CHRONOLOGY OF IBA SHAFT TOMBS IN THE SOUTHERN LEVANT: INTEGRAL PART OF THE IBA CULTURE FROM BEGINNING TO END

ABSTRACT Vast burial fields, some with hundreds of burials, categorize the southern Levant’s Intermediate Bronze Age period (IBA). This phenomenon contrasts with a limited number of burials found from the preceding Early Bronze III period. This paper presents the first radiocarbon dating research of sampled bones from shaft tombs from five IBA burial sites across Israel: Yehud, Jebel Qaaqir, Sheikh-Danon, Hazorea, and Kefar-Veradim. Prescreening methods, including Fourier transform infrared analysis, were applied to identify best-preserved collagen in archaeological bones for radiocarbon dating. Overall, the measured date ranges cover the IBA timeline, supporting the observation that the IBA signature shaft tombs are a fundamental tradition of the IBA culture, at least in Israel. A single IBA shaft tomb at Jebel Qaaqir which contained remains of multiple humans, supplied different dates for various people, spanning over a few hundred years. These results suggest a tribal or family-oriented IBA community with a long-lasting tradition reflected in centuries of collective burial practices.


INTRODUCTION
The Intermediate Bronze Age (IBA hereafter, also known as EB-IV) populated the southern Levant in the second half of the third millennium BCE. It was a pastoral-rural culture with clear differentiation in settlement patterns and material culture from the urban Early-Bronze III culture (EB-III) preceding it. Scholars identify distinct cultural aspects in IBA, including, among others, its burial habits. Dozens of IBA burial sites, some containing hundreds of tombs, have been discovered to date ( Figure 1). Most IBA burials include grave goods accompanying the deceased on their eternal journey, mainly pottery vessels, copper alloy objects, beads, and animal parts. The most common IBA burials found are in shaft tombs, dug into the bedrock, or in the ground. One type is a primary burial(s) within a single chamber (Figure 2a), as in the burial fields of Bet Dagan (Yannai et al. 2014), Yehud (Govrin 2015), and some Jericho tombs (Kenyon 1965). Another shaft tomb type is of secondary burials with disarticulated bones within one or several tomb chambers (Figure 2b), as in Megiddo (Guy 1938), Hazorea (Meyerhof 1989), and Jebel Qaaqir (Dever 2014). Less common are IBA cist tombs that are stoned-lined or slab-roofed (Figure 2c), as in Tell el-Ajjul (Kennedy 2015) and Tiwal esh-Sharqi (Tubb 1990). Some dolmen and tumulus/cairn burials were also attributed to the IBA (Figure 2d), e.g., in the Golan (Epstein 1985;Sharon et al. 2017) and the Negev (Dever 2014:213-216). Major IBA burial sites were excavated, among others, also at Beth Shan (Oren 1973), Lachish (Tufnell 1958), Gibeon (Prichard 1963), 'Ein Asawir (Horowitz 2016), Dhahr Mirzbaneh (Lapp 1966), 'Ein Samiya (Dever 1972), Tiwal esh-Sharqi (Helms 1983;Tubb 1990), Umm el-Bighal (Helms et al. 1988), and Khirbat Iskandar (Richard et al. 2010). EB III sites with substantial burial activity are an exception. Such sites are Jericho with rockhewn tombs and Bab edh-Dhra with unique above-the-ground charnel houses. Other than that, only several more tombs in the southern Levant were attributed to EB-III (Ilan 2002:96-99 with references). The vast number of burials discovered from the IBA is in striking contrast to the low number of tombs found from the preceding period of EB III. Yet, the published IBA absolute dates are from settlements, not burials. A possible exception is one date from a multiperiod tomb at Tell al-Husn in northern Jordan (Al-Muheisen et al. 2012).
The EB "High Chronology" based on a systematic analysis of 14 C dates suggests that EB III cities ceased to exist around 2500 BCE, and IBA sites already existed around the same time (Regev et al. 2012(Regev et al. , 2014Höflmayer et al. 2014;Lev et al. 2020;Fall et al. 2021). The high chronology extended the duration of the IBA period from about 300 years in the previous consensus (Mazar 1990;de Miroschedji 2009) up to 500 or 600 years. It is essential to determine when the drastic change in burial practices between EB III and IBA (described above) occurred within the IBA duration of half a millennium. When did IBA-type burials start? Were they common throughout all of the IBA period? Exploring this item can help us better understand the IBA culture and its development. Although progress has been made lately in IBA pottery relative periodization (D'Andrea 2012(D'Andrea , 2020Shalev et al. 2022), it still cannot tell us much about IBA burials chronology. Radiocarbon absolute dating is a potential tool to explore IBA burials chronology. The best practice in bone radiocarbon dating is isolating and dating the collagen fraction within the bone (Yizhaq et al. 2005;Brock et al. 2010). Unfortunately, human bones from ancient tombs in the southern Levant often undergo considerable diagenesis due to climatic and environmental conditions in this region. Bones are often found fragmented and in a deteriorated condition, and many times there is below minimal content or insufficient quality of collagen to enable trustable radiocarbon dating. In most of the IBA burials excavated in Israel during the last several decades, human bones were not preserved well or not researched.
Nevertheless, in the presented research, we succeeded in dating IBA human bones from several IBA burial sites, sampling bones during new excavations of IBA burials, and sampling stored IBA bones from a few past excavations. Chronology of IBA Shaft Tombs in the Southern Levant 971

