Hunter-gatherer environments at the Late Pleistocene sites of Mwanganda's Village and Bruce, northern Malawi

Mwanganda's Village (MGD) and Bruce (BRU) are two open-air site complexes in northern Malawi with deposits dating to between 15 and 58 thousand years ago (ka) and containing Middle Stone Age (MSA) lithic assemblages. The sites have been known since 1966 and 1965, respectively, but lacked chronometric and site formation data necessary for their interpretation. The area hosts a rich stone artifact record, eroding from and found within alluvial fan deposits exhibiting poor preservation of organic materials. Although this generally limits opportunities for site-based environmental reconstructions, MGD and BRU are located at the distal margins of the alluvial fan, where lacustrine lagoonal deposits were overprinted by a calcrete paleosol. This has created locally improved organic preservation and allowed us to obtain ecological data from pollen, phytoliths, and pedogenic carbonates, producing a regional- to site-scale environmental context for periods of site use and abandonment. Here, we integrate the ecological data into a detailed site formation history, based on field observations and micromorphology, supplemented by cathodoluminescence microscopy and μ-XRF. By comparing local, on-site environmental proxies with more regional indicators, we can better evaluate how MSA hunter-gatherers made decisions about the use of resources across the landscape. Our data indicate that while tree cover similar to modern miombo woodland and evergreen gallery forest prevailed at most times, MSA hunter-gatherers chose more locally open environments for activities that resulted in a lithic artifact record at multiple locations between 51 and 15 ka.publishedVersio

Faunal Assemblages From Lower Bed I (Oldupai Gorge, Tanzania)

Palaeobiological and archeological excavations at the site of Ewass Oldupa, found in the western Plio-Pleistocene rift basin of Oldupai Gorge (also Olduvai Gorge), Tanzania, revealed rich fossiliferous levels and the earliest remains of human activity at Oldupai Gorge, dated to 2 million years ago. This paper provides zooarchaeological taxonomic, taphonomic, and behavioral analyses, applying several methods to explore the setting in which the assemblage was formed. We identified agency behind bone surface modifications, such as cut, tooth and percussion marks, and determined the frequency of carnivore tooth marks as well as their distribution on both discrete specimens and across species. In addition, our work revealed co-occurrence of modifications to include butchering marks and carnivore tooth marks. Ravaging levels were estimated as percentage. The faunal accumulation from Ewass Oldupa contains two cut marked specimens, together with low degrees of percussion and carnivore tooth marks, moderate ravaging, and diagenetic changes suggestive of water flow. Thus, multiple lines of evidence indicate a palimpsest accumulation. Taxonomic diversity is high, with up to 22 taxa representing diverse habitats, ranging from open grassland to wooded bushlands, as well as moist mosaics during Bed I. Overall, this archaeo-faunal assemblage speaks to increased behavioral versatility among Oldowan hominins and interactions with the carnivore guild.This work was supported by the Canadian Social Sciences and Humanities Research Council under its Partnership Grant Program No. 895-2016-1017. PA and PS are supported by AGAUR (project no. 2017 SGR-1040) and the URV (2018PFR-URV-B2-91). PA’s doctoral program was funded by the Canadian Social Sciences and Humanities Research Council as well as the Leakey Foundation Franklin Mosher Baldwin Fellowship.Peer reviewe

Structural characterization and decontamination of dental calculus for ancient starch research

Ancient dental calculus research currently relies on destructive techniques whereby archaeological specimens are broken down to determine their contents. Two strategies that could partly remediate a permanent loss of the original sample and enhance future analysis and reproducibility include: 1) structural surface characterization through spectroscopy along with crystallographic and spectroscopic analysis of its molecular structure, and 2) surface decontamination protocols in which the efficacy of cleaning dental calculus prior to extraction is demonstrated. Dental calculus provides ancient starch research a niche where granules may be adsorbed to minerals, coated, overgrown, entrapped, and/or protected from chemical degradation. While encapsulation offers protection from degradation, it does not shield the sample’s surface from contamination. The most common approach to retrieving microbotanical particles from archaeological calculus has been the direct decalcification of the sample, after a cleaning stage variously consisting of immersion in water, acids, and mechanical dislodgment via gas, sonication, and/or toothbrushes. Little is known about the efficiency of these methods for a complete removal of sediment/soil and unrelated microbotanical matter. In this paper, controlled laboratory experimentation leads to chemical structural characterization and a decontamination protocol to eradicate starch granules. Several concentrations of acids, bases, and enzymes were tested at intervals to understand their potential to gelatinize and fully destroy starch granules; arriving at a procedure that effectively eradicates modern starch prior to dissolution without damaging the matrix or entrapped starch microremains. This is the first attempt at creating synthetic calculus to understand and systematically test effective decontamination protocols for ancient starch research

