Finite strain analysis in the Seydan anticline using ammonoid spiral shells, Zagros, Iran

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• 作者：Babak Samani ; Ali Faghih
• 关键词：Finite strain ; Ammonoid ; Logarithmic spiral ; Seydan anticline ; Zagros ; Iran
• 刊名：Journal of African Earth Sciences
• 出版年：February, 2014
• 年：2014
• 卷：90
• 期：Complete
• 页码：25-30
• 全文大小：2844 K

文摘

Fossils with a spiral shape can be used as strain markers in quantitative strain analysis. Several methods have been suggested for strain analyses that exploit the logarithmic spiral laws governing development and growth of ammonoids. In this study, ammonoid spiral shells were measured to estimate strain variations along the northwestern limb of the Seydan anticline in the Zagros Fold-and-Thrust Belt, Iran. Results show an increase in strain from SE to NW along the Seydan anticline. These results, combined with other structural evidence, reveal a logical relationship between the intensity of folding and increasing strain. Strain variations are related to different amounts of slip along the Sivand thrust fault, which played a significant role in the development of the Seydan anticline as a fault-propagation fold.