Stratigraphy and Palaeontology
Fatemeh Vaez-Javadi; Mahdi Abbaszadeh
Abstract
Middle Jurassic sediments of the Hojedk Formation have been well-exposed in the Central East of Iran. In this study, plant macrofossils, which are collected from a coal exploratory well in the Mazino area, southwest of the Tabas were studied, so that 29 species of well-preserved plant macrofossils belonging ...
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Middle Jurassic sediments of the Hojedk Formation have been well-exposed in the Central East of Iran. In this study, plant macrofossils, which are collected from a coal exploratory well in the Mazino area, southwest of the Tabas were studied, so that 29 species of well-preserved plant macrofossils belonging to 15 genera of various orders such as Equisetales, Filicales, Caytoniales, Bennettitales, Cycadales, and Pinales were identified. One local biozone- Ptilophyllum harrisianum-Klukia exilis interval zone was recognized. The lower and the upper boundaries of this biozone were identified by the first and the last occurrences of index species. Based on the occurrences of the Equisetites sp. cf. E. beanii, Klukia exilis, Ptilophyllum harrisianum, Nilssonia macrophylla, and Elatides thomasii, an early Middle Jurassic age (Aalenian-Bajocian) was suggested for this plant assemblage. The relative abundance of Filicales (ferns), Cycadales, Pinales, and Equisetales are 43.18, 31.82, 13.63, and 4.64 percent, respectively. Moreover, the results of similarity indices of plant macrofossils indicate relatively strong value of similarity between the plant macrofossil assemblage of the Mazino area and elsewhere in the Tabas Block. Besides, the floral gradient score of this assemblage is 54.89. Based on the paleontological and lithological evidence, a humid ‘warm temperate biome’ is considered for this locality. Moreover, it is confirmed that a uniform vegetation and palaeoclimate occurred in Tabas Block during the Middle Jurassic and that Iran was located within Vakhrameev’s Euro-Sinian region, as Transcaspian subprovince.
F Vaez-Javadi
Abstract
The East Yurt mine, SE Azadshahr, Golestan Province contains well preserved plant macrofossils containing nineteen species allocated to thirteen genera of various orders viz., Equisetales, Filicales, Cycadales, Bennettitales, Ginkgoales, and Coniferales. The plant macrofossils in this area are studied ...
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The East Yurt mine, SE Azadshahr, Golestan Province contains well preserved plant macrofossils containing nineteen species allocated to thirteen genera of various orders viz., Equisetales, Filicales, Cycadales, Bennettitales, Ginkgoales, and Coniferales. The plant macrofossils in this area are studied for the first time. Based on the occurrence of Pterophyllum bavieri, Pterophyllum nathorsti,and Baiera muensteriana a Rhaetian age is suggested for this assemblage. Since, there was no differentiation between formations in geological map, these flora confirms spreading of the Kalariz Formation in this area. The East Yurt mine flora is correlated to the plant macrofossil assemblages of Minoodasht, Narges-Chal, Zirab, Tazareh, Ashtar, Abiek, and Jajarm (Alborz Mountains), Ghadir Member of the Nayband Formation in the Parvadeh mines (Tabas Block), and Darbid-Khun (Kerman Basin). Moreover, this assemblage evidenced in Europe (Germany, Austria, Sweden, Greenland, France, Denmark), China, Turkistan, and the Central Asia. Therefore, there were close floristic relationships between North and Central-East Iran (Kerman Basin and Tabas Block) and these area were palaeogeographically closely related, probably forming a uniform paleoenvironment and palaeoclimate during the Late Triassic. Furthermore, Iran was located at the Middle Asia Province among the Euro-Sinian Region of Vakhrameev climatic belt subdivisions and the South-western Region of Dubroskina’s subdivisions during this time.
F. Vaez Javadi
Abstract
There is a well-preserved plant macrofossils florizone near the Tiar village, south Amol, Central Alborz, Iran. It contains abundant plant maccrofossils belonging to 9 taxa of various orders, such as Equisetales, Filicales, Bennettitales, Cycadales, Ginkgoales and Coniferales. Based on the occurrence ...
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There is a well-preserved plant macrofossils florizone near the Tiar village, south Amol, Central Alborz, Iran. It contains abundant plant maccrofossils belonging to 9 taxa of various orders, such as Equisetales, Filicales, Bennettitales, Cycadales, Ginkgoales and Coniferales. Based on the occurrence of Equisetites beanii and Elatides thomasii an earlyMiddle Jurassic age is suggested for this assemblage. This florizone can be correlated to the plant macrofossils assemblage of Iva (Baladeh), Rudbarak (NE Semnan), Central Alborz; Golmakan (Binalud, Kopehdagh) and Pabdana and Hashooni (KermanBasin).
J. Saadat Nejad
Abstract
Investigation on plant macrofossils of the Jurassic sediments of Shemshak Formation in Eshkevarat-e-Olia area has been resulted in introducing two species, consisting of Ptilophyllum sahnii and Ptilophyllum sakrigaliensis. Thesespecies belong to Phylum Cycadophyta and order Bennettitales. The above mentioned ...
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Investigation on plant macrofossils of the Jurassic sediments of Shemshak Formation in Eshkevarat-e-Olia area has been resulted in introducing two species, consisting of Ptilophyllum sahnii and Ptilophyllum sakrigaliensis. Thesespecies belong to Phylum Cycadophyta and order Bennettitales. The above mentioned macrofossils are reported for the first time from Iran.Based on the stratigraphical distribution of these two plant macrofossils and accompanied species such as Todites williamsoni, Cladophlebis aktashensis, Nilssonia tenuinervis, Ptilophyllum cutchense, Klukia exilis, Klukia westii, Coniopteris hymenophylloides , Ptilophyllum acutifolium, Nilssonia harrisi, Nilssonia macrophylla, Pseudoctenis herriesi and Elatides thomasi the age of the Shemshak Formation for these sedimentary bed in Eshkevarat-e-Olia is assigned to the Upper Liassic (Toarcian) – Bajocian.