Sites Sampled for IBA Burials Dating
A human skeleton within a single-phase burial cave is a safe and secure context for radiocarbon dating the tomb's contents. The first 14 C dates of human bones published from IBA burial sites in Israel are presented here. These 14 C dates are all of human bones found within well verified IBA contexts within the following burial sites (see circled sites in Figure 1): The following sections present the bone sampling details for each of the above sites:

Jebel Qaaqir
In cemetery B at Jebel Qaaqir, 59 tombs were excavated by W. Dever (Dever 2014). Most of them were robbed in antiquity, but a few seemed intact. Sealed tomb B-54 with its two chambers (A, B) is one of the richest caves found at Jebel Qaaqir ( Figure 3). Disarticulated human bones of at least nine individuals, five females and four males, were identified in tomb B-54. Seven were adults 40 to 60 years old, and two were adolescents (Smith 1982). Three bronze objects and ten intact ceramic vessels were found in this tomb and identified as IBA-related. Bones from this tomb were sampled from the NNH collections at the Hebrew University with permission from P. Smith. We have chosen and dated five left-side radii and a rib that showed sufficient collagen preservation, thus ensuring we dated five different individuals. However, we could not associate each dated bone to a specific individual.

Yehud Burial Ground
Salvage excavations of burial grounds at Yehud, including over 100 IBA single shaft tombs and several MB shaft tombs, were directed by Yehuda Govrin on behalf of the Hebrew Union College during 2008/2009 (Govrin 2015) and 2012 (Govrin forthcoming). The 2012 excavation uncovered a field of shaft tombs dug into the natural Hamra soil. Most tombs, including all those dated in this research, contained a single human skeleton in articulation and several distinctive IBA ceramic vessels ( Figure 4). Some other tombs were identified as from the MB period according to their pottery. Bones from the Yehud burial field were documented and stored. Systematic collagen tests over bone fragments from the 2012season excavated IBA shaft tombs were performed. Overall, 149 bone samples from 52 IBA tombs were tested to assess their suitability for 14 C dating. Bones from fourteen (14) IBA tombs included suitable collagen and were radiocarbon dated. Thirteen dated bones are from the main burials concentration. Dated sample RTD-8948 from tomb L2000 was located in a smaller tomb concentration, abutting the main burial field from the southwest.

Sheikh Danon
Salvage excavations led by Zach Horowitz on behalf of the Israel Antiquities Authority were conducted during the winter of 2018 in a burial cave on the northern slopes of the village of Seikh Danon on Israel's northern coastal plain, five km East of Nahariya (permit 8212/18. To be published). The cave appears to be a part of an IBA burial ground in that location (Getzov 2008). The excavated cave consists of two rectangular rooms. A rectangular entry shaft leads into the main chamber, with a smaller room as its extension. Over 40 complete pottery vessels, a few copper alloy objects, and disarticulated scattered Human bones of at least ten individuals were unearthed within ∼40 cm of accumulated sediment and collapsed ceiling debris on the bottom of this cave's two rooms ( Figure 5). All material culture found was identified as belonging to the IBA period. Several human bones from various locations in the cave entry room were collected for 14 C dating, and three bones that displayed sufficient Collagen amounts were processed and dated. The dated bone fragments were collected at least two meters apart. Yet, the bones in this cave were disarticulated and scattered around, and we are not sure if they represent different individuals. settlement (Covello-Paran 2020). In shaft tomb chamber L142 (Figure 6), disturbed human bones were located alongside an IBA jar fragment and a few copper/bronze elements. A human long-bone fragment from this chamber (labeled L142-a) was radiocarbon dated.

Hazorea
The IBA cemetery discovered in the southern part of Kibbutz Hazorea in the Jezreel Valley was excavated periodically between the 1950s and the 1980s by E. Anati and E. Meyerhof (Meyerhof 1989; see also Covello-Paran 2015:226-241). Human bones from tomb-3 at Hazorea (Figure 7) were located at the IAA storage facility. Two bones were tested positive for suitable collagen and were radiocarbon dated (Lev et al. 2021). The two dated bone fragments were found in separate bone accumulations within separate rooms and most probably belonged to different individuals.

