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The paper presents records of lithofacial succession in the sediments of the Bagno Staw alkaline fen (Western Polesie Lowland, Eastern Poland), documenting the phase of rapid morphogenetic transformations during LG/H in the Lublin chalkland. Environmental conditions responsible for the morphogenesis and evolution of the site (from a shallow periglacial lake to an alkaline fen) were reconstructed. A detailed geological survey in combination with the analysis of Cladocera assemblages revealed the presence of numerous palaeodepressions under the plain covered today by the alkaline fen, which were initially small shallow lakes with a well-developed phytolittoral zone. Geochemical data and the analysis of stable O and C isotopes indicated that these lakes were supplied by ascending waters. Karstic phenomena under periglacial conditions, including subsidence at the bottom of biogenic accumulation basins, played an important role in the transformation of this site. These changes were largely determined by the chronology and dynamics of permafrost degradation.

In eastern Africa, ecologists have found that when mobile pastoralists abandon their temporary encampments, the accumulation of burned animal dung, wood, and other organic waste enriches the concentration of nutrients (e.g., calcium, phosphorous, magnesium) essential to soil health, in comparison to other soils without prior human habitation. These nutrient-enriched soils promote glade development and greater biodiversity. Geoarchaeological research on the time depth of this anthropogenic “nutrient hotspot” phenomenon has demonstrated that soils at several archaeological sites in southern Kenya still remain enriched in these soil macro- and micro- nutrients after several thousand years. However, soil scientists and geoarchaeologists do not yet understand how these anthropogenic soils vary over the extensive geographic conditions of eastern Africa. The discovery of a Pastoral Neolithic site (ca. 3000 BP) at Luxmanda on the Mbulu Plateau, Tanzania, provides an opportunity to examine if similar patterns of nutrient enrichment can be detected in a different geological and climatic zone. In this paper, we use geochemical and sedimentary analyses to determine how archaeological soils at Luxmanda differ from adjacent off-site soils and known archaeological soils in Kenya, as well as from computationally derived soil nutrient models for eastern Africa. Our results indicate that soils derived from anthropogenic sediments and ashy dung are 4 to 16-fold more abundant in soil macro nutrients relative to off-site or modeled values. This pattern fits previous studies’ observations that elevated macro- and micro-nutrients in soils are strongly correlated with ancient pastoralist habitation sites. We conclude that anthropogenic soils found at Pastoral Neolithic archaeological sites may be a valuable, but unappreciated, soil resource in eastern Africa.

This paper addresses the timing of accelerated soil erosion and landscape degradation in central Mexico. It shows data on erosion sequences in the Valley of Teotihuacan, an area where agricultural dates back to at least since 1100 BCE, and an ideal setting to test ideas on the effect of preconquest versus post-conquest anthropogenic impacts on the environment. The methods include stratigraphy, detailed description of soil profiles and soil micromorphology, along with analysis of pottery sherds and radiocarbon dating. A chronology of events for two catenas, focusing on periods of landscape stability and change, establish the sequence of erosion events from pre-Hispanic to modern times. Six erosion phases are recognized over the last 2000 years in Teotihuacan. Although results suggest that the most intense erosion occurred after Spanish conquest, in the 16th century, several erosion phases took place during pre-Hispanic times and also in the postcolonial period, including the 20th century. Probable causes for these impacts are related to settlement dynamics, population variability, and land use changes. Thus, it provides new information for the discussion on the timing and causes of erosion, sedimentation and landscape modification in the central Mexican Highlands during the late Holocene.

The responding mechanism of wetland ecosystem to climate change is currently unclear due to a lack of long-term records incorporating multiple ecological factors. This paper presents a well-dated and multi-proxy cored record from a natural freshwater wetland developed in a paleo-pingo-related depression on the Sanjiang Plain. The study aims to reconstruct the wetland water-level and vegetational regimes during the past ~6.0 ka BP and discuss the wetland evolution response to the East Asian summer monsoon (EASM) circulation. The results show that a shallow-water lake with hygrophilous herbs developed in the depression with a strong EASM during ~6.0–4.5 ka BP. The paleolake was succeeded by a wetland with a lowered mean water level and an increase in tree cover controlled by the weakened EASM during the past 4.5 ka BP. Such an ecological lake-to-wetland transition corresponds well to the sharp decline of the EASM around 4.5 ka BP which has been well documented in various geological records across the EASM domain. During the wetland developing stage over the past 4.5 ka BP, the water-level and vegetational changes in the studied depression were also closely related to the EASM variations. The strengthened EASM usually generated higher water levels with more hygrophilous herbs around 4.0 ka BP, 3.5 ka BP, 3.0 ka BP, 2.0 ka BP, and 1.3 ka BP. Considering the prevalent EASM climate serving as the predominant water supply for the wetlands on the modern Sanjiang Plain, we suggest the EASM circulation has played a critical role in driving the wetland ecological evolution during the mid-to-late Holocene Epoch. The past 0.4 ka BP is an exception as the local Trees/Herbs ratio visibly increased with the declined water level, while the monsoonal precipitation shows no equivalent shift. The wetland evolution at this stage was attributed to human interference.

