Archaeomagnetic Dating of the Outer Revetment Wall at Tel Lachish.

The fortifications of Lachish, a key site in archaeology of the Iron Age Southern Levant, are the focus of ongoing debate. The Outer Revetment Wall, encircling nearly the entire site, was traditionally associated with Levels IV-III and was thought to have been in use during the Assyrian campaign in 701 BCE. It has recently been suggested that it was built a millennium earlier. Here we present archaeomagnetic dating of a mudbrick tower incorporated in this wall, indicating that it was burnt during the Iron Age and was most likely built during this period. Combining archaeological, historical and archaeomagnetic data reveals the intense fire that occurred during the 701 BCE Assyrian siege. This fire could have been set by the people of Lachish, in a desperate attempt to damage the Assyrian siege engines or siege ramp, as depicted in the well-known Lachish relief, or by the Assyrians as part of their siege tactics.

Exploring geomagnetic variations in ancient mesopotamia: Archaeomagnetic study of inscribed bricks from the 3rd-1st millennia BCE.

This study presents 32 high-resolution geomagnetic intensity data points from Mesopotamia, spanning the 3rd to the 1st millennia BCE. These data contribute to rectifying geographic disparities in the resolution of the global archaeointensity curve that have hampered our understanding of geomagnetic field dynamics and the viability of applying archaeomagnetism as a method of absolute dating of archaeological objects. A lack of precise and well-dated intensity data in the region has also limited our ability to identify short-term fluctuations in the geomagnetic field, such as the Levantine Iron Age geomagnetic Anomaly (LIAA), a period of high field intensity from ca. 1050 to 550 BCE. This phenomenon has hitherto not been well-demonstrated in Mesopotamia, contrary to predictions from regional geomagnetic models. To address these issues, this study presents precise archaeomagnetic results from 32 inscribed baked bricks, tightly dated to the reigns of 12 Mesopotamian kings through interpretation of their inscriptions. Results confirm the presence of the high field values of the LIAA in Mesopotamia during the first millennium BCE and drastically increase the resolution of the archaeointensity curve for the 3rd-1st millennia BCE. This research establishes a baseline for the use of archaeomagnetic analysis as an absolute dating technique for archaeological materials from Mesopotamia.

The stone-to-metal transition reflected in the Iron Age copper production sites of Timna Valley, Israel.

Metalwork was a major technological innovation that displaced stone-tool technologies and transformed human society and the environment. However, our understanding of these processes remains partial. In this paper, we approach the stone-to-metal transition from a novel angle-the presence of flint knapping at metal production sites. Drawing on excavations at the Late Bronze and Iron Age copper smelting sites in Timna Valley, Israel, we demonstrate that systematic production of expedient stone tools was integral to these sites' industrial operations, placing it at the heart of the very same metal circulation networks that were presumably responsible for its displacement. The observations from Timna, coupled with evidence for the use of chipped stone technology in other early Iron Age metallurgical contexts, support the hypothesis that it was probably both the high accessibility of iron and its qualities that put an end to the stone tool industry. Copper and bronze could not easily fulfill the function of the ad hoc stone tools and were not used to replace stone tools even if they were available and accessible.

Applying thermal demagnetization to archaeological materials: A tool for detecting burnt clay and estimating its firing temperature.

