Revising the Relative and Absolute Chronology of Tepe Hegmataneh, Hamadan, Iran: Based on the Finds and the Results of Thermo-Luminescent and Radiocarbon Dating

Historical site known as Tepe Hegmataneh is located in eastern edge of Central Zagros, Hamadan Province, Iran (34°48’15.61”N, 48°31’3.25”E). There are always some questions about the Site: 1- when and by the order of whom, the Standard Architectural Pattern (SAP) were built? 2- what was the function of SAP?Charles fosses directed the frist excavation in Tepe Hegmateneh, he worked for six mounth in 1913. Eric schmidt took some aerial photo from Hamadan between 1935 to 1937. Because of the first world war, the archaeological excavations were stopped. The first Iranian expedition worked in Tepe Hegmataneh for 11 successive seasons under supervision of M.R.Sarraf from 1983 to 2000, these excavations led to discovering some parts of an enclosure and SAP in central, southern and western workshops. However Sarraf could not find reliable answers for the already mentioned questions. Second round of excavation (12th to 15th seasons) was undertaken by M. Azarnoush for four seasons from 2004 to 2008, the aim was “to clarify the dating and stratigraphical sequence of the site” .In the 14th season, the excavated tranches were distributed all over the site in order to exam the yeilded results of Trench AR-AS40. Three workshops AV68, AY47 and AS39 were the most important excavated tranches in this season. Tranch AS39 is located in the north of Trench AR-AS40, and SAP remains was discovered in the last phase of this trench as same as remains in Trench AR-AS40. Excavation in Trench AV68 led to determinate a small part of SAP; second determined cultural period in this tranch includes some deposit in which potsherds with Parthian charactristics such as clinky were found. Tranch AY47 comprises cultural deposit and adobe stracture (SAP) which cannot be dated earlier than Parthian period. In addition, a great layer of soil was excavated Below the Standard Architectural Pattern (BSAP), also were detected in the 12th season of excavation in Tranch AR-AS40. The existence of this layer, raise the hypothesis that before building SAP, the ups and downs of the bedrock were filled by soil. The first absolute dating is related to 9th seasons of excavation. However Sarraf did not accept the result of TL dating as valid done. After that fifteen samples of 14th season were taken for TL dating, two of which dated to Sassanid, two dated to Early Islamic and the others dated to Parthian period. In the 14th season, nine samples of charcoals and bones from Trench AY47, AV68 and AS39 sent to Laboratory of Oxford University for 14C dating. From seven samples of Tranch AY47, three verified as invalid, and four dated to Middle of Parthian period. Regarding the TL dating and sequence of layers, two other samples from Trench AV68 and AS39 for 14C dating (no.8 and 9), surly cannot be valid; because the no.9 in 14C dating, was taken from the lower layer of no.12 and 14 tested with TL, suggested dating is TL yr BP (e.g. ‘1805±45 BP’), but for no.9 is 14C yr BP (e.g. ‘1494±28 BP’). The no.8 in 14C dating was derived from the lower layer of no.15 and 16; result of TL dating for these two samples is TL yr BP (e.g. ‘1690±45 BP’). But the result of 14C dating for no.8 is 14C yr BP (e.g. ‘1451±25 BP’). Therefore only no.1, no.3, no.4, no.5 are valid samples.The result of 14C and TL dating (19 samples from 24) indicates that Standard Architectural Pattern (SAP) was built in the Middle of Parthian to Early of Sassanid period (180 BC to 350 AD). Regarding the 50 hectare expanse of the site, which will be extened to 100 hectare, it is likely to discover Median and Achaemenian capital in Hamadan; but this cannot be contray that the SAP dates to Parthian period.