Geomorphological investigations coupled with sedimentological, petrographical, and SEM analyses allowed to identify, for the first time, a paleo-fixed and inland aeolian dune field in the Gioia Tauro Plain, on the Tyrrhenian side of southern Calabria (southern Italy). The aeolian landforms, extended over an area of 43 km2, are characterized by smoothed and elongated NW-SE trending vegetation-fixed linear dunes, varying in height from a few meters up to 20 m. Forty sand samples were collected from dunes to perform laboratory analyses. Grain size analyses showed that samples are composed of unimodal coarse-grained sands (Mz = 0.820 φ), moderately sorted (σ = 0.862), positively skewed (Sk1 = 0.173) and mesokurtic (KG = 1.115). Petrographic analyses highlighted a composition dominated by quartz and minor feldspars. Modal data, and especially the high F/Q ratio and the Rg:Rs:Rm triangular plot, suggest a plutoniclastic supply from the Aspromonte Massif crystalline source rocks. SEM analyses of sand grains clearly displayed the presence of typical wind-generated features mainly represented by rounded form with low relief, bulbous edges, and dish-shaped depressions. These results combined with morphological analyses showed that these aeolian deposits fall into the category of sand sheets. Furthermore, geological and geoarchaeological data evidenced that dune field was formed in the time interval between ~28 ka and the VI - IV century B.C. The dune filed formation has been interrupted presumably by the combined effect of Holocene tectonics, along the Gioia Tauro-San Ferdinando normal fault, and the lowering of sea level, during the Last Glacial period, originating a natural barrier to windblown sand particles. The findings of the paper will help in understanding both inland aeolian products in southern Europe associated to the second colder phase of the Last Glacial period in the Mediterranean area and the complex patterns of spatial and temporal distribution, as well as the control factors determining preservation of the aeolian sediments throughout the rock record.

The Assif n’Imserdane valley, located in the Jebel Toubkal area of the High Atlas, Morocco, is a highly dynamic geomorphological setting. The valley was glaciated during the Late Pleistocene, and subsequently experienced a catastrophic rock avalanche leading to the formation of one of the largest mass movement landforms in North Africa. Recent research (Hughes et al., GSA Bulletin 126: 1093–1104) has dated the formation of the rock avalanche to the mid-Holocene at 4.5 ± 0.5 ka. In this paper, we examine the sedimentological (organic matter content, magnetic susceptibility, particle size and XRF) and palaeoecological (pollen and spores, non-pollen palynomorphs (NPPs), microcharcoal and conifer tracheid fragments) record of a small infilled basin located adjacent to a Late Pleistocene moraine and close to the rock avalanche in the Arroumd sector. The deposits, primarily fine-grained and minerogenic with a low concentration of organic microfossils including pollen, coprophilous ascospores, wood and charcoal microfragments, are enriched in fine silts and ferrimagnetic minerals, consistent with erosional sources from surrounding slope soils. Three radiocarbon dates from the deposit indicate that the infill event occurred during the first millennium AD (after 430–640 AD). As such, the deposits point to a phase of slope instability and erosion that is not linked to either deglaciation processes or to the mid-Holocene rock avalanche. Instead, the nature and timing suggest that an anthropogenic trigger of degradation to the natural vegetation cover may be implicated, consistent with an increasing scale and intensity of pastoral activity in the southern High Atlas during the early Islamic period in Morocco. The record casts light on a previously undocumented phase of landscape instability in the dynamic setting of the Assif n’Imserdane valley, and highlights the potential for further exploration of small infilled basins in the High Atlas to illuminate the geoecological history of the region.

