85 results
Search Results
2. Commentary: Human brains have shrunk: the questions are when and why.
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De Caro, Liberato and Gilissen, Emmanuel Paul
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HUMAN origins ,CRANIOMETRY ,BIOLOGICAL evolution ,HOMO naledi ,TIME series analysis ,NEANDERTHALS - Abstract
The given text is a list of references and acknowledgments for a research article on the topic of human brain size and evolution. It includes various studies and papers that have explored the changes in brain size over time, as well as the factors that may have influenced these changes. The article discusses different perspectives and theories on the subject, including the impact of climate change and the transition to complex societies. The references cover a wide range of topics related to human evolution and brain morphology, providing a comprehensive overview of the current research in the field. [Extracted from the article]
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- 2024
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3. Holocene flood records and human impacts implied from the pollen evidence in the Daming area, North China Plain.
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Jinsong Yang, Linjing Liu, Roberts, Harry, Zhe Liu, Lei Song, Peng Zhang, Junghyung Ryu, Zhixiong Shen, and Yuecong Li
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HOLOCENE Epoch ,POLLEN ,ALLUVIAL plains ,STRATIGRAPHIC correlation ,PLAINS ,COTTON ,FERNS - Abstract
Understanding the environmental significance of pollen and spores in alluvial plains is important for stratigraphic correlation and paleoenvironmental reconstruction. This paper presents palynological data from the North China Plain and explores their relationship with paleoflood records and human impacts since the Holocene. Our data reveal that pollen concentration and pollen assemblage vary in flood deposits (including overbank deposits and slackwater deposits) and inter-flood deposits (including sandy soils and lacustrine deposits). Flood deposits have higher fern percentages (28.6%) and lower herbaceous percentages (14.8%) compared to inter-flood deposits, though slackwater deposits share similar pollen concentrations and assemblages with sandy soils. Notably, overbank deposits are characterized by pollen-poor zones and aggregation of deteriorated pollen grains, especially in Unit III (755-385 cm, ca. 3.2-2.2 ka) and Unit V (190-0 cm, after ca. 0.6 ka). These findings suggest that overbank deposits correspond to strengthened hydrodynamic conditions at the flood-peak stage. Furthermore, the indicative pollen and spores provide compelling evidence for intensifying human impact in the North China Plain since the late Holocene. An aggregation of Selaginella sinensis at the depth of 640-610 cm indicates deforestation in the uplands since ca. 2.9 ka. Similarly, a sharp increase in Malvaceae percentage at the depth of 285-215 supports historical records of initial cotton planting in the Tang Dynasty (ca. 1.4-1.1 ka). The study underscores the value of palynological analysis for reconstructing paleoenvironment and human-environment interactions, providing a robust framework for understanding landscape evolution in the North China Plain. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Mosses recognized as glacial relicts from their postglacial distribution in Poland
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Drzymulska, Danuta
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- 2024
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5. Holocene Geomagnetic Excursions in Peat Deposits
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Peskov, A. Yu., Didenko, A. N., Karetnikov, A. S., Klimin, M. A., Arkhipov, M. V., Kozhemyako, N. V., and Tikhomirova, A. I.
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- 2024
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6. Latitudinal patterns of shifts in cladoceran communities throughout the Holocene: A paleoecological case study of northwestern Russia.
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Ibragimova, Aisylu G., Krolenko, Ivan I., Frolova, Larisa A., Subetto, Dmitry A., Potakhin, Maksim S., Belkina, Natalya A., Grekov, Ivan M., and Kotov, Alexey A.
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BODIES of water , *SEDIMENT analysis , *PALEOECOLOGY , *SEDIMENT sampling , *HOLOCENE Epoch - Abstract
Paleolimnology is a rapidly expanding field within the natural sciences. To date, many scientific papers have been published focusing on studies of remains from single sediment cores in specific lakes, or a few cores from the same water body. However, few previous publications have provided a comprehensive comparative analysis of taphocenosis (and maternal community) changes in different water bodies from a large geographical region during whole Holocene using multivariate statistical methods. We conducted a joined statistical analysis of data obtained as a result of the cladoceran analysis of the sediment samples from six cores taken along the North-South transect from the Kola Peninsula to the Karelian Region (North-West Russia). Our aim was to identify, based on quantitative statistical methods, general whole-Holocene patterns in cladoceran taphocenosis changes. All taphocenoses in all cores from six lakes can be classified into six clusters based on their species composition. Our unexpected conclusion is that different taphocoenoses are formed by the same set of species, but their proportions vary significantly. This suggests that the same species may play different functional roles in different maternal communities. During whole Holocene, we observed a single taphocenosis cluster in the Holocene core from Lake Antyukh-Lambina, and four taphocenosis clusters in the Lake Medvedevskoe, with an intermediate number of clusters in the lakes between them. Furthermore, it can be asserted that the potential for cluster changes in the core is greater for the more southern studied water bodies (0–3 clusters for northern lakes vs. 4 clusters for southern lakes). Based on our data, we hypothesize that the diversity of cladoceran associations during the Holocene was lower in Arctic/Subarctic lakes, possibly due to their formation by ubiquitous species. Our study suggests that at least some Arctic lake ecosystems have remained unchanged since deglaciation times. Further studies are necessary to determine if this is a general rule. [ABSTRACT FROM AUTHOR]
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- 2024
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7. The 4.2 ka event: A review of palaeoclimate literature and directions for future research.
