TY - CHAP T1 - Uncertainties in Archaeointensity Research: Implications for the Levantine Archaeomagnetic Curve T2 - “And in Length of Days Understanding”(Job 12: 12) Essays on Archaeology in the Eastern Mediterranean and Beyond in Honor of Thomas E. Levy Y1 - 2023 A1 - Tauxe, Lisa A1 - Shaar, Ron A1 - Cych, Brendan A1 - Ben-Yosef, Erez JF - “And in Length of Days Understanding”(Job 12: 12) Essays on Archaeology in the Eastern Mediterranean and Beyond in Honor of Thomas E. Levy PB - Springer ER - TY - JOUR T1 - Destruction by fire: Reconstructing the evidence of the 586 BCE Babylonian destruction in a monumental building in Jerusalem JF - Journal of Archaeological Science Y1 - 2023 A1 - N. Shalom A1 - Vaknin, Y. A1 - R. Shaar A1 - Ben-Yosef, E. A1 - O. Lipschits A1 - Y. Shalev A1 - Y. Gadot A1 - E. Boaretto KW - Archaeomagnetism KW - Babylonian destruction KW - Fire analysis KW - FTIR spectroscopy KW - Iron age Jerusalem AB - Evidence of fire is one of the most important features for identifying and characterizing destruction events. Analysis of microscopic remains of fire has developed exceedingly in recent years, enabling archaeologists to examine new questions relating to the intensity of destruction events and to the circumstances of the creation of destruction layers. One of the most crucial events in the history of the Southern Levant is the Babylonian destruction of Judah and its capital Jerusalem in 586 BCE, which shaped the biblical narrative and theology for generations to come. Building 100 was an extraordinarily large and rich elite building, thoroughly destroyed during the Babylonian campaign. This paper presents a study of the destruction layer excavated within the rooms of the building. FTIR spectrometry and archaeomagnetic analysis were combined in the micro-archaeological study of the remains in order to create a detailed reconstruction of the destruction event. This reconstruction sheds new light on how the Babylonian destruction was manifested in reality in the elite buildings of Jerusalem. VL - 157 UR - https://www.sciencedirect.com/science/article/pii/S0305440323001036 ER - TY - CHAP T1 - Tel Beth-Shean in the Tenth–Ninth Centuries BCE: A Chronological Query and Its Possible Archaeomagnetic Resolution T2 - “And in Length of Days Understanding”(Job 12: 12) Essays on Archaeology in the Eastern Mediterranean and Beyond in Honor of Thomas E. Levy Y1 - 2023 A1 - Vaknin, Yoav A1 - Mazar, Amihai A1 - Shaar, Ron A1 - Ben-Yosef, Erez JF - “And in Length of Days Understanding”(Job 12: 12) Essays on Archaeology in the Eastern Mediterranean and Beyond in Honor of Thomas E. Levy PB - Springer ER - TY - JOUR T1 - Applying thermal demagnetization to archaeological materials: A tool for detecting burnt clay and estimating its firing temperature JF - Plos one Y1 - 2023 A1 - Vaknin, Yoav A1 - Shaar, Ron A1 - Lipschits, Oded A1 - Eliyahu Behar, Adi A1 - Maeir, Aren M A1 - Ben-Yosef, Erez PB - Public Library of Science San Francisco, CA USA VL - 18 IS - 10 ER - TY - JOUR T1 - Archaeomagnetism in the Levant and Mesopotamia reveals the largest changes in the geomagnetic field JF - Journal of Geophysical Research: Solid Earth Y1 - 2022 A1 - Shaar, Ron A1 - Gallet, Yves A1 - Vaknin, Yoav A1 - Gonen, Lilach A1 - Martin, Mario AS A1 - Adams, Matthew J A1 - Israel Finkelstein PB - Wiley Online Library UR - https://doi.org/10.1029/2022JB024962 ER - TY - JOUR T1 - Reconstructing biblical military campaigns using geomagnetic field data JF - Proceedings of the National Academy of Sciences Y1 - 2022 A1 - Vaknin, Yoav A1 - Shaar, Ron A1 - Lipschits, Oded A1 - Mazar, Amihai A1 - Maeir, Aren M A1 - Garfinkel, Yosef A1 - Freud, Liora A1 - Faust, Avraham A1 - Tappy, Ron E A1 - Kreimerman, Igor A1 - others PB - National Acad Sciences VL - 119 IS - 44 ER - TY - JOUR T1 - Paleointensity Estimates from the Pleistocene of Northern Israel: Implications for hemispheric asymmetry in the time averaged field JF - Geochemistry, Geophysics, Geosystems Y1 - 2022 A1 - Tauxe, Lisa A1 - Asefaw, Hanna A1 - Behar, Nicole Andrea A1 - Koppers, Anthony AP A1 - Shaar, Ron UR - https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010473 ER - TY - JOUR T1 - Late Acheulian Jaljulia–Early human occupations in the paleo-landscape of the central coastal plain of Israel JF - PloS one Y1 - 2022 A1 - Shemer, Maayan A1 - Greenbaum, Noam A1 - Taha, Nimer A1 - Brailovsky-Rokser, Lena A1 - Ebert, Yael A1 - Shaar, Ron A1 - Falgueres, Christophe A1 - Voinchet, Pierre A1 - Porat, Naomi A1 - Faershtein, Galina A1 - others PB - Public Library of Science San Francisco, CA USA VL - 17 IS - 5 ER - TY - JOUR T1 - Holocene wet episodes recorded by magnetic minerals