The River Trent, UK, is renowned for a rich palimpsest of alluvial archaeological remains buried within the Holocene sands and gravels of the valley floor. Since the late 1990's extraction of these postglacial deposits at Shardlow quarry in the middle reach of the valley, close to the confluence of the River Trent and River Derwent, has been investigated and monitored on a weekly basis by a project team including geoarchaeologists. Such monitoring of large exposures of floodplain sand and gravel and adjacent Pleistocene terrace deposits, initially by volunteer activity, but latterly, funded by the aggregate company under a formal planning agreement, has revealed significant alluvial archaeological remains including two logboats, a possible brushwood platform, several fish weirs and organic-rich palaeochannel deposits. This paper provides a summary of the wealth of this resource, but also reflects on the challenges of undertaking geoarchaeological studies in complex alluvial environments over such an extended time period. It concludes by providing advice for best practice that could be applied to other long term studies within similar environments.

Chains of ponds are a discontinuous river type found in Australia. Their unusual morphology, important ecological functions and increasing rarity make them a priority for conservation, and yet very little research has investigated their physical structure, behaviour and evolution. This paper reconstructs the Holocene evolution and environmental history of Crisp's Creek, a headwater chain of ponds in the Southern Tablelands of NSW Australia. This history establishes baseline information on the physical template that can be used to assess a range of other biophysical processes and design appropriate river rehabilitation and management strategies for these rivers. Sedimentary aggradation began in the Late Holocene, at least 3.7–1.3 ka, broadly synchronous with aggradation phases at other sites in southeast Australia. Since European arrival in the Nineteenth Century, parts of the river incised, destroying intact ponds and smothering formerly swampy floodplains with post-incision alluvium. However, sections unaffected by incision provide a rare opportunity to examine the evolutionary trajectory of an intact variant of these rivers. This research deepens our understanding of the evolutionary context for contemporary river behaviour as relevant for designing appropriate and effective conservation and rehabilitation strategies for chains of ponds.

Rhythmic nature of tufa deposits and analysis of hydrochemical proxies offer the potential to reconstruct the history of regional palaeo-hydrological and palaeo-climatic change. This paper investigates the tufa deposits of Sparkling Lake in the Jiuzhaigou gully of the eastern Tibetan Plateau (ETP). Detailed analysis of mineral composition, major elements and stable isotope (δ13C, δ18O) distinguished seven “dirty tufa layers” that are characterized by quartz-rich sediments, high kaolinite and high K, Na and Al. Compared with clean tufa deposits, dirty components in the tufa deposits were a result of surface soil erosion activity during strong monsoon rainfall periods within the catchment. The chronology of tufa deposits is established by using radiocarbon (14C) dating of organic material from the dirty tufa layers. Seven flood-rich periods and eight flood-poor periods during the early and mid-Holocene were recorded by the dirty tufa layers interbedded with clean tufa layers in the Jiuzhaigou gully. The tufa records are more sensitive response to regional hydroclimate change, in comparison with the peat, lake sediments and stalagmite records. The low values of δ18O and δ13C in the dirty tufa layers indicate the flood-rich periods (10310–8390, 7120, 6910, 6340, 5900, 5620, 5020 a BP) were mainly triggered by strong monsoon rainfall events during early and mid-Holocene. Considering the chronological uncertainties and sampling resolution, some other abrupt climate events (i.e, 8200 a BP and 5500 a BP) may be also recorded in the tufa deposits. These results greatly improve our understanding of hydroclimate change in the ETP during the early and mid-Holocene.

Understanding Holocene vegetation response regimes will improve predictions of future vegetation dynamics in mountain areas of semi-arid north China. In this paper, we statistically analyzed the relationship between a pollen record in a mountain area of semi-arid north China and influencing variables independent of pollen data, in the hope that potential vegetation forcing and response regimes can be explored. Our result suggests that the cool deciduous forest (CDF) at high elevation and the temperate deciduous forest (TDF) at middle and lower elevation were sensitive in responding to temperature before 6000 cal. yr BP, but were not sensitive to the summer monsoon (SM). Since 6000 cal. yr BP, the CDF and TDF were sensitive in responding to the SM instead of temperature. Hence, a shift of response regimes can be placed at ∼6000 cal. yr BP, which happened to be consistent with the time that forest expansion changed to deforestation. The insensitive response to the SM during the early Holocene might be attributed to the vegetation elevational movement, the topographic barrier for forest migration from refugia, and/or the topographically related high resistance and resilience of mountain forests. The sensitive response of CDF and TDF to the weakening SM since 6000 cal. yr BP was mainly caused by the cumulative moisture deficit caused by the continual weakening of the SM. Human activity had little impact on mountain forests until several centuries ago. Mountain forest expansion in response to climate warming during the early to middle Holocene can provide analogues for the prediction of forest dynamics of future warming.

