A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Euro... more A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Europe and the Mediterranean for five decades, setting the time frame for prehistory. However, as measurement precision increases, there is mounting evidence for some small but substantive regional (partly growing season) offsets in same-year radiocarbon levels. Controlling for interlaboratory variation, we compare radiocarbon data from Europe and the Mediterranean in the second to earlier first millennia BCE. Consistent with recent findings in the second millennium CE, these data suggest that some small, but critical, periods of variation for Mediterranean radiocarbon levels exist, especially associated with major reversals or plateaus in the atmospheric radiocarbon record. At high precision, these variations potentially affect calendar dates for prehistory by up to a few decades, including, for example, Egyptian history and the much-debated Thera/Santorini volcanic eruption.
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.
Spruce and tamarack logs dating from the Younger Dryas and Early Holocene (YD–EH; ~12.9–11.3k cal... more Spruce and tamarack logs dating from the Younger Dryas and Early Holocene (YD–EH; ~12.9–11.3k cal a BP) were found at Bell Creek in the Lake Ontario lowlands of the Great Lakes region, North America. A 211-year tree-ring chronology dates to ~11 755–11 545 cal a BP, across the YD–EH transition. A 23-year period of higher year-to-year ring-width variability dates to around 11 650 cal a BP, infers strong regional climatic perturbations and may represent the end of the YD. Tamarack and spruce were dominant species throughout the YD–EH interval at the site, indicating that boreal conditions persisted into the EH, in contrast to geographical regions immediately south and east of the lowlands, but consistent with the Great Lakes interior lowlands. This infers that Bell Creek was at the eastern boundary of a boreal ecotone, perhaps a result of its lower elevation and the non-analog dynamics of the Laurentide Ice Sheet. This finding suggests that the ecotone boundary extended farther east during the YD–EH transition than previously thought.
Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fen... more Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other "Old World" climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the "Old World Drought…
Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fen... more Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other " Old World " climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the " Old World Drought Atlas " (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.
The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the hear... more The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the heart of the Byzantine Empire, Constantinople (modern day Istanbul) was a pivotal trade hub for the Aegean region. Establishing a precise and accurate dating framework for the development of this remarkable city and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikapı, Istanbul, along with timbers from other sites and buildings around the city, including one of the most famous sites on the Istanbul sky-line d Hagia Sophia. They provide potential for new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami struck the city, and during which dramatic changes in climate have been recorded in other paleo- environmental proxies. The chronology is the fi rst published tree-ring series from the Aegean region to cover the ‘ event ’ years of AD 536 e 7 and 542 which are characterized by anomalous growth in other tree- ring series from around the world, but interestingly these event years are not evident in this tree-ring sequence.
The vast region of northwestern Mexico and the American Southwest is a rich and dynamic zone of b... more The vast region of northwestern Mexico and the American Southwest is a rich and dynamic zone of both ancient and contemporary indigenous cultures. Its diversity in terms of both complexity and material culture have rendered it an especially fruitful region for addressing a range of pertinent anthropological issues, including social complexity, connectivity, and identity. For nearly four decades, Ben A. Nelson has dedicated his expertise to this region and its compelling issues, and has likewise encouraged generations of archaeologists in the careful study of ancient sites and landscapes both within the region and beyond. In this symposium, students and colleagues share their archaeological contributions in tribute to Dr. Ben Nelson’s broad influence and benevolent guidance as an archaeologist and mentor.
La vasta región que abarca el noroeste de México y el suroeste de los Estados Unidos es una zona rica y dinámica de culturas indígenas antiguas y actuales. Su diversidad en términos de la complejidad y la cultura material la hace una región fructífera para abordar una amplia gama de cuestiones antropológicos oportunos, incluyendo la complejidad, la conectividad, y la identidad social. A lo largo de casi cuatro décadas, Ben A. Nelson ha dedicado su conocimiento y especialización a esta región y a sus apasionantes temas, asimismo ha alentado a generaciones de arqueólogos en el estudio detallado de los sitios y paisajes antiguos tanto dentro de la región como fuera de ésta. En este simposio, los estudiantes y colegas comparten sus aportaciones arqueológicas en homenaje a Dr. Ben Nelson y a su gran influencia y orientación benevolente como arqueólogo y mentor.
A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Euro... more A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Europe and the Mediterranean for five decades, setting the time frame for prehistory. However, as measurement precision increases, there is mounting evidence for some small but substantive regional (partly growing season) offsets in same-year radiocarbon levels. Controlling for interlaboratory variation, we compare radiocarbon data from Europe and the Mediterranean in the second to earlier first millennia BCE. Consistent with recent findings in the second millennium CE, these data suggest that some small, but critical, periods of variation for Mediterranean radiocarbon levels exist, especially associated with major reversals or plateaus in the atmospheric radiocarbon record. At high precision, these variations potentially affect calendar dates for prehistory by up to a few decades, including, for example, Egyptian history and the much-debated Thera/Santorini volcanic eruption.
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.
Spruce and tamarack logs dating from the Younger Dryas and Early Holocene (YD–EH; ~12.9–11.3k cal... more Spruce and tamarack logs dating from the Younger Dryas and Early Holocene (YD–EH; ~12.9–11.3k cal a BP) were found at Bell Creek in the Lake Ontario lowlands of the Great Lakes region, North America. A 211-year tree-ring chronology dates to ~11 755–11 545 cal a BP, across the YD–EH transition. A 23-year period of higher year-to-year ring-width variability dates to around 11 650 cal a BP, infers strong regional climatic perturbations and may represent the end of the YD. Tamarack and spruce were dominant species throughout the YD–EH interval at the site, indicating that boreal conditions persisted into the EH, in contrast to geographical regions immediately south and east of the lowlands, but consistent with the Great Lakes interior lowlands. This infers that Bell Creek was at the eastern boundary of a boreal ecotone, perhaps a result of its lower elevation and the non-analog dynamics of the Laurentide Ice Sheet. This finding suggests that the ecotone boundary extended farther east during the YD–EH transition than previously thought.
Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fen... more Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other "Old World" climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the "Old World Drought…
Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fen... more Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other " Old World " climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the " Old World Drought Atlas " (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.
The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the hear... more The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the heart of the Byzantine Empire, Constantinople (modern day Istanbul) was a pivotal trade hub for the Aegean region. Establishing a precise and accurate dating framework for the development of this remarkable city and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikapı, Istanbul, along with timbers from other sites and buildings around the city, including one of the most famous sites on the Istanbul sky-line d Hagia Sophia. They provide potential for new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami struck the city, and during which dramatic changes in climate have been recorded in other paleo- environmental proxies. The chronology is the fi rst published tree-ring series from the Aegean region to cover the ‘ event ’ years of AD 536 e 7 and 542 which are characterized by anomalous growth in other tree- ring series from around the world, but interestingly these event years are not evident in this tree-ring sequence.
The vast region of northwestern Mexico and the American Southwest is a rich and dynamic zone of b... more The vast region of northwestern Mexico and the American Southwest is a rich and dynamic zone of both ancient and contemporary indigenous cultures. Its diversity in terms of both complexity and material culture have rendered it an especially fruitful region for addressing a range of pertinent anthropological issues, including social complexity, connectivity, and identity. For nearly four decades, Ben A. Nelson has dedicated his expertise to this region and its compelling issues, and has likewise encouraged generations of archaeologists in the careful study of ancient sites and landscapes both within the region and beyond. In this symposium, students and colleagues share their archaeological contributions in tribute to Dr. Ben Nelson’s broad influence and benevolent guidance as an archaeologist and mentor.
La vasta región que abarca el noroeste de México y el suroeste de los Estados Unidos es una zona rica y dinámica de culturas indígenas antiguas y actuales. Su diversidad en términos de la complejidad y la cultura material la hace una región fructífera para abordar una amplia gama de cuestiones antropológicos oportunos, incluyendo la complejidad, la conectividad, y la identidad social. A lo largo de casi cuatro décadas, Ben A. Nelson ha dedicado su conocimiento y especialización a esta región y a sus apasionantes temas, asimismo ha alentado a generaciones de arqueólogos en el estudio detallado de los sitios y paisajes antiguos tanto dentro de la región como fuera de ésta. En este simposio, los estudiantes y colegas comparten sus aportaciones arqueológicas en homenaje a Dr. Ben Nelson y a su gran influencia y orientación benevolente como arqueólogo y mentor.
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Papers by Carol Griggs
PAPER IS OPEN ACCESS:
https://advances.sciencemag.org/content/6/12/eaaz1096
and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by
dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikapı, Istanbul, along with timbers from other sites and buildings around the city,
including one of the most famous sites on the Istanbul sky-line
d
Hagia Sophia. They provide potential for
new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami
struck the city, and during which dramatic changes in climate have been recorded in other paleo-
environmental proxies. The chronology is the
fi
rst published tree-ring series from the Aegean region to
cover the
‘
event
’
years of AD 536
e
7 and 542 which are characterized by anomalous growth in other tree-
ring series from around the world, but interestingly these event years are not evident in this tree-ring
sequence.
Upcoming Presentations/Sessions by Carol Griggs
La vasta región que abarca el noroeste de México y el suroeste de los Estados Unidos es una zona rica y dinámica de culturas indígenas antiguas y actuales. Su diversidad en términos de la complejidad y la cultura material la hace una región fructífera para abordar una amplia gama de cuestiones antropológicos oportunos, incluyendo la complejidad, la conectividad, y la identidad social. A lo largo de casi cuatro décadas, Ben A. Nelson ha dedicado su conocimiento y especialización a esta región y a sus apasionantes temas, asimismo ha alentado a generaciones de arqueólogos en el estudio detallado de los sitios y paisajes antiguos tanto dentro de la región como fuera de ésta. En este simposio, los estudiantes y colegas comparten sus aportaciones arqueológicas en homenaje a Dr. Ben Nelson y a su gran influencia y orientación benevolente como arqueólogo y mentor.
PAPER IS OPEN ACCESS:
https://advances.sciencemag.org/content/6/12/eaaz1096
and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by
dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikapı, Istanbul, along with timbers from other sites and buildings around the city,
including one of the most famous sites on the Istanbul sky-line
d
Hagia Sophia. They provide potential for
new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami
struck the city, and during which dramatic changes in climate have been recorded in other paleo-
environmental proxies. The chronology is the
fi
rst published tree-ring series from the Aegean region to
cover the
‘
event
’
years of AD 536
e
7 and 542 which are characterized by anomalous growth in other tree-
ring series from around the world, but interestingly these event years are not evident in this tree-ring
sequence.
La vasta región que abarca el noroeste de México y el suroeste de los Estados Unidos es una zona rica y dinámica de culturas indígenas antiguas y actuales. Su diversidad en términos de la complejidad y la cultura material la hace una región fructífera para abordar una amplia gama de cuestiones antropológicos oportunos, incluyendo la complejidad, la conectividad, y la identidad social. A lo largo de casi cuatro décadas, Ben A. Nelson ha dedicado su conocimiento y especialización a esta región y a sus apasionantes temas, asimismo ha alentado a generaciones de arqueólogos en el estudio detallado de los sitios y paisajes antiguos tanto dentro de la región como fuera de ésta. En este simposio, los estudiantes y colegas comparten sus aportaciones arqueológicas en homenaje a Dr. Ben Nelson y a su gran influencia y orientación benevolente como arqueólogo y mentor.