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Palaeoclimatic records from southern tip of South America during the Last Holocene, indicate important climate intervals, such as the Medieval Climate Anomaly and Little Ice Age, which offered new scenarios to hunter-gatherer groups who inhabited the region. The aim of this paper is to explore the social practices carried out by hunter-fisher-gatherer societies of the southern part of the Atlantic Coast of Tierra del Fuego island (53–55°S, 66–74°W) in order to deal with these environmental changes. From our perspective, foragers have played an active role in designing strategies to cope with environmental fluctuations. Consequently, we argue that in a context of ecological uncertainty, these societies would have developed flexible strategies in terms of subsistence, technology and settlement patterns. In order to test this proposal, zooarchaeological and technological analysis of different archaeological assemblages dated between the 1300 to 220 BP were undertaken. The results show that these hunter-fisher-gatherer societies exploited a broad range of faunal resources using a versatile technology which encompassed tools with low production values and high use values. Likewise, the analysis of landscape organization revealed a settlement strategy centered on the most productive habitats, which were preferentially reoccupied. We suggest that these strategies, supported by cumulative knowledge and material conditions, could have enhanced social resilience and sustainability. [ABSTRACT FROM AUTHOR]

Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to be excellent tools in understanding paleoenvironmental, paleoecological, and paleoclimatic changes that took place during the Holocene period, and how these changes interacted with urban development and growth. This paper presents sedimentological, high-resolution x-ray fluorescence (XRF scanning), micropaleontological, and x-ray diffraction (XRD) data from three shallow sediment cores that were retrieved from Aliki (ancient Siphai or Tipha) salt pond. The study area is located in a unique, highly tectonic geographical region, at the northeast part of the Gulf of Corinth in Greece. Beachrock deposits that form a barrier between the salt pond and the marine environment seem to play an important role in the evolution of the area. The chronological framework was set at around 3100 cal. BP by four 14C radiocarbon dates, and the evolutionary model that was established indicates four different changes taking place during this period at the study area. From around 3100 to 1600 cal. BP, a transition from a closed to an open lagoonal environment was identified, interrupted by a fluvial terrestrial deposit at around 2500 cal. BP. A shift toward a closed lagoonal system at around 1600 cal. BP and the establishment of a salt pond environment seem to correlate with tectonic activity. The study provides important information about the evolution of coastal landscape in such a tectonic active region and points the interaction between regional human activity and climatic changes during the late-Holocene period. [ABSTRACT FROM AUTHOR]

High-latitude permafrost peatlands are sensitive to global warming, and understanding their paleohydrological evolution is critical for assessing future hydrological and environmental changes. This paper presents a diatom record from a peat deposit covering the past 3300 years to reconstruct the moisture and acidity conditions in the Tuqiang permafrost peatland in the northern Greater Khingan Mountains of northeast China. Our findings are integrated with previously published records of plant macrofossils, palynology, and geochemistry from the same profile. From 3300 to 2800 cal yr BP, planktonic and benthic diatoms were equally abundant, indicating relatively high moisture conditions, while the low abundance of acidophilous diatoms reflects relatively high pH during this interval. Pollen data show dominance by sedges with input from the surrounding Pinus forest, while LOI data and lithology suggest that the site was a non-peat accumulating wetland. During the period 2800–1100 cal yr BP, the dominance of planktonic diatoms indicates a wetter local environment, concurrent with the dominance of peat-forming sedges (Eriophorum), indicating the development of a peatland. Between 1100 and 500 cal yr BP, a short-lived increase in acidophilous diatoms (Eunotia) marks a decrease in pH. Since 500 cal yr BP, the dominance of benthic diatoms reflects a drier environment, while a vegetation shift from an Eriophorum -dominated rich fen to a Sphagnum- and Ericaceae-dominated poor fen. An increase in Eunotia diatoms prior to the Sphagnum peak may indicate that diatoms are more sensitive to local acidified habitats than moss. Peatland development in the northern Greater Khingan Mountains was likely induced by the onset of a cooler and wetter climate starting at approximately 2800 cal yr BP, a scenario supported by regional paleoclimate records. Since 700 cal yr BP, the peatland has been affected by both anthropogenic activities and climatic changes, as a drying climate and intensified human activities around the study area reduced diatom species diversity and peat accumulation. Under the background of future global warming and enhanced human activities, the decreasing species diversity and carbon accumulation rate of peatlands in high-latitude permafrost regions need more attention. • Diatoms can indicate local moisture and acidity in permafrost peatlands. • Diatoms are likely more sensitive to microhabitats than bryophytes. • TQ peatland formed after 2800 cal yr BP caused by the cooler and wetter climate. • Rich-fen shifted to poor-fen which co-influenced by deforestation and dry climate at LIA. [ABSTRACT FROM AUTHOR]

