcanic facies distribution is consistent with the new age-data.

Original languageEnglish
Pages (from-to)325-332
Number of pages8
JournalGeologica Carpathica
Volume55
Issue number4
Publication statusPublished - Aug 1 2004

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Keywords

  • Debris-avalanche
  • Eastern Carpathians
  • Gurghiu Mountains
  • K-Ar data
  • Volcanology

ASJC Scopus subject areas

  • Geology

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