Rosa M. Albert

Phytolith analysis on dental calculus, enamel surface, and burial soil: Information about diet and paleoenvironment

Silica phytoliths (microscopic remains originating in plant tissues) have been identified on the enamel surface and dental calculus of a sample of teeth selected from well preserved skeletons from a Late Roman necropolis in Tarragona (Spain). Phytoliths were observed by scanning electron microscopy (SEM) and their siliceous nature was confirmed by X-ray microanalysis. The phytoliths were compared to those of soil samples from both the areas of the tombs corresponding to the abdomen and the periphery of the skeletons, and were classified taxonomically by comparison with a large collection of silica particles from modern plants in the Mediterranean area. Most of the phytoliths identified on the enamel and the dental calculus belong to the family of Poaceae, while the phytoliths from the abdominal area belong to Poaceae, Leguminosae, Cyperaceae, and Chenopodiaceae. Results are concordant with archaeological, ecological, and historical data from the same site, and with the human Mediterranean diet. If done properly, the study of phytoliths can provide direct information about the vegetable diet of past human populations, and could be applied to the study of human fossils.

Landscape distribution of Oldowan stone artifact assemblages across the fault compartments of the eastern Olduvai Lake Basin during early lowermost Bed II times.

The density and composition of Oldowan stone artifact assemblages deposited during the first ca. 20,000 years of lowermost Bed II times show a recurrent pattern of variation across recognized synsedimentary faults that compartmentalized landscapes of the eastern Olduvai Lake Basin. When active, the faults created minor topographic relief. The upthrown fault footwalls accumulated assemblages with relatively high densities of artifacts, including types retaining potential usefulness, particularly volcanic flaked pieces, manuports, pounded pieces, and split cobbles. Values for these assemblage characteristics decline toward the lower-lying hangingwall of the fault compartments, accompanied by an increase in the proportionate weight of artifact assemblages comprising quartzite, particularly flaking shatter and potentially useful detached pieces. Values reverse once again at faults, either on the downthrown, hangingwall side or on the upthrown side. The patterns are stronger for the volcanic components of the artifact assemblages than for the quartzite components, reflecting the additional influence of distance from the local source on quartzite assemblage characteristics reported previously. The landscape distributions of artifact assemblages are consistent with a landscape-fault model in which minor fault-induced topographic relief at times created a mosaic of vegetation environments repeated within each of the three fault compartments of the lake margin and distal alluvial fan. The fault-compartmentalized landscape model is currently supported only by sediment thickness and facies changes across synsedimentary faults, but it provides predictions for spatial variation in the cover abundance of trees, freshwater reservoirs and associated distributions of resources and hazards associated with stone artifact use and discard that can be tested if sample sizes of key paleoenvironmental indicators are increased.

Vegetation during UMBI and deposition of Tuff IF at Olduvai Gorge, Tanzania (ca. 1.8 Ma) based on phytoliths and plant remains.

As part of ongoing research at Olduvai Gorge, Tanzania, to determine the detailed paleoenvironmental setting during Bed I and Bed II times and occupation of the basin by early hominins, we present the results of phytolith analyses of Tuff IF which is the uppermost unit of Bed I. Phytoliths were identified in most of the levels and localities on the eastern paleolake margin, but there are not always sufficient numbers of identifiable morphologies to infer the specific type of vegetation due to dissolution. Some surge surfaces and reworked tuff surfaces were vegetated between successive ash falls, as indicated by root-markings and the presence of a variety of phytolith morphotypes. Dicotyledonous wood/bark types were dominant except at the FLK N site just above Tuff IF when monocots are dominant and for the palm-dominated sample from the reworked channel cutting down into Tuff IF at FLK N. The area between the two fault scarps bounding the HWK Compartment, approximately 1 km wide, was vegetated at various time intervals between some of the surges and during the reworking of the Tuff. By lowermost Bed II times the eastern margin was fully vegetated again. Climate and tectonic activity probably controlled the fluctuating lake levels but locally the paleorelief and drainage were probably the controlling factors for the vegetation changes. These data support a scenario of small groups of hominins making brief visits to the paleolake during uppermost Bed I times, followed by a more desirable vegetative environment during lowermost Bed II times.

Fire in prehistory: an experimental approach to combustion processes and phytolith remains.

