Stratigraphy, Paleontology and Sedimentary Environment of the Lower Cretaceous rocks in the northern foothill of Shirkuh (Yazd)

Majidifard, Mahmoudreza

Stratigraphy, Paleontology and Sedimentary Environment of the Lower Cretaceous rocks in the northern foothill of Shirkuh (Yazd)

Author

Mahmoudreza Majidifard

Geological Survey of Iran, Tehran, Iran

Abstract

There are adequate outcrops belonging to early Cretaceous rocks in the northern foothill of Shirkuh Lying within the Southwest yazd in this area, thin bedded to thick bedded Rudist-Orbitolina bearing limestones (Taft Fm., aged, Barm.-Apt.) constitutes a major portion of Cretaceous Period. The latter Nonconformity overlies Shirkuh Granite (With an approximate age of 175 m.y. ago ), i.e., several meters of grey, fine, gained conglomerate as well as red sandstone (Sangestan Fm.) overlies the Granite. Above Orbitolina limestones there is a succession of olive-green shales and yellowish grey, glauconitic marly limestone (Darreh-zanjir shales) of Albian age. Darreh, zanjir shales contains so abundant macrofossils among which are Ammonites, Gastropods, Corals, Bivalves, Belemnites and fish teeth. Within the above-mentioned shales,2 Ammonite horizons and 5 Ammonite Zones have been recognized as well.
The influences of the middle Kimmerian movements in the area is well evident from the extant evidences, including Shirkuh Granite, metamorphism of the lower Jurassic Rocks and the unconformity between lower Jurassic and lower Cretaceous Rocks.
By Studying the thin sections and identifying the sedimentary microfacies, three sedimentary environments have been recognized, including open marine, Barrier and lagoonal conditions respectively.

Keywords

Lower Cretaceous, Shirkuh, Yazd

Subjects

Stratigraphy and Palaeontology

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Scientific Quarterly Journal of Geosciences

Volume 5, Issue 20
Summer 1996, vol. 5, No. 20
Summer 1996
Pages 2-31

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Scientific Quarterly Journal of Geosciences

Stratigraphy, Paleontology and Sedimentary Environment of the Lower Cretaceous rocks in the northern foothill of Shirkuh (Yazd)

Volume 5, Issue 20Summer 1996, vol. 5, No. 20Summer 1996Pages 2-31

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Volume 5, Issue 20
Summer 1996, vol. 5, No. 20
Summer 1996
Pages 2-31