OPTICAL DATING OF ANTHROPOGENIC SEDIMENTS AT THE ARCHAEOLOGICAL SITE OF HERRENBRUNNENBUCKEL,BRETTEN-BAUERBACH (GERMANY)*

Optical dating was applied to natural and anthropogenic silts at an Iron Age settlement in southern Germany. The natural sediments were dated accurately and allowed study of the human impact on the landscape. The studied anthropogenic sediments were infills of cellars and ditches. Again, deposits derived from soil erosion proved to be datable using infrared-optically stimulated luminescence. However, optical dating of fine grained sediments was at its limits when sediments consisted of a mixture of bleached and unbleached grains. This is shown on sediments of known age originating from cellar infills. Improvements were obtained when using the 560 nm emission and a partial bleach approach. Experimental evidence shows that the D_E versus shine-time plot discloses insufficient bleaching only in cases in which all grains are insufficiently bleached to the same degree.     

Identification of pastoral sites using stable nitrogen and carbon isotopes from bulk sediment samples: a case study in modern and archaeological pastoral settlements in Kenya

The identification of pastoral sites in the East African archaeological record is problematic. Recently, a method for the identification of degraded livestock enclosure sediments had been developed that takes into account the geoarchaeological indicators of micromorphology, phytolith concentrations and the mineral assemblages. This suite of indicators may not always be present in degraded livestock enclosure sediments. This study presents an additional indicator by which degraded livestock enclosure sediments may be identified, namely the isotopic composition of organic nitrogen measured on bulk sediment samples. We studied a highly controlled ethnoarchaeological sequence of abandoned Maasai livestock enclosure sediments sampled in Rombo area, southern Kenya. The results were compared to archaeological sediments from the Elmenteitan Pastoral Neolithic site of Sugenya, southwestern Kenya, radiocarbon dated to ca. 2000 BP (uncalibrated). The sediments from both sites were studied using all four types of analyses, i.e., micromorphology, mineralogy, phytolith concentrations, and stable carbon and nitrogen isotopic compositions on bulk sediment samples. The results show that in abandoned livestock enclosure sediments of known ages a significant enrichment in the heavy nitrogen isotope (¹⁵N) occurs, and that carbon isotopic compositions may be useful for differentiating cattle from caprine enclosures following their dietary preferences (i.e., grazers vs. browsers). A similar pattern of ¹⁵N enrichment is observed in sediments sampled within the site of Sugenya while sediments sampled outside the site's perimeter are generally depleted in ¹⁵N. The micromorphological, mineralogical and phytolith analyses support the conclusion that the sediments from within the site of Sugenya represent degraded livestock enclosure sediments. The carbon isotopic composition from the degraded dung deposits strongly suggests that livestock kept at Sugenya were cattle. Overall, this study presents new empirical data that can be used for the identification of livestock enclosures, and shows that the isotopic signatures and geoarchaeological indicators can preserve for at least two millennia.     

Sediments exposed to high temperatures: reconstructing pyrotechnological processes in Late Bronze and Iron Age Strata at Tel Dor (Israel)

Many of the sediments analysed from Tel Dor (Israel) show structural alterations indicating that they were exposed to high temperatures. This observation is consistent with the abundant evidence for use of pyrotechnology from the earliest exposed Middle Bronze Age strata through the Roman period. Such structurally altered sediments may well represent one of the more widespread and durable records of pyrotechnology, and as such could be invaluable for reconstructing past human activities. The specific aims of this research are therefore to develop the means for identifying local sediments that were altered by different pyrotechnological activities and to elucidate the varying circumstances whereby sediments were exposed to high temperatures in a Late Bronze and Iron Age 1 section.     

PALAEOMAGNETIC AND MINERAL MAGNETIC STUDIES OF SEDIMENTS FROM PETRALONA CAVE,GREECE

Palaeomagnetic measurements on sediments from Petralona cave. Greece indicate a stable, single component remanence of normal polarity. Redeposition experiments established the ability of the sediments to acquire the direction of the geomagnetic field. Magnetic properties and Mössbauer spectra of sediments and magnetic concentrates show that magnetite, which is slightly non-stoichiometric, and haematite are present in the sediments from the cave. The magnetite dominates the magnetic properties and exhibits pseudosingle domain behaviour. Using rstimated deposition rates for the sediments in the cave. and the fact that U Th and ESR dates which can be stratigraphically correlated to the palaeomagnetic section range from 200 to 750 ka. implies that the section represents a time span of about 150 180 ka within the Brunhes epoch. From this. the age of a human cranium found in the cave 25 years ago is estimated to be not older than 620 ka.     