Preparation of Bone Samples
Potential bones/teeth material for dating found within excavation was collected in aluminum foil envelopes. Bones from IBA tombs located in excavation storages were verified to be with no treatment, gluing, or preservation activities following their excavation. Sufficient collagen preservation is required in the bone (or the tooth dentine) to be a candidate for radiocarbon dating. The verification involved "prescreening" of the bone to assess the probability of collagen preservation by FTIR (Fourier transformed infrared spectroscopy) SF (splitting factor) indication (Weiner et al. 1990), followed by another prescreening test for collagen existence on 200 mg of powdered bone which is pretreated with 1N HCl acid to dissolve the bone apatite. If the FTIR spectrum of the bone/tooth insoluble fraction indicates a good collagen signal, then the bone is a probable candidate for radiocarbon dating. Chosen bones for dating went through a collagen extraction and purification procedure Chronology of IBA Shaft Tombs in the Southern Levant 975 (Yan et al. 2021). In the hot and humid Mediterranean regions, bone preservation is usually low after being buried in sediment for thousands of years. Screening techniques were enhanced to validate the dating suitability of bones with collagen W% < 1%, including 35 wt% as the minimal accepted presence of carbon in the extracted collagen and careful comparison of the extracted collagen FTIR spectrum with that of collagen standard.

Combustion and Graphitization
Combustion and graphitization of bone samples up to RTD-9292 were done at the Kimmel Center for Archaeological Science lab, Weizmann Institute of Science. The pretreated samples were combusted to CO 2 in vacuumed quartz tubes with 200 mg of copper oxide by heating to 900°C for 200 min. The CO 2 was reduced to graphite using 2 mg Fe powder as a catalyst and hydrogen and heated to 600°C for 20 hr.
Pretreated samples after RTD-9292 were combusted and graphitized by the new Vario Isotope Select Elemental Analyzer (EA), coupled with AGE-3 graphitization system (Wacker et al. 2010), at D-REAMS, Weizmann Institute of Science. Pretreated samples weighed in tin cups were dropped into the EA combustion tube wherein the presence of external oxygen flash combustion occurred at a temperature of 950°C. CO 2 was separated from the rest of the gaseous combustion products and transferred by Helium carrier gas into the AGE-3 graphitization unit, where carbon was converted to graphite through reduction by hydrogen over iron as catalyst. Carbon and nitrogen concentrations are measured to determine C/N atomic ratio and carbon weight percentage in the collagen (Van Klinken 1999). The graphite 14 C content was measured by the D-REAMS accelerator at the Weizmann Institute of Science (Regev et al. 2017). Radiocarbon ages were reported in conventional radiocarbon years BP (Before Present, where "present" is defined as the year 1950) following international conventions (Stuiver et al. 1977). All calculated 14 C ages have been corrected for the isotopic fractionation to be equivalent to the standard of δ 13 C value of -25‰. The radiocarbon ages were calibrated using the OxCal 4.4 online version (https:// c14.arch.ox.ac.uk/oxcal/OxCal.html) and the IntCal 20 calibration curve (Reimer et al. 2020).

Preservation of Bones
The percentage of dated bones in each site is presented in Table 1. The chemical parameters of the dated bones are shown in Table 2. The extent of collagen preservation within ancient bones (verified by SF, FTIR, and element ratios) appears to depend on the local environment of the bones resting place. Moist sediments, as in Qanat el Jaar and Yehud, seem to be a nonfavorable environment for collagen preservation. The collagen better preserves in dry, arid environments, as in Jebel Qaaqir or Sheikh Danon. We also found that some bones sampled from the same tomb or adjacent tombs only one meter apart proved to have different collagen preservation. For example, in Yehud burial ground, tomb L269 bone insoluble fraction presented a good FTIR collagen signal, while adjacent tomb L270 did not (Figure 8).
SF was shown to be an effective indicator for insufficient (low amount) collagen in the bones sampled in this research. Of the bones, 50% had SF > 3.3. None of the bones with SF > 3.3 had sufficient collagen for dating (Figure 9). On the other hand, SF below the value of 3.3 by itself could not predict sufficient collagen as only 26 bones out of 96 tested bones that showed SF < 3.3 proved to have sufficient collagen and were dated (27% of the bones with SF < 3.3). Thus, only if the FTIR spectrum of the insoluble fraction of the bone/tooth sample after HCl treatment presented clear collagen absorbance peaks, then the sample was considered a candidate for further processing towards radiocarbon dating. The SF ratio tests on bones from different IBA burial sites show a similar bone diagenesis pattern. The bones with sufficient collagen for dating present 2.6 < SF < 3.3, regardless of the FWHM (Asscher et al. 2011).   , and the different spectrum C that is dominated by characteristic quartz absorbance peaks (prominent peak at 1084 cm -1 ), with only a low signal of organic compounds.