The loess-paleosol proxy records from mid-latitude Asia have been instrumental in the reconstruction of regional paleoclimate evolution and its relationship with global climatic changes. The present study explores the discrete occurrence of a loess and paleosol sequence (LPS) in the Southern Zanskar Range (SZR), NW Himalaya. Stratigraphic variations in sediment texture, supplemented with geochemical, organic and magnetic proxies, indicate two broad phases of loess accretion (L-1) and paleosol formation (PS-1). The older phase of loess accretion (L-1) is dated between 2.5 ± 0.3 ka and >2.0 ka, whereas the L-2, which fully transformed into the modern soil (MS) probably deposited during the Little Ice Age (LIA) phase. The textural attributes (high sand content) of loess indicate source proximal deposition, whereas the geochemical and magnetic proxies point towards the pre-depositional weathering (in the source area). The PS-1 dated to 2189 ± 296 cal yr BP indicates improved moisture conditions, whereas the MS is assigned to post LIA warm phase. These findings provide an important step towards better understanding the sensitivity of loess accretion and paleosol formation in the SZR linked to late Holocene climate variability. [ABSTRACT FROM AUTHOR]

Past vegetation and environmental changes and the role of climate as well as human activities are of major interest. The Hyrcanian region with a high number of endemic species has a poorly known paleoenvironmental history, especially the western region of northern Iran. This study aims to investigate a radiocarbon-dated sediment core of the Kholasht-Kouh Lake (KHL) for the recorded between ca. 510 and 1180 cal yr BP. KHL is located at 2000 m elevation and surrounded with steppe vegetation above the present-day forest line. Multi-proxy analyses including pollen, non-pollen palynomorphs, charcoal, loss on ignition, and X-ray fluorescence were applied to reconstruct past environmental dynamics. The results indicate the dominance of herbaceous vegetation (mainly Poaceae, Artemisia, and Amaranthaceae) around the lake during the whole record, except for the period between 1010 and 740 cal yr BP. During this period of the Medieval Climatic Anomaly (1000–700 cal yr BP) mixed forest increased, consisting mainly of Quercus, Fagus, Carpinus, and Juniperus. The K, Ti and Si elements (as indicators for increased in detrital inputs) suggest relatively humid condition between 1180 and 1010 cal yr BP. Furthermore, higher lake levels may indicate from low values of the Mn/Ti, Ca/Ti and Sr/Ti ratios. After 1010 until 740 cal yr BP the highest value of the Si/Fe ratio, suggested warmest period of the record. While the lowest value of the Si/Fe ratio, in line with the reduction of other elements and ratios, between 740 till 510 cal yr BP represented cold and dry period. Humans were present around the study area at least since beginning of the record, but did not played an important role impacting the vegetation. [ABSTRACT FROM AUTHOR]

This paper presents the first high-resolution Holocene stalagmite record of Taiwan from Jianfei Cave (22°50.873 N; 120°21.255 E) in Dagangshan Mountain, South Taiwan. The 13.6-cm long stalagmite (DGS-1) has been dated by AMS 14 C dating, spanning from AD 700 to AD 1933. The δ 18 O, δ 13 C and XRF scanned elemental profiles reveal interannual variations in climate and environmental conditions, with light δ 18 O and δ 13 C excursions reflecting wet climate and better vegetation coverage under stronger East Asia Summer Monsoon (EASM). Dark layers in DGS-1 containing high Fe, Mn and Sr contents were formed during dry episodes. Five periods with different climate regimes and vegetation conditions can be identified in the DGS-1 record: Period I (AD 700–1200) and Period V (AD 1810–1933) had warm and wet climates with good vegetation coverage. A drying trend probably corresponding to the switch from El Niño-like to La Niña-like oceanic condition occurred during Period II (AD 1200–1400). Cold but relatively wet climates with good vegetation coverage were prevailed during Period III (AD 1400–1610), whereas cold and dry climates with poor vegetation coverage were dominated during Period IV (AD 1610–1810). Based on the rainfall record of Tainan since AD 1897 and the stalagmite record, we found that stronger total solar irradiation (TSI) resulting in strong EASM produces heavy rainfall in South Taiwan on interannual-to-decadal scales; and vice versa. The 117-yr instrumental rainfall record of Tainan showed that rainfall in Tainan decreased during April-to-June and strongly increased during July-to-September in many La Niña years (positive SOI and negative Niño 3.4). This may be because weaker Meiyu rainfall but stronger tropical Equatorial Pacific cyclones (or typhoon) under La Niña condition. Thus, it is better to use seasonal rainfall for detecting relationship between Tainan rainfall and ENSO. On decadal-to-centennial scales, strong El Niño-like state and warm Pacific Decadal Oscillation (PDO) phase are in favor of wet conditions in South Taiwan. [ABSTRACT FROM AUTHOR]