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Helama, Samuli
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NORTH Atlantic oscillation , *LITTLE Ice Age , *PALEOCLIMATOLOGY , *MIDDLE Ages , *CHRONOSTRATIGRAPHY - Abstract
In recent years, much evidence has been presented on the 4.2 ka event. A review of 317 palaeoclimate papers shows that dry conditions were common during the event, especially from Eastern Mediterranean to India. The 4.2 ka event was not, however, a global drought event. Wet conditions were reported especially for central/northern Europe and sub-Saharan Africa. The 4.2 ka event is typically characterized either as short (4.2–4.0 ka) or long (4.4–3.8 ka) episode, possibly developing over an extended interval of time, in keeping with the North Atlantic forcing and correlating with the Bond 3 event of ice-rafted debris. This forcing is understood to drive a southward migration of the Inter-Tropical Convergence Zone (ITCZ), resulting in decreased rainfall over most of the Asian monsoon region, with possibility that an interplay of El Niño–Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) has modulated the global circulation. Cold conditions were also reported but less frequently, in comparison to other Bond events such as the 8.2 ka event, Dark Ages Cold Period and Little Ice Age. Some high-resolution records show a double peak structure of which two anomalies are tree-ring dated to 4.14–4.05 ka and 3.97 ka. Accurately and precisely dated high-resolution records indicative of various climatic variables, especially outside of the traditional study region (Mediterranean–Middle East–India–China), including reconstructions of the ENSO and NAO histories and ITCZ migrations, are crucially needed for rigorous examination of the global scale characteristics of the 4.2 ka event and its forcings. Such research seems to be just beginning. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Holocene vegetation and flora dynamics of the west Cork/Kerry region, south-western Ireland
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O’Connell, Michael and Overland, Anette
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- 2024
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9. The Stonehenge bluestones did not come from Waun Mawn in West Wales.
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John, Brian
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BUILDING stones , *GLACIAL drift , *NEOLITHIC Period , *ARCHAEOLOGISTS - Abstract
This paper examines the hypothesis that Waun Mawn in West Wales provided the bluestone monoliths that were used at Stonehenge. Some archaeologists believe that the site supports the last remains of a giant stone circle or 'Proto Stonehenge' which was dismantled and transported to Salisbury Plain around 5000 years ago. It was claimed, after three excavation seasons at Waun Mawn in 2017, 2018 and 2021, that there is firm evidence of some standing stones which were later removed or broken up, but it has still not been demonstrated that there ever was a small stone circle here, let alone a 'giant' one. Furthermore, there have been no control studies in the neighbourhood which might demonstrate that the speculative feature has any unique characteristics. There is nothing at Waun Mawn to link this site in any way to Stonehenge, and this is confirmed by recent cited research. No evidence has been brought forward in support of the claim that 'this was one of the great religious and political centres of Neolithic Britain'. It is concluded that at Waun Mawn and elsewhere in West Wales there has been substantial 'interpretative inflation' driven by the desire to demonstrate a Stonehenge connection. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Zooarchaeological perspectives in the framework of the Anthropocene: Contributions to ecological, environmental and conservation studies from South America.
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Mignino, Julián, López, José Manuel, and Samec, Celeste Tamara
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ENVIRONMENTAL protection , *ENVIRONMENTAL sciences , *MARINE mammals , *BIOLOGICAL extinction , *ANIMAL communities , *MAMMAL communities , *BIRD populations , *ECOSYSTEMS - Abstract
This special volume considers major recent changes in southern South American animal communities. Eleven papers consider megafauna, pinnipeds, marine mammals, small terrestrial mammals and birds and are grouped under four sub-headings: (1) Isotopic insights into guanaco populations; (2) Historical sources and marine ecosystem change; (3) Changes in small mammal communities and human impacts; and (4) megafaunal extinction, domestication, avifauna and recent interactions with humans. Although some of these contributions include changes that occurred earlier in the Holocene, many highlight a current decrease in the taxonomic diversity of communities and ecosystems in different environments, which are likely to have been caused by modern human activities. The Anthropocene concept is seen as providing a useful framework for understanding and mitigation of such adverse human impacts. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Dynamics of the Vegetation of Central Yamal in the Holocene
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Lapteva, E. G., Korona, O. M., and Kosintsev, P. A.
