Holistic geoarchaeology in the Penobscot Valley,Maine, USA: context,scale, and interpretation

A holistic landscape approach to cultural resource analysis of a set of archaeological sites in the central Penobscot Valley led to inferences regarding the Holocene physical and biological environmental context. Targeted environmental studies include (1) examination of forest and wetland changes through time and (2) lake-level studies as a key to paleohydrology. These studies were combined with broad-scale geomorphic investigations and detailed stratigraphic analyses, and studies of archaeological sites and their artifact assemblages. Together, these studies provide a picture of dramatic changes to the physical and vegetational landscape. These included reestablishment of a major river following deglaciation, evolution of extensive lakes to uplands and peatlands, and a shifting mosaic of open and closed forest composed of a variety of hardwood and softwood species. Inferences based on buried soils exposed in archaeological excavations supported climatic interpretations based on vegetation and paleohydrology. As a result, this work allowed evaluation of (1) site formation and preservation processes and (2) occupational patterns. Site formation and preservation of Early Holocene sites can be linked to sedimentation by hydraulic damming upstream of rapids at the mouths of tributary streams. Shifting human land use reflected by changes in occupation patterns appears to correspond to changes in forest composition as well as wetland and stream evolution through time.     

Contacts under the lens: Perspectives on the role of microstratigraphy in archaeological research

Achieving an accurate perception of time and context remains a major challenge in archaeology. This paper highlights the potential benefits of microstratigraphic study to address this goal, drawing on case studies from Lower, Middle, and Upper Paleolithic, Neolithic, and Iron Age archaeological sites. First, we discuss the importance of site formation reconstruction and the ways in which current field methods approach the sedimentary record. Then, we focus on both field identification and high-resolution study of stratigraphic contacts, which are ubiquitous in archaeological deposits. Examples are presented to highlight the role of microstratigraphy in characterizing the nature of contacts and their significance for archaeological interpretation. A microstratigraphic approach is especially useful for distinguishing between contacts that originate from changes in depositional processes and contacts that form as a result of post-depositional processes such as pedogenesis, diagenesis, or burning. Further examples show how “invisible” anthropogenic surfaces and different kinds of occupation deposits can come to light at a microscopic scale of observation. Finally, we illustrate cases in which what appeared to be sterile layers in the field yielded anthropogenic elements. In the end, we discuss how archaeological projects might incorporate microstratigraphic analyses and their results within broader research frameworks that prioritize site formation process reconstruction.     

Garumele Revisited: Retracing Vanished Fired-Brick Elite Constructions and New Data on Settlement Foundation

Some of the most notable and largely endangered archaeological remains from the Lake Chad area consist of the ruins of fired-brick elite constructions connected to the Kanem-Borno Empire (ca. eighth–nineteenth century AD). In the course of the last 200 years, several of the elite structures known west of the lake were destroyed as a consequence of war, later having their fired-bricks looted for constructions elsewhere. One of the largest and most thoroughly plundered of those structures once stood within the walled settlement of Garumele, SW Niger Republic. In the scope of an experimental field study at that location and with a view to future work at related sites, we demonstrate that it is still possible to retrace the ground plans of Kanem-Borno fired-brick structures, even if these have been already completely pillaged. In addition, we present new chronological evidence suggesting that Garumele—as a walled urban settlement—was founded sometime between the mid-fifteenth and mid-seventeenth centuries, but most probably between the late sixteenth to mid-seventeenth centuries AD.     

The Pleistocene of Rabat (Morocco): Mollusks,Coastal Environments and Human Behavior

The Rabat-Témara region of the Moroccan Atlantic coast reveals a succession of Quaternary palaeobeaches. This coastal area is dotted with numerous prehistoric caves. The study of the Upper Pleistocene coastal landscape associated with these caves is of paramount importance in the knowledge of human population subsistence. During the Upper Pleistocene, the ocean level changes drastically influenced the coastal geomorphology as well as the fauna assemblages. The chrono-lithostratographical analysis of the coastal sedimentary formations allows the distinction of three sequences rich in marine fauna. These sequences date from MIS 11 to MIS 5. The identification of malacofauna species from these deposits revealed 39 species, along with Bryozoans, Crustaceans, and Echinoids. These assemblages show a constant fauna cortege highlighted by the dominance of the amphi-Atlantic species Stramonita haemastoma. This species shows an increase in the number of specimens in the uppermost part of marine deposits, probably in relation with a climate warming in the MIS 5. This fauna of both intertidal rocky substrates and sandy substratum indicates environmental conditions close to the present-day Rabat-Témara coastline. As in other coastal locations of Africa from MIS 5, the Middle Stone Age Homo sapiens population benefitted from a littoral environment rich in coastal resources. Comparison between thanatocenoses and archaeological records allows us to identify both species available for Middle Stone Age population and those preferred for human use.     

