Papers by Brita Lorentzen
PLoS One, 2024
The Kyrenia Ship, found off the north coast of Cyprus, is a key vessel in the history of scientif... more The Kyrenia Ship, found off the north coast of Cyprus, is a key vessel in the history of scientific underwater excavations and in the history of Greek shipbuilding. The first volume of the site’s final publication appeared in 2023 and provides detailed archaeological information tightly constraining the dating of the ship. A very specific date range is proposed: ca. 294–290 BCE, but is based on a less than certain reading of one coin recovered from the ship. While there is clear benefit to finding high-precision dates for the Kyrenia Ship and its rich assemblage using independent scientific dating (combined with Bayesian chronological modeling), efforts to do so proved more challenging and complex than initially anticipated. Strikingly, extensive dating on both wooden materials from the ship and on short-lived contents from the final use of the ship fail to offer dates using the IntCal20 calibration
curve—the current Northern Hemisphere radiocarbon calibration curve at the time of writing—that correspond with the archaeological constraints. The issue rests with a segment of IntCal20 ca. 350–250 BCE reliant on legacy pre-AMS radiocarbon data. We therefore measured new known-age tree-ring samples 350–250 BCE, and, integrating another series of new known-age tree-ring data, we obtained a redefined and more accurate calibration
record for the period 433–250 BCE. These new data permit a satisfactory dating solution for the ship and may even indicate a date that is a (very) few years more recent than current estimations. These new data in addition confirm and only very slightly modify the dating recently published for the Mazotos ship, another Greek merchant ship from the southern coast of Cyprus. Our work further investigated whether ship wood samples impregnated with a common preservative, polyethylene glycol (PEG), can be cleaned successfully, including a known-age test.
Geochemistry, Geophysics, Geosystems, 2015
Geomagnetic models based on direct observations since the 1830s show that the relative decadal ra... more Geomagnetic models based on direct observations since the 1830s show that the relative decadal rate of change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question we investigate two ancient slag mounds in Cyprus -Skouriotissa Vouppes (SU1, 4 th to 5 th centuries CE, 21 meter in height), and Mitsero Kokkinoyia (MK1, 7 th to 5 th BCE, 8 meter in height). The mounds are multi-layered sequences of industrial slag and charcoals that accumulated near ancient copper production sites. We collected geo-referenced slag and charcoals from vertical sections excavated from the mounds, and generated two independent sub-century scale paleointensity time series. We modeled the age-height relation using radiocarbon dates, and estimated paleointensities using Thellier-type IZZI experiments with additional anisotropy, cooling rate, and non-liner TRM assessments. To screen out non singledomain data with ambiguous interpretations we applied strict selection criteria at the specimen/sample levels. To ensure objectivity, consistency, and robust error estimation we employed an automatic interpretation technique and put all the data available in the MagIC database. Only a small percentage of the samples yielded satisfying behavior but they provide highly reliable paleointensity estimates. Eleven indistinguishable estimates from MK1 indicate relatively stable field at the time the mound accumulated. However, ten paleointensity estimates from SU1 demonstrate a rate of change comparable to the highest rate in the historical field anywhere on Earth. We suggest that high secular variations rates observed in the ancient Levant are not coincidental. Geomagnetic models from the past 170 years show two longitudinally-paired geomagnetically active regions: the Middle East and South Africa. This analysis implies a link to persistently active quasi-stationary columnar convection cells.
Dating Mediterranean shipwrecks: the Mazotos ship, radiocarbon dating and the need for independent chronological anchors
Antiquity, 2022
Studies of ancient Mediterranean trade and economy have made increasing use of sophisticated mode... more Studies of ancient Mediterranean trade and economy have made increasing use of sophisticated modelling and network analyses of shipwreck evidence. The dating of most of these wrecks, however, is based solely on assessments of associated ceramic material, especially transport amphorae. The resulting dates are approximate at best, and, as the example of the recently investigated Mazotos ship highlights, sometimes incorrect. Here, the authors describe a widely applicable independent approach based on the integration of tree-ring analysis
and radiocarbon dating. Interrogating the subjective assumptions and stepwise logic transfers involved in ceramic-based dating, the authors demonstrate how to produce a more robust and better-defined basis for
the analysis of the ancient Mediterranean shipwreck record.