Albert, R.M. and Cabanes, D. 2007. Fire in prehistory: An experimental ap proach to combustion processes and phytolith remains. Isr. J. Earth sci. 56: 175–189. Silica phytoliths are commonly found in hearths as a result of the combustion of plants. Their study in prehistoric hearths has enabled the identification of fire remains not visible to the naked eye due to the postdepositional processes. It has also enabled determination of the type of fuel used for the fires, and a better understanding of the functionality of hearths. However, little work has been done on understanding the combustion properties of fires and their relationship to the amount, distribution, and preservation of burned phytolith remains. We present here results of experiments carried out to shed more light on these questions. These results indicate that there are important differences in the combustion properties of fires. The remaining burned residues of the combustion depend on the use of naturally-dried or fresh fuel. These differences are related to the relationship between the presence of ash and charcoal fragments, the proportion of the acid-insoluble fraction, the amount and morphological distribution of phytoliths in the different fractions, and the refractive indices of the phytoliths. To recognize these properties it is essential to sieve the samples into different size fractions prior to the phytolith and mineralogical study. Postdepositional processes need to be taken into account as well when analyzing archaeological fire remains. The preference of one type of fuel over the other may have important implications related to the collection strategies and the proximity of available resources, as well as to the various possible uses of caves.

Bamboo feeding and tooth wear of three sika deer (Cervus nippon) populations from northern Japan

Abstract Sika deer (Cervus nippon) in the Japanese archipelago are cervids known to have high ecological plasticity, which is reflected in latitudinal variation in their feeding habits. The northern populations are grazers that depend on dwarf bamboos, whereas the southern ones feed on browse and fruits. These differences in plant composition of the diet should affect the tooth wear patterns because the different plants have different concentrations and morphologies of phytoliths (microscopic silica bodies that precipitate in and around cells in many plants). We studied 2 mainland populations (Mt. Goyo and Oshika Peninsula) and 1 island population (Kinkazan Island) of sika deer from northern Japan to understand how dwarf bamboo (Sasa nipponica and Sasamorpha borealis) affects tooth wear on the mainland populations in comparison to the lawn grass (Zoysia japonica) consumed by the island population. Fruits are not considered in this study because only northern populations are examined. The combined analyzes of tooth mesowear and microwear permitted us to detect seasonal differences in the feeding habits of sika deer. The tooth wear pattern also reflected differences directly related to the type of plant ingested. The grass Zoysia japonica, available on Kinkazan Island, had a highly abrasive effect on sika deer enamel. The bamboo species S. nipponica and S. borealis, more abundant on the Mt. Goyo and Oshika Peninsula areas, respectively, were less abrasive than Z. japonica. Differences also were detected in the wear patterns produced by the 2 species of bamboo. Tooth mesowear suggests that S. nipponica is more abrasive than S. borealis, which was confirmed by the high phytolith content found in the plant, especially in the stem of S. nipponica, the part consumed by the sika deer in late winter.

Neanderthal use of plants and past vegetation reconstruction at the Middle Paleolithic site of Abrigo de la Quebrada (Chelva, Valencia, Spain)

Despite phytoliths having been used to understand past human use of plants and palaeoenvironment in Middle Paleolithic sites, little is known on this aspect in the well-documented central region of Mediterranean Iberia. This paper presents the first phytolith and mineralogical study conducted at Abrigo de la Quebrada (Chelva, Valencia). Forty-one samples were analyzed through phytoliths and Fourier transform infrared spectroscopy (FTIR) from different areas, stratigraphic levels, and archeological contexts (hearth, hearth-related, and non-hearth-related sediments) of the shelter. The results obtained point towards a different pattern of preservation in the site depending firstly on the stratigraphy and secondly on the area where the samples were collected. Postdepositional processes that may have chemically affected phytolith preservation are discussed. Grasses are the main plant component identified in all the samples while woody plants are scarce. The abundance of grasses in the non-hearth-related sediments might be related, at least partially, to the dispersion of ashes from hearths, as indicated by the FTIR results. The results are indicative of an occupation of the site during the spring-autumn season. At this time, the area would be dominated by a semi-open environment with supramediterranean vegetation.

Tracing microfossil residues of cereal processing in the archaeobotanical record: an experimental approach

Interdisciplinary methodological approaches are fundamental for studying tool use and crop processing patterns in the archaeological record. Many archaeological studies of plant microfossil evidence, primarily those of phytoliths, starch grains and pollen, are concerned with processing methods which can be replicated through experimentally produced plant residues. However, most of these studies rely on crop identification through the presence or absence of such microfossils while giving little or hardly any weight to taphonomy and formation processes, which are critical for interpreting archaeological contexts. An investigation of experimentally produced phytolith and pollen assemblages provides the opportunity to evaluate the impact of cereal processing on both microfossils. Controlled experiments were conducted at the Museum of Menorca, Balearic Islands, Spain, for assessing microfossil taphonomy using Iron Age Talayotic tools and Hordeum vulgare (hulled barley) grown nowadays on the island. For dehusking, a sandstone mortar and a wooden pestle were used outdoors, whereas grinding took place indoors using a limestone quern and handstone. The results indicate that the size of multicellular or anatomically connected phytoliths decreases as a result of mechanical degradation suffered through processing activities, whereas the proportion of cereal pollen grains increases through these processes. Additionally, experimental samples from dehusking and sieving provided abundant evidence of floral bracts, and also of other plant parts and even different plant species, such as phytoliths from leaves and stems and non cereal pollen taxa, which were also to be found on the surfaces of the ground stone tools. These findings highlight the importance of integrating different lines of microfossil evidence and taking into account formation and taphonomic aspects, as well as the value of experimentally produced data for a better understanding of tool use and crop processing.