In the Central Atacama Desert (22°-24°S; henceforth CAD), around 3700 cal yrs BP, human economies begin to transition from relying mostly on hunting and gathering to increasingly incorporating horticulture and pastoralism became more intensive during the Late Intermediate Period (LIP; beginning at ca. 1050 cal yrs BP/900 AD). In this extreme environment, the well-being of past and present farming and herding communities is directly tied to water availability. The lack of proper paleoclimatic/environmental records in terms of their temporal/spatial resolution impeded evaluation whether sedentarization was synchronous, in some degree, with the amelioration of dry conditions recorded during the Late Holocene at millennial timescales. The present paper thus aims (1) to reconstruct the past environmental and climatic dynamics in the CAD (22°S) during the late Holocene at millennial to sub-centennial scales based on the pollen record of fossil rodent middens of Cuesta Chita site and; (2) to discuss their possible relationship to changes in cultivation and water management as seen at the archaeological sites of Topaín, Paniri and Turi, located in the Salado River basin. The CCH rodent midden pollen record reflects wetter (drier) than present phases around 4400, 3650, 3000, 2200–2100, 1600, 855–840, 520–450 and 100 cal yrs BP (980, 450-115 cal yrs BP). By the time that wetter-than-present conditions occurred in the CAD (Formative Period, 3500-1050 cal yrs BP), local communities had already developed small-scale horticultural practices, yet they did not develop extensive or intensive agricultural practices. Indeed, historical processes leading to economic transformations and the rapid adoption of intensive agriculture throughout the CAD after 1000 cal yrs BP occurred and were probably favored by wetter than present conditions, suggesting positive correlations between climatic and cultural change. However, these correlations are complex and non-deterministic. In fact, decreased moisture between 650 and 600 cal yrs BP in the Turi Basin was met by agropastoralists at Topaín with complex local strategies that included changing water management practices and significantly extending farmed lands. Similarly, the Topaín fields were abandoned during a period of much-wetter-than-present conditions. The chronologically fine-grained comparison of the CCH and archaeological records reveals that the relationship between climate and culture is complex, non-deterministic, and historically contingent, with examples of agricultural expansion during a time of water stress, and the abandonment of fields during a time of abundance. • Human-environment dynamics in the Central Atacama Desert during the Late Holocene. • Late Holocene climatic variability at millennial to sub-centennial resolution based on pollen records. • Wet (dry) phases occurred ∼4400, 3650, 3000, 2200-2100, 1600, 855-840, 520-450 and 100 (980, 450-115) cal yrs BP. • Human responses to climatic change are various and there is no simple relationship between water availability and land use. [ABSTRACT FROM AUTHOR]

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In this study, late Holocene vegetation, climate and human impacts were investigated using multiproxy data-pollen percentages, pollen accumulation rates (PAR), humification and loss-on-ignition (LOI)-measured from peat sediments from Daiyun Mountain, southeast China. A stratigraphic chronology was established on the basis of four radiocarbon dates. The 4,350 year sequence of vegetation history and climate change exhibits three distinctive stages: (1) 4,350-1,000 cal bp, during which the vegetation was dominated by evergreen forests mainly composed of broad-leaf trees, indicating a warm and wet climate; (2) 1,000-550 cal bp, during which the climate was thought to be cool and dry, based on a decrease in pollen percentages and the PARs of trees, shrubs and wetland herbs, and an increase in the pollen percentage and PAR of dry land herbs, as well as high overall LOI values; and (3) 550 cal bp to modern times, during which higher pollen percentages of dry land and wetland herbs, along with low pollen percentage and PAR of trees and shrubs, as well as low absorbance and LOI values, suggest relatively cooler but wetter climate conditions. In addition, major climatic events, such as the warm period from ad 670-960, the Medieval Warm Period ( ad 1050-1520) and the Little Ice Age ( ad 1580-1850), could be identified within the peat sediments in this study, with climatic conditions at these times being characteristically warm and wet, warm and dry, and cold and wet, respectively. Pollen signals indicate significant human impact since 1,000 cal bp, which may be linked to the development of the local porcelain industry and a rapid increase in the population in the study region. [ABSTRACT FROM AUTHOR]

