Abstract
Behbahan plain in Southwest of Iran, is a region where high peaks of the Zagros Mountain meet the lowland plains of Khuzistan. The plain, due to several rivers including the Maroun River which originates from the high peaks deep into the Zagros, and fertile lands has been a locus for nucleation and subsequent development of human settlements since prehistoric periods to the modern times. In August and October of 2007, the authors of this article were conducted a settlement survey in Mansour Abad area, North and Northeast of the Behbahan plain, covering 150 km. The principal aim of the survey was identification of ancient sites in an area which was subjected to seismic prospection for the Iranian Oil Company. In fact, it was a rescue operation to minimize the possible risks to the ancient sites of the area. The survey method was extensive using GPS to locate the surveyed sites on topographic maps with scale 1/25000. The surface materials were gathered using random survey. The surveyed region can be divided into several landscapes, including: Mansour Abad Plain, the hilltop rolling hills in North, East, Northeast and Northwest of the Behbehan Plain and the mountainous region including Khaeiz and Badil Mountains. The most important feature of the mountainous region is the existence of several valleies. At the end of the archaeological surveys of the Mansourabad region, in addition to known sites which have been identified previously during the Behbahan survey project, we could identify 55 sites ranging in date from the prehistory to the Late Islamic Period, with highest number at Middle Islamic Period. The surveyed sites could be divided into several types including mound, sherd/flint scatter, hill-top site, cave and various standing architectures including Imamzadeh (shrines), water-mills, fortresses, and settlement structures of the Islamic Period. These sites usually have low frequency of surface sherds, some none.
Keywords: Behbehan, Mansourabad, Archaeology Survey, Relative Chronology.    
 
Introduction          
The Behbehan plain, due to several rivers including the Maroun River which originates from the high mountains of Eastern parts of the Kohgiluyeh region, and fertile lands has been a locus for nucleation and subsequent development of human settlements since prehistory well into the modern times. The region, 150 km in area, was surveyed in August and October 2007. The main goal of the survey was identification of ancient sites in an area which was subjected to seismic prospection for the Iranian Oil Company. During the survey we identified 55 sites ranging in date from the prehistory to the Late Islamic Period. The survey method was extensive using GPS to locate the surveyed sites on topographic maps with scale 1/25000. Archaeologically, one of the important aspects of the Behbehan plain is its potential to track the cultural interactions between Khuzestan and Fars especially in the prehistoric period. Previous research in the region were excavations and surveys by Nissen (Nissen, 1971; 1973, Nissen and Redman, 1971) and Dittman (Dittman, 1984), conducted a few decades ago. The chance discovery of the Elamite Tomb of Arjan in the early 1980 striggered a series of research in the region (e.g. Alizadeh, 1985, Saraf, 1992, Majidzadeh, 1992, Stronach, 2003, Alwarezmon, 2006).  
Of these one may point to the archaeological survey of the Behbehan plain in the early 2000s (Abdi, 2008). New phase of the systematic archaeological research in the region has been launched by A. Moghaddam since 2014. In these investigations, in addition to excavation at the site of Chahe- Naft, a series of period-oriented archaeological surveys aiming identification of early settlements at the region were conducted (Moghaddam, 2014: 287-8). 

The Surveyed Sites 
As mentioned above, in general, 55 sites ranging in date from the prehistory to the Late Islamic Period were identified. The sites are belonged to the Protoliterate, Proto-Elamite, Elamite, Achaemenid, Parthian, Sassanid and Islamic Periods. Of Protoliterate period, just one site, Taytou, was identified. Stone tools collected from the surface of the site includ bladelet cores, end-scraper and a number of debitages. Three sites (Karayale Talaw, Zaminhaye Partaki and Gasawz) can be dated to the Proto-Elamite and Elamite periods. They are distributed at the foothills of the Badil Mountains. In addition to Tange Takab’s ossuaries, four sites (Zaminhaye Partaki, Talaw, Darebazar and Konar Tepe) which are sherd scatter and mounded sites, are datable to the Achaemenid, Parthian and Sassanid periods. Of these, Zaminhay Partaki is located in the Mansourabad plain and other sites are distributed in the foothills of Badil Mountains. These sites range in area from 1.2 to 16 ha.   
The highest number of the identified sites belongs to the Islamic period. In total, 46 sites of several types including mounds, sherd scatters and various standing architectures including Imamzadeh (shrines), water-mills, castles, and settlement structures were identified. These sites are located in various landscapes of the region like high altitude, at the mouth and inside the gorges, rolling hills and the Mansourabad plain. Save for the site of Karatowal, which accoding to an inscribed sherd found on its surface belong to the Early Islamic centuries, most sites of this period are related to the Middle and Late Islamic Periods.  

Conclusion
At the end of the survey, in addition to known sites which have been identified previously during the Behbahan survey project, we could identify 55 sites range in date from the prehistory to the Late Islamic period, with highest number at Middle Islamic Period. The surveyed sites could be grouped into several types including sherd/flint scatters, mounds, hill-top sites, caves and various standing architectures including Imamzadeh (shrines), water-mills, fortresses, and settlement structures of the Islamic Period. A considerable number of the surveyed sites belong to settlements with stone structures dating to the Islamic Period. These sites usually have low frequency of surface sherds, some none.