Anthropocene and early human behavior

When is the baseline for Anthropocene? The first indications of human impact on earth closely relate to early human behavior and use of resources. First agricultural societies modified the landscape with the aim of generating their own resources to satisfy the needs of an increasing population. This new system was the result of years of learning and continuous interaction with landscape. Hunter-gatherer societies had shown a vast knowledge of their surrounding environment, which allowed them to exploit and optimize the available resources. But, had these societies the capacity to modify the landscape in such a way that can be traced up until today? How far back in time can we go to find the first evidence of human impact on earth? In this paper, we will try to analyze early human behavior and the possible impact of their activities on the landscape. We will use the paleoanthropological site of Olduvai Gorge (northern Tanzania) as a case study to suggest that the baseline for Anthropocene, taking the term as human impact on earth through cognitive-behavioral strategies, can be moved back to the time when early hominins visited Olduvai. Olduvai Gorge is perfectly suited for this study since the latest scientific research and publications have yielded a detailed knowledge of the vegetation, the landscape, and of the wildlife that lived in the area.

Plant uses in different Bronze and Iron Age settlements from the Nuoro province (Sardinia). The results of phytolith analyses from several ceramic fragments and grinding stones

Ceramic vessels and milling stones are important components of the archaeological record in several nuraghi from the Pranemuru Plateau (Sardinia). For information on the possible uses of the milling stones and content vessels it is of great interest to understand the economical activities carried out in these sites by the populations. One of the approaches to obtain information on the plant uses was the phytolith analyses of the sediment adhered both to the surface of the milling stones and to the surface of the vessel content. In the whole, we analysed eleven archaeological samples and two control samples collected from five different nuraghi in the Pranemuru Plateau (Nuoro Province, Sardinia). The nuraghi were located in an area of 10 km and were chronologically ascribed to the Bronze and Iron Ages. The phytolith morphological analyses are characterised by two different results. The absence of multicellular structures, which on the one hand, suggests that the plants identified have undergo a grounding process -both the ones recovered from the milling stones and the vessels- and on the other hand this absence did not allow us to identify the type of grass represented in the phytolith record. The second important result is the dominance in the samples of phytoliths formed in the bark of dicotyledonous plants (probably small branches). According to these results, the plants identified could have been used as vegetal temper to prepare the ceramic.

Palaeoenvironmental record of the Cal Maurici wetland sediment archive in Barcelona (NE Iberian Peninsula) between c. 6000 and 4000 cal. yr BP

This study presents the results of a multi-proxy analysis conducted to improve our understanding of the palaeoenvironmental conditions of the freshwater and brackish marshes of Cal Maurici (Barcelona, Spain) and the human impact on them during the mid-Holocene (6171–3891 cal. yr BP). The study integrates data from pollen, phytolith, diatom, charcoal, seeds and malacological analyses and helps to reconstruct the ecological conditions during the early establishment of farming communities in western Mediterranean facade. The results indicate a landscape dominated by Mediterranean vegetation with aquatic plants in the shallow marshes and well-developed forests in the nearby area, providing for the first time in the Holocene of NE Iberian Peninsula the palaeoecological conditions of deltaic areas. Ecofactual evidence indicates an initial landscape dominated by brackish marshes (6171–5773 cal. yr BP) in which Ruppia cf. maritima was predominant and human impact was low. Between 5026 and 4839 cal yr. BP, freshwater conditions expanded with an increase in Potamogeton sp. and the presence of Typha angustifolia and Spirogyra sp. algae with well-developed oak woodlands and deciduous trees in nearby areas. The expansion of evergreen forest occurred later (from 4960 to 4825 cal. yr BP until 3712 cal. yr BP), with the decline of deciduous woodland and the expansion of evergreen oaks, pinewoods, wild olive trees and box, coinciding with a period of increased human activity in the area. Additionally, the presence of marine resources at several archaeological excavation sites and domestic plants at Cal Maurici provides an opportunity to evaluate the interaction between earlier farmers and marine or deltaic ecosystems.