Chalcolit hic and Bronze Ages are among the most important eras in prehistoric periods of Iran; they serve different cultural data, such as, pottery, architectures, burial, etc. For instance,
potteries from Chalcolit hic are buff in surface and use different geometrical mot ifs; whereas, in Bronze Age, we see sudden changes in pottery evidences. In this era, the tradit ion of buff
wares had abolished and black-gray ones wit h carved designs occupied the wide range. This cultural difference followed by pottery variet ies have been well ident ified in cultural layers of
the most parts of the Iran, especially in northwest areas. In respect with the cultural differences of the area and the properties of Bronze whether they have been derived from new
Chalcolit hic culture or new works give evidence of a newly arrived nat ion/culture, there were advent of debates. But in spite of existed disagreement on the case as well as on the unsolved
issues between the two eras, it seems that using experimental methods might provide so me responses to all of them. Current study aimed to invest igate the potsherds obtained from
Chalcolit hic, and Bronze layers by studying the petrographic of Kul Tappeh at Hadishahr in northwest of Iran, this study attempts to find some informat ion about the soil used in them
and their native status. Kul Tepe is a
mult i-period tell, about 6 ha in extent and rising 19 m above the surrounding land. The site was originally discovered by an expedit ion in the province of East Azerbaijan in 1968 under
the supervision of Kambakhsh Fard, and was later reported by other authors such as Edwards, Kliess, Kroll and Omrani as well. Kul Tepe is located precisely in the northwestern corner of
Iran, which is the gateway between the Southern Caucasus and northwestern Iran. Kul Tepe is located next to a broad valley, at the center of the highlands and at the crossroads of major
routes linking the Iranian plateau to Anatolia and the Caucasus to Northern Mesopotamia. The first season of excavat ion at Kul Tepe were carried out from June to August in 2010. Because
of the huge quantit y of material and deposits at Kul Tepe, the site needs mor e research and excavat ion to better understand the cultural situation in the region. The second season of
excavat ion was from August to October 2013 in order to answer certain quest ions about the region and extend the studied areas. Ten characterist ic potsherds (5 for each era) from Late
Chalcolit hic and Early Transcaucasia culture (Kura-Araxes) were studied by thin section microscopic (petrographic) method. These potsherds had been obtained during the excavat ions on Kul Tepe. Due to obtained result s as wel l as external heterogeneit ies in the two era's potsherds texture, we will find other significant differences among them, including their fabric and texture type. Dominant texture in the potsherds of the Chalcolit hic is of silt or tiny crystals, where as that of Bronze are coarse and puffery. Yet, no one found any volcanic glasses in the potsherds of the Chalcolit hic, whereas potsherds of the other era have volcanic glasses as well as crescent and circle-like pieces. Wit h due attention to the area's geology, fishy sedimentation basin, volcanic stones, pyroclastic stone, calcareous stones, and … existed in the area, one could clearly state that origin of the Bronze potsherds is local; because, unexceptionally some pieces of volcanic or pyroclastic stones will be seen in all of them.