Bone-Dating Results
The dates presented here (Table 3, Figure 10) are the first radiocarbon dates of human bones published from IBA burial sites in the southern Levant. The two Hazorea tomb-3 dates above were also presented recently elsewhere (Lev et al. 2021). The dated bones were all found within well verified IBA burial contexts, accompanied by typical IBA burial goods.

IBA Shaft Burials Dating
The dated human bones in this research originated in shaft tombs of five different sites from various regions in Israel: from Jebel Qaaqir in the southern Judean hill region and up to Kefar Veradim in upper Galilee (Figure 1). The measured date ranges cover most of the IBA timeframe: bones' date-range medians span from the 25th century BCE, through IBA central dates and up to the beginning of the 20th century BCE. This sample of burials follows the same chronological pattern presented by the absolute dating of IBA settlements in the southern Levant (Regev et al. 2012;D'Andrea 2014: Chapter 2;Lev 2020: Chapter 8). Thus, the current research shows evidence for a parallel chronological range of IBA settlements and IBA burials, supporting an observation that the IBA signature shaft tomb burials are a fundamental part of the IBA culture from start to end, alongside its other characteristic material culture.

IBA Collective Burials
The dates from bones belonging to five out of at least nine individuals counted in one shaft tomb labeled B54 at Jebel Qaaqir (Dever 2014:32-33) were presented above ( Table 3). The dated bones produced a sufficient amount of good quality collagen, as validated by the FTIR spectra and the chemical analysis (see Table 2). The calibrated date range medians of Tomb B54 bones span from around 2300 BCE to 2000 BCE, presenting for the first time a single IBA shaft tomb that contains human remains accumulated through generations and spanning over a few hundred years. The Jebel Qaaqir dates indicate a tribal, lineage, or family-oriented community with long-lasting tradition reflected in ongoing collective burial practice, as seen in tomb B54. The phenomenon of a few generations gap between individuals buried in the same tomb was also observed at Seikh Danon (Table 3). Another common feature in these collective burials is scattered and disarticulated partial skeletons, including mainly larger bones, thus suggesting secondary burials or moving aside old bones when adding remains of new people to the chamber.

Yehud Burial Ground Observations
The dating results from the Yehud IBA burial site show that it was active during IBA for over a century, keeping the same burial tradition and style. In the burials, the dead were laid in similar positions in the same type of shaft tombs dug until the boundary between the Hamra soil and the yellow sand layer below it. Similar burial goods were found in the tombs, including (mainly) jars, cups, and open bowls. Tombs with earlier calibrated date range medians (before 2230 BCE) were sampled from the eastern part of the field (except for RTD-9292), and those with later calibrated date range medians (after 2230 BCE) were sampled from the western part (except for RTD-8930), suggesting an expansion of the burial field from east to west through time (Figure 11). Many shafts were dug into the local Hamra soil, some are very close, yet the tombs did not cut each other. The above observations suggest that the IBA  people knew the location of the tombs at the Yehud burial ground, including those from past generations. They kept the burial traditions very similar for over a century, and as the burial area became crowded, they extended the burial field to the west. Such behavior suggests a longstanding social organization that keeps standard and orderly burial practices for several generations.

CONCLUSION
This research performed the first absolute dating measurements on Intermediate Bronze Age human remains from southern Levant burial sites. The measured date ranges cover most of the IBA timeframe, demonstrating that the signature shaft tomb burials were integrated into the IBA culture throughout its entire lifespan. Collective burial in the same shaft tomb supplied dates centuries apart between the humans buried in that tomb. This phenomenon suggests a traditional tribal or familial community with long-term cultural memory as reflected in their burial traditions. The conservative nature of the IBA culture is also apparent in tombs quarried for over a century at Yehud with identical structures and the same burial arrangement. The above findings complement previous observations that the same pottery types and metal tools are found in contexts dated throughout half a millennium of the IBA. The overall emerging picture is of a very conservative rural community, keeping its rigid way of life and its traditions for many centuries.
Further radiocarbon dating of IBA burials with their rich pottery assemblages also holds promising potential for improving the IBA pottery chronology precision. Figure 11 Partial schematic plan of Yehud main area tombs spatial distribution. Triangles mark tombs that produced earlier calibrated distribution ranges (mean before 2230 BCE). Squares mark tombs that produced later calibrated distribution ranges (mean after 2230 BCE). The related sample number is displayed by each dated tomb. Black marked tombs were sampled but had insufficient collagen for dating. Non-colored tombs were not sampled.
Chronology of IBA Shaft Tombs in the Southern Levant 985