The impacts on global climate of the AD 536 and 541 volcanic eruptions are well attested in palaeoclimatic datasets and in Eurasian historical records. Their effects on farmers in the arid uplands of western North America, however, remain poorly understood. The authors investigate whether extreme cold caused by these eruptions influenced the scale, scope and timing of the Neolithic Transition in the northern US Southwest. Archaeological tree-ring and radiocarbon dates, along with settlement survey data, suggest that extreme cooling generated the physical and social space that enabled early farmers to transition from kin-focused socio-economic strategies to increasingly complex and widely shared forms of social organisation that served as foundational elements of burgeoning Ancestral Pueblo societies.

Cultural ecological theory is applied to a spatially and temporally bounded archaeological data set to document long-term paleoecological processes and associated sociopolitical behaviors. Volumetric excavations, treating the material culture of an archaeological matrix similar to an ecological core, can yield quantifiable frequencies of surplus goods that provide a multiproxy empirical lens into incremental changes in land use practices, natural resource consumption, and, in this case, likely overexploitation. Archaeological methods are employed to quantify cultural ecological processes of natural resource exploitation, industrial intensification, sustainability and scarcity, and settlement collapse during the colonial transition between Carthaginian and Roman North Africa. The data indicate that overexploitation of olive timber for metallurgical fuel taxed the ecological metabolism of the Zita resource base, likely contributing to a collapse of the entire local economic system.

PreviousNext No Access18th International Conference on Ground Penetrating Radar, Golden, Colorado, 14–19 June 2020On GPR surveying of historical cemeteries and ancient graveyards to aid forensic researchAuthors: Brian N. DamiataJacky WalkerAnn StansellJohn M. SteinbergBrian N. DamiataCotsen Institute of Archaeology, UCLA, United StatesSearch for more papers by this author, Jacky WalkerSan Fernando Valley Historical Society, United StatesSearch for more papers by this author, Ann StansellNational Park Service, Santa Monica Mountains, United StatesSearch for more papers by this author, and John M. SteinbergFiske Center for Archaeological Research, UMASS Boston, United StatesSearch for more papers by this authorhttps://doi.org/10.1190/gpr2020-059.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract The GPR surveying of historical cemeteries and ancient graveyards can contribute to forensic research (Pringle and Ruffell, 2017). For example, knowledge of how long skeletal remains or burial pits are detectable in different environmental settings is of interest to cold-case research. In general, cemeteries allow for semi-controlled field studies to be conducted where certain information may be known a priori as gleaned from gravestones and death certificates (e.g., burial age, presumed burial orientation and estimation of body size based on age at death) but with other lacking (e.g., use and type of burial container, if any). For ancient graveyards, prior information may be limited or absent but when archaeologically excavated provide important data to ground-truth the GPR interpretations. Here we present some examples from GPR surveying of cemeteries and graveyards with a focus on forensic relevance (Figure 1). Additionally, some suggestions for future work are given. Keywords: GPR, diffraction, interpretation, reflectionPermalink: https://doi.org/10.1190/gpr2020-059.1FiguresReferencesRelatedDetails 18th International Conference on Ground Penetrating Radar, Golden, Colorado, 14–19 June 2020ISSN (online):2159-6832Copyright: 2020 Pages: 455 publication data© 2020 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 11 Nov 2020 CITATION INFORMATION Brian N. Damiata, Jacky Walker, Ann Stansell, and John M. Steinberg, (2020), "On GPR surveying of historical cemeteries and ancient graveyards to aid forensic research," SEG Global Meeting Abstracts : 220-223. https://doi.org/10.1190/gpr2020-059.1 Plain-Language Summary KeywordsGPRdiffractioninterpretationreflectionPDF DownloadLoading ...