Diverse origins and timing of formation of basinal brines in the Gulf of Mexico sedimentary basin

A review of five different field areas in the Gulf of Mexico sedimentary basin (GOM) illustrates some of the potentially diverse chemical and physical processes which have produced basinal brines. The elevated salinities of most of the formation waters in the GOM are ultimately related to the presence of the Middle Jurassic Louann Salt. Some of these brines likely inherited their salinity from evaporated Mesozoic seawater, while other saline fluids have been produced by subsequent dissolution of salt, some of which is occurring today. The timing of the generation of brines has thus not been restricted to the Middle Jurassic. The mechanisms of solute transport that have introduced brines throughout much of the sedimentary section of the GOM are not entirely understood. Free convection driven by spatial variations in formation water temperature and salinity is undoubtedly occurring around some salt structures. However, the driving mechanisms for the broad, diffusive upward solute transport in the northern Gulf rim of Arkansas and northern Louisiana are not known. In the Lower Cretaceous of Texas, fluid flow was much more highly focused, and perhaps episodic. It is clear that many areas of the Gulf basin are hydrologically connected and that large‐scale fluid flow, solute transport, and dispersion have occurred. The Na‐Mg‐Ca‐Cl compositions of brines in the areas of the Gulf Coast sedimentary basin reviewed in this article are products of diagenesis and do not reflect the composition of the evaporated marine waters present at the time of sediment deposition. Large differences in Na, Ca, and Mg trends for waters hosted by Mesozoic versus Cenozoic sediments may reflect differences in: (i) the sources of salinity (evaporated seawater for some of the Mesozoic sediments, dissolution of salt for some of the Cenozoic sediments); (ii) sediment lithology (dominantly carbonates for much of the Mesozoic sediments, and dominantly siliciclastics for the Cenozoic sediments); or (iii) residence times of brines associated with these sediments (tens of millions of years versus perhaps days).     

FIFTY YEARS OF LUMINESCENCE DATING*

Luminescence techniques for dating both heated materials (e.g., pottery and burnt stone) and sediments have gone through three phases in the past 50 years. The first 22 years, from 1957 to 1979, were devoted to thermoluminescence (TL) techniques applied to heated material. In the next six years, from 1979 to 1985, it was found that TL dating could be applied to sediments. However, the TL signals of both quartz and feldspar grains observed for modern sediments were small, but were not zero, thus making them useful only for older sediments. A new luminescence signal that was totally zeroed by exposure to sunlight for a relatively short period of time, a few hours or less, was found; this led to the development of optically stimulated luminescence (OSL) dating techniques in 1985. Further developments have continued to the present day. Within the past 22 years, 1999 was also a year with major developments. A reliable procedure for single aliquots of quartz that have a rapidly bleached (‘fast’) OSL component was formalized and an instrument that allowed rapid measurement of equivalent doses for single grains was constructed. These developments have led to OSL becoming a major dating tool in Quaternary geology, at least for the past 100 000 years, and in archaeology, particularly as related to the dispersal of modern humans.     

Reconstruction of Fire History Using ‘Dry’ Sediments,An Approach for Microcharcoal Studies from the Sierras Pampeanas,NW Argentina

A new accessible and easy method for studying past fire events using ‘dry sediments’ is presented. The method was developed for analysing samples from 17 locations in the Ambato Valley, NW Argentina, to study fire regimes in the area. Based on earlier researchers’ methods, guidelines to use microcharcoals in ‘dry’ sediments as a palaeoenvironmental proxy are provided. The procedures outlined include sampling/extraction in the field, preparations of the samples, laboratory analysis and quantification of the samples. The new approach was useful to meet the objectives and answer the questions initially proposed in our research about past fire regimes affecting the past Aguada society.     

The Accumulation of Silica in Lakes

On the basis of available data on recent and fossil lake sediments with a high content of authigenic silica—diatomite—an attempt is made to identify those factors in the surrounding landscape and in the lake environment that account for the formation of these siliceous sediments. The presence of cause-and-effect relationships and the wide distribution of siliceous lake sediments, both at present and in the geological past, suggest that diatomite lakes can be treated as a distinctive lake type in a lake typology and limnological regionalization previously proposed by the author.     