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- 2024
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12. Disentangling late quaternary fluvial and climatic drivers of palaeohydrological change in the Najaf Sea basin, Western Iraq.
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Briant, R. M., Jotheri, J., Al‐Ameri, I., Ahmed, A., Bateman, M. D., Engels, S., Garzanti, E., Nymark, A., and Reynolds, T. E.
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OPTICALLY stimulated luminescence dating ,WATERSHEDS ,ARCHAEOLOGICAL excavations ,SHORELINES ,MINERAL analysis ,HEAVY minerals ,RADIOCARBON dating - Abstract
The water resource provided by lake basins in the western desert of Iraq is important for human occupation of areas outside the Tigris‐Euphrates floodplain, both in the past and into the future. This paper presents the first geomorphological and geochronological study of the date of formation of the Najaf Sea and the only such study of any lake basin to the west of Mesopotamia. Geomorphological shoreline features and a palaeochannel linking to the Euphrates were studied and dated using optically stimulated luminescence (OSL) and radiocarbon dating. Provenance was determined using heavy mineral analysis. Past environments in the Najaf Sea were reconstructed by molluscan analysis. The earliest OSL ages date from c. 30 000 and 22 000 years ago and seem to predate lake formation. Younger OSL ages date the highest lake level at c. 19 m asl to between 1620–1760 AD (base) to 1906–1974 AD (near surface). The radiocarbon ages are affected by a freshwater reservoir effect, but the maximum ages recorded for either of the c. 15 m and c. 17 m asl shorelines are c. 800 cal. BC. This predates the first archaeological sites in the Najaf basin and is similar to maximum ages of c. 850 and c. 1100 cal. BC from the associated palaeochannel. This timing does not seem to be linked to a humid climate event. We therefore conclude that the establishment of the Najaf Sea in the Najaf basin occurred as a result of an avulsion event within the Euphrates system that diverted flow to the basin. The trigger for this avulsion event likely related to rapid sediment accumulation and may have been either autogenic or driven by human activity. This study therefore suggests that Najaf Sea formation facilitated human expansion beyond the Tigris‐ Euphrates floodplain and occurred due to avulsion of the Euphrates. [ABSTRACT FROM AUTHOR]
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- 2024
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13. First palynological results from Spila nad Procjepom cave, Mljet island (Croatia).
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Bakrač, Koraljka, Sirenko, Olena, Hruševar, Dario, Baniček, Ivona, Novak, Vibor, Kletečki, Nataša, and Sršen, Ankica Oros
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FOREST degradation , *CAVES , *FOREST plants , *GROUND cover plants , *VEGETATION dynamics , *GROUND vegetation cover - Abstract
This paper presents the first results of palynological research from the Spila nad Procjepom cave, situated in the Mljet National Park, Croatia. The palynological data obtained, enables a partial insight into the local vegetation cover, temporal changes in the vegetation during the accumulation of studied deposits (at ca. 3500 cal years BP), and post-depositional processes that influenced the palynomorph assemblage. Results of palynofacies analysis indicate changes from fluvial (channel deposits), through palustrine to terrestrial environments. Although the interpretation of changes in plant cover, due to the lack of statistical significance, should be taken with caution, preserved pollen types confirm the dominance of the Mediterranean evergreen forest vegetation on Mljet island. Moreover, a high proportion of non-arboreal pollen (NAP) indicates some level of forest degradation, ranging from Mediterranean open forest to degraded maquis. Abundant charcoal additionaly confirms that the cave was inhabited by humans. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Editorial: Paleolimnology: insights from sedimentary archives.