This paper is devoted to a study of the nature and origin of the mineral matter in the Vasyugan Mire in Western Siberia. Based on mineralogical and geochemical analyses, new results were obtained concerning the mineral composition within the bottom part of the peat deposit for different landscape zones in the Vasyugan Mire. This part of the peat deposit represents a transition sequence from peat through organo-mineral sediments (OMS) to basal loams and is characterized by a gradient change in the physicochemical and environmental conditions with depth. In the same sequence, pH and peat ash yield increase, while moisture decreases. The clay minerals identified in the basal layers of the mire, consisting of loam, OMS and peat, include illite, chlorite, kaolinite and smectite. All these clay minerals found in the OMS and peat layers are believed to have been inherited with little change from the underlying loam layer during the initial transient stage of mire development. That this is indeed the case is strongly suggested by the extraordinary correspondence in the mean content of over 40 trace elements between the OMS and loam layers. In the overlying peat layer, however, some elements, including U, W, Sb, Sn, Mo, Zn, Cd, Nb, Ta, Br and B, are present in higher concentrations than in the OMS and loam. Scanning electron microscope observations suggest that this can be at least partly accounted for by the precipitation of sulfide phases in the strongly reducing and acidic environment of the peat, although whether by inorganic or microbial processes is unknown. The age of the Vasyugan Mire within the Holocene succession is discussed and it is concluded that it developed either during the Atlantic Period (8 ka–6 ka BP) or during the upper part of the Sub-Boreal Period (4 ka BP).

The Tafi valley (Northwest Argentina) was densely occupied by agropastoral societies during the Late Holocene. These peoples made profound changes in the landscape during the development of productive economies. Previous geomorphological and geoarchaeological studies have produced good basic information about the Holocene landscape evolution of this semiarid region. However, little is known about the relationship between human activities and landscape responses. The alluvial fans forming the valley´s piedmonts show morphosedimentary records that could be related to environmental changes and, from Late Holocene, with human activities. Agropastoral settlements started in the Formative Period (ca. 2500 yr BP) and land exploitation practices produced a profound degradative impact. This paper applies geoarchaeological techniques to explore the magnitude of the geomorphological and edaphic alterations introduced by man. Analyzed records enabled us to make an evaluation of erosive and degradative processes produced as dynamic geomorphological responses to human interventions. These processes were decisive for the current configuration of the valley. Fil: Sampietro Vattuone, Maria Marta. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Peña Monné, José Luis. Universidad de Zaragoza; España Fil: Roldán, Jimena. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Dip, Alejandra Belén. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Maldonado, Mario Gabriel. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Lefebvre, Maria Gisela. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Geoarqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: Vattuone, Marta Amelia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina

Extreme events disturb the development paths of geomorphological systems. The effect of such events on relief tends to persist for long periods of time and affects the future development of such systems. This paper focuses on changes in middle mountain valleys associated with an extreme hydro-geomorphological event that occurred in the Western Tatra Mountains (Polish Carpathian Mountains) in June of 2007. The geomorphological effects were mapped and an analysis of valley-bottom deposits and dendro-geomorphological data on tree roots and stems was used to identify patterns in the geomorphological transformation taking place during such events. In addition, the organic material obtained from fans was dated by means of carbon-14 dating. The effects of previous extreme events in the study area and their geomorphological outcomes were compared. Four main valley section types were identified in the valley longitudinal profile. Unevenly aged (from 14C 390 ± 30 years YBP (1441–1631 cal AD) to 14C 3760 ± 70 YBP (4318–3962 cal BP)) organic material was revealed at different depths of each studied fan. A complex structure with alternating layers of fine and coarse material from the analysed fans was identified. The colluvial-alluvial structure of fans suggests that extreme high-energy events did occur more than once per century during the Holocene. This type of fan structure can be referred to as a patchwork. In the study area, rainfall with high energy potential occurs once in every 6–9 years and extreme hydro-geomorphological events occur every 15 years. This type of extreme event may not be exceptional in the history of middle mountain areas.