THE USE OF TEXTURAL PARAMETERS IN THE ANALYSIS OF CAVE SEDIMENTS

This paper considers the presentation of the results of the mechanical analysis of cave sediments, suggesting that the use of grain size parameter scatter diagrams is preferable to the older method of cumulative percentage frequency graphs. A sequence of samples was taken from an ideally-situated cave, the Badger Hole at Wookey, and first subjected to the standard soil analytical tests, followed by a detailed mechanical analysis. It is hoped that this preliminary work will encourage a more quantitative approach to granulometric analysis for archaeological purposes, leading eventually to the extraction of more precise environmental data from cave sediments.     

ESR dose response of Al center measured in quartz samples from the Yellow River (China): Implications for the dating of Upper Pleistocene sediment

The ESR dating method requires to describe the evolution of the ESR signal intensities vs. increasing gamma doses, then to extrapolate the equivalent dose of radiation received by the sample since its deposition using mathematical fitting. The function classically used to describe the growth curves of ESR aluminium signal in quartz was recently discussed and challenged for Lower Pleistocene sediments. In the present work, some alluvial sediments sampled in Upper Pleistocene fluvial terraces of the Yellow River system (China) permit us to test the application of another extrapolation function (linear + exponential) recently proposed for Lower Pleistocene sediments. The equivalent doses obtained here for the recent deposits of the Yellow River system and the corresponding ages are promising and indicate the potential of ESR to date quartz deposits from Upper Pleistocene times.     

Development of quartz cathodoluminescence for the geological grouping of archaeological ceramics: firing effects and data analysis

Cathodoluminescence (CL) spectrometry reveals genetic crystallographic and chemical characteristics of quartz grains specific to the thermodynamic conditions in which they crystallised and their mineralisation history. These genetic characteristics have been used successfully to determine the provenance of sediments. Geological sediments are the raw material for archaeological ceramics which means quartz CL has a potential application in ceramic provenance studies, particularly for fine wares and fabrics in which quartz is the only identifiable inclusion.     

Absolute dating of hominids and palaeolithic artifacts of the cave of La Chaise-de-Vouthon (Charente), France

Two adjacent chambers of the cave of La Chaise, Grotte de Bourgeois-Delaunay (B-D) and Grotte Suard, have been studied. Both were partly filled with detrital sediments containing lower and middle Palaeolithic artifacts and skeletal remains of pre-Neanderthalian hominids. Layers of stalagmitic calcite occur interstratified in the sediments of both chambers. Dates obtained by ²³⁰Th/²³⁴U ratios have provided a time scale for hominid and cultural evolution as represented in this cave.In B-D the lower travertine rests on a breccia containing cranial remains of juvenile Neanderthals. The base of the travertine dates to 151 ± 15 Ky (Ky = 1000 years BP); the top of the travertine yields a date of 112±5 Ky. The travertine contains pollen of an interglacial flora. Overlying detrital sediments 1·2 m in thickness contain artifacts transitional from Acheulian to Mousterian industries. They are capped by a travertine (Layer 7) whose base is dated at 100±6 Ky, and which is capped by stalagmites ranging in age down to 58±7 Ky. Overlying the travertine is sediment containing first Mousterian, and then Aurignacian artifacts.Near the base of the sediments filling Grotte Suard is a stalagmite layer dated to 249±30 Ky. It contains interglacial pollen and presumably dates to the beginning of the isotope stage 7 interglacial. Neanderthaloid hominid teeth and cranial fragments are found scattered through the overlying sediments, up to a capping stalagmitic layer whose base is dated at 101±7 Ky. The best described hominids from Suard are from a section that was probably overlying the capping stalagmite. The capping stalagmite is temporally correlated with layer 7 of B-D.     

OPTICAL DATING RESULTS FOR BRITISH ARCHAEOLOGICAL SEDIMENTS

In this paper optical dating results for a range of British archaeological sediments are presented to illustrate the potential this method offers for archaeologists. The optical dating is shown to offer an absolute method for directly dating the deposition of sediments for an age range of approximately 1–300ka. Problems have been found with recuperation of the optically stimulated luminescence signal and insufficient bleaching at deposition of the sediment. A suitable correction method for the recuperation has been found and a method of identifying insufficient bleaching is suggested.     