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Bao, Kunshan, Aranguiz-Acuna, Adriana, and Cao, Xiaofeng
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PALEOLIMNOLOGY ,WETLANDS ,GLOBAL environmental change ,LAST Glacial Maximum ,GLOBAL warming ,BIOTIC communities - Abstract
This article discusses the field of paleolimnology, which studies lake and wetland sedimentary profiles to understand past environmental changes. These sedimentary archives provide valuable information about natural and human-induced changes in the environment, allowing researchers to investigate the interactions between past climate dynamics and human activities. The article highlights the importance of accurate dating methods and the integration of modern environmental data into paleoenvironmental studies. It also presents several case studies from different regions, showcasing the diverse applications of paleolimnology in studying climate change, biogeochemical cycles, environmental pollution, and species invasions. The article concludes by emphasizing the growing importance of paleolimnology and its contribution to our understanding of long-term environmental changes. [Extracted from the article]
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- 2024
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15. Pollen-based seasonal temperature reconstruction in Northeast China over the past 10,000 years, and its implications for understanding the Holocene Temperature Conundrum.
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Geng, Rongwei, Zhao, Yan, Herzschuh, Ulrike, Cui, Qiaoyu, Zheng, Zhuo, Xiao, Xiayun, Ma, Chunmei, and Liang, Chen
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PARTIAL least squares regression , *FOSSIL pollen , *COLD (Temperature) , *ATMOSPHERIC models , *CLIMATE change - Abstract
The Holocene Temperature Conundrum refers to the mismatch between proxy-based temperature records and those based on climate model simulations. A possible reason for this mismatch is a putative proxy-based bias in reconstructed summer temperatures, and therefore, regional reconstructions of seasonal temperature are crucial for resolving the conundrum. In this paper, we reconstruct vegetation and climate changes over the last ∼10,000 years BP based on a high-resolution pollen record from Gushantun peatland, Changbai Mountains, Northeast China. Multiple quantitative reconstruction approaches were used and weighted averaging partial least squares regression (WAPLS) was found to be the most appropriate method for reconstructing Holocene temperature and precipitation. The reconstructed climate record shows that the Holocene Climate Optimum occurred between 8 ka and 6 ka and exhibited a cold month mean temperature that was 3 °C warmer than modern temperatures. Climate gradually cooled during late Holocene with a minimum cold month temperature of −19.6 °C. Four prominent cold events occurred around 8.7 ka BP, 7.8 ka BP, 5.7 ka BP, and 2.5 ka BP with an amplitude variation up to 3 °C. The synthesized seasonal temperature time series and a comparison with other proxies show that the decreasing trend in mean annual temperature is not a seasonal bias caused by summer temperature change. This study provides evidence of a Holocene seasonal temperature change at a regional scale and insights for further understanding of the Holocene Temperature Conundrum. • Reconstructed seasonal temperature changes based on a new high-resolution fossil pollen record in the Changbai Mountains • Synthesized climatic series in Northeast China to investigate the characteristics of regional temperature changes and their driving factors • Reconstructed winter temperature as evidence to address the alleged seasonal bias for the Holocene temperature conundrum [ABSTRACT FROM AUTHOR]
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- 2024
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16. Lithic technology before and after the Storegga tsunami (8200 cal BP): Dissolving large-scale regional trends to identify social impact of crisis in western Norway.
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Damlien, Hege, Nyland, Astrid J, and Redmond, James J
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REGIONAL development , *SOCIAL impact , *TSUNAMIS , *RADIOCARBON dating , *MODERN society - Abstract
Around 8200 years ago, the Storegga tsunami hit the west coast of South Norway. The physical extent of the tsunami has been well documented but the consequences of the event for contemporary societies have received little attention beyond broad generalizations and, more recently, demographic studies based on statistical modeling of radiocarbon dates. In this paper, we explore whether the different physical impacts of the Storrega tsunami could have initiated observed regional developments in lithic technology. We have analyzed lithic assemblages from 30 carefully selected Middle and Late Mesolithic sites (dated between c. 7500 and 5000 cal BC) spread across six designated “focus areas” along the coast of western South-Norway. We identified five blade production concepts in use during the Late Mesolithic and highlight potentially significant differences in their spatial and temporal distribution. Although neither the tsunami nor the environmental stresses experienced by Mesolithic communities appear to have prompted large breaks in traditional practices, we suggest that the event marks a point in time from where specific differences and modifications in lithic technology start developing at a local scale. We argue that sudden, yet transitory events such as the Storegga tsunami, may rupture the historical contingency of social networks and communication lines resulting in changing social contexts influencing material change. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Block alignments/talus flatiron stages as response to lithological factors and dynamic slope changes in the Central Ebro Basin, NE Spain.