Annual of the Department of Antiquities of Jordan, 2022
Journal of Archaeological Science: Reports, 2020
The 19th century was an era of increasing mechanization and globalization, which transformed mari... more The 19th century was an era of increasing mechanization and globalization, which transformed maritime networks and shipbuilding in and beyond the Mediterranean. Shipwrecks offer valuable physical evidence of such maritime connectivity and evolving shipbuilding techniques but must be dated within a high-resolution timeframe to be synchronized with, and thereby enhance, historical records. We focus here on high-resolution dating of the Akko Tower Shipwreck, the remains of an Ottoman merchant brig found inside the harbor of Akko, Israel. We use dendrochronology, 14C wiggle-matching, and Bayesian chronological modeling to determine that the ship was likely constructed in the mid-1850s, and therefore called at Akko’s harbor after the town’s 1840 bombardment, a period of decline traditionally under-studied in Ottoman historical narratives. Using dendroprovenancing methods, we find that the ship’s hull used timbers from the Anatolian Black Sea region, although it was built in the French construction tradition, and used British metal rigging and fasteners, which reflect shifting Anglo-French influence and socioeconomic interconnections with the Ottoman Empire during the 19th century.
The Akko Tower Shipwreck is the first shipwreck from Israel to be dendrochronologically dated and provenanced. Our results show how dendrochronology and Bayesian chronological modeling can be used successfully not only for high-precision dating, but also for untangling the shipbuilding processes and the socioeconomic networks that made ship construction possible. We also re-evaluate East Mediterranean oak sapwood datasets and develop an approximate new sapwood model that provides more robust estimates of felling dates for tree-ring analysis of this region’s oak wooden cultural heritage.
Excavations at the Ottoman Military Compound (Qishle) in Jaffa, 2007, 2009, 2021
This discusses a collection of 19th cedar timbers sampled from the Ottoman military compound in J... more This discusses a collection of 19th cedar timbers sampled from the Ottoman military compound in Jaffa, Israel. Dendrochronological methods were used to date and source these timbers to forests in southwestern Anatolia and reconstruct Ottoman timber trade.
Resolving Indigenous village occupations and social history across the long century of European permanent settlement in Northeastern North America: The Mohawk River Valley ~1450-1635 CE
PLOS ONE, 2021
The timeframe of Indigenous settlements in Northeast North America in the 15th-17th centuries CE ... more The timeframe of Indigenous settlements in Northeast North America in the 15th-17th centuries CE has until very recently been largely described in terms of European material culture and history. An independent chronology was usually absent. Radiocarbon dating has recently begun to change this conventional model radically. The challenge, if an alternative, independent timeframe and history is to be created, is to articulate a high-resolution chronology appropriate and comparable with the lived histories of the Indigenous village settlements of the period. Improving substantially on previous initial work, we report here high-resolution defined chronologies for the three most extensively excavated and iconic ancestral Kanienʼkehá꞉ka (Mohawk) village sites in New York (Smith-Pagerie, Klock and Garoga), and a fourth early historic Indigenous site, Brigg’s Run, and re-assess the wider chronology of the Mohawk River Valley in the mid-15th to earlier 17th centuries. This new chronology confirms initial suggestions from radiocarbon that a wholesale reappraisal of past assumptions is necessary, since our dates conflict completely with past dates and the previously presumed temporal order of these three iconic sites. In turn, a wider reassessment of northeastern North American early history and re-interpretation of Atlantic connectivities in the later 15th through early 17th centuries is required. Our new closely defined date ranges are achieved employing detailed archival analysis of excavation records to establish the contextual history for radiocarbon-dated samples from each site, tree-ring defined short time series from wood charcoal samples fitted against the radiocarbon calibration curve (‘wiggle-matching’), and Bayesian chronological modelling for each of the individual sites integrating all available prior knowledge and radiocarbon dating probabilities. We define (our preferred model) most likely (68.3% highest posterior density) village occupation ranges for Smith-Pagerie of ~1478–1498, Klock of ~1499–1521, Garoga of ~1550–1582, and Brigg’s Run of ~1619–1632.