Soil and plant phytoliths from the Acacia-Commiphora mosaics at Oldupai Gorge (Tanzania)

This article studies soil and plant phytoliths from the Eastern Serengeti Plains, specifically the Acacia-Commiphora mosaics from Oldupai Gorge, Tanzania, as present-day analogue for the environment that was contemporaneous with the emergence of the genus Homo. We investigate whether phytolith assemblages from recent soil surfaces reflect plant community structure and composition with fidelity. The materials included 35 topsoil samples and 29 plant species (20 genera, 15 families). Phytoliths were extracted from both soil and botanical samples. Quantification aimed at discovering relationships amongst the soil and plant phytoliths relative distributions through Chi–square independence tests, establishing the statistical significance of the relationship between categorical variables within the two populations. Soil assemblages form a spectrum, or cohort of co-ocurring phytolith classes, that will allow identifying environments similar to those in the Acacia-Commiphora ecozone in the fossil record

Soil and Plant Phytoliths from the Acacia-Commiphora Mosaics at Oldupai Gorge (Tanzania)

Abstract This paper studies soil and plant phytoliths from the Eastern Serengeti Plains, specifically the Acacia-Commiphora mosaics from Olduvai Gorge, Tanzania. The soil phytolith transect extends 100 ha and comprises 35 samples. Botanic collection was aimed at investigating the range of species present in the study area, learning about their phytolith production and morphotype characteristics, and comparing the botanical dataset with the soil group. We studied 29 species (20 genera, 15 families). Quantification aimed at discovering relationships amongst the soil and plant phytoliths relative distributions through Chi–square independence tests, establishing the statistical significance of the relationship between categorical variables within the two populations. For the soils we tallied 10,745 phytoliths (64 morphotypes grouped into 15 classes). Plants yielded 4,310 phytoliths (morphotypes = 52, classes = 13). In topsoils, the woody phytolith group dominates all terrain ranks, and appears to increase with denser plant cover, while grass phytoliths peak in sparsely vegetated terrain. The morphotypes from woody plants are led by the spherical class. The Poaceae produce ovates, towers, and horned towers. We provide a phytolith analog for the Acacia-Commiphora ecozone, explore whether soil phytoliths mirror the physiognomy and composition of vegetation aboveground, issues of catchment size, as well as time averaging, heterogeneity, and adequate sampling methods. From a phytolith perspective, this analog comprises seven phytolith classes: Four from woody tissue and three from grasses. In addition, we created a phytolith reference collection of characteristic plants from this ecosystem that can aid in the taxonomic identification of phytoliths from ancient sediments and soils

Soil and Plant Phytoliths from the Acacia-Commiphora Mosaics at Oldupai Gorge (Tanzania)

This paper studies soil and plant phytoliths from the Eastern Serengeti Plains, specifically the Acacia-Commiphora mosaics from Oldupai Gorge, Tanzania, as present-day analogue for the environment that was contemporaneous with the emergence of the genus Homo. We investigate whether phytolith assemblages from recent soil surfaces reflect plant community structure and composition with fidelity. The materials included 35 topsoil samples and 29 plant species (20 genera, 15 families). Phytoliths were extracted from both soil and botanical samples. Quantification aimed at discovering relationships amongst the soil and plant phytoliths relative distributions through Chi–square independence tests, establishing the statistical significance of the relationship between categorical variables within the two populations. Soil assemblages form a spectrum, or cohort of co-ocurring phytolith classes, that will allow identifying environments similar to those in the Acacia-Commiphora ecozone in the fossil record

