Study and Presentation of Toarcian - Bajocian Plant Macrofossils of Gorakhk-Shandiz Region, North East of Iran

For age determination of detrital sediments that have been deposited on metamorphic rocks in 1:25000 map of Shandiz, several macrofossils are collected. In this study, 22 genus and 39 species are identified and presented. They consist of Horsetails; natural Ferns seed Ferns & Gymnosperms and consist of Cycades, Gynkgoes & Conifers. Seven genus consist of Carpolithes, Cycadocarpidium, Pacypteris, Phoenicopsis, Pseudoctenis, Ptilophyllum & Sphenarion and five species consist of Dictyophyllum nervulosum, Ginkgoites baieraformis, Neocalamites ishpushtensis, Nilssonia ingens & Nilssonia undulate are report for the first time from Binaloud zone. Mesozoic detrital sediments in this map consists of 4 members (from base to top) including Conglomerate beds Jc1 (without plant fossil), Conglomerate beds Jc2, Shaly – Sandstone bed sh.s and Conglomerate beds Jc3. According to their stratigraphical distribution and assemblage of two genus Coniopteris and Phoenicopsis in Conglomerate beds Jc2 and stratigraphical position of this beds and also presence of species such as Cladophlebis denticulate, Dictyophyllum nervulosum, Ginkgoites baieraformis, Ginkgoites cordilobata, Klukia exilis, Nilssona ingens & Nilssonia feriziensis in Shaly – Sandstone bed sh.s, latest Late Liassic (Toarcian) to Early Dogger (Aalenian) age are suggested for both of Jc2 and sh.s beds. Based on the presence of index species from Conglomerate beds Jc3 such as Cladophlebis cf. feriziensis, Cladophlebis denticulate, Coniopteris hymenophylloides, Klukia exilis, Neocalamites ishpushtensis & Sagenopteris cf. Iranica and abundance of 3 genus consist of Coniopteris, Klukia and Phoenicopsis that are present in the sh.s bed, Early Dogger (Aalenian – Bajocian) age are suggested for this bed.