Agricultural Sustainability and Environmental Change at Ancient Gordion, by John M. Marston. Gordion Special Studies 8. Philadelphia: University of Pennsylvania Press, 2017. xi + 203 pp., figs., tables. Hardcover. $59.95
Bulletin of the American Schools of Overseas Research
Scientific Reports, 2020
The new IntCal20 radiocarbon record continues decades of successful practice by employing one cal... more The new IntCal20 radiocarbon record continues decades of successful practice by employing one calibration curve as an approximation for different regions across the hemisphere. Here we investigate three radiocarbon time-series of archaeological and historical importance from the Mediterranean-Anatolian region, which indicate, or may include, offsets from IntCal20 (~0–22 14C years). While modest, these differences are critical for our precise understanding of historical and environmental events across the Mediterranean Basin and Near East. Offsets towards older radiocarbon ages in Mediterranean-Anatolian wood can be explained by a divergence between high-resolution radiocarbon dates from the recent generation of accelerator mass spectrometry (AMS) versus dates from previous technologies, such as low-level gas proportional counting (LLGPC) and liquid scintillation spectrometry (LSS). However, another reason is likely differing growing season lengths and timings, which would affect the...
Quaternary Science Reviews, 2020
Reconstruction of paleo relative sea level (RSL) is based on multi-proxy disciplines including ar... more Reconstruction of paleo relative sea level (RSL) is based on multi-proxy disciplines including archaeology. Saltpans, like fish tanks which are considered a reliable method for acquiring RSL index points, are also anthropogenic intertidal facilities, used continuously in the Mediterranean from early antiquity. The Dalmatian shore contains a large number of preserved and historically dated ancient saltpans, now flooded by the rising sea, providing great potential for past RSL indication. The primary objective of this study is to develop a new holistic approach for producing high quality elevation measurements of the saltpan structures and estimating paleo RSL during the last 2 ka. The study combined aerial photo-grammetry of the site, bathymetry acoustics scanning, and underwater archaeological survey of the man-made structures, as well as sampling wood and mortar in situ where available. Evaluation of each site's RSL and the functional height is based on the same assumptions and interpretations made for fish tanks, using elevation measurements on the top of the separation walls and the bottom of the sluice gates. In all the sites analyzed here, we achieved reliable digital surface models with continuous high-resolution data on the indicative structures with single centimeters level of accuracy. The study finds that during the 5th-6th centuries, RSL was -92 ± 25 cm, increased to -62 ± 21 cm during the 7th-11th centuries, and decreased to -104 ± 20 cm in the 14th century. Medieval RSL can be explained either by strong tectonic subsidence post 1300 AD or by fluctuations as observed in the East Mediterranean, which requires validation by further Medieval indicators.