in stalagmites from Soreq Cave, Israel JF - https://doi.org/10.1130/G49383.1 Y1 - 2022 A1 - Burstyn, Yuval A1 - Shaar, Ron A1 - Keinan, Jonathan A1 - Ebert, Yael A1 - Ayalon, Avner A1 - Bar-Matthews, Miryam A1 - Feinberg, Joshua M. VL - 50 UR - https://doi.org/10.1130/G49383.1 IS - 3 ER - TY - JOUR T1 - על חורבן ירושלים בימי הבית הראשון והשדה המגנטי של כדור הארץ JF - מחקרי עיר דוד וירושלים הקדומה, דברי הכנס העשרים ושניים Y1 - 2021 A1 - יואב וקנין A1 - רון שער A1 - יובל גדות A1 - יפתח שלו A1 - עודד ליפשיץ A1 - ארז בן יוסף ER - TY - JOUR T1 - Decadal geomagnetic secular variations from greigite bearing Dead Sea sediments JF - Geochemistry, Geophysics, Geosystems Y1 - 2021 A1 - Ebert, Yael A1 - Shaar, Ron A1 - Stein, Mordechai PB - Wiley Online Library UR - https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021GC009665 ER - TY - JOUR T1 - Magnetostratigraphy and cosmogenic dating of Wonderwerk Cave: New constraints for the chronology of the South African Earlier Stone Age JF - Quaternary Science Reviews Y1 - 2021 A1 - Shaar, Ron A1 - Matmon, Ari A1 - Liora K. Horwitz A1 - Ebert, Yael A1 - Michael Chazan A1 - M. Arnold A1 - G. Aumaître A1 - D. Bourlès A1 - K. Keddadouche KW - Acheulean KW - African Quaternary KW - Kalahari KW - Oldowan KW - Pleistocene chronology AB - Cave sediments pose dating challenges due to complex depositional and post-depositional processes that operate during their transport and accumulation. Here, we confront these challenges and investigate the stratified sedimentary sequence from Wonderwerk Cave, which is a key site for the Earlier Stone Age (ESA) in Southern Africa. The precise ages of the Wonderwerk sediments are crucial for our understanding of the timing of critical events in hominin biological and cultural evolution in the region, and its correlation with the global paleontological and archaeological records. We report new constraints for the Wonderwerk ESA chronology based on magnetostratigraphy, with 178 samples passing our rigorous selection criteria, and fourteen cosmogenic burial ages. We identify a previously unrecognized reversal within the Acheulean sequence attributed to the base of the Jaramillo (1.07 Ma) or Cobb Mtn. subchrons (1.22 Ma). This reversal sets an early age constraint for the onset of the Acheulean, and supports the assignment of the basal stratum to the Olduvai subchron (1.77–1.93 Ma). This temporal framework offers strong evidence for the early establishment of the Oldowan and associated hominins in Southern Africa. Notably, we found that cosmogenic burial ages of sediments older than 1 Ma are underestimated due to changes in the inherited 26Al/10Be ratio of the quartz particles entering the cave. Back calculation of the inherited 26Al/10Be ratios using magnetostratigraphic constraints reveals a decrease in the 26Al/10Be ratio of the Kalahari sands with time. These results imply rapid aeolian transport in the Kalahari during the early Pleistocene which slowed during the Middle Pleistocene and enabled prolonged and deeper burial of sand while transported across the Kalahari Basin. VL - 259 UR - https://www.sciencedirect.com/science/article/pii/S0277379121001141 ER - TY - JOUR T1 - Synchronizing geomagnetic field intensity records in the Levant between the 23rd and 15th centuries BCE: chronological and methodological implications JF - Geochemistry, Geophysics, Geosystems Y1 - 2020 A1 - Shaar, Ron A1 - Bechar, Shlomit A1 - Israel Finkelstein A1 - Gallet, Yves A1 - Martin, Mario AS A1 - Ebert, Yael A1 - Keinan, Jonathan A1 - Gonen, Lilach PB - Wiley Online Library UR - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GC009251 ER - TY - JOUR T1 - Magnetic properties of late Holocene Dead Sea sediments as a monitor of regional hydroclimate JF - Geochemistry, Geophysics, Geosystems Y1 - 2020 A1 - Y. Ebert A1 - R. Shaar A1 - Levy, EJ A1 - Zhao, X A1 - Roberts, AP A1 - Stein, M PB - Wiley Online Library SN - 1525-2027 UR - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GC009176 ER - TY - JOUR T1 - The Earth’s magnetic field in Jerusalem during the Babylonian destruction: A unique reference for field behavior and an anchor for archaeomagnetic dating JF - PloS one Y1 - 2020 A1 - Vaknin, Yoav A1 - Shaar, Ron A1 - Gadot, Yuval A1 - Shalev, Yiftah A1 - Lipschits, Oded A1 - Ben-Yosef, Erez PB - Public Library of Science San Francisco, CA USA VL - 15 UR - https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237029 IS - 8 ER - TY - JOUR T1 - The effect of early diagenesis in methanic sediments on sedimentary magnetic properties: Case study from the SE Mediterranean continental shelf JF - Frontiers in Earth Science Y1 - 2020 A1 - Amiel, Nitai A1 - Shaar, Ron A1 - Sivan, Orit PB - Frontiers VL - 8 UR - https://www.frontiersin.org/articles/10.3389/feart.2020.00283/full ER - TY - JOUR T1 - Experimental determination of remanent magnetism of dusty ice deposits JF - Earth and Planetary Science Letters Y1 - 2020 A1 - Grossman, Yuval A1 - Aharonson, Oded A1 - Shaar, Ron A1 - Kletetschka, Gunther PB - Elsevier VL - 545 UR - https://www.sciencedirect.com/science/article/pii/S0012821X20303526 ER - TY - JOUR T1 - Geochronology, paleogeography, and archaeology of the Acheulian locality of ‘Evron Landfill in the western Galilee, Israel JF - Quaternary Research Y1 - 2019 A1 - Shemer, Maayan A1 - Crouvi, Onn A1 - Shaar, Ron A1 - Ebert, Yael A1 - Matmon, Ari A1 - Horwitz, Liora Kolska A1 - Eisenmann, Véra A1 - Enzel, Yehouda A1 - Barzilai, Omry A1 - ASTER Team A1 - others PB - Cambridge University Press VL - 91 IS - 2 ER - TY - JOUR T1 - Paleomagnetism and paleosecular variations from the Plio-Pleistocene Golan Heights volcanic plateau, Israel JF - Geochemistry, Geophysics, Geosystems Y1 - 2019 A1 - Behar, Nicole A1 - Shaar, Ron A1 - Tauxe, Lisa A1 - Asefaw, Hanna A1 - Ebert, Yael A1 - Heimann, Ariel A1 - Koppers, Anthony AP A1 - Ron, Hagai PB - Wiley Online Library ER - TY - JOUR T1 - Archaeomagnetism of burnt cherts and hearths from Middle Palaeolithic Amud Cave, Israel: Tools for reconstructing site formations processes and occupation history JF - Journal of Archaeological Science Y1 - 2019 A1 - Zeigen, Chen A1 - Shaar, Ron A1 - Ebert, Yael A1 - Hovers, Erella PB - Elsevier VL - 107 ER - TY - JOUR T1 - A Rejoinder on the Value of Archaeomagnetic Dating: Integrative Methodology Is the Key to Addressing Levantine Iron Age Chronology JF - Near Eastern Archaeology Y1 - 2018 A1 - Stillinger, M.D. A1 - Feinberg, J. A1 - Ben-Yosef, E. A1 - Shaar, R., A1 - Hardin, J.W. A1 - Blakely, J.A. VL - 81 UR - https://www.jstor.org/stable/10.5615/neareastarch.81.2.0141 IS - 2 ER - TY - JOUR T1 - The First Catalog of Archaeomagnetic Directions From Israel With 4,000 Years of Geomagnetic Secular Variations JF - Frontiers in Earth Sciences Y1 - 2018 A1 - R. Shaar A1 - Hassul, E. A1 - Raphael, K. A1 - Y. Ebert A1 - Segal, Y, A1 - Eden, I. A1 - Vaknin, Y. A1 - Marco. S. A1 - Nowaczyk, N. A1 - Chauvin, A. A1 - Agnon, A. VL - 164 UR - https://doi.org/10.3389/feart.2018.00164 ER - TY - JOUR T1 - Overwriting of sedimentary magnetism by bacterially mediated mineral alteration JF - geology Y1 - 2018 A1 - Y. Ebert A1 - R. Shaar A1 - Emmanuel, S. A1 - Nowaczyk, N. A1 - Stein, M. VL - 46 UR - https://pubs.geoscienceworld.org/gsa/geology/article/46/4/291/527272/overwriting-of-sedimentary-magnetism-by IS - 4 ER - TY - JOUR T1 - Fire and collapse: Untangling the formation of destruction layers using archeomagnetism. JF - Geoarchaeology Y1 - 2018 A1 - Shahack-Gross, R. A1 - R. Shaar A1 - Hassul, E. A1 - Y. Ebert A1 - Forget, M. A1 - Nowaczyk, N. A1 - Marco, S. A1 - Finkelstein, I. A1 - Agnon, A. VL - 33 UR - https://doi.org/10.1002/gea.21668 ER - TY - JOUR T1 - Quantitative vectorial magnetic imaging of multi domain rock forming minerals using nitrogen-vacancy centers in diamond JF - Spin Y1 - 2017 A1 - E. Farchi A1 - Y. Ebert A1 - Farfurnik, D. A1 - G. Haim A1 - R. Shaar A1 - Bar-Gill, N. VL - 7 UR - https://arxiv.org/abs/1705.03346 IS - 3 ER - TY - JOUR T1 - Further evidence of the Levantine Iron Age geomagnetic anomaly from Georgian pottery JF - Geophysical Research Letters Y1 - 2017 A1 - Shaar, R. A1 - Tauxe, L. A1 - Goguitchaichvili, A. A1 - Devidze, M. A1 - Licheli, V. VL - 44 UR - http://onlinelibrary.wiley.com/doi/10.1002/2016GL071494/full ER - TY - JOUR T1 - Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles. JF - Proceedings of the National Academy of Sciences Y1 - 2017 A1 - Ben-Yosef, E. A1 - Milman, M. A1 - Shaar, R. A1 - Tauxe, L. A1 - Lipschits, O. UR - http://www.pnas.org/content/early/2017/02/07/1615797114.short ER - TY - CHAP T1 -

The Tel Megiddo paleointensity project: toward a high resolution reference curve for archaeomagnetic dating

T2 - Megiddo VI Y1 - 2017 A1 - Shaar, Ron A1 - Tauxe, Lisa A1 - Ron, Hagai A1 - Agnon, Amotz A1 - Ebert, Yael A1 - Israel Finkelstein JF - Megiddo VI PB - Tel-Aviv University CY - Tel Aviv ER - TY - CHAP T1 - paleomagnetic geochronology of Quaternary sequences in the Levant T2 - Quaternary Environments, Climate Change, and Humans in the Levant Y1 - 2017 A1 - R. Shaar A1 - Ben-Yosef, E. JF - Quaternary Environments, Climate Change, and Humans in the Levant ER - TY - JOUR T1 -
PmagPy: Software package for paleomagnetic data analysis and a bridge to the Magnetics Information Consortium (MagIC) Database." Geochemistry, Geophysics, Geosystems (2016).
