Charlotte L. Pearson

Olive Tree-Ring Problematic Dating: A Comparative Analysis on Santorini (Greece)

Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece) show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ.

New evidence for an early date for the Aegean Late Bronze age and Thera eruption

The authors report on radiocarbon data derived from carefully selected organic material from Late Minoan IA and IB contexts. The results suggest that the accepted chronology of the period should be revised by 100 years and that the eruption of Thera/Santorini most likely occurred c. 1650-1620 BC.

14C record and wiggle-match placement for the Anatolian (Gordion Area) juniper tree-ring chronology ~1729 To 751 cal BC, and typical Aegean/Anatolian (growing season related) regional 14C offset assessment.

The East Mediterranean Radiocarbon (inter-)Comparison Project (EMRCP) has measured the 14C ages of a number of sets of tree rings from the Gordion Area dendrochronology from central Anatolia at the Heidelberg Radiocarbon Laboratory. In several cases, multiple measurements were made over a period from the 1980s to 2009. This paper presents the final data set from this work (128 high-precision measurements), and considers (i) the relationship of these data against the standard Northern Hemisphere 14C calibration data set (IntCal09), and (ii) the optimum calendar dating of this floating tree-ring record on the basis of the final set of high-precision 14C data. It finds good agreement between the Anatolian data and IntCal09 in some important intervals (e.g. ~1729 to 1350 cal BC) and observes one period (9th?8th centuries BC) where there appears to be some indication of a regional/growing season signal, and another period (later 14th?13th centuries BC) where IntCal09 may not best reflect the real 14C record. The scale of the typical growing-season-related regional 14C offset (?R) between the Aegean/Anatolian region and IntCal09 is also assessed (for the mid-2nd millennium BC and mid-2nd millennium AD), and found to be usually minor (at times where there are no major additional forcing factors and/or issues with the IntCal09 data set): of the order of 2?4 ? 2?4 yr.

The olive-branch dating of the Santorini eruption

The date of the volcanic eruption of Santorini that caused extensive damage toMinoan Crete has been controversial since the 1980s. Some have placed the event in the late seventeenth century BC. Others have made the case for a younger date of around 1500 BC. A recent contribution to that controversy has been the dating of an olive tree branch preserved within the volcanic ash fall on Santorini. In this debate feature Paolo Cherubini and colleagues argue that the olive tree dating (which supports the older chronology) is unreliable on a number of grounds. There follows a response from the authors of that dating, and comments from other specialists, with a closing reply from Cherubini and his team.

Dating volcanic eruptions with tree-ring chemistry

Dendrochemical analyses of absolutely dated, overlapping sequences of tree rings allow identification of temporally conscribed, volcanically influenced periods of environmental change. Dendrochemistry, or the study of tree-ring elemental composition, is a promising new technique for reconstructing climate/environmental history at annual resolution. In particular, dendrochemistry may be useful for identifying periods of climatically and/or environmentally effective volcanic activity. Airborne pollution from major volcanic eruptions in the form of increased environmental acidity from sulfur dioxide can cause changes in availability and concentration of certain elements and can increase the availability of those elements in the soil, resulting in increased uptake by trees from the substrate or direct from the atmosphere. In particular, spikes, dips, or major changes in trace element concentration may be an indication of changes in soil or atmospheric chemistry (e.g., Padilla and Anderson 2002). Although there are other records of past volcanism (especially from ice-cores - e.g. Vinther et al. 2005), tree-ring based work (e.g. Salzer and Hughes 2007) offers several important advantages: first, tree-ring series are available with wide spatial coverage from most of the globe, and second, they are datable with annual and even subannual resolution on a fixed (absolute) calendar timescale (whereas even the best ice-core work has errors of several years or more beyond the last few hundred years).

Bronze Age catastrophe and modern controversy: dating the Santorini eruption

The date of the volcanic eruption of Santorini that caused extensive damage to Minoan Crete has been controversial since the 1980s. Some have placed the event in the late seventeenth century BC. Others have made the case for a younger date of around 1500 BC. A recent contribution to that controversy has been the dating of an olive tree branch preserved within the volcanic ash fall on Santorini. In this debate feature Paolo Cherubini and colleagues argue that the olive tree dating (which supports the older chronology) is unreliable on a number of grounds. There follows a response from the authors of that dating, and comments from other specialists, with a closing reply from Cherubini and his team.

Dendro-archeo-ecology in North America and Europe: Re-purposing Historical Materials to Study Ancient Human-Environment Interactions

The unique position of dendrochronology at the nexus of archeology, ecology, and climatology allows it to play a pivotal role in the study of past human-environment interactions. Yet, few tree-ring studies in Europe and eastern North America have been used to study pre-industrial land-use changes, forest ecology, and carbon dynamics and thus to constrain the uncertainties surrounding the Early Anthropocene hypothesis (Ruddiman Clim Chang 61:261–293, 2003; Rev Geophys 45(4):RG4001, 2007). Here, we discuss the potential of dendro-archeo-ecology—the use of dendroarcheological material in the study of forest ecology—to document past human land-use and forest alteration, which started in the Neolithic Era (∼12,000–4000 BP) in Europe and after European immigration into eastern North America in the 1620s. In this context, we focus on the dendro-archeo-ecology of (1) Neolithic pile dwellings in the Euro-Mediterranean region and (2) old-growth forest dynamics in eastern North America. We discuss recurring challenges (e.g., low sample depth, short series length) and uncertainties (e.g., species and tree size bias) related to the use of (pre)historic timbers for ecological purposes that need to be carefully addressed. We advocate for a concerted effort to move the use of dendro-archeological material from strictly archeological applications towards exploration of its ecological potential and for a close alliance of dendrochronology with related disciplines that aim to address the same subjects.

Medieval fishing structures and baskets at Sudbrook Point, severn estuary, Wales

AN UNUSUAL SYRINGE-LIKE OBJECT FROM AN EARLY ANGLO-SAXON CEMETERY IN CAMBRIDGESHIRE This note presents an extremely unusual artefact of possible medicinal function from an early medieval context and explores potential interpretations of it. In doing so, it highlights the complexity of identifying and understanding unique artefacts and demonstrates the limitations of establishing the relationship between unusual grave goods and the deceased in Anglo-Saxon burials. The early Anglo-Saxon cemetery at Gunthorpe, Peterborough (Cambridgeshire, NGR: TF 5186 3024) was excavated in 1987 by the Fenland Archaeological Trust in advance of development: the 31 inhumations and one possible cremation recovered were probably not the full extent of the cemetery. Analysis of the grave furnishings suggested that the burials dated from the 6th century ad and followed the typical early Anglo-Saxon dichotomy of weapons for adult males and jewellery for girls and adult females.1 Among the more unusual objects recovered was a lead artefact found in an undecorated accessory urn accompanying the single supine extended inhumation of an adult male,2 supported by the typical adult male grave-good assemblage (Grave F5) (Fig 1). The nature and significance of the bone shown next to the pot on the grave plan is uncertain. Out of anatomical position, it is unlikely be part of the deceased and is possibly a deliberate or accidental inclusion in the grave (there is no evidence of the grave cutting any others, however). The bone has not been retained as part of the small-find assemblage and Christine Osborne’s original human bone report does not mention it.MEDIEVAL FISHING STRUCTURES AND BASKETS AT SUDBROOK POINT, SEVERN ESTUARY, WALES The Severn Estuary contains some of the best-preserved evidence for historic fishing structures from the British Isles. The majority of these are medieval and later in date.122 During January 2007, storms and more than usually vigorous tidal currents scoured away the loose sediment from the foreshore at Sudbrook, located below the Welsh landfall of the Second Severn Crossing (Fig 18), revealing a range of exceptionally well-preserved medieval fishing structures. This is the most remarkable collection of such structures found to date in the Severn Estuary. The significance of these finds lies not just in the quantity of organic remains and the quality of their preservation, but in their variety, including several finely woven globular fishing baskets of a type never

Annual radiocarbon record indicates 16th century BCE date for the Thera eruption

New annual radiocarbon calibration data offer a resolution to controversial dating of the Bronze Age eruption of Thera. The mid-second millennium BCE eruption of Thera (Santorini) offers a critically important marker horizon to synchronize archaeological chronologies of the Aegean, Egypt, and the Near East and to anchor paleoenvironmental records from ice cores, speleothems, and lake sediments. Precise and accurate dating for the event has been the subject of many decades of research. Using calendar-dated tree rings, we created an annual resolution radiocarbon time series 1700–1500 BCE to validate, improve, or more clearly define the limitations for radiocarbon calibration of materials from key eruption contexts. Results show an offset from the international radiocarbon calibration curve, which indicates a shift in the calibrated age range for Thera toward the 16th century BCE. This finding sheds new light on the long-running debate focused on a discrepancy between radiocarbon (late 17th–early 16th century BCE) and archaeological (mid 16th–early 15th century BCE) dating evidence for Thera.

Beneath the Basilica of San Marco: New light on the origins of Venice

Abstract The origins of Venice have been of great interest to Venetians and to scholars more generally for centuries. Long shrouded in myth and legend due to the dearth of pre-ninth-century AD evidence, recent archaeological research is now illuminating how the famous city built on water began. Using high-resolution AMS dating of peach stones (pits) from below the Basilica of San Marco, the authors provide the first evidence for human activity at what is now the location of Piazza San Marco. Dating to between AD 650 and 770, this activity included canal in-filling and ground consolidation intended to create an area that was to become the citys civic centre in the early ninth century.