Martin Kehl

The progressive evolution of a continental climate in southeast-central European lowlands during the Middle Pleistocene recorded in loess paleosol sequences

1 ABSTRACT Little is known about the long-term Quaternary climate evolution of central and south- east Europe, because suitable terrestrial paleoenvironmental records are scarce. We present a multiproxy record of loess paleosol sequences in the Middle and Lower Danube Basins over the past 700 k.y. In these lowlands, the continentality of interglacial climate progressively increased during the Middle Pleistocene. Corresponding trends are seen in other climate prox- ies in the same region and in the lowlands of the northern Black Sea, but not, or less clearly, in climate archives from outside these lowlands. We conclude that a small-scale increase in paleoelevation of central European mountain ranges (the Alps, Carpathians, and Dinarides) during the Middle Pleistocene might be the cause of the progressive increase in climate conti- nentality of southeast European lowlands.

Holocene environmental change and human impact in NE Morocco: Palaeobotanical evidence from Ifri Oudadane

The littoral site of Ifri Oudadane is one of the most important recently excavated sites in the Mediterranean Maghreb. The shelter presents Epipalaeolithic and Neolithic layers and therefore offers the possibility to investigate the Neolithic transition in the region. Besides introducing the archaeological context, this paper focuses on palaeobotanical data in order to reconstruct Holocene environmental change and human use of plant resources for the period c. 11 to 5.7 ka cal. BP. Results show intense landscape transformations resulting from anthropic and climatic factors. First human occupations start at the beginning of the Holocene with favourable conditions in this otherwise harsh semi-arid stretch of land. A wooded environment with evergreen sclerophyllous oaks and riparian forests is documented and exploited by hunter-gatherers. From c. 7.6 ka cal. BP farming activities are well attested together with significant human impact, herding pressure and a progressive decline of arboreal components. After 6.6 ka cal. BP conditions become less favourable and markers for aridity increase. Riparian taxa disappear (Alnus) or decrease (Fraxinus, Populus, Salix); shrubs (Tamarix) and grasses (Artemisia) increase with a degradation of forest into shrubland (macchia). During 6.6 and 6.0 ka cal. BP there is a general occupation gap in arid and semi-arid Morocco and evidence for that change is also found in the alluvial deposits of the Moulouya, NE Morocco. Indicators for food production decrease at the same time and the site is abandoned during the first half of the 6th millennium cal. BP.

Precise dating of the Middle-to-Upper Paleolithic transition in Murcia (Spain) supports late Neandertal persistence in Iberia

The late persistence in Southern Iberia of a Neandertal-associated Middle Paleolithic is supported by the archeological stratigraphy and the radiocarbon and luminescence dating of three newly excavated localities in the Mula basin of Murcia (Spain). At Cueva Antón, Mousterian layer I-k can be no more than 37,100 years-old. At La Boja, the basal Aurignacian can be no less than 36,500 years-old. The regional Middle-to-Upper Paleolithic transition process is thereby bounded to the first half of the 37th millennium Before Present, in agreement with evidence from Andalusia, Gibraltar and Portugal. This chronology represents a lag of minimally 3000 years with the rest of Europe, where that transition and the associated process of Neandertal/modern human admixture took place between 40,000 and 42,000 years ago. The lag implies the presence of an effective barrier to migration and diffusion across the Ebro river depression, which, based on available paleoenvironmental indicators, would at that time have represented a major biogeographical divide. In addition, (a) the Phlegraean Fields caldera explosion, which occurred 39,850 years ago, would have stalled the Neandertal/modern human admixture front because of the population sink it generated in Central and Eastern Europe, and (b) the long period of ameliorated climate that came soon after (Greenland Interstadial 8, during which forests underwent a marked expansion in Iberian regions south of 40°N) would have enhanced the “Ebro Frontier” effect. These findings have two broader paleoanthropological implications: firstly, that, below the Ebro, the archeological record made prior to 37,000 years ago must be attributed, in all its aspects and components, to the Neandertals (or their ancestors); secondly, that modern human emergence is best seen as an uneven, punctuated process during which long-lasting barriers to gene flow and cultural diffusion could have existed across rather short distances, with attendant consequences for ancient genetics and models of human population history.