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Peña-Monné, José Luis, Sampietro-Vattuone, María Marta, Picazo-Millán, Jesús, and Alcolea-Gracia, Marta
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LITTLE Ice Age , *TALUS (Geology) , *RADIOCARBON dating , *EVOLUTIONARY models , *IRONS (Pressing) - Abstract
The central sector of the Ebro Depression is characterized by an abundance of isolated buttes with relict talus flatiron morphologies and block slopes on the footslopes. This paper presents two unusual study cases where the block slopes are aligned in parallel with the retreating escarpment. The evolutionary process of both buttes started with the formation of talus flatirons and ended with aligned block slopes. This is because both buttes initially had a detrital caprock (Pleistocene pediment) which eroded away to expose a sandstone layer that functioned as a new caprock and so changed the slope dynamics. Seven stages were identified at La Cobeta butte and five at Puyalón butte. The relative ages obtained for stages II and IV enabled an estimation of the escarpment retreat rates. The chronologies of the other stages of block alignments were estimated using Schmidt-hammer rebound values. The estimated age of the stage II (ca. 6588-6222 cal yr BP) coincides with three radiocarbon datings obtained in the deposit. Stage III (ca. 4235-3684 cal yr BP) is contemporary with the 4.2 Bond event. Stage IV (ca. 2800-2500 cal yr BP) coincides with the 2.8 Bond event and is associated with ceramic potsherds and radiocarbon datings. Stages V and VI developed during the Warm Roman period and the Medieval Climatic Anomaly respectively. Lastly, stage VII was formed during the Little Ice Age. The information obtained regarding the morphological arrangement improves our knowledge of the regional evolutionary model where talus flatirons and block slopes develop in a semiarid environment. • Slope dynamics and evolution can be establish with a block alignments study. • Schmidt-hammer records were applied to make chronological estimations. • Chronological estimations were partially controlled using absolute and relative datings. • Seven evolutionary stages including talus flatiron and block alignments were established. • Block alignments provide more accurate data than talus flatiron on scarp retreat rates. [ABSTRACT FROM AUTHOR]
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- 2024
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18. A Holocene fire history from Terra Nova National Park, Newfoundland, Canada: vegetation and climate change both influenced the fire regime.
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Lake, Nickolas F., Arsenault, Andre, Cwynar, Les C., Willard, Debra, and Ali, Adam A.
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LITTLE Ice Age ,WHITE pine ,PALYNOLOGY ,INTERVAL analysis ,TAIGAS - Abstract
Fire is the largest natural disturbance factor in the boreal forest and plays a critical role in the composition, structure, and succession of stands and landscapes. The island of Newfoundland, located in eastern Canada, is subjected to a greater maritime influence, which may result in longer fire return intervals. The limited data on the fire regime does not account for interactions between fire, vegetation, and climate throughout the Holocene. We used sediment cores from Arnold's Pond, Terra Nova National Park, which covered the last ~11,800 cal. yr BP, to investigate these interactions. We recognize 4 pollen zones and macroscopic charcoal analysis detected 45 local fire events. The 250-year mean fire return interval associated with the current vegetation is longer than a previous estimate for the park, but significantly shorter than other estimates for the island. Our mean fire return interval is within the range of fire estimates from Quebec with similar vegetation. Our results suggest that the fire regime was primarily influenced by vegetation and climate. The transition to an open forest from a shrub tundra resulted in increased fire activity and fire frequency, which were likely driven by additional fuel on the landscape, but could have also been influenced by unknown climatic factors. We identified several examples of changes in the fire frequencies and/or charcoal accumulation that coincided with regional climate shifts, but we also identified a non-synchronous change. The non-synchronous shift to drier conditions resulted in a ~500-year time lag between peak Pinus strobus abundance and maximum fire frequency. Synchronous shifts in fire activity and/or fire frequency coincided with the 8200 event, Medieval Climate Anomaly and Little Ice Age. We also noted a decrease in fire frequency between 2600-1500 cal. yr BP that coincided with similar changes in the fire frequency from ~3000-1000 cal. yr BP in Que bec. Our study highlights the complex interactions influencing the fire regime in our study area during the Holocene. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Revisiting the current phyto-scape of Boomplaas Cave (South Africa) and the possible implications of this for past day-range foraging.
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Lombard, Marlize and Pargeter, Justin
- Abstract
Copyright of Azania: Archaeological Research in Africa is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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20. Taxonomy of Ostracoda (Subfamilies Cytherurinae and Paracytherideinae) from the Southern and Eastern Brazilian Continental Shelves.
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Inês Feijó Ramos, Maria, Carlos Coimbra, João, and Trescastro Bergue, Cristianini
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CONTINENTAL shelf ,MARINE biodiversity ,FOSSILS ,SEDIMENT sampling ,HOLOCENE Epoch - Abstract
A study on Holocene ