Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza,Argentina)

Well constrained numerical ages of alluvial fan sediments are key to understanding the chronology of alluvial episodes and tectonic activity at the front of the Andean Precordillera. We tested the application of radiocarbon and optically stimulated luminescence (OSL) dating in the distal part of an alluvial fan five kilometers north of Mendoza. For OSL dating a large number of aliquots (n > 70) — each composed of ∼50 quartz grains — were measured in order to obtain reliable burial ages despite scattered dose distributions. Owing to a feldspar contamination in all samples, an infrared stimulation was inserted before each OSL measurement, which reduced the feldspar OSL signal successfully. By using the minimum age model we obtained stratigraphically consistent burial ages of alluvial deposits in a depth profile. The uppermost ∼1 m of sediment is composed of debris flow deposits buried 770±76 years ago. Three plant remnants used for radiocarbon dating from the same layer, however, yielded ages younger than 350 years, which are interpreted to underestimate the depositional age. Underneath the debris flow, a major unconformity cuts a series of distal alluvial fan sediments with interstratified floodplain deposits, which are composed of sandy and calciterich silt layers, respectively. Three samples from this unit which were distributed over one meter of sediment thickness yielded statistically concordant OSL ages of 12.3±1.2 ka, 12.3±1.2 ka, and 11.7±1.1 ka. The deposition of these sediments during the latest Pleistocene coincides with a phase of cool and humid climate, which occurred before the alluvial fan propagated farther into the foreland. The overlying debris flow sediments are associated with alluvial fan incision during the arid Late Holocene.     

Proposing new approaches for dating young volcanic eruptions by luminescence methods

The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.     

Multidisciplinary analysis of a mummified cranium claimed to be that of a medieval execution victim

This article presents a multidisciplinary analysis of a human skull with preserved soft tissue curated by a small museum in Boscastle, Cornwall, UK. The skull lacks a mandible and is coated in a black tar-like substance. Records left by a previous museum curator (now deceased) claimed the skull to be the head of a medieval execution victim. The skull was purportedly recovered from a London church that was destroyed during the Second World War where it had been kept in a carved oak box. If these details are correct, the skull would appear to have been venerated as a relic. The skull and box have been analysed using a range of techniques including computerised tomography, laser scanning, microscopy, infrared spectroscopy and radiocarbon dating. These analyses demonstrated the skull in fact to be that of an Egyptian mummy dating from the Ptolemaic period. Other instances have been noted of parts of Egyptian mummies being presented as European saintly relics, and the ‘Boscastle skull’ would appear to be an example of such. A wider point illustrated by the work presented here is that sufficient application of modern analytical techniques may reveal considerable information regarding human remains which otherwise have little or no provenance. This point strengthens arguments for the retention of such remains by curating institutions.     

硼氢化钾对于氧化纸质文物的还原作用研究

纸质文物的病害主要来自纤维素的水解和氧化。对于纸质文物的保护通常采取脱酸处理,但对于纤维素的氧化病害并没有起到作用。本文提出在纸质文物的保护处理中加入硼氢化钾作为还原剂,重点作用于纤维素氧化造成的病害。通过还原作用使纤维素分子链上的氢键作用得以恢复,进而达到提高纤维自身强度的目的。本文开展一系列实验研究,通过pH值、色差的改变,以及羰基含量变化和纤维素结晶度对研究硼氢化钾的还原作用效果进行综合评价。     

Powerful Pots,Humbling Holes,and Regional Ritual Processes: Towards an Archaeology of Huedan Vodun,ca. 1650–1727

Situated along the “Slave Coast” of West Africa, the international coastal trading entrepôt of Ouidah is infamous as the point of embarkation for hundreds of thousands of people spirited into the Middle Passage. Accordingly, scholars have looked to it and the surrounding region as a font of culture and history for diasporic groups. In scholarly narratives, the larger Gbe-speaking region surrounding Ouidah is characterized as the homeland of Vodun, a religious tradition that influenced diasporic religions throughout the Atlantic world. This paper explores early Huedan Vodun at a local level and works to bolster, and at the same time problematize, the project of addressing Vodun at increasing geographic scales and temporal depths. It builds on longstanding research which recognizes that context is critical for interpreting possible ritual or religious significance of archaeological material.     

Variability in Eritrea and the Archaeology of the Northern Horn During the First Millennium BC: Subsistence,Ritual, and Gold Production

Around the margins of Asmara, Eritrea, hundreds of sites dating to the early and mid-first millennium BC have been documented. They range from single family dwellings to small and large hamlets, small and large villages, and small towns. We call these Ancient Ona sites, using the Tigrinya term for ruin. Our findings testify to significant subsistence, ritual, and economic variation within a region of 12 by 17 km: (1) different subsistence strategies in the well-watered, open basin to the west of Asmara (emmer wheat, barley; cattle) compared to the uplands north and east of Asmara (lentil, teff; goats/sheep); (2) ritual events, marked by stone bulls' heads and a huge ash deposit at Sembel Kushet, that brought people together in rites of passage and intensification during Meskel-like ceremonies, including ritual exchange; and (3) the exploitation of gold north of Asmara among heterarchically organized communities that exchanged specialized products within this region.