Israeli scientists have reinvented archaeology with a new approach for evaluating charred materials, verifying the Biblical account of Gaths damage and offering new insights into ancient building innovations. This image reveals among the studied charred mudbricks. Credit: Dr. Yoav VakninNew technology analyzes archaeological findings from Biblical times.The brand-new research study scientifically proves an occasion described in the Second Book of Kings– the conquest of the Philistine city of Gath by Hazael King of Aram.The technique is based upon measuring the electromagnetic field tape-recorded in scorched bricks. The researchers: “Our findings are very important for figuring out the strength of the fire and the scope of damage in Gath– the biggest and most powerful city in the land at the time, and likewise for understanding building practices in the region.” An advancement accomplished by researchers from 4 Israeli universities– Tel Aviv University, The Hebrew University of Jerusalem, Bar-Ilan University, and Ariel University– will make it possible for archaeologists to recognize scorched materials discovered in excavations and estimate their firing temperatures.Applying their approach to findings from ancient Gath (Tell es-Safi in main Israel), the scientists validated the Biblical account: “About this time Hazael King of Aram increased and attacked Gath and recorded it. He turned to attack Jerusalem.” (2 Kings 12, 18). They explain that, unlike previous approaches, the new method can figure out whether a particular item (such as a mud brick) went through a shooting event even at fairly low temperature levels, from 200 ° C and up. This details can be vital for correctly translating the findings.Multidisciplinary Research TeamThe multidisciplinary research study was led by Dr. Yoav Vaknin from the Sonia & & Marco Nadler Institute of Archaeology, Entin Faculty of Humanities, at Tel Aviv University, and the Palaeomagnetic Laboratory at The Hebrew University. Other contributors consisted of: Prof. Ron Shaar from the Institute of Earth Sciences at The Hebrew University, Prof. Erez Ben-Yosef and Prof. Oded Lipschits from the Sonia & & Marco Nadler Institute of Archaeology at Tel Aviv University, Prof. Aren Maeir from the Martin (Szusz) Department of Land of Israel Studies and Archaeology at Bar-Ilan University and Dr. Adi Eliyahu Behar from the Department of Land of Israel Studies and Archaeology and the Department of Chemical Sciences at Ariel University. The paper was released in the clinical journal PLOS ONE.The studied location throughout excavation. Credit: Tell es-Safi/Gath Archaeological Project, Bar-Ilan UniversityProf. Lipschits: “Throughout the Bronze and Iron Ages the primary building product in most parts of the Land of Israel was mud bricks. This readily available and inexpensive product was utilized to construct walls in many buildings, often on top of stone structures. Thats why its so crucial to comprehend the technology used in making these bricks.” Dr. Vaknin adds: “During the same period residents of other lands, such as Mesopotamia where stone was hard to come by, would fire mud bricks in kilns to increase their strength and toughness. This technique is discussed in the story of the Tower of Babel in the Book of Genesis: They stated one to another, Come, let us make bricks and fire them thoroughly. They utilized brick for stone. (Genesis 11, 3) Most scientists, nevertheless, think that this technology did not reach the Land of Israel until much later on, with the Roman conquest. Until that time the residents used sun-dried mud bricks. Therefore, when bricks are discovered in a historical excavation, a number of concerns must be asked: First, have the bricks been fired, and if so, were they fired in a kiln prior to building or in situ, in a damaging blaze event? Our approach can provide definitive answers.” Innovative Magnetic Analysis TechniqueThe brand-new technique counts on determining the electromagnetic field tape-recorded and locked in the brick as it cooled and burned down.Dr. Vaknin: “The clay from which the bricks were made consists of millions of ferromagnetic particles– minerals with magnetic residential or commercial properties that act thus lots of small compasses or magnets. In a sun-dried mud brick, the orientation of these magnets is practically random, so that they counteract one another. The general magnetic signal of the brick is weak and not uniform.” Heating to 200 ° C or more, as occurs in a fire, launches the magnetic signals of these magnetic particles and, statistically, they tend to line up with the earths magnetic field at that specific time and location. When the brick cools down, these magnetic signals remain locked in their new position and the brick attains a strong and evenly oriented electromagnetic field, which can be determined with a magnetometer. This is a clear indication that the brick has, in reality, been fired.” Dr. Yoav Vaknin. Credit: Tel Aviv UniversityLaboratory Testing and ApplicationsIn the second phase of the procedure, the scientists slowly eliminate the bricks electromagnetic field, using a process called thermal demagnetization. This includes heating the brick in a special oven in a palaeomagnetic laboratory that reduces the effects of the earths magnetic field. The heat releases the magnetic signals, which as soon as again organize themselves arbitrarily, canceling each other out, and the overall magnetic signal becomes weak and loses its orientation.Dr. Vaknin: “We perform the process slowly. Initially, we warm the sample to a temperature level of 100 ° C, which launches the signals of only a small portion of the magnetic minerals. We then cool it down and measure the staying magnetic signal. We then repeat the procedure at temperatures of 150 ° C, 200 ° C, and so on, proceeding in small actions, approximately 700 ° C. In this way the bricks electromagnetic field is slowly removed. The temperature level at which the signal of each mineral is unlocked is around the like the temperature at which it was at first locked, and eventually, the temperature level at which the magnetic field is totally eliminated was reached throughout the initial fire.” The scientists evaluated the method in the lab: they fired mud bricks under regulated conditions of temperature level and electromagnetic field, determined each bricks gotten electromagnetic field, then gradually eliminated it. They found that the bricks were entirely demagnetized at the temperature level at which they had been burned– showing that the technique works.Dr. Vaknin: “Our technique makes it possible for identifying burning which occurred at much lower temperatures than any other technique. A lot of techniques utilized for identifying charred bricks are based on actual