Andrea Zerboni

Inside the “African Cattle Complex”: Animal Burials in the Holocene Central Sahara

Cattle pastoralism is an important trait of African cultures. Ethnographic studies describe the central role played by domestic cattle within many societies, highlighting its social and ideological value well beyond its mere function as ‘walking larder’. Historical depth of this African legacy has been repeatedly assessed in an archaeological perspective, mostly emphasizing a continental vision. Nevertheless, in-depth site-specific studies, with a few exceptions, are lacking. Despite the long tradition of a multi-disciplinary approach to the analysis of pastoral systems in Africa, rarely do early and middle Holocene archaeological contexts feature in the same area the combination of settlement, ceremonial and rock art features so as to be multi-dimensionally explored: the Messak plateau in the Libyan central Sahara represents an outstanding exception. Known for its rich Pleistocene occupation and abundant Holocene rock art, the region, through our research, has also shown to preserve the material evidence of a complex ritual dated to the Middle Pastoral (6080–5120 BP or 5200–3800 BC). This was centred on the frequent deposition in stone monuments of disarticulated animal remains, mostly cattle. Animal burials are known also from other African contexts, but regional extent of the phenomenon, state of preservation of monuments, and associated rock art make the Messak case unique. GIS analysis, excavation data, radiocarbon dating, zooarchaeological and isotopic (Sr, C, O) analyses of animal remains, and botanical information are used to explore this highly formalized ritual and the lifeways of a pastoral community in the Holocene Sahara.

Human Communities in a Drying Landscape: Holocene Climate Change and Cultural Response in the Central Sahara

Dagge and Hamad (2008) report that Syria is in the midst of an environmental emergency occasioned by a drought that has affected the region since 2006. Massive crop failure with harvests down by a half has produced conditions where famine and even societal collapse might be expected. Fortunately, the Syrian government has been able to ameliorate the problem with imports of food and potable water. In the distant past disasters could not have been avoided in this way, and famine would have resulted in the disaggregation of the community or at least would have forced a drastic change in survival strategies. Episodes similar to those now affecting Syria have caused societal crises throughout prehistory and history, with climate change and human abuse of landscape and natural resources playing crucial roles (Diamond 2005). Of course, local differences need to be understood and treasured. The reaction of the physical environment (the landscape) to stress is not uniform across the globe, regardless of whether we consider climate change, the impact of grazing, or any other human activity.

The loess-paleosol sequence at Monte Netto: a record of climate change in the Upper Pleistocene of the central Po Plain, northern Italy

PurposeAt the northern fringe of the Po Plain (northern Italy), several isolated hills exist, corresponding to the top of Late Quaternary anticlines. These hills were thoroughly surveyed for their soils and surficial geology, furnishing detailed archives of the palaeoenvironmental evolution of the area. A new, thick and complex loess-paleosol sequence, resting upon fluvial/fluvioglacial deposits, exposed in a quarry at the top of the Monte Netto hill was studied in detail to elucidate its significance.Materials and methodsHighly deformed fluvial and fluvioglacial deposits, probably of Middle Pleistocene age, are exposed in a clay pit at Monte Netto, underneath a 2- to 4-m-thick loess-paleosol sequence. A geopedological, sedimentological and micropedological investigation of the sequence shows a distinctive difference between the B horizons forming the sequence, while luminescence and radiocarbon age determinations and the occurrence of Palaeolithic lithic assemblages elucidate the chronology of the sequence.Results and discussionThe pedosedimentary sequence consists of several loess layers showing different degrees of alteration; loess deposition and weathering occurred, according to optically stimulated luminescence (OSL) and AMS-14C dating as well as archaeological materials, during the Upper Pleistocene. The lower part of the section consists of strongly weathered colluvial sediments overlying fluvial and fluvioglacial sediments. A tentative model of the exposed profiles involves the burial of the anticline, which forms the core of the hill, by loess strata since Marine Isotopic Stage (MIS) 4 and their subsequent weathering (and truncation) during subsequent interstadials. The degree of weathering of buried B horizons increases from the top of the sequence toward the bottom, suggesting a progressive decrease in the intensity of pedogenesis. Finally, the highly rubified paleosol at the top of the hill is regarded as a buried polygenetic soil or a vetusol, developed near the surface since the Middle Pleistocene.ConclusionsThe palaeopedological, geochronological and geoarchaeological analyses permit to define the phases and steps of development of the Monte Netto pedosedimentary sequence; the lower part of the sequence is dated to the Mid-Pleistocene, whereas loess accumulation occurred between MIS 4 and MIS 2. Moreover, analyses help to clarify the climatic and environmental context of alternating glacial and interstadial phases, during which the sediments where deposited, deformed and weathered.