JF - eochemistry, Geophysics, Geosystems Y1 - 2016 A1 - Tauxe, L. A1 - Shaar, R. A1 - L. Jonestrask A1 - N. L. Swanson‐Hysell A1 - R. Minnett A1 - A. A. P. Koppers A1 - C. G. Constable A1 - N. Jarboe A1 - K. Gaastra UR - http://onlinelibrary.wiley.com/doi/10.1002/2016GC006307/epdf ER - TY - JOUR T1 - Large geomagnetic field anomalies revealed in Bronze to Iron Age archeomagnetic data from Tel Megiddo and Tel Hazor, Israel JF - Earth and Planetray Science Letters Y1 - 2016 A1 - Shaar, Ron A1 - Tauxe, Lisa A1 - Ron, Hagai A1 - Ebert, Yael A1 - Zuckerman, Sharon A1 - Israel Finkelstein A1 - Agnon, Amotz VL - 442 UR - http://www.sciencedirect.com/science/article/pii/S0012821X16300553 ER - TY - JOUR T1 - Instability of thermoremanence and the problem of estimating the ancient geomagnetic field strength from non-single-domain recorders JF - Proceedings of the National Academy of Sciences of the United States of America Y1 - 2015 A1 - Shaar, R. A1 - Tauxe, L. AB -

Data on the past intensity of Earth’s magnetic field (paleointensity) are essential for understanding Earth’s deep interior, climatic modeling, and geochronology applications, among other items. Here we demonstrate the possibility that much of available paleointensity data could be biased by instability of thermoremanent magnetization (TRM) associated with non-single-domain (SD) particles. Paleointensity data are derived from experiments in which an ancient TRM, acquired in an unknown field, is replaced by a laboratory-controlled TRM. This procedure is built on the assumption that the process of ancient TRM acquisition is entirely reproducible in the laboratory. Here we show experimental results violating this assumption in a manner not expected from standard theory. We show that the demagnetization−remagnetization relationship of non-SD specimens that were kept in a controlled field for only 2 y show a small but systematic bias relative to sister specimens that were given a fresh TRM. This effect, likely caused by irreversible changes in micromagnetic structures, leads to a bias in paleointensity estimates.

UR - http://www.pnas.org/content/112/36/11187.full.pdf ER - TY - JOUR T1 - Decadal-scale variations in geomagnetic field intensity from ancient Cypriot slag mounds JF - Geochemistry Geophysics Geosystems Y1 - 2015 A1 - Shaar, R. A1 - Tauxe, L. A1 - Ben-Yosef, E. A1 - Kassianidou, V. A1 - Lorentzen, B. A1 - Feinberg, J. M. A1 - Levy, T. E. KW - earths magnetic-field secular variation remanence anisotropy paleointensity data western-europe cooling rate copper slag pottery curves thermoremanence AB - Geomagnetic models based on direct observations since the 1830s show that the averaged relative 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, fourth to fifth centuries CE, 21 m in height), and Mitsero Kokkinoyia (MK1, seventh to fifth centuries BCE, 8 m in height). The mounds are multilayered sequences of slag and charcoals that accumulated near ancient copper production sites. We modeled the age-height relation of the mounds using radiocarbon dates, and estimated paleointensities using Thellier-type IZZI experiments with additional anisotropy, cooling rate, and nonlinear TRM assessments. To screen out ambiguous paleointensity 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 the data available in the MagIC database. The analyses yielded two independent subcentury-scale paleointensity time series. The MK1 data indicate relatively stable field at the time the mound accumulated. In contrast, the SU1 data demonstrate changes that are comparable in magnitude to the fastest changes inferred from geomagnetic models. We suggest that fast changes observed in the published archaeomagnetic data from the Levant are driven by two longitudinally paired regions, the Middle East and South Africa, that show unusual activity in geomagnetic models. VL - 16 UR - ://WOS:000349839000012 N1 - Cb7wj Times Cited:1 Cited References Count:66 ER - TY - CHAP T1 - Archaeomagnetic investigations of copper slag deposits in Cyprus T2 - Studies in Mediterranean Archaeology, Introduction to the Archaeometallurgy of Cyprus Y1 - 2014 A1 - Ben-Yosef, E. A1 - Shaar, R. A1 - Tauxe, L. A1 - Levy, T. E. A1 - Kassianidou, V. A1 - Lorentzen, B. ED - Kassianidou, V. ED - Papasavvas, G. JF - Studies in Mediterranean Archaeology, Introduction to the Archaeometallurgy of Cyprus PB - Astrom Editions CY - Uppsala ER - TY - JOUR T1 - On improving the selection of Thellier-type paleointensity data JF - Geochemistry Geophysics Geosystems Y1 - 2014 A1 - Paterson, G. A. A1 - Tauxe, L. A1 - Biggin, A. J. A1 - Shaar, R. A1 - Jonestrask, L. C. KW - paleointensity archeointensity data selection cretaceous normal superchron submarine basaltic glass earths magnetic-field geomagnetic-field intensity thermoremanence reliability multidomain remanence criteria AB - The selection of paleointensity data is a challenging, but essential step for establishing data reliability. There is, however, no consensus as to how best to quantify paleointensity data and which data selection processes are most effective. To address these issues, we begin to lay the foundations for a more unified and theoretically justified approach to the selection of paleointensity data. We present a new compilation of standard definitions for paleointensity statistics to help remove ambiguities in their calculation. We also compile the largest-to-date