Burnt materials are very common in the archaeological record. Their identification and the reconstruction of their firing history are crucial for reliable archaeological interpretations. Commonly used methods are limited in their ability to identify and estimate heating temperatures below ~500°C and cannot reconstruct the orientation in which these materials were burnt. Stepwise thermal demagnetization is widely used in archaeomagnetism, but its use for identifying burnt materials and reconstructing paleotemperatures requires further experimental verification. Here we present an experimental test that has indicated that this method is useful for identifying the firing of mud bricks to 190°C or higher. Application of the method to oriented samples also enables reconstruction of the position in which they cooled down. Our algorithm for interpreting thermal demagnetization results was tested on 49 miniature sun-dried "mud bricks", 46 of which were heated to a range of temperatures between 100°C to 700°C under a controlled magnetic field and three "bricks" which were not heated and used as a control group. The results enabled distinguishing between unheated material and material heated to at least 190°C and accurately recovering the minimum heating temperature of the latter. Fourier-Transform Infrared Spectroscopy (FTIR) on the same materials demonstrated how the two methods complement each other. We implemented the thermal demagnetization method on burnt materials from an Iron Age structure at Tell es-Safi/Gath (central Israel), which led to a revision of the previously published understanding of this archaeological context. We demonstrated that the conflagration occurred within the structure, and not only in its vicinity as previously suggested. We also showed that a previously published hypothesis that bricks were fired in a kiln prior to construction is very unlikely. Finally, we conclude that the destruction of the structure occurred in a single event and not in stages over several decades.

Reconstructing biblical military campaigns using geomagnetic field data.

The Hebrew Bible and other ancient Near Eastern texts describe Egyptian, Aramean, Assyrian, and Babylonian military campaigns to the Southern Levant during the 10th to sixth centuries BCE. Indeed, many destruction layers dated to this period have been unearthed in archaeological excavations. Several of these layers are securely linked to specific campaigns and are widely accepted as chronological anchors. However, the dating of many other destruction layers is often debated, challenging the ability to accurately reconstruct the different military campaigns and raising questions regarding the historicity of the biblical narrative. Here, we present a synchronization of the historically dated chronological anchors and other destruction layers and artifacts using the direction and/or intensity of the ancient geomagnetic field recorded in mud bricks from 20 burnt destruction layers and in two ceramic assemblages. During the period in question, the geomagnetic field in this region was extremely anomalous with rapid changes and high-intensity values, including spikes of more than twice the intensity of today's field. The data are useful in the effort to pinpoint these short-term variations on the timescale, and they resolve chronological debates regarding the campaigns against the kingdoms of Israel and Judah, the relationship between the two kingdoms, and their administrations.

Fuel exploitation and environmental degradation at the Iron Age copper industry of the Timna Valley, southern Israel.

Economic and industrial progress frequently comes at the expense of environmental sustainability. For the early Iron Age (~ eleventh to ninth centuries BCE) smelters of the ancient copper industry of the Timna Valley, southern Israel, where today the hyper-arid Aravah Desert provides sparse vegetation, woody fuel for metallurgical furnaces constituted the greatest limiting factor for continued operations. This study presents the first investigation into the fuel sources relied upon by this industry during its most intensive period, as reflected by hundreds of charcoal samples collected from two well-stratified and chronologically anchored accumulations of industrial waste. The two sites demonstrate similar results: a heavy reliance on the local vegetation, particularly Retama raetam (white broom) and the ecologically significant Acacia spp. (acacia thorn trees), two high-calorific and high-burning taxa best suited for such purposes. It was also observed that over the course of the industry, the search for fuel expanded, as evidenced by the later appearance of taxa unsuited for the prevailing regional conditions, hinting at the detrimental toll the industry took on the local ecosystem. Altogether, it is suggested that the lucrative copper industry ended due to limits in the availability of fuel, caused by anthropogenic hastening of desertification and environmental degradation.

The strength of the Earth's magnetic field from Pre-Pottery to Pottery Neolithic, Jordan.

Constraining secular variation of the Earth's magnetic field strength in the past is fundamental to understanding short-term processes of the geodynamo. Such records also constitute a powerful and independent dating tool for archaeological sites and geological formations. In this study, we present 11 robust archaeointensity results from Pre-Pottery to Pottery Neolithic Jordan that are based on both clay and flint (chert) artifacts. Two of these results constitute the oldest archaeointensity data for the entire Levant, ancient Egypt, Turkey, and Mesopotamia, extending the archaeomagnetic reference curve for the Holocene. Virtual Axial Dipole Moments (VADMs) show that the Earth's magnetic field in the Southern Levant was weak (about two-thirds the present field) at around 7600 BCE, recovering its strength to greater than the present field around 7000 BCE, and gradually weakening again around 5200 BCE. In addition, successful results obtained from burnt flint demonstrate the potential of this very common, and yet rarely used, material in archaeomagnetic research, in particular for prehistoric periods from the first use of fire to the invention of pottery.