Luminescence characteristics and dose distributions for quartz and feldspar grains from Mumba rockshelter,Tanzania

Mumba rockshelter is a key archaeological site for the Middle and Later Stone Age occupation of East Africa, but its chronology has remained unresolved. We report the results of a dating study, focussing on the characterisation of the optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) properties of quartz- and potassium-rich feldspar grains. Quartz has previously proven troublesome for dating in East Africa. We identified five general types of quartz grain behaviour, based on the shapes of their OSL decay and dose–response curves. Dose recovery experiments and measurement of the natural samples revealed particular problems with quartz grains that had hyperbolic dose–response curves, low characteristic saturation doses and anomalously large changes in sensitivity between regenerative-dose cycles. The use of pulsed irradiation during measurement and standard and additional quality-assurance criteria during data analysis reduced the number of grains that suffered from these problems. We applied these procedures to individual grains of quartz from eight samples and, using appropriate statistical models, identified post-depositional mixing in three samples. The remaining samples had scattered equivalent-dose distributions typical of quartz grains that had received variable beta dose rates during burial. Stratigraphically consistent OSL ages were obtained for all but the deepest sample. Feldspar ages were estimated for the latter sample and three other samples, using the elevated temperature IRSL signal that exhibited low rates of anomalous fading. Fading-corrected feldspar ages for the latter three samples are consistent with their single-grain quartz ages, but single-grain dating is needed to address problems of post-depositional mixing.     

The Late Upper Palaeolithic Occupation of the Moroccan Northwest Maghreb During the Last Glacial Maximum

New work at Kehf el Hammar Cave provides the first well-dated palaeoenvironmental sequence for the Late Upper Palaeolithic in this region of the northwest Maghreb. The archaeological layers are dated via a combination of AMS radiocarbon and luminescence dating methods. The sequence contains charcoal-rich occupation layers with faunal, human and lithic finds. Local vegetational patterns are reconstructed on the basis of preliminary analysis of the charcoal evidence. Using standard calibration curves the AMS radiocarbon dates are compared with proxy evidence for climatic change from sea core records in the Alborán Sea. These appear to show that the Late Upper Palaeolithic occupation of the region coincides closely with Heinrich Event 1, a period marked by intense aridification and dating to ca. 16,700–17,250 calendar years ago.Les nouvelles recherches dans la grotte de Kehf el Hammar ont permis d’obtenir la première séquence paléoenevironnementale bien datée du Paléolithique supérieur tardif au Nord Ouest du Maghreb. En effet, les niveaux archéologiques ont été datés par le radiocarbone par accélérateur (AMS) et des méthodes radiométriques basées sur la luminescence. En revanche, les paléoenvironnements végétaux ont été partiellement reconstitués à base des premières analyses des charbons de bois. Les dates AMS calibrées ont été comparées aux données climatiques issues des carottes marines dans la mer Alborán. Ainsi, les occupations humaines du Paléolithique supérieur tardif dans la région ont sensiblement coïncidé avec l’événement climatique Heinrich 1. Celui-ci correspond à une période qui a été marquée par une aridification intense entre 16.700 et 17.250 ans (cal.).     

MODELLING OF RC MEMBERS UNDER CYCLIC BIAXIAL FLEXURE AND AXIAL FORCE

A model is proposed for the incremental force-deformation behaviour of reinforced concrete sections and members, under generalised load or deformation histories in 3D, including cyclic loading, up to ultimate deformation. At the section level the model is of the Bounding Surface type and accounts for the coupling between the two directions of bending and between them and the axial direction. For the construction of the member tangent flexibility matrix on the basis of the section tangent flexibility matrix, a piecewise-linear variation along the member is assumed for the nine terms of the tangent section flexibility matrix. Model parameters are derived on the basis of available test results for: (a) the force-deformation response under cyclic biaxial bending with normal force; (b) the hysteretic energy dissipation; (c) the secant-to-yield member stiffness, and (d) the ultimate deformation of the member under cyclic biaxial load paths.     

Earth science and archaeology

Rapp, George, Jr., and John A. Gifford. eds. Archaeological Geology. New Haven: Yale University Press, 1985. xvii + 435 pp. including figures, chapter references, appendix, and index. $35.00 cloth.

Stein, Julie K., and William R. Farrand, eds. Archaeological Sediments in Context. Orono: University of Maine, Center for the Study of Early Man, Peopling of the Americas Edited Volume Series 1, 1985. xi + 147 pp. including figures, chapter references, and index. $19.00 paper.