Fire history reconstruction from Black Carbon analysis in Holocene cave sediments at Ifri Oudadane, Northeastern Morocco

Fire residues elucidate the where, when, and how of land use. Charcoal analysis provides insights into wood-burning practices, but is restricted by the size of identifiable particles. The present paper is the first to apply a black carbon (BC) method to archaeological sediment deposits. This method oxidizes charcoal and soot particles from the bulk sediment to benzene polycarboxylic acids (BPCAs), independent of size. Our aim was to test the potential of BC analysis in order to elucidate the input from grass and wood fires and discuss the potential limitations of the method on sediments of the Ifri Oudadane rock shelter, Morocco. Sediments cover the cultural transition from hunter–gatherers to food-producing communities (Epipaleolithic to Neolithic period, 11–6 kyr cal. BP), which has previously been shown to affect the geochemical, palynological, and archaeological inventories of these sediments. We found respective changes in BC; specifically, content was highest during the Epipaleolithic, with an average of 35% BC in organic carbon (Corg) compared with Neolithic sediments with an average of 24% BC in Corg. The fire temperature (expressed by BPCA composition) changed significantly, which suggests that wood fires dominated in the Epipaleolithic and grass fires dominated in the Neolithic period. These findings agree with a previously suggested shift in usage. We are able to show here that BC analysis, when combined with other proxy data and archaeological findings, can contribute to a deepened understanding of past human activities.

A context for the last Neandertals of interior Iberia: Los Casares cave revisited

Introduction and objectives Although the Iberian Peninsula is a key area for understanding the Middle to Upper Paleolithic transition and the demise of the Neandertals, valuable evidence for these debates remains scarce and problematic in its interior regions. Sparse data supporting a late Neandertal persistence in the Iberian interior have been recently refuted and hence new evidence is needed to build new models on the timing and causes of Neandertal disappearance in inland Iberia and the whole peninsula. In this study we provide new evidence from Los Casares, a cave located in the highlands of the Spanish Meseta, where a Neandertal-associated Middle Paleolithic site was discovered and first excavated in the 1960’s. Our main objective is twofold: (1) provide an updated geoarcheological, paleoenvironmental and chronological framework for this site, and (2) discuss obtained results in the context of the time and nature of the last Neandertal presence in Iberia. Methods We conducted new fieldwork in an interior chamber of Los Casares cave named ‘Seno A’. Our methods included micromorphology, sedimentology, radiocarbon dating, Uranium/Thorium dating, palinology, microfaunal analysis, anthracology, phytolith analysis, archeozoology and lithic technology. Here we present results on site formation processes, paleoenvironment and the chronological setting of the Neandertal occupation at Los Casares cave-Seno A. Results and discussion The sediment sequence reveals a mostly in situ archeological deposit containing evidence of both Neandertal activity and carnivore action in level c, dated to 44,899–42,175 calendar years ago. This occupation occurred during a warm and humid interval of Marine Isotopic Stage 3, probably correlating with Greenland Interstadial 11, representing one of the latest occurrences of Neandertals in the Iberian interior. However, overlying layer b records a deterioration of local environments, thus providing a plausible explanation for the abandonment of the site, and perhaps for the total disappearance of Neandertals of the highlands of inland Iberia during subsequent Greenland Stadials 11 or 10, or even Heinrich Stadial 4. Since layer b provided very few signs of human activity and no reliable chronometric results, and given the scarce chronostratigrapic evidence recorded so far for this period in interior Iberia, this can only be taken as a working hypothesis to be tested with future research. Meanwhile, 42,000 calendar years ago remains the most plausible date for the abandonment of interior Iberia by Neandertals, possibly due to climate deterioration. Currently, a later survival of this human species in Iberia is limited to the southern coasts.

Luminescence Dating of Fluvial Deposits in the Rock Shelter of Cueva Antón, Spain

Abstract The fluvial sediments at Cueva Antón, a Middle Palaeolithic rock shelter located in the valley of the River Mula (Southeast Spain), produced abundant lithic assemblages of Mousterian affinities. Radiocarbon dates are available for the upper part of the archaeological succession, while for the middle to lower parts chronometric data have been missing. Here we present luminescence dating results for these parts of the succession. Quartz OSL on small aliquots and single grain measurements yield ages ranging from 69 ± 7 ka to 82 ± 8 ka with a weighted mean of 72 ± 4 ka for sub-complexes AS2 to AS5. Equivalent dose estimates from large aliquots were highest and inconsistent with those from single grains and small multiple grain aliquots. This is probably caused by the presence of over-saturating grains, which have been quantified by single grain measurements. Additional post-IR IRSL measurements on coarse grained feldspar give strong support to a well-bleached quartz OSL signal. While independent chronometric control is missing, the results are within the expected age range and support the notion of a rapid accumulation of the fluvial deposits.