Early evidence of royal purple dyed textile from Timna Valley (Israel).

In the context of a broad study aimed at examining dyeing technologies in the Timna textiles collection, three samples of prestigious fibers dyed with murex sea snail were identified. Our identification is based on the presence of 6-monobromoindigotin and 6,6-dibromoindigotin components (detected using HPLC analysis), which is considered unequivocal evidence for the use of murex-derived purple dyestuff. Furthermore, by comparing the analytical results with those obtained in a series of controlled dyeing experiments we were able to shed more light on the specific species used in the dyeing process and glean insights into the ancient dyeing technology. The samples originated from excavations at the extensive Iron Age copper smelting site of "Slaves' Hill" (Site 34), which is tightly dated by radiocarbon to the late 11th-early 10th centuries BCE. While evidence for the important role of purple dyes in the ancient Mediterranean goes back to the Middle Bronze Age (early 2nd millennium BCE), finds of dyed textiles are extremely rare, and those from Timna are the oldest currently known in the Southern Levant. In conjunction with other observations of the very high quality of the Timna textiles, this provides an exceptional opportunity to address questions related to social stratification and organization of the nomadic society operating the mines (early Edom), the "fashion" of elite in the region during the early Iron Age, trade connections, technological capabilities, and more.

The Earth's magnetic field in Jerusalem during the Babylonian destruction: A unique reference for field behavior and an anchor for archaeomagnetic dating.

Paleomagnetic analysis of archaeological materials is crucial for understanding the behavior of the geomagnetic field in the past. As it is often difficult to accurately date the acquisition of magnetic information recorded in archaeological materials, large age uncertainties and discrepancies are common in archaeomagnetic datasets, limiting the ability to use these data for geomagnetic modeling and archaeomagnetic dating. Here we present an accurately dated reconstruction of the intensity and direction of the field in Jerusalem in August, 586 BCE, the date of the city's destruction by fire by the Babylonian army, which marks the end of the Iron Age in the Levant. We analyzed 54 floor segments, of unprecedented construction quality, unearthed within a large monumental structure that had served as an elite or public building and collapsed during the conflagration. From the reconstructed paleomagnetic directions, we conclude that the tilted floor segments had originally been part of the floor of the second story of the building and cooled after they had collapsed. This firmly connects the time of the magnetic acquisition to the date of the destruction. The relatively high field intensity, corresponding to virtual axial dipole moment (VADM) of 148.9 ± 3.9 ZAm2, accompanied by a geocentric axial dipole (GAD) inclination and a positive declination of 8.3°, suggests instability of the field during the 6th century BCE and redefines the duration of the Levantine Iron Age Anomaly. The narrow dating of the geomagnetic reconstruction enabled us to constrain the age of other Iron Age finds and resolve a long archaeological and historical discussion regarding the role and dating of royal Judean stamped jar handles. This demonstrates how archaeomagnetic data derived from historically-dated destructions can serve as an anchor for archaeomagnetic dating and its particular potency for periods in which radiocarbon is not adequate for high resolution dating.

Ancient technology and punctuated change: Detecting the emergence of the Edomite Kingdom in the Southern Levant.