Icelandic settlement (Landnám) period farmsteads offer opportunities to explore the nature and timing of anthropogenic activities and environmental impacts of the first Holocene farming communities. We employ Bayesian statistical modelling of archaeological, paleoenvironmental and documentary datasets to present a framework for improving chronological robustness of archaeological events. Specifically, we discuss events relevant to the farm Hrísbrú, an initial and complex settlement site in southwest Iceland. We demonstrate that tephra layers are key in constraining reliable chronologies, especially when combined with related datasets and treated in a Bayesian framework. The work presented here confirms earlier interpretations of the chronology of the site while providing increased confidence in the robustness of the chronology. Most importantly, integrated modelling of AMS radiocarbon dates on Hordeum vulgare grains, palynological data, documented evidence from textual records and typologically diagnostic artefacts yield increased dating reliability. The analysis has also shown that AMS radiocarbon dates on bone collagen need further scrutiny. Specifically for the Hrísbrú farm, first anthropogenic footprint palynomorph taxa are estimated to around AD 830–881 (at 95.4% confidence level), most likely before the tephra fall out of AD 877 ± 1 (the Landnám tephra layer), demonstrating the use of arable fields before the first known structures were built at Hrísbrú (AD 874–951) and prior to the conventionally accepted date of the settlement of Iceland. Finally, we highlight the importance of considering multidisciplinary factors for other archaeological and paleoecological studies of early farming communities of previously uninhabited island areas.

The results of a ground-penetrating radar (GPR) survey over a Viking-Age Christian churchyard (ca. 10001100 CE) that was subsequently fully excavated are reported. During excavation, broadband time-domain reflectometry (TDR) measurements of apparent relative permittivity were made of various features which helped to constrain interpretations of the radar data. Although four probes of different lengths were used (0.1, 0.15, 0.2 and 0.3 m), the longest waveguide yielded effective frequencies that most closely matched the bandwidth of the radar data, which was collected using a 500 MHz antenna. The excavation revealed 25 graves. Comparison of the radar data to the archaeological record indicated that all graves containing skeletal remains produced signatures from the bones, but only half of those were interpreted as such prior to excavation. The skeletons of three adults and two children as well as two pairs of isolated leg bones were identified beforehand, whereas five sets of remains (small child, infants and neonates) were noted only after reanalysis of the radar data following the excavation. Thirteen of the graves had been re-dug and their bones removed prior to 1100 CE presumably for interment to a nearby more recent churchyard. The only indication of burial pits in the radar profiles was a break in a sub-horizontal reflector that corresponded to a perforated in situ volcanic tephra sequence. Six of the 25 burial pits were identified prior to excavation, eight more after reanalysis, and 11 had no signature because of the absence of preserved tephra in their vicinity. The TDR measurements confirmed the general lack of contrast between backfill material within pits and soil surrounding pits. This study provides one of the best documented cases for comparison of radar data to the archaeological record for a fully excavated churchyard, and confirms the direct detection of skeletal remains by GPR. (C) 2017 Elsevier Ltd. All rights reserved.

El Chichón volcano is the only active volcano located within the Chiapanecan Volcanic Arc in southern Mexico, which lies between the Trans-Mexican Volcanic Belt and the Central American Volcanic Arc. Previous studies have shown that ~12 eruptions have occurred at El Chichón within the last 8000years, forming a complex of lava domes with a central crater and surrounding pyroclastic deposits. Here, we report the discovery of zircon in Holocene El Chichón rocks, which were analyzed by high spatial resolution imaging (color cathodoluminescence CCL) and isotopic (secondary ionization mass spectrometry SIMS) methods to resolve core and rim crystallization ages. Pumice samples from five proximal pyroclastic flow and fall-out deposits were collected based on published stratigraphy. Two of the samples were further (re-)classified by new 14C dates. In addition, we sampled two lavas from the 1982 eruption and from remnants of the older Somma lava complex. Zircon crystals were dated using 230Th/238U disequilibrium (U–Th) and U–Pb geochronology. U–Th zircon ages fall between near eruption ages and ca. 84ka, with overlapping ages in all samples. By contrast, zircon core U–Pb ages range between ca. 290Ma and 1.9Ga. These ages are consistent with xenocrystic origins and their heterogeneity indicates derivation from clastic country rocks. Strong age contrasts between inherited xenocrystic and young magmatic domains in individual zircon crystals are evidence for arrested assimilation of crustal rocks where initially zircon-undersaturated magmas cooled rapidly to form a crystal mush or subsolidus amalgamate as a crustally contaminated boundary layer. This layer contributed zircon crystals to eruptible magma during episodic recharge events followed by partial melt extraction, mixing and homogenization. Zircon overgrowths are significantly older than major minerals whose U-series ages and sharp zonation boundaries suggest crystallization only within a few ka before eruption. This implies that zircon can detect magmatic longevity which is obscured in the major mineral record.