modifications in the minerals, which generally occur at temperature levels greater than 500 ° C– when some minerals are converted into others.” Dr. Eliyahu Behar: “One of the typical methods for determining mineralogical changes in clay (the primary component of mud bricks) due to direct exposure to heats is based on modifications in the absorption of infrared radiation by the various minerals. In this study we utilized this technique as an extra tool to validate the results of the magnetic approach.” Dr. Vaknin: “Our method is much more sensitive than others since it targets modifications in the intensity and orientation of the magnetic signal, which take place at much lower temperature levels. We can begin to discover changes in the magnetic signal at temperatures as low as 100 ° C, and from 200 ° C and up the findings are definitive.” In addition, the method can figure out the orientation in which the bricks cooled down. Dr. Vaknin: “When a brick is fired in a kiln before building and construction, it records the instructions of the earths electromagnetic field at that specific time and place. In Israel, this means north and downward. But when contractors take bricks from a kiln and develop a wall, they lay them in random orientations, thus randomizing the taped signals. On the other hand, when a wall is burned in situ, as might occur when it is ruined by an enemy, the electromagnetic fields of all bricks are secured the very same orientation.” Case Study: Tell es-SafiAfter showing the techniques validity, the scientists used it to a particular historical conflict: was a specific brick structure found at Tell es-Safi– determined as the Philistine city of Gath, home of Goliath– constructed of pre-fired bricks or burned on area? The common hypothesis, based upon the Old Testament, historical sources, and Carbon-14 dating characteristics the destruction of the structure to the devastation of Gath by Hazael, King of Aram Damascus, around 830 BCE. A previous paper by researchers consisting of Prof. Maeir, head of the Tell es-Safi excavations, proposed that the building had not burned down, however rather collapsed over years, and that the fired bricks found in the structure had actually been fired in a kiln prior to building and construction. If this hypothesis were right, this would be the earliest instance of brick-firing innovation found in the Land of Israel.To settle the disagreement, the present research study group applied the new technique to samples from the wall at Tell es-Safi and the collapsed debris discovered beside it. The findings were conclusive: the magnetic fields of all bricks and collapsed debris showed the very same orientation– north and downwards.Dr. Vaknin: “Our findings represent that the bricks burned and cooled down in situ, right where they were discovered, specifically in a conflagration in the structure itself, which collapsed within a couple of hours. Had actually the bricks been fired in a kiln and after that laid in the wall, their magnetic orientations would have been random. Furthermore, had the structure collapsed in time, not in a single fire event, the collapsed debris would have displayed random magnetic orientations.” We think that the main factor for our colleagues incorrect analysis was their inability to recognize burning at temperatures below 500 ° C. Since heat rises, products at the bottom of the building burned at relatively low temperatures, below 400 ° C, and as a result, the former study did not determine them as scorched– leading to the conclusion that the structure had actually not been destroyed by fire. At the exact same time, bricks in the upper parts of the wall, where temperature levels were much greater, went through mineralogical changes and were for that reason identified as burnt– leading the researchers to conclude that they had been fired in a kiln prior to building and construction.” Our technique allowed us to figure out that all bricks in both the wall and particles had burned during the blaze: those at the bottom burned at reasonably low temperature levels, and those that were discovered in higher layers or had actually fallen from the top– at temperature levels higher than 600 ° C.” Implications and Future DirectionsProf. Maeir: “Our findings are extremely essential for deciphering the strength of the fire and scope of destruction at Gath, the largest and most effective city in the Land of Israel at the time, in addition to comprehending the building methods dominating because age. Its essential to examine conclusions from previous studies, and sometimes even refute previous interpretations, even if they originated from your own school.” Prof. Ben-Yosef adds: “Beyond their historical and historic significance, ancient structure techniques also had significant environmental implications. The brick firing innovation requires large quantities of combustive products, and in ancient times this might have resulted in vast deforestation and even loss of tree types in the location. Particular species of shrubs and trees made use of by the ancient copper market in the Timna Valley have not recovered to this day and the industry itself ultimately collapsed once it had utilized up its natural fuels. Our findings show that the brick shooting technology was probably not practiced in the Land of Israel in the times of the Kings of Judah and Israel.” Reference: “Applying thermal demagnetization to historical products: A tool for detecting charred clay and approximating its firing temperature” by Yoav Vaknin, Ron Shaar, Oded Lipschits, Adi Eliyahu Behar, Aren M. Maeir and Erez Ben-Yosef, 9 October 2023, PLOS ONE.DOI: 10.1371/ journal.pone.0289424.
Hence, when bricks are found in an archaeological excavation, several questions must be asked: First, have the bricks been fired, and if so, were they fired in a kiln prior to building and construction or in situ, in a devastating conflagration event?” Innovative Magnetic Analysis TechniqueThe new technique relies on determining the magnetic field taped and locked in the brick as it burned and cooled down.Dr. When the brick cools down, these magnetic signals stay locked in their new position and the brick obtains a strong and consistently oriented magnetic field, which can be measured with a magnetometer.” The scientists evaluated the technique in the lab: they fired mud bricks under regulated conditions of temperature and magnetic field, measured each bricks obtained magnetic field, then gradually removed it.” Case Study: Tell es-SafiAfter showing the approachs credibility, the scientists used it to a specific archaeological dispute: was a specific brick structure found at Tell es-Safi– recognized as the Philistine city of Gath, home of Goliath– developed of pre-fired bricks or burned on area?