Resumo

YOUSEFIRAD, Mostafa; GHANBARI, Somayeh  e  PARVANEHNEJAD SHIRAZI, Mahnaz. Using conodont elements to distinguish Permian-Triassic boundary disconformity near Haftad Gholleh, central Iran. Earth Sci. Res. J. [online]. 2013, vol.17, n.1, pp.61-65. ISSN 1794-6190.

The present study focuses on the stratigraphy of the Permian-Triassic boundary in the Haftad Gholleh area in eastern Arak and north of Mahallat,located in central Iran. This boundary of erosional unconformity or disconformity and as in other Iranian sequences related to the Permian period, contains dolomitic limestone and shale and sandstone disconformably located below the Triassic sequence. A detailed measured stratigraphic section has provided conodonts from the Permian-Triassic boundary (PTB) sequences in the area being studied. Three conodont areas have been recognied which place the PTB in this section by precise biostratigraphy. One of the most upper Permian sequences belongs to the Guadalupian period. The Triassic sequence consists of vermiculate limestone layers with coloured shale inter beds belonging to the Early Triassic period; unconformity at the Permian-Triassic boundary therefore represents a hiatus of about 10 million years.

Palavras-chave : Conodont; Haftad Gholleh; Permian-Triassic; stratigraphy.

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