data set of raw paleointensity data from historical locations and laboratory control experiments with which to test the effectiveness of commonly used sets of selection criteria. Although most currently used criteria are capable of increasing the proportion of accurate results accepted, criteria that are better at excluding inaccurate results tend to perform poorly at including accurate results and vice versa. In the extreme case, one widely used set of criteria, which is used by default in the ThellierTool software (v4.22), excludes so many accurate results that it is often statistically indistinguishable from randomly selecting data. We demonstrate that, when modified according to recent single domain paleointensity predictions, criteria sets that are no better than a random selector can produce statistically significant increases in the acceptance of accurate results and represent effective selection criteria. The use of such theoretically derived modifications places the selection of paleointensity data on a more justifiable theoretical foundation and we encourage the use of the modified criteria over their original forms. VL - 15 UR - ://WOS:000336493400022 N1 - Ah9vr Times Cited:10 Cited References Count:37 ER - TY - JOUR T1 - Rock magnetic properties of dendrites: insights from MFM imaging and implications for paleomagnetic studies JF - Geochemistry Geophysics Geosystems Y1 - 2013 A1 - Shaar, R. A1 - Feinberg, J. M. KW - mfm dendrites rock magnetism slag volcanic glass geomagnetic-field copper slag intensity titanomagnetite basalts growth AB - Dendrites are crystals that grow in branches that diverge along crystallographically defined directions. Despite the importance of dendrites in paleomagnetic research, little is known about how dendrites act as magnetic recorders, because they exhibit complicated magnetic domain structures. In this study, we experimentally examine how textures and sizes of dendrites affect their magnetic domain structure and magnetic properties. We study two basaltic glass samples and three synthetic slag samples, which collectively define a wide range of dendritic morphologies. We use electron microscopy to characterize the morphology of the dendrites and magnetic force microscopy (MFM) to observe their magnetic domain structure. We characterize the dendrites' bulk properties by firs-order reversal curve distributions, Thellier-style paleointensity experiments, anisotropy of remanence, and anisotropy of susceptibility. The samples with the thinnest dendrites have high coercivity, stable single-domain (SD) - pseudo single-domain magnetization, and yield ideal Arai plots. By contrast, the sample with the thickest dendrites has the lowest coercivity and shows the most extreme multidomain (MD) behavior. All samples except one, exhibit significant remanence and susceptibility anisotropy. MFM observations show that dendrites built from branches of interconnected octahedra, typical for basaltic glass, have a stable, high coercivity, SD-like magnetization despite the fact that their overall dimensions exceed the SD-MD threshold. Their stability is likely due to interactions between the octahedra and their narrow rod-like interconnections. Dendrites that crystallize in faster cooling environments, such as in archaeological slag, display finer branch thicknesses (< 1 mu m) and few, if any, octahedra. The tips of these dendrites consist of closely intergrown, rounded, acicular branches that behave as pseudo single-domain grains due to interactions between the branches. The largest, thickest dendrites show MD behavior and MFM images show their magnetic domain walls to be arranged in crystallographically controlled, geometrically repetitive patterns within elongated branches, which give rise to their anisotropy characteristics. VL - 14 UR - ://WOS:000317823900009 N1 - 129FH Times Cited:4 Cited References Count:25 ER - TY - JOUR T1 - Thellier GUI: An integrated tool for analyzing paleointensity data from Thellier-type experiments JF - Geochemistry Geophysics Geosystems Y1 - 2013 A1 - Shaar, R. A1 - Tauxe, L. KW - paleointensity magic database thellier submarine basaltic glass earths magnetic-field geomagnetic-field intensity bootstrap criteria flows rocks line slag AB - Thellier-type experiments are a method used to estimate the intensity of the ancient geomagnetic field from samples carrying thermoremanent magnetization. The analysis of Thellier-type experimental data is conventionally done by manually interpreting data from each specimen individually. The main limitations of this approach are: (1) manual interpretation is highly subjective and can be biased by misleading concepts, (2) the procedure is time consuming, and (3) unless the measurement data are published, the final results cannot be reproduced by readers. These issues compound when trying to combine together paleointensity data from a collection of studies. Here, we address these problems by introducing the Thellier GUI: a comprehensive tool for interpreting Thellier-type experimental data. The tool presents a graphical user interface, which allows manual interpretation of the data, but also includes two new interpretation tools: (1) Thellier Auto Interpreter: an automatic interpretation procedure based on a given set of experimental requirements, and 2) Consistency Test: a self-test for the consistency of the results assuming groups of