Geomorphological Map of the Tadrart Acacus Massif and the Erg Uan Kasa (Libyan Central Sahara)

Here we present a geomorphological map of the Tadrart Acacus Massif and Erg Uan Kasa (SW Libya, central Sahara). The geomorphological mapping of the area was carried out by means of satellite imagery analysis followed by detailed control of units in the field. The Tadrart Acacus is a sandstone massif delimited to the West by a high scarp and cut by a dendritic fossil drainage network of W-E-oriented wadis. The massif has been shaped since the Tertiary by etchplanation and solutional processes; the latter is demonstrated by the ruiniform landscape and the high number of caves and rock shelters that dot the vertical cliffs of the wadis. To the East, the Tadrart Acacus merges below a complex system of sand ridges that form the Erg Uan Kasa. The large interdune corridors of the sand sea are dotted by lake sediments, which formed during the Pleistocene interglacials and the African Humid Period of the Holocene, when piezometric lakes were sustained by intense monsoonal rainfall. Geomorphological investigation demonstrates that the extant landscape originated thanks to the overlap of surface processes triggered by divergent (humid/arid) environmental conditions.

Geomorphological Map of the Messak Settafet and Mellet (Central Sahara, SW Libya)

Abstract Please click here to download the map associated with this article. The Messak is a central Saharan massif cut into Cretaceous sandstone and delimited to the north and the west by a high scarp. It is a relict of a peneplain, dissected by dendritic wadis, and has originated since the late Tertiary under a rich water supply. Geomorphological mapping of the area was carried out by means of field survey and satellite imagery analysis. Due to the almost complete absence of vegetation (related to arid environmental conditions), the analysis of multispectral data permitted the identification of the main geomorphological units, while a band ratio allowed characterization of the properties of the exposed land surface. The main physiographic units correspond to residual surfaces (hamada and serir, resulting from etchplanation and linear erosion), solutional depressions, slope deposits, and a composite escarpment. Most of the geomorphological features are fossil, originating during warm and rainy phases dated to the Tertiary, the Pleistocene interglacials, and the Early Holocene.

Progressive offset and surface deformation along a seismogenic blind thrust in the Po Plain foredeep (Southern Alps, Northern Italy)

Here we present, for the first time in the Po Plain foredeep (Northern Italy), the middle to late Pleistocene growth history of an outcropping secondary fold and related faults, whose progressive deformation over an intermediate time window (105 years) is driven by an underlying seismogenic blind thrust. We trenched and logged an outcropping decametric secondary anticline, related to a deeper blind compressional structure, which deforms fluvial sediments and an overlying loess-paleosol sequence. Folded units were dated, using radiocarbon and optically stimulated luminescence methods, to the late Pleistocene–Holocene and tentatively correlated with glacial-interglacial phases occurring during the time interval from marine isotope stage 6 to the present. A multistep retrodeformation of the fold allowed us to calculate uplift rates for this secondary and shallow anticline, varying between 0.02 and 0.1 mm/yr since circa 200 kyr. Trishear forward deformation modeling of the fold indicates that the amplification of the observed fold could be caused by two shallow thrusts formed through a break-backward activation. This generated a decametric surface fold whose most recent growth was associated with bending-moment normal faulting in the crestal and forelimb region. Our observations demonstrate that near-surface compressive tectonics can be caused by blind thrusting, via a complex array of fault and folds: upward strain propagation and generation of shallow low-angle thrust and related folding seem to be mainly due to secondary fold-related faulting, according to an out-of-syncline thrusting mechanism.

Climate, Environment, and Population Dynamics in Pleistocene Sahara

The study area witnessed alternate paleoenvironmental and population events influenced by glacial/interglacial conditions. Paleosols, relict fluvial bodies, lacustrine carbonatic deposits, sand dunes, and other features underline the severely fluctuating activity of water resources. The study region (SW Libya) provides two different data sets: (1) two stratified, dated, Middle Stone Age/Aterian sites; and (2) hundreds of surface lithic scatters rarely associated with paleoenvironmental proxies. Early/Middle Pleistocene human occupation is presumable, but the bulk of evidence is from the late Middle/Late Pleistocene. Productive environments possibly housed human groups with a Late Acheulean technology during MIS 7. Most of the MSA evidences are barely diagnostic from a techno-typological point of view. Exceptions are made for scanty but precise similarities with sub-Saharan early MSA finds, suggesting the presence of modern humans in MIS 6, and for the Aterian, an example of MIS 4 arid landscape adaptation. Although MIS 3/2 post-Aterian human presence is not demonstrable, signs of a generalized LSA technology are recognizable in the Messak, where stony raw materials could have attracted task-specific temporary occupants.