While the punctuated equilibrium model has been employed in paleontological and archaeological research, it has rarely been applied for technological and social evolution in the Holocene. Using metallurgical technologies from the Wadi Arabah (Jordan/Israel) as a case study, we demonstrate a gradual technological development (13th-10th c. BCE) followed by a human agency-triggered punctuated "leap" (late-10th c. BCE) simultaneously across the entire region (an area of ~2000 km2). Here, we present an unparalleled, diachronic archaeometallurgical dataset focusing on elemental analysis of dozens of well-dated slag samples. Based on the results, we suggest punctuated equilibrium provides an innovative theoretical model for exploring ancient technological changes in relation to larger sociopolitical conditions-in the case at hand the emergence of biblical Edom-, exemplifying its potential for more general cross-cultural applications.

Early evidence (late 2nd millennium BCE) of plant-based dyeing of textiles from Timna, Israel.

In this article, we focus on the analysis of dyed textile fragments uncovered at an early Iron Age (11th-10th centuries BCE) copper smelting site during new excavations in the Timna Valley conducted by the Central Timna Valley (CTV) Project, as well as those found by the Arabah Expedition at the Hathor Temple (Site 200), dated to the Late Bronze/early Iron Ages (13th-11th centuries BCE). Analysis by HPLC-DAD identified two organic dyestuffs, Rubia tinctorum L. and indigotin, from a plant source (probably Isatis tinctoria L.). They are among the earliest plants known in the dyeing craft and cultivated primarily for this purpose. This study provides the earliest evidence of textiles dyed utilizing a chemical dyeing process based on an industrial dyeing plant from the Levant. Moreover, our results shed new light on the society operating the copper mines at the time, suggesting the existence of an elite that was interested in these high quality textiles and invested efforts in procuring them by long-distance trade.

Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles.

Earth's magnetic field, one of the most enigmatic physical phenomena of the planet, is constantly changing on various time scales, from decades to millennia and longer. The reconstruction of geomagnetic field behavior in periods predating direct observations with modern instrumentation is based on geological and archaeological materials and has the twin challenges of (i) the accuracy of ancient paleomagnetic estimates and (ii) the dating of the archaeological material. Here we address the latter by using a set of storage jar handles (fired clay) stamped by royal seals as part of the ancient administrative system in Judah (Jerusalem and its vicinity). The typology of the stamp impressions, which corresponds to changes in the political entities ruling this area, provides excellent age constraints for the firing event of these artifacts. Together with rigorous paleomagnetic experimental procedures, this study yielded an unparalleled record of the geomagnetic field intensity during the eighth to second centuries BCE. The new record constitutes a substantial advance in our knowledge of past geomagnetic field variations in the southern Levant. Although it demonstrates a relatively stable and gradually declining field during the sixth to second centuries BCE, the new record provides further support for a short interval of extreme high values during the late eighth century BCE. The rate of change during this "geomagnetic spike" [defined as virtual axial dipole moment > 160 ZAm2 (1021 Am2)] is further constrained by the new data, which indicate an extremely rapid weakening of the field (losing ∼27% of its strength over ca. 30 y).

High-precision radiocarbon dating and historical biblical archaeology in southern Jordan.

Recent excavations and high-precision radiocarbon dating from the largest Iron Age (IA, ca. 1200-500 BCE) copper production center in the southern Levant demonstrate major smelting activities in the region of biblical Edom (southern Jordan) during the 10th and 9th centuries BCE. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked to a geographic information system developed to control on-site spatial analyses of archaeological finds and model data with innovative visualization tools. The new radiocarbon dates push back by 2 centuries the accepted IA chronology of Edom. Data from Khirbat en-Nahas, and the nearby site of Rujm Hamra Ifdan, demonstrate the centrality of industrial-scale metal production during those centuries traditionally linked closely to political events in Edom's 10th century BCE neighbor ancient Israel. Consequently, the rise of IA Edom is linked to the power vacuum created by the collapse of Late Bronze Age (LB, ca. 1300 BCE) civilizations and the disintegration of the LB Cypriot copper monopoly that dominated the eastern Mediterranean. The methodologies applied to the historical IA archaeology of the Levant have implications for other parts of the world where sacred and historical texts interface with the material record.