Carroll College and the Helena National Forest are working in a 6-year research partnership designed to investigate the relationship between paleoclimate change and human adaptation in the Big Belt Mountains of central Montana, USA. This ongoing project is designed to gather archaeological and paleoenvironmental data from three diverse ecosystems within one drainage basin: high-altitude park areas (1800–2100 m), mid-altitude conifer forests (1200–1500 m), and low-altitude locales (under 1500 m) along the Missouri River. These data will represent paleoecological and archaeological changes through time and will detect synchrony and diversity across an elevation gradient. Thus far, excavation of two mid-altitude sites, dating to 2400 and 4500 BP, and one high-altitude site, dated to 2400 BP, revealed evidence of a significant drought period about 2000 years ago. To date, the excavated sites evidence a shift in pollen to drier species, a shift to higher sedimentation rates, and changes in snail and vertebrate species. [ABSTRACT FROM AUTHOR]

It is currently suggested that climate change on the northeastern Tibetan Plateau (TP) was influenced alternately by the monsoon and the Westerlies. However, the mechanisms driving Holocene climate change on the TP remain unclear, since the extent of the influence of individual atmospheric circulation systems has not yet been clearly defined because of the shortage of high-quality paleoclimatic records. This is especially true in the central TP, where only a few ice core and paleolimnological records are available. Here, we present a decadal-resolution temperature record from Dagze Co in the central TP for the past 2000 years, based on the unsaturation index of long-chain alkenones, using an updated temperature calibration, and a record of precipitation isotopes from compound-specific isotope ratios of leaf waxes. The centennial-scale variation of the temperature and precipitation isotope records captures well-known climatic events over the past 1000 years, for example, the ‘Little Ice Age’, which was cooler and drier than the ‘Medieval Warm Period’. However, the relationship between temperature and the precipitation isotope records differed during the interval at 2000–1000 cal. yr BP compared to the past 1000 years, probably because of changes in precipitation seasonality and the additional influence of the Westerlies on the central TP. In addition, the temperature records exhibit a prominent 210-year cyclicity, suggesting a possible influence of solar radiation on temperature variability. [ABSTRACT FROM AUTHOR]

Annually laminated (varved) sediments from Lake Kallio-Kourujärvi, Central Finland, provide high-resolution sedimentological data for the last three millennia. These varves consist of two laminae that represent (1) deposition during the spring-to-autumn growing season, composed of degraded organic matter and a variety of microfossils, and (2) deposition during winter, composed of fine-grained homogenous organic matter. Because of the absence of a clastic lamina, these varves differ from the typical, well-described, clastic-organic varve sequences in Fennoscandian lakes. Such organic varves in Finnish lakes have not been studied in detail before. Three thousand varves were counted and their seasonal deposition was distinguished. Comparison of varve thickness with meteorological data revealed a positive correlation between organic varve thickness and precipitation. This suggests that catchment erosion processes and consequent organic matter and nutrient inputs are important factors in organic varve formation. The correlation between temperature and growing-season lamina thickness varied from insignificant, to positive, to negative during different time spans. This suggests that organic matter accumulation can sometimes have a significant, but unpredictable role in organic varve formation, via organic matter production and degradation, processes that are influenced strongly by water column temperature. The organic varves of Lake Kallio-Kourujärvi enable a unique, high-resolution approach for the study of past climate and environment. Our results suggest that decadal periods of increased precipitation occurred during BP 2150-2090, 1710-1620, 1410-1360, 920-870 (1030-1080 AD), and after 370 BP (1580 AD). Dryer intervals occurred during BP 2750-2720, 1900-1850, 1800-1740, 1600-1500, and 780-700 (1170-1250 AD), 590-520 (1360-1430 AD). [ABSTRACT FROM AUTHOR]

There is currently no consensus on the importance of climate change in Mesoamerican prehistory. Some invoke drought as a causal factor in major cultural transitions, including the abandonment of many sites at 900 CE, while others conclude that cultural factors were more important. This lack of agreement reflects the fact that the history of climate change in many regions of Mesoamerica is poorly understood. We present paleolimnological evidence suggesting that climate change was important in the abandonment of Cantona between 900 CE and 1050 CE. At its peak, Cantona was one of the largest cities in pre-Columbian Mesoamerica, with a population of 90,000 inhabitants. The site is located in the Cuenca Oriental, a semiarid basin east of Mexico City. We developed a subcentennial reconstruction of regional climate from a nearby maar lake, Aljojuca. The modern climatology of the region suggests that sediments record changes in summer monsoonal precipitation. Elemental geochemistry (X-ray fluorescence) and δ18O from authigenic calcite indicate a centennial-scale arid interval between 500 CE and 1150 CE, overlaid on a long-term drying trend. Comparison of this record to Cantona's chronology suggests that both the city's peak population and its abandonment occurred during this arid period. The human response to climate change most likely resulted from the interplay of environmental and political factors. During earlier periods of Cantona's history, increasing aridity and political unrest may have actually increased the city's importance. However, by 1050 CE, this extended arid period, possibly combined with regional political change, contributed to the city's abandonment. [ABSTRACT FROM AUTHOR]