PLoS ONE, 2020
There has been considerable focus on the main, expansionary, and interregionally linked or 'globa... more There has been considerable focus on the main, expansionary, and interregionally linked or 'globalising' periods in Old World pre-and proto-history, with a focus on identifying, analyzing and dating collapse at the close of these pivotal periods. The end of the Early Bronze Age in the late third millennium BCE and a subsequent 'intermediate' or transitional period before the Middle Bronze Age (~2200-1900 BCE), and the end of the Late Bronze Age in the late second millennium BCE and the ensuing period of transformation during the Early Iron Age (~1200-900 BCE), are key examples. Among other issues, climate change is regularly invoked as a cause or factor in both cases. Recent considerations of "collapse" have emphasized the unpredictability and variability of responses during such periods of reorganization and transformation. Yet, a gap in scholarly attention remains in documenting the responses observed at important sites during these 'transformative' periods in the Old World region. Tell Tayinat in southeastern Turkey, as a major archaeological site occupied during these two major 'in between' periods of transformation, offers a unique case for comparing and contrasting differing responses to change. To enable scholarly assessment of associations between the local trajectory of the site and broader regional narratives, an essential preliminary need is a secure, resolved timeframe for the site. Here we report a large set of radiocarbon data and incorporate the stratigraphic sequence using Bayesian chronological modelling to create a refined timeframe for Tell Tayinat and a secure basis for analysis of the site with respect to its broader regional context and climate history.
PLoS ONe, 2020
There has been considerable focus on the main, expansionary, and interregionally linked or 'globa... more There has been considerable focus on the main, expansionary, and interregionally linked or 'globalising' periods in Old World pre-and proto-history, with a focus on identifying, analyzing and dating collapse at the close of these pivotal periods. The end of the Early Bronze Age in the late third millennium BCE and a subsequent 'intermediate' or transitional period before the Middle Bronze Age (~2200-1900 BCE), and the end of the Late Bronze Age in the late second millennium BCE and the ensuing period of transformation during the Early Iron Age (~1200-900 BCE), are key examples. Among other issues, climate change is regularly invoked as a cause or factor in both cases. Recent considerations of "collapse" have emphasized the unpredictability and variability of responses during such periods of reorganization and transformation. Yet, a gap in scholarly attention remains in documenting the responses observed at important sites during these 'transformative' periods in the Old World region. Tell Tayinat in southeastern Turkey, as a major archaeological site occupied during these two major 'in between' periods of transformation, offers a unique case for comparing and contrasting differing responses to change. To enable scholarly assessment of associations between the local trajectory of the site and broader regional narratives, an essential preliminary need is a secure, resolved timeframe for the site. Here we report a large set of radiocarbon data and incorporate the stratigraphic sequence using Bayesian chronological modelling to create a refined timeframe for Tell Tayinat and a secure basis for analysis of the site with respect to its broader regional context and climate history.
This chapter discusses the radiocarbon results from Tel Kabri Phases V, IV, and III. While Phases... more This chapter discusses the radiocarbon results from Tel Kabri Phases V, IV, and III. While Phases V and IV are mainly represented by charcoal samples, a significant amount of short-lived samples are available for Phase III (late Middle Bronze Age II). The results are significantly higher than the Middle Bronze Age low chronology but are in agreement with several other studies on radiocarbon dates for the Middle Bronze Age. According to our results, the end of Phase III at Tel Kabri (late Middle Bronze Age II) should be dated around 1700bc.
In 2014, the Edom Lowlands Regional Archaeology Project renewed excavations at Khirbat al-Jariya ... more In 2014, the Edom Lowlands Regional Archaeology Project renewed excavations at Khirbat al-Jariya (KAJ), an Iron Age copper smelting site in Faynan, Jordan. Located roughly 3 km from the prominent smelting center Khirbat en-Nahas (KEN), KAJ was an integral component of Early Iron Age (ca. 1200–800 B.C.) copper production in Faynan, one of the largest copper ore deposits in the southern Levant. To date, the site had only been investigated by surveys and limited excavation; the 2014 excavations opened two areas (the largest extant building and a slag mound sounding) to explore the social dynamics and temporal intricacies of copper production. The excavation results, detailed site remapping, paleobotanical analysis, and new radiocarbon dates suggest KAJ more rapidly developed into a large-scale copper production center than previously believed, likely as a strategic expansion to the industry at KEN. This reinterpretation sheds new light on the development of the Iron Age industrial landscape in Faynan.
