Mehraj Aghazadeh, Adel Sarkhoshi, ,
Volume 16, Issue 41 (5-2015)
Abstract
In the North of Bam city there were extensive volcanism and outcrops are basic and felsic volcanic rocks that crosscut by various dykes The volcanic rocks have sub alkaline and calc-alkaline to shoshonitic characteristic, however dykes are alkaline and potassic in nature. In the spider diagram all samples show enrichment in the LILEs and depletion and troughs in the HFSs elements that coincide with subduction related and upper crust rocks features. The studied samples represent enrichment in the LREE with various (La/Yb)N ratio and rhyolites show clear trough in Eu. According to geochemical features, studied rocks generated from different sources. Trachy andesy basalts and trachy andesites formed from 1-10% partial melting of metasomatized spinal lherzolite source. Dacitic magma generated from partial melting of mafic source in the lower crust while rhyolites formed from partial melting of metagreywacke source. The olivine basaltic and basaltic dykes generated from less than 1% and 3-5% partial melting of metasomatized garnet- spinel- bearing lherzolitic mantle source, respectively. Eocene volcanism in the Bam area has been occurred during subduction of Neo-Tethys oceanic crust beneath central Iran in the continental volcanic arc tectonic setting.
M Soltani Najafabadi, Sa. Babazadeh,
Volume 16, Issue 42 (5-2015)
Abstract
The various species of Alveolina for biostratigraphy of Eocene sedimentary rocks are very important. In this research, the species of Alveolina are reported for the first time in three cross sections: Chalonak, Kalaterood and East Beinabad. These sections are attributes to Early- Middle Eocene age. The 55 samples collected from Chalonak section and the thickness is reached to 245 m. In this section, four biozones are distinguished. They are following: Alveolina globula-Alveolina solida interval range zone, Alveolina solida-A .globosa interval range zone, Alveolina globusa total range zone and Alveolina aragonesis total range zone. On the basis of index fossils such as Alveolinana avellana, A. aragonensis,A. globula, A. leupoldi, A. globusa, A. elliptica nutalli, A. rotundata, A. corbarica, A.solida, which are existing in these biozones, the age of this section is attributed to Early Eocene. Of course two species of Nummulites (Nummulites globulus, N. atacicus) and Cuvilierina valensis are determined in Chalonak section. The 80 samples are collected from Kalaterood section and the thickness is reached to 242 m. In this section, four biozones are distinguished. They are following: Alveolina solida- A. globosa interval range zone, Alveolina globosa total range zone, Alveolina aragonensis-A. canavarii interval range zone and A. canavarii total range zone. The several index fossils are found in this section following: Alveolina aragonensis, A. decipiens, A. Avellana, A. laxa, A. pasticillata, A. canavari, A . globosa and A. solida. The age of this section is Early Eocene. The 150 samples are collected from East Binabad section and the thickness is reached to 900 m. In this section, four biozones are presented. They are Glomalveolina lepidula – Alveolina solida interval rage zone. Alveolina elliptica nutali- Alveolina corbarica interval range zone, Alveolina corbarica total range zone and Alveolina ruetimeyeri-Alveolina levantina assemblage zone. There are several index fossils such as Alveolina corbarica, A. elliptica nuttalli, A.levantina, A. roetimeyeri and A. decipiens, Glomalveolina lepidula. The age of this section is early Eocene.