An archaeological survey of the Viking Age settlement pattern in the Langholt region of North Iceland suggests that being early in this sequence conferred tremendous advantages to the settlers of this previously uninhabited landscape. Many of the farms established during the settlement of Iceland (which began about a.d. 870) are in use today. However, accessing the Viking Age landscape is difficult. In Langholt the earliest layers of most farmsteads are buried under a thousand years of occupational debris, while the abandoned sites have been covered by extensive soil deposition. Here we report on our coring and test excavation results that outline Viking Age farmstead location, establishment date, and maximum size by the end of the Viking Age. There is a strong correlation between farmstead size and establishment date. This correlation suggests that during the rapid settlement of Iceland, the farmsteads established by earlier settlers were wealthier and that wealth endured.

Excavations of the Egyptian New Kingdom fortress in Jaffa (Tel Yafo, ancient Yapu), on the southern side of Tel Aviv, were renewed by the Jaffa Cultural Heritage Project from 2011 to 2014. This work is an outgrowth of the project’s reappraisal of Jacob Kaplan’s excavations in the Ramesses Gate area from 1955 to 1962. As the Egyptian fortress in Jaffa is the only one excavated in Canaan, its archaeological record provides a unique perspective on resistance to Egyptian rule from ca. 1460 to 1125 B.C.E., but especially during the second half of the 12th century B.C.E., when Jaffa was twice destroyed. Radiocarbon dates from these two destructions are presented, and it is suggested that they offer the clearest basis thus far for proposing ca. 1125 B.C.E. as a terminus post quem for the end of Egyptian rule in Canaan. The archaeological evidence, taken together with textual sources, yields a picture of local resistance to the Egyptian military presence in Jaffa likely originating in Canaanite centers located throughout the coastal plain. This article is also available as open access on AJA Online.

Uppgrofturinn er hluti af þverfaglegu þriggja ara islensk-bandarisku rannsoknarverkefni, Skagfirsku kirkju- og byggðasogurannsokninni (Skagafjorður Church and Settlement Survey – SCASS). Rannsoknin er samstarfsverkefni Byggðasafns Skagfirðinga (BSk) og Fiske rannsoknarstofnunarinnar i fornleifafraeði við Massachusetts haskola i Boston (UMass Boston)

Detailed ground-penetrating radar surveys were conducted at separate Viking Age and Medieval churchyards on the Stóra-Seyla farm in Skagafjörður, northern Iceland. Surveying over a previously unknown site (ca. AD 1000) that is located just a few meters above the Skagafjörður valley bottom delineated the remnants of a buried circular turf wall that encloses a church structure and several graves. The radar profiles over the graves contain strong hyperbolic reflections that emanated from the skeletal remains. Over one of the graves, an air-filled void within the chest cavity had been detected as noted by reflections with normal polarity which indicated a boundary towards increasing microwave velocity. During excavation, the soil surrounding an intact rib cage collapsed thus confirming the presence of the void. In general, the skeletal remains were very well preserved and yielded strong reflections which permitted the orientation of the body to be determined. Conversely, the radar profiles over a grave from a more recent churchyard (ca. AD 1200) show ground disturbance but lack hyperbolic reflections. Upon excavation, only teeth were recovered. The poor preservation of the skeletal remains is attributed to increase contact with infiltrating groundwater from an overlying gravel layer. Interpretations were aided by time-slice overlay imaging, forward modeling and analysis of the reflection coefficient.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2011Time‐lapse gravity as a water resource management tool — Applications to unconfined aquifersAuthors: Dennis L. HarryWilliam E. SanfordCarter GehmanJoshua WoodworthBrian N. DamiataDennis L. HarryColorado State UniversitySearch for more papers by this author, William E. SanfordColorado State UniversitySearch for more papers by this author, Carter GehmanHess Corp.Search for more papers by this author, Joshua WoodworthShell Oil Co.Search for more papers by this author, and Brian N. DamiataUniversity of California at Los AngelesSearch for more papers by this authorhttps://doi.org/10.1190/1.3627978 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Time‐lapse gravity surveys involve gravity campaigns conducted at different times. Differences in gravity measured at given locations between the surveys, after corrections for barometric pressure changes, Earth Tides, and instrument drift, reflect changes in subsurface mass. In this study, we associated these mass changes to changes in groundwater storage. We demonstrate that, in unconfined surficial aquifers, water table elevation changes of ca. 70 cm can be detected, and, if drawdown data are available, specific yield, storativity, and specific storage can be estimated (although specific storage is poorly constrained). We present two case studies, one involving an artificial recharge project in which water table changes are mapped via time‐lapse gravity over a ca. 10 km2 region and a second in which estimates of specific yield, transmissivity, and specific storage are obtained at a single location during a pumping test.Permalink: https://doi.org/10.1190/1.3627978FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2011ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2011 Pages: 4424 Publisher:Society of Exploration Geophysicists HistoryPublished: 25 May 2012 CITATION INFORMATION Dennis L. Harry, William E. Sanford, Carter Gehman, Joshua Woodworth, and Brian N. Damiata, (2011), "Time‐lapse gravity as a water resource management tool — Applications to unconfined aquifers," SEG Technical Program Expanded Abstracts : 3718-3721. https://doi.org/10.1190/1.3627978 Plain-Language Summary PDF DownloadLoading ...

The gravitational response to hydraulic testing of shallow unconfined aquifers (<50m) has been simulated to assess whether gravity surveying can be used as a practical tool to detect groundwater extraction. A general expression is derived to calculate the response based on the gravitational attraction of the drawdown cone. The expression can accommodate any radially symmetric drawdown solution that assumes instantaneous release of groundwater above the moving water table as exemplified by Neuman's solution. Based on simulations, hydraulic testing of shallow unconfined aquifers with typical properties produces gravitational responses on the order of several tens of microGals (1μGal=1×10−8m/s2) at the pumping well. The response at the 1μGal level can extend hundreds of meters away from the pumping well. At a distance of 1m, survey resolutions between 0.002 to 0.15 and 0.03 to 2μGal are required to delineate incremental drawdown at the 0.02- and 0.3-m levels, respectively, below the point of measurement.

Owing to the proximity of an insulating ground surface, normal resistivity logging at shallow depths (less than 30 m) can yield an apparent resistivity that exceeds 200% of the formation resistivity for a homogeneous medium. The distortion is more acute for long‐normal than for short‐normal logging. Three examples from a landfill site in southern California are presented to show such distortion. The patterns of distortion are similar for logging devices consisting of either two point‐source electrodes or one point‐source and one finite length, line‐source electrode. The former electrode array is a generally accepted approximation of the latter. However, the simulated apparent resistivity for the line‐source array is greater than that for the point‐source array at any given depth. A resistivity contrast between the formation and the borehole fluid can shift the magnitude of the background apparent resistivity but does not significantly alter the pattern of distortion. The magnitude of the distortion can be reduced by placing the reference‐ground potential electrode at a radial distance that is about equal to the spacing between the downhole upper potential electrode and the upper current electrode. It can also be removed by including the radial distance in an array‐dependent geometric factor that accounts for the resistivity of the borehole fluid and the proximity of the logging device to the ground surface.