Journal of Field Archaeology, 2020
In 2014, the Edom Lowlands Regional Archaeology Project renewed excavations at Khirbat al-Jariya ... more In 2014, the Edom Lowlands Regional Archaeology Project renewed excavations at Khirbat al-Jariya (KAJ), an Iron Age copper smelting site in Faynan, Jordan. Located roughly 3 km from the prominent smelting center Khirbat en-Nahas (KEN), KAJ was an integral component of Early Iron Age (ca. 1200–800 B.C.) copper production in Faynan, one of the largest copper ore deposits in the southern Levant. To date, the site had only been investigated by surveys and limited excavation; the 2014 excavations opened two areas (the largest extant building and a slag mound sounding) to explore the social dynamics and temporal intricacies of copper production. The excavation results, detailed site remapping, paleobotanical analysis, and new radiocarbon dates suggest KAJ more rapidly developed into a large-scale copper production center than previously believed, likely as a strategic expansion to the industry at KEN. This reinterpretation sheds new light on the development of the Iron Age industrial landscape in Faynan.
Journal of Archaeological Science, Jan 2014
The Akko 1 shipwreck is the remains of an eastern Mediterranean naval or auxiliary brig, which wa... more The Akko 1 shipwreck is the remains of an eastern Mediterranean naval or auxiliary brig, which was found inside the ancient harbor of Akko, Israel. The shipwreck and finds were recorded underwater, and some of the ship components, along with the majority of the finds, were retrieved and analyzed. A Bayesian dating model, incorporating 14C wiggle-matching of the ship timbers, tree-ring analysis, and 14C dates from short-lived finds, is used to model the ship’s construction and wrecking dates. These new data, combined with the results of archaeological research and available historical records, suggest that the ship was built during the first third of the 19th century as part of Muhammad Ali’s fleet. Akko 1 then possibly plied the eastern Mediterranean under the Egyptian flag during the First Egyptian-Ottoman War in 1831-1833. The wrecking event apparently occurred during the 1840 naval bombardment of Akko. This is the first time that 14C wiggle-matching and Bayesian analyses have been used to date the construction and wrecking of a shipwreck in the southeastern Mediterranean. The results show that Bayesian analysis and 14C wiggle-matching techniques are valuable tools for analyzing the region’s shipwrecks, including those from recent historical periods.
During the 1st millennium AD, a fundamental set of changes in ship design, building methods, and ... more During the 1st millennium AD, a fundamental set of changes in ship design, building methods, and sequence of construction took place in the Mediterranean. This process is known as the “Transition in Construction.” Before the “transition,” ship hull design was based longitudinally on the ship’s strakes (“shell-first”). By about the mid-1st millennium AD, the concept and construction of ship hulls had changed and were based on the ship’s frames (“frame-based”). The Transition was a complex, nonlinear evolution. High-precision dating of the construction and service period of ships built during the 1st millennium is essential for elucidating the Transition process. Such dating precision is possible using 14C wiggle-matching and Bayesian analysis techniques. In the following study, we use these techniques to determine the construction, launch, and final voyage (wrecking) dates of Dor 2001/1, a Byzantine shipwreck from northern Israel that was built based on frames. Our results indicate that Dor 2001/1 was likely constructed and launched in the first third of the 6th century AD and was wrecked no later than AD 540. This is one of the earliest frame-based ships found in the Mediterranean so far. Dor 2001/1 is therefore an important shipwreck in understanding the Transition, since it provides evidence that frame-based hulls were already being built by the mid-1st millennium AD, about 500 years earlier than has been commonly accepted.
500 years of ancient Near Eastern history from the earlier second millennium BCE, including such ... more 500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681-1673 BCE (68.2% highest posterior density range), ~20 years earlier than previous assessments, indicating that it likely has no association with the subsequent Santorini volcanic eruption.