samples that should have the same paleointensity values. We apply the new tools to data from two case studies. These demonstrate that interpretation of non-ideal Arai plots is nonunique and different selection criteria can lead to significantly different conclusions. Hence, we recommend adopting the automatic interpretation approach, as it allows a more objective interpretation, which can be easily repeated or revised by others. When the analysis is combined with a Consistency Test, the credibility of the interpretations is enhanced. We also make the case that published paleointensity studies should include the measurement data (as supplementary files or as a contributions to the MagIC database) so that results based on a particular data set can be reproduced and assessed by others. VL - 14 UR - ://WOS:000317825000011 N1 - 129FS Times Cited:9 Cited References Count:39 ER - TY - JOUR T1 - A New Chronological Framework for Iron Age Copper Production at Timna (Israel). JF - Bulletin of the American Schools of Oriental Research Y1 - 2012 A1 - Ben-Yosef, E. A1 - Shaar, R. A1 - Tauxe, L. A1 - Ron, H. VL - 366 ER - TY - ABST T1 - Evaluating the potential seismic hazards of the Ahihud Ridge fault system by paleomagnetic and morphological analyses of calcretes Y1 - 2011 A1 - Zilberman, E. A1 - Ron, H. A1 - Shaar, R. PB - Geological Survey of Israel ER - TY - JOUR T1 - Geomagnetic field intensity: How high can it get? How fast can it change? Constraints from Iron Age copper slag JF - Earth and Planetary Science Letters Y1 - 2011 A1 - Shaar, R. A1 - Ben-Yosef, E. A1 - Ron, H. A1 - Tauxe, L. A1 - Agnon, A. A1 - Kessel, R. KW - archaeomagnetism paleomagnetism paleointensity secular variations iron age slag timna archaeometallurgy radiocarbon c-14 thellier submarine basaltic glass earths core secular variation dipole-moment paleointensity millennia holocene curves models flows AB - The intensity of the geomagnetic field varies over different time scales. Yet, constraints on the maximum intensity of the field as well as for its maximum rate of change are inadequate due to poor temporal resolution and large uncertainties in the geomagnetic record. The purpose of this study is to place firm limits on these fundamental properties by constructing a high-resolution archaeointensity record of the Levant from the 11th century to the early 9th century BCE, a period over which the geomagnetic field reached its maximum intensity in Eurasia over the past 50,000 years. We investigate a C-14-dated sequence of ten layers of slag material, which accumulated within an ancient industrial waste mound of an Iron Age copper-smelting site in southern Israel. Depositional stratigraphy constrains relative ages of samples analyzed for paleointensity, and C-14 dates from different horizons of the mound constrain the age of the whole sequence. The analysis yielded 35 paleointenisty data points with accuracy better than 94% and precision better than 6%, covering a period of less than 350 years, most probably 200 years. We construct a new high-resolution quasi-continuous archaeointensity curve of the Levant that displays two dramatic spikes in geomagnetic intensity, each corresponding to virtual axial dipole moment (VADM) in excess of 200 ZAm(2). The geomagnetic spikes rise and fall over a period of less than 30 years and are associated with VADM fluctuations of at least 70 ZAm2. Thus, the Levantine archaeomagnetic record places new constraints on maximum geomagnetic intensity as well as for its rate of change. Yet, it is not clear whether the geomagnetic spikes are local non-dipolar features or a geomagnetic dipolar phenomenon. (C) 2010 Elsevier B.V. All rights reserved. VL - 301 UR - ://WOS:000286640400030 N1 - 712CM Times Cited:25 Cited References Count:43 ER - TY - JOUR T1 - Paleomagnetic field intensity derived from non-SD: Testing the Thellier IZZI technique on MD slag and a new bootstrap procedure JF - Earth and Planetary Science Letters Y1 - 2011 A1 - Shaar, R. A1 - Ron, N. A1 - Tauxe, L. A1 - Kessel, R. A1 - Agnon, A. KW - paleointensity archeomagnetism thellier slag trm multi-domain paleointensity experiments geomagnetic-field single-domain partial thermoremanence ferromagnetic grains multidomain behavior 1st-order symmetry pseudo-single copper slag lava flows AB - Experimental techniques to determine paleomagnetic field intensity are based on a theoretical framework that is valid only for single-domain (SD) ferromagnetic particles. Yet, most of the available materials exhibit distinctly non-SD properties. Designing the optimal paleointensity methodology for non-SD is, therefore, a fundamental challenge in paleomagnetism. The objective of this study is to experimentally test the IZZI Thellier absolute paleointensity method on small MD recorders. The test has two purposes: 1) to describe the characteristic non-SD patterns occurring in Arai plots, and 2) to identify the optimal approach in interpreting non-SD behavior. We carried out paleointensity experiments on 40 specimens from 4 synthetic re-melted slag samples with identical magnetic properties (mineralogy, texture, and non-SD state) produced under different field intensities. We ran three batches of IZZI experiments using different conditions that allow for a detailed characterization of the non-SD behavior. We find that the curvature of the Arai plot is systematically dependent on the angle and the