Archaeopedological analyses around a Neolithic hearth and the beginning of Sabaean irrigation in the oasis of Ma'rib (Ramlat as-Sab'atayn,Yemen)

Archaeopedological analyses in the oasis of Ma'rib (Yemen) yield new information of Neolithic land use, Bronze Age soil formation, and Sabaean irrigation. The AMS radiocarbon age of a Neolithic fireplace buried under Sabaean irrigation sediments in the Southern oasis indicates Pre-Sabaean human activities in Wadi Dhana about 5600 years ago. The associated Mid-Holocene palaeosol, developed in fluvial sediments of Wadi Dhana and also in the filling of the hearth, marks the Bronze Age-land surface before it was covered with irrigation sediments. Based on AMS radiocarbon data from charcoal in reservoir sediments of the “Great Dam” and an estimated time span of pedogenesis of the Mid-Holocene palaeosol in this region, we propose the beginning of the irrigation in Ma'rib in the period of 2500–1000 cal yr BC.     

Trace Metal Distribution Within Marine and Estuarine Sediments of Western Moreton Bay,Queensland, Australia: Relation to Land Use and Setting

This broad‐scale investigation provides an overview of trace metal concentration and distribution within sediments in the subtropical setting of Moreton Bay on the eastern Australian coast. Samples of sediment in one‐metre long PVC cores were collected from the intertidal zone of the western shoreline of the Bay and within its main estuaries. The material is typically silty sand along the Bay shoreline, becoming more clayey within the estuaries. Downcore pH is typically between 7.0 and 8.0, with layers in some cores of pH 6.0 to 7.0. Locally, pH can fall below 5.0 due to pyrite oxidation or exceed 8.0 due to the presence of shell fragments. A comparison with results of similar studies in other highly populated centres in Australia shows that overall the Moreton Bay area sediments have relatively low metal content. Typically, concentrations are two to three times higher in fine‐grained, estuarine sediments than in sandy material along the Bay shoreline. Compared with Australian and New Zealand Environment and Conservation Council Guidelines for metal concentrations in sediments, the elements most commonly elevated and warranting further assessment are Ni, Hg, Pb, Zn, and occasionally Cd, As and Cr. The highest metal concentrations are found in estuaries, close to more populated or industrialised areas, notably along the Brisbane River. Overall, the distribution of metals in unconsolidated material is controlled by (a) the heavy metal affinity for Fe‐ and Mn‐rich oxidised sediments, (b) grain size, (c) background concentrations in local rocks, and (d) conditions of weathering and deposition. For example, natural elevation of Fe occurs in marine sediments adjacent to areas of Tertiary basalts and this has produced a relative increase in a number of trace metals in those sediments. Typically, trace metals correlate well with Al, and with Fe and Mn oxyhydroxides. The results of this study show that in the western Moreton Bay region, natural controls have the major influence over metal distribution; although urban and industrial inputs exist, for much of the area they are secondary. The main sources of introduced trace metals are presumed to be light industry (such as maritime and port facilities, petroleum refineries and storage, manufacturing and chemical processes), landfills, agriculture and intensive fertilising (for example, golf courses) as well as the composite effect of urban centres. Overall, higher concentrations of metals are closely related to intense development. If specific locations are targeted for focussed sampling, elevated concentrations of metals are likely to be found locally.     

Degradation of mud brick houses in an arid environment: a geoarchaeological model

A common assumption in Near Eastern tell archaeology is that the majority of sediments originate from degraded mud bricks. Little is known about the mechanism of mud brick wall degradation. Here we present a detailed macro- and microscopic ethnoarchaeological study of the degradation of a mud brick house and propose a comprehensive mechanism for tell formation processes in arid environments. The study took place in southern Israel by trenching a ca. 60 year old abandoned mud brick house, followed by extensive sediment sampling. Macroscopic observations showed that mud brick walls degrade by collapse of single bricks and/or collapse of intact wall parts, either inwards or outwards. In addition, infill sediments within the house and outside it, in close proximity to its walls, form alternating sedimentary layers of various colors and textures. The degraded mud brick material lost its distinctive macroscopic structure, which makes it impossible to accurately identify this material by field observations alone. Mineralogical and elemental analyses established the sources of the house infill sediments, namely mud bricks and wind blown sediments. Alternating layers mostly originate from mixing between degraded mud brick material and wind blown sediments. Micromorphological observations revealed microscopic mechanisms of mud brick degradation and include processes of mud slurry gravity flows, sediment coatings and infillings, wind abrasion of walls, small-scale puddling, and bioturbation. This study provides a working scheme for site formation of abandoned mud brick structures in arid environments. It provides a set of criteria by which it is possible to differentiate floors from post-abandonment sedimentary features and thus improves the reliability of activity area research.     