Dendrochronological research in North-Central Europe and the East Mediterranean has produced netw... more Dendrochronological research in North-Central Europe and the East Mediterranean has produced networks of long regional oak (Quercus sp.) reference chronologies that have been instrumental in dating, provenancing, and paleoclimate research applications. However, until now these two important tree-ring networks have not been successfully linked. Oak forests and historical/archaeological sites in southeastern Europe provide the key for linking the North-Central European and East Mediterranean tree-ring networks, but previous dendrochronological research in this region has been largely absent. This article presents the initial results of a project, in which we have built oak tree-ring chronologies from forest sites and historical/archaeological sites along a north-south transect between Poland and northwestern Turkey, with the aim of linking the North-Central European and East Mediterranean tree-ring networks and creating a new pan-European oak data set for dendrochronological dating and paleoclimatic reconstruction. Correlation among tree-ring chronologies and the spatial distribution of their teleconnections are evaluated. The southeastern European chronologies provide a solid bridge between both major European dendrochronological networks. The results indicate that a dense network of chronologies is the key for bridging spatial and temporal gaps in tree-ring records. Dendrochronological sampling should be intensively continued in southeastern Europe because resources for building long oak chronologies in the region are rapidly disappearing.
Fluctuating radiocarbon offsets observed in the southern Levant and implications for archaeological chronology debates
Considerable work has gone into developing high-precision radiocarbon (14C) chronologies for the ... more Considerable work has gone into developing high-precision radiocarbon (14C) chronologies for the southern Levant region during the Late Bronze to Iron Age/early Biblical periods (∼1200–600 BC), but there has been little consideration whether the current standard Northern Hemisphere 14C calibration curve (IntCal13) is appropriate for this region. We measured 14C ages of calendar-dated tree rings from AD 1610 to 1940 from southern Jordan to investigate contemporary 14C levels and to compare these with IntCal13. Our data reveal an average offset of ∼19 14C years, but, more interestingly, this offset seems to vary in importance through time. While relatively small, such an offset has substantial relevance to high-resolution 14C chronologies for the southern Levant, both archaeological and paleoenvironmental. For example, reconsidering two published studies, we find differences, on average, of 60% between the 95.4% probability ranges determined from IntCal13 versus those approximately allowing for the observed offset pattern. Such differences affect, and even potentially undermine, several current archaeological and historical positions and controversies.
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https://www.pnas.org/content/115/24/6141
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Papers by Brita Lorentzen
curve—the current Northern Hemisphere radiocarbon calibration curve at the time of writing—that correspond with the archaeological constraints. The issue rests with a segment of IntCal20 ca. 350–250 BCE reliant on legacy pre-AMS radiocarbon data. We therefore measured new known-age tree-ring samples 350–250 BCE, and, integrating another series of new known-age tree-ring data, we obtained a redefined and more accurate calibration
record for the period 433–250 BCE. These new data permit a satisfactory dating solution for the ship and may even indicate a date that is a (very) few years more recent than current estimations. These new data in addition confirm and only very slightly modify the dating recently published for the Mazotos ship, another Greek merchant ship from the southern coast of Cyprus. Our work further investigated whether ship wood samples impregnated with a common preservative, polyethylene glycol (PEG), can be cleaned successfully, including a known-age test.
and radiocarbon dating. Interrogating the subjective assumptions and stepwise logic transfers involved in ceramic-based dating, the authors demonstrate how to produce a more robust and better-defined basis for
the analysis of the ancient Mediterranean shipwreck record.
The Akko Tower Shipwreck is the first shipwreck from Israel to be dendrochronologically dated and provenanced. Our results show how dendrochronology and Bayesian chronological modeling can be used successfully not only for high-precision dating, but also for untangling the shipbuilding processes and the socioeconomic networks that made ship construction possible. We also re-evaluate East Mediterranean oak sapwood datasets and develop an approximate new sapwood model that provides more robust estimates of felling dates for tree-ring analysis of this region’s oak wooden cultural heritage.
OPEN ACCESS:
https://www.pnas.org/content/115/24/6141