proportion between the field used in the paleointensity experiment (B-TRM) and the field in which the NRM was acquired (B-NRM). Straight-line Arai plot occur when the two fields are parallel and equal, and seems to always give the 'true' slope. Convex curves occur when B-TRM is parallel and significantly stronger than B-NRM. Concave curves occur in all the other cases and yield two end-case slopes that are always different than the 'true' slope. In addition, zigzagged patterns increase with the angle the proportion between B-TRM and B-NRM. We test the accuracy of the 'best fitting' line approach and conclude that 'best fitting' line in curved plots cannot provide robust paleointensity estimates. Yet, the two 'end-case' slopes in concave curves provide adequate constraints for the true value. We introduce a new procedure to calculate a 95% confidence interval of the paleointensity from curved plots using bootstrap statistics. We substantiate the new procedure by conducting two independent tests. The first uses synthetic re-melted slag produced under known field intensities - 3 SD samples and 4 non-SD samples. The second compares paleointensity determinations from archeological slag samples of the same age - 34 SD samples and 10 non-SD samples. The two tests demonstrate that the bootstrap technique may be the optimal approach for non-ideal dataset. (C) 2011 Elsevier BM. All rights reserved. VL - 310 UR - ://WOS:000298273500005 N1 - 864XJ Times Cited:7 Cited References Count:44 ER - TY - CHAP T1 - Earth's magnetic field: new discoveries from archaeomagnetic study of copper slag from Arava valley T2 - Melakh Haaretz (Salt of the Earth) Y1 - 2010 A1 - Shaar, Ron A1 - Ben-Yosef, Erez ED - Starinsky, Abraham JF - Melakh Haaretz (Salt of the Earth) PB - The Hebrew University Magnes Press Ltd. CY - Jerusalem VL - 5 ER - TY - JOUR T1 - Petrology and rock magnetism of the gabbro of Troodos ophiolite JF - Physics of the Earth and Planetary Interiors Y1 - 2010 A1 - Ebert, Y. A1 - Kessel, R. A1 - Shaar, R. A1 - Agnon, A. A1 - Ron, H. KW - magnetite rock magnetism inclusions pyrrhotite gabbro troodos hysteresis properties oriented inclusions midocean ridge single-domain basalts titanomagnetite clinopyroxene complex AB - In order to determine the nature of remanence carriers of the layered gabbro of the Troodos ophiolite, Cyprus, we report optical and electron microscopic observations, together with rock magnetic and paleomagnetic experiments. Above all, the study aims to understand and clarify the time of magnetic acquisition relative to the brittle deformation of the oceanic crust manifested by the ridge-transform intersection (Solea graben and the Arakapas transform). Petrographic examination of pyroxene grains revealed isolated magnetite inclusions ranging in size from single-domain (SD) to multi-domain (MD) and in addition, MD pyrrhotite inclusions residing in veins and cracks. Thermal demagnetization and thermomagnetic procedures indicate two components, low and high temperature. We argue that the low temperature component, <350 degrees C, and the high component, <580 degrees C, are the contribution of the pyrrhotite and magnetite, respectively. The SD magnetite inclusions exsolved in pyroxene are the dominant carriers of magnetic remanence in Troodos Gabbro. The initial formation of these inclusions occurred via exsolution reaction at temperatures between 520 and 850 degrees C, above the Curie temperature of pure magnetite during the solidification of the magma. Therefore, acquisition of remanent magnetization of the Troodos gabbro took place during the earliest stages of crustal accretion, before any brittle deformation associated with the spreading ridge and the transform fault occurred. (C) 2010 Elsevier B.V. All rights reserved. VL - 183 UR - ://WOS:000286085800005 N1 - 704WH Times Cited:2 Cited References Count:26 ER - TY - JOUR T1 - Testing the accuracy of absolute intensity estimates of the ancient geomagnetic field using copper slag material JF - Earth and Planetary Science Letters Y1 - 2010 A1 - Shaar, R. A1 - Ron, H. A1 - Tauxe, L. A1 - Kessel, R. A1 - Agnon, A. A1 - Ben-Yosef, E. A1 - Feinberg, J. M. KW - paleointensity archeomagnetism slag rock magnetism thellier method jacobsite earths magnetic-field thellier paleointensity experiments cooling-rate partial thermoremanence ferromagnetic grains multidomain behavior 1st-order symmetry lava flows anisotropy AB - The Middle-Eastern copper slag is a promising new material for studying intensity variations in the geomagnetic field with high resolution and precision. The purpose of this study is to test the accuracy of archaeointensity estimates determined using copper slag by addressing two questions: 1) "Does slag material display the magnetic properties required for valid Thellier experiments?" and 2) "What is the accuracy of the archaeointensity estimates derived from Thellier-style experiments on optimal samples?" We address the first question through a comprehensive microscopic and magnetic study of representative archaeological slag samples in order to identify the properties responsible for optimal behavior in Thellier experiments. To address the second question, we reproduced slag samples in the laboratory under controlled magnetic fields and analyzed them using the same 1721 paleointensity technique used for the ancient slag. Microscopic analyses of the archaeological