Petrographic Characterization of Raw Material Sources at Oldupai Gorge, Tanzania

Oldupai Gorge is located within the Ngorongoro Conservation Area, a UNESCO World Heritage Site in northern Tanzania along the western margin of the East African Rift System. Oldupai’s sedimentary record exhibits a complex sequence of inter-stratified lithic assemblages associated with the Early, Middle, and Later Stone Age. While diachronic technological change is perceptible, the totality of locally available rocks remained largely unchanged through time. Here, thin section petrography, Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy, and Electron Probe Micro Analysis were employed to characterize source lithologies in the Oldupai region. One of our goals was to determine if outcrops have rock types with unique mineral compositions amenable for sourcing lithic artifacts. Geological samples were collected in primary and secondary positions, from which sixty-two samples were selected for analysis. Comparative analyses show that five outcrops have quartzites with unique mineral compositions, seven meta-granite varieties are unique to five individual outcrops, Engelosin phonolite samples are texturally and mineralogically unique, and magmatic samples recovered in secondary position may be sourced to their volcanic center. Our results demonstrate it is feasible to differentiate between source materials using optical mineralogy which implies that sourcing lithic artifacts based on mineral compositions is possible. This is further substantiated by assigning the source/s for previously described fuchsitic quartzite artifacts from three archaeological sites at Oldupai as this raw material type uniquely occurs at two nearby outcrops. Systematic archaeological testing will allow future researchers to glean new understandings of hominin behavior and resource procurement within the Oldupai paleobasin

Structural characterization and decontamination of dental calculus for ancient starch research

Ancient dental calculus research currently relies on destructive techniques whereby archeological specimens are broken down to determine their contents. Two strategies that could partly remediate a permanent loss of the original sample and enhance future analysis and reproducibility include (1) structural surface characterization through spectroscopy along with crystallographic and spectroscopic analysis of its molecular structure, and (2) surface decontamination protocols in which the efficacy of cleaning dental calculus prior to extraction is demonstrated. Dental calculus provides ancient starch research a niche where granules may be adsorbed to minerals, coated, overgrown, entrapped, and/or protected from chemical degradation. While encapsulation offers protection from degradation, it does not shield the sample’s surface from contamination. The most common approach to retrieving microbotanical particles from archeological calculus has been the direct decalcification of the sample, after a cleaning stage variously consisting of immersion in water, acids, and mechanical dislodgment via gas, sonication, and/or toothbrushes. Little is known about the efficiency of these methods for a complete removal of sediment/soil and unrelated microbotanical matter. In this paper, controlled laboratory experimentation leads to chemical structural characterization and a decontamination protocol to eradicate starch granules. Several concentrations of acids, bases, and enzymes were tested at intervals to understand their potential to gelatinize and fully destroy starch granules; arriving at a procedure that effectively eradicates modern starch prior to dissolution without damaging the matrix or entrapped starch microremains. This is the first attempt at creating synthetic calculus to understand and systematically test effective decontamination protocols for ancient starch research

Petrographic Characterization of Raw Material Sources at Oldupai Gorge, Tanzania

Oldupai Gorge is located within the Ngorongoro Conservation Area, a UNESCO World Heritage Site in northern Tanzania along the western margin of the East African Rift System. Oldupai’s sedimentary record exhibits a complex sequence of inter-stratified lithic assemblages associated with the Early, Middle, and Later Stone Age. While diachronic technological change is perceptible, the totality of locally available rocks remained largely unchanged through time. Here, thin section petrography, Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy, and Electron Probe Micro Analysis were employed to characterize source lithologies in the Oldupai region. One of our goals was to determine if outcrops have rock types with unique mineral compositions amenable for sourcing lithic artifacts. Geological samples were collected in primary and secondary positions, from which sixty-two samples were selected for analysis. Comparative analyses show that five outcrops have quartzites with unique mineral compositions, seven meta-granite varieties are unique to five individual outcrops, Engelosin phonolite samples are texturally and mineralogically unique, and magmatic samples recovered in secondary position may be sourced to their volcanic center. Our results demonstrate it is feasible to differentiate between source materials using optical mineralogy which implies that sourcing lithic artifacts based on mineral compositions is possible. This is further substantiated by assigning the source/s for previously described fuchsitic quartzite artifacts from three archaeological sites at Oldupai as this raw material type uniquely occurs at two nearby outcrops. Systematic archaeological testing will allow future researchers to glean new understandings of hominin behavior and resource procurement within the Oldupai paleobasin