Palaeoenvironment and basin architecture of the Lower Jurassic Ab-Haji Formation, east-central Iran
The Lower Jurassic Ab-Haji Formation of the Kalmard, Tabas and Lut blocks, east-central Iran, has been studied using an integrated stratigraphic-sedimentologic approach. The Ab-Haji Formation is mostly composed of greenish sandstones and siltstones and locally contains thin coal seams. Four well e...
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| Autores principales: | , , , |
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| Formato: | article artículo publishedVersion |
| Lenguaje: | Inglés |
| Publicado: |
Instituto de Fisiografía y Geología. Facultad de Ciencias Exactas, Ingeniería y Agrimensura. Universidad Nacional de Rosario
2015
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| Materias: | |
| Acceso en línea: | http://hdl.handle.net/2133/5142 http://hdl.handle.net/2133/5142 |
| Aporte de: |
| Sumario: | The Lower Jurassic Ab-Haji Formation of the Kalmard, Tabas and Lut blocks, east-central Iran, has been
studied using an integrated stratigraphic-sedimentologic approach. The Ab-Haji Formation is mostly composed of
greenish sandstones and siltstones and locally contains thin coal seams. Four well exposed sections were measured
and studied in order to identify lithofacies and facies associations and to interpret the palaeoenvironment. This
formation reaches a thickness up to 350 m in northern Tabas Block but may locally be reduced to few tens of meters or
even missing. Field studies have led to the recognition of sixteen lithofacies grouped into five facies associations:
fluvial plain, coastal plain, delta front, prodelta and shallow siliciclastic shelf. Reconstruction of the palaeogeography
of east-central Iran marks a west–east continental-to-marine gradient. Thickness variations, lateral facies changes and
basal unconformity of the siliciclastic rocks of the Ab-Haji Formation on the Kalmard, Tabas and Lut blocks show
palaeo-relief on the fault-bounded Yazd Block in the west and the Shotori Swell at the eastern edge of the Tabas Block.
The pattern of thickness variations and rapid EW facies changes is best explained by a tectonic model showing large
tilted fault blocks in an extensional basin. The obtained results are important for palaeogeographic and
palaeoenvironmental reconstructions of the east-central Iran since its sediments record the geodynamic history of this
region, as well as an even larger area, during and in the aftermath of the main Cimmerian event, from the beginning of
the Early Jurassic. |
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