Progress in the holocene chrono-climatostratigraphy of Polish territory

The Holocene delivers a unique possibility to establish climatic stratigraphic boundaries based on detailed chronostratigraphy reflected in various facies of continental sediments, in their lithological parameters and organic remains. These sediments are dated by the ¹⁴C method in the case of organic remains, by counting annual laminations in lacustrine facies, and by dendrochronological method in the case of fluvial sediments. The existence of well dated profiles enables to reconstruct various climatic parameters like amplitudes of seasonal temperatures, types and frequency of extreme rainfalls and floods and, finally, to distinguish rare rapid changes and most frequent gradual ones. This reconstruction is based on the analogous effects of various types of present-day rainfalls. The current authors present a critical review of existing chronostratigraphic divisions starting from simple millennial division by Mangerud based on Scandinavian palynological stratigraphy of peat-bogs and Starkel’s concept based on fluctuations in rainfall and runoff regime reflected in fluvial and other facies of continental deposits. In the last decades, the calibration of ¹⁴C dates allowed a new approach to be used for the construction of the probability distribution function of these dates in various facies or types of sediments, which formed a background for distinguishing and correlating climatic phases and defining boundaries between them. These approaches have been creating new opportunities for revision of the existing chronostratigraphy. The aim of this paper is to present a revised version of chronostratigraphic division based on climatic fluctuations reflected in various facies of sediments on the territory of Poland and discuss their correlation with other European regions and global climatic changes.     

Geo-Ethnoarchaeology of Pastoral Sites: The Identification of Livestock Enclosures in Abandoned Maasai Settlements

The earliest food producers in Africa were mobile pastoralists who left limited archaeological traces. As a result archaeologists studying the spread of food production in the region have difficulty distinguishing early pastoralists from hunter-gatherers with whom they interacted. This geo-ethnoarchaeological study contributes to the resolution of the problem through identification of sediments distinctive of livestock enclosures, and thus of pastoral settlements. Sediments were sampled in and around currently occupied and recently abandoned Maasai livestock enclosures ranging in age between one and 40 years. Twenty to thirty years after site abandonment, there is no visible difference between enclosure and regional sediments. Micromorphological, mineralogical, and phytolith analyses, of enclosure sediments, however, allow differentiation of enclosure from regional sediments. Our results show that a unique undulating microlaminated structure is distinctive of enclosure sediments. Enclosure sediments, especially small stock, also contain a rare mineral, monohydrocalcite (CaCO₃ . H₂O). In addition, large amounts of opal (SiO₂ . nH₂O), in the form of phytoliths, are found in enclosure relative to regional sediments. These differences are likely to be preserved in the archaeological record, and this approach will allow better understanding of the spread of pastoralism in Africa and elsewhere.     

Archaeological sedimentology of overbank silt deposits on the floodplain of the Ohio river near Louisville,Kentucky

The surface of the floodplain of the Ohio River about 20km southwest of Louisville, Kentucky, is a series of linear ridges and swales that are subparallel to the channel of the river, which here is relatively straight and flows southward. Numerous prehistoric occupational sites are located on these ridges. The sediments that underlie the ridges, which were examined in four archaeological excavations as deep as 8 m, are predominantly sandy silt and silty fine to very fine sand and appear to be mainly the product of overbank deposition from suspended load. Abundant cultural material and occupational sites dating as early as 10,000 years BP are found in the sediments at depths as great as 6·5 m. The fine sediments of the floodplain are underlain by sand and gravel.The context of the cultural materials and the stratigraphy and morphology of the deposits indicate that the ridged deposits began as linear riverside sand and gravel bars. These were succeeded upward by fine-grained overbank deposits in which the ridged morphology was maintained because the overbank silt and fine sand were deposited as prograding elongate bars at high water. As the floodplain ridge built upward, the sedimentation rate decreased and the sand content of the sediments diminished, and as the river channel occasionally shifted, the ridged deposits were built in successive subparallel sequences.Two archaeological consequences are implicit in this depositional model of orderly growth of the floodplain. First, available archaeological data from floodplain segments along other parts of the river should confirm the model; and second, the model should make it possible to search the floodplains of the Ohio River for stratified sites of any desired age.