Accuracy Assessment of Landform Classification Approaches on Different Spatial Scales for the Iranian Loess Plateau

An accurate geomorphometric description of the Iranian loess plateau landscape will further enhance our understanding of recent and past geomorphological processes in this strongly dissected landscape. Therefore, four different input datasets for four landform classification methods were used in order to derive the most accurate results in comparison to ground-truth data from a geomorphological field survey. The input datasets in 5 m and 10 m pixel resolution were derived from Pleiades stereo satellite imagery and the “Shuttle Radar Topography Mission” (SRTM), and “Advanced Spaceborne Thermal Emission and Reflection Radiometer” (ASTER GDEM) datasets with a spatial resolution of 30 m were additionally applied. The four classification approaches tested with this data include the stepwise approach after Dikau, the geomorphons, the topographical position index (TPI) and the object based approach. The results show that input datasets with higher spatial resolutions produced overall accuracies of greater than 70% for the TPI and geomorphons and greater than 60% for the other approaches. For the lower resolution datasets, only accuracies of about 40% were derived, 20–30% lower than for data derived from higher spatial resolutions. The results of the topographic position index and the geomorphons approach worked best for all selected input datasets.

Paleosols and Past Climate Change

Paleosols in Iran have received less attention than modern soils, although Quaternary deposits and exposures therein are widespread. The chapter gives a short introduction into the general nature of buried and relict paleosols and on methodological aspects how to recognize, characterize and date paleosols. Examples are given for Pre-quaternary and Quaternary paleosols in Iran. The focus is on paleosols in loess-soil sequences in Northern Iran, which have been studied in more detail. These loess exposures contain paleosols of various development degrees separated by layers of more or less unweathered sediment. Strongly developed argillic horizons of paleo-Luvisols occur as well as very weakly developed brown horizons reflecting syngenetic soil formation. The loess-paleosol sequences are excellent geological archives of climate change, where paleosols mark periods of increased humidity and layers of unweathered loess dry phases. The paleosols most probably correlate with interglacial and interstadial periods of the last glacial cycles suggesting that climate change in Northern Iran was in phase with well-known cycles recorded in the temperate zone of the northern hemisphere. The high potential of paleosols as stratigraphic markers and geological archives of climate change and landscape evolution in Iran is still widely unchallenged.

Combined effects of polyacrylamide and nanomagnetite amendment on soil and water quality, Khorasan Razavi, Iran

Nanotechnology is increasingly being used to remediate polluted soil and water. However, few studies are available assessing the potential of nanoparticles to bind surface particles, decrease erosion, and minimize the loading of water pollutants from agricultural surface discharge. To investigate this potential, we treated in situ field plots with two practical surface application levels of anionic polyacrylamide (PAM only) with and without nanomagnetite (PAM-NM), examined soil physical properties, and evaluated the impact of this amendment on contaminant sorption and soil erosion control. Polyacrylamide and PAM-NM treatments resulted in 32.2 and 151.9 fold reductions in Mn2+, 1.8 and 2.7 fold for PO43--P, and 2.3 and 1.6 fold for NH4+-N, respectively, compared to the control. Thus, we found that the combination of PAM and NM, had an important inhibitory effect on NH4+-N and PO43--P transport from soil-pollutants which can contribute substantially to the eutrophication of surface water bodies. Additionally, since the treatment, especially at a high concentration of NM, was effective at reducing Mn2+concentrations in the runoff water, the combination of PAM and NM may be important for mitigating potential risks associated with Mn2+ toxicity. Average sediment contents in the runoff monitored during the rainfall simulation were reduced by 3.6 and 4.2 fold for the low and high concentration PAM-NM treatments when compared to a control. This treatment was only slightly less effective than the PAM-only applications (4.9 and 5.9 fold, respectively). We report similar findings for turbidity of the runoff (2.6-3.3 fold for PAM only and 1.8-2.3 fold for PAM-NM) which was caused by the effects of both PAM and NM on the binding of surface particles corresponding to an increase in aggregate size and stability. Findings from this field-based study show that PAM-modified NM adsorbents can be used to both inhibit erosion and control contaminant transport.

New investigations at the Middle Stone Age site of Pockenbank Rockshelter, Namibia

In southern Africa, Middle Stone Age sites with long sequences have been the focus of intense international and interdisciplinary research over the past decade (cf. Wadley 2015). Two techno-complexes of the Middle Stone Age—the Still Bay and Howiesons Poort—have been associated with many technological and behavioural innovations of Homo sapiens. The classic model argues that these two techno-complexes are temporally separated ‘horizons’ with homogenous material culture (Jacobs et al. 2008), reflecting demographic pulses and supporting large subcontinental networks. This model was developed on the basis of evidence from southern African sites regarded as centres of subcontinental developments.