slag show that ferromagnetic phases occur as three-dimensional dendritic structures whose branches consist of submicronelongated particles. Magnetic analyses show that these dendrites behave as an assemblage of shape-controlled, single-domain-like particles and that their magnetization is thermoremanent. We conclude that slag material can be magnetically suitable for valid Thellier experiments. The laboratory-produced slag material demonstrated similar magnetic and mineralogical properties as the archaeological slag. IZZI experiments showed that nonlinear TRM acquisition, even at field strengths similar to Earth's, and TRM anisotropy are important factors to monitor during paleointensity studies of slag material. Anisotropy and non-linearity are probably related to the dendritic shape of the oxide grains. Intensity estimates derived from three laboratory-produced slag samples demonstrated accuracy to within similar to 5% after applying the required corrections. (C) 2009 Elsevier B.V. All rights reserved. VL - 290 UR - ://WOS:000274844700023 N1 - 559RU Times Cited:17 Cited References Count:61 ER - TY - JOUR T1 - Timing of relay ramp growth and normal fault linkage, Upper Galilee, northern Israel JF - Tectonics Y1 - 2010 A1 - Matmon, A. A1 - Katz, O. A1 - Shaar, R. A1 - Ron, H. A1 - Porat, N. A1 - Agnon, A. KW - san-andreas fault paleomagnetic data large earthquakes pull-apart california slip propagation geometry basin deformation AB - We investigate a kilometer-scale steep relay ramp structure in the Galilee, northern Israel. The data indicate an asymmetric fold above the buried tip of the southern boundary fault as well as at the lower part of the ramp. Structural analysis suggests that the buried tip of the bounding fault is only a few hundred meters below the surface. A sequence of colluvial wedges, exposed at the base of the southern flank of the relay ramp over the blind tip of the boundary fault, presents successively decreasing angles from 67 at the bottom to 30 at the top. The lower three wedges rest at angles greater than the angle of repose, suggesting tilting during and after deposition. We suggest that the increasing angle of the wedges is the result of the development of the monocline over the buried tip of the boundary fault, which in turn reflects the development of the entire relay ramp structure. Paleomagnetic measurements test this hypothesis. Samples from three of the four lower wedges and the carbonate fill in the fractured bedrock yield northerly declination and positive inclination. Inclination anomalies are 19.4 +/- 3.3 and 11.3 +/- 1.8 for the fractured bedrock and the wedges, respectively. These anomalies reflect part of the tilt. Paleomagnetic measurements and optically stimulated luminescence (OSL) constrain the time of initial deformation of the monocline above the southern boundary fault between 780 ka and 461 +/- 75 ka (OSL age of wedge 1) and the termination of deformation to 176 +/- 22 ka (OSL age of wedge 5). These bounding ages suggest tilting rates that range between 1 degrees/16 kyr and 1 degrees/8 kyr. Termination of tilting along the southern flank of the relay ramp and the fact that the tip of the buried normal fault is only a few hundreds of meters below the surface suggest that the relay ramp may be close to being breached by a connecting fault. Citation: Matmon, A., O. Katz, R. Shaar, H. Ron, N. Porat, and A. Agnon (2010), Timing of relay ramp growth and normal fault linkage, Upper Galilee, northern Israel, Tectonics, 29, TC2016, doi: 10.1029/2009TC002510. VL - 29 UR - ://WOS:000276831900001 N1 - 585NH Times Cited:2 Cited References Count:54 ER - TY - JOUR T1 - Geomagnetic intensity spike recorded in high resolution slag deposit in Southern Jordan JF - Earth and Planetary Science Letters Y1 - 2009 A1 - Ben-Yosef, E. A1 - Tauxe, L. A1 - Levy, T. E. A1 - Shaar, R. A1 - Ron, H. A1 - Najjar, M. KW - archaeomagnetism paleomagnetism secular variations iron age copper slag faynan archaeometallurgy radiocarbon field intensity lava flows archaeology hawaii core AB - In paleomagnetism, periods of high field intensity have been largely ignored in favor of the more spectacular directional changes associated with low field intensity periods of excursions and reversals. Hence, questions such as how strong the field can get and how fast changes occur are still open. In this paper we report on data obtained from an archaeometallurgical excavation in the Middle East, designed specifically for archaeomagnetic sampling. We measured 342 specimens from 72 samples collected from a 6.1 m mound of well stratified copper production debris at the early Iron Age (12th-9th centuries BCE) site of Khirbat en-Nahas in Southern Jordan. Seventeen samples spanning 200 yr yielded excellent archaeointensity results that demonstrate rapid changes in field intensity in a period of overall high field values. The results display a remarkable spike in field strength, with sample mean values of over 120 mu T (compared to the current field strength of 44 mu T). A suite of 13 radiocarbon dates intimately associated with our samples, tight control of sample location and relative stratigraphy provide tight constraints on the rate and magnitude of changes in archaeomagnetic field intensities. (C) 2009 Elsevier B.V. All rights reserved. VL - 287 UR - ://WOS:000272010800026 N1 - 522PQ Times Cited:35 Cited References Count:30 ER -