Colour in context. Pigments and other coloured residues from the Early-Middle Holocene site of Takarkori (SW Libya)

We present the multidisciplinary investigation of pigments and artefacts with traces of colour from the Early-Middle Holocene site of Takarkori, located in the Tadrart Acacus Mountains (central Sahara, SW Libya). Here, geological, archaeological, taphonomic and chemical studies (Raman, Fourier-transform infrared, X-ray powder diffraction, gas chromatography–mass spectrometry) are used to examine a vast range of artefacts (raw materials, grinding stones, painted items, as well as lithic, bone, wooden and ceramic tools) equally distributed from Late Acacus contexts related to hunter-gatherers (ca. 8900–7400 uncal years bp) to pastoral groups (ca. 7400–4500 uncal years bp). The exploited minerals (goethite, hematite, kaolinite and jarosite, among others) are locally procured and processed using quartzarenite grinding stones of different shapes and sizes. Thermal treatment of the minerals is also suggested by X-ray powder diffraction (XRD) and Raman studies. Gas chromatography–mass spectrometry (GC-MS) analyses show the addition of a lipid binder to small lumps of pigments in order to obtain a sticky product. Their fatty acid distribution differs from the residues on grinding stones, pointing to a specific use of these lumps. The grinding stones have also been used to crush and pulverize the pigments and as base for colour preparation. A sample of colour from a fallen painted slab referable to late pastoral phases shows the presence of a binder, chemically identified as casein. Taken together, the evidence collected at Takarkori conveys to suggest an articulated chaîne opératoire, not only directed towards the preparation of pigments for the parietal rock art but also to other non-utilitarian functions, such as body care and ornamentation and decoration of artefacts.

Il significato paleoclimatico dei carbonati continentali olocenici centro-sahariani: memoria delle forzanti orbitali e di eventi climatici rapidi

Palaeoclimatic significance of Holocene continental carbonates from the central Sahara: memory of orbital forcing and high frequency events.We identified in the hyperarid central Sahara several outcrops of freshwater continental carbonates, formed in correspondence of former springs and in lake sedimentary environments. They are not in equilibrium with the present-day environmental and climatic conditions and therefore they indicates a wetter period dating to the Holocene. Sampled deposits were submitted to radiometric dating (U-series and 14C) and stable isotopes were measured to get palaeoclimatic information. Calcareous tufa from fossil springs in the Tadrart Acacus massif confirm higher precipitation for the early Holocene and a their progressive decline later on; springs dried out at c. 8000 years BP. At the mean time, the outcrop of the water table in the edeyen of Murzuq allowed the formation of constant and freshwater piezometric lakes. As a consequence of decreased rainfalls, the level of the lakes fell at c. 8000 years BP; after few centuries of aridity, the level of the water raised again. Geochemical, sedimentological, and paleontological analyses demonstrate that lakes suffered seasonal oscillations of the level. Our data confirm that the African Humid Period began soon after the Pleistocene/Holocene transition and the intensity of precipitation strongly decreased during the middle Holocene, in accordance with the modifications of the orbital forcing. Moreover, the central Saharan carbonates recorded also a short arid phase that is in relation with the 8.2 BP event.

Geomorphology of Mount Ararat/Ağri Daği (Ağri Daği Milli Parki, Eastern Anatolia, Turkey)

ABSTRACT This paper presents a geomorphological map of Mount Ararat/Ağri Daği in Eastern Anatolia (Turkey). Mount Ararat/Ağri Daği is a volcanic complex covered by a unique ice cap in the Near East. The massif is the result of multiple volcanic phases, and present day landforms are the result of subsequent and overlapping glacial, periglacial, and slope processes. The geomorphological mapping of Mount Ararat/Ağri Daği was firstly performed on the basis of desktop studies, by applying remote-sensing investigations using high-resolution satellite imagery (PLEIADES and SPOT images). A preliminary draft of the map was crosschecked and validated in the field as part of an interdisciplinary campaign carried out in the 2014 summer season. All the collected data suggest that the Mount Ararat/Ağri Daği glaciation played a crucial role in the evolution of the landscape and that even today glaciers are significant features in this area. Currently, ice bodies cover 7.28 km2 and include peculiar glacier types. Among these are three well-developed debris-covered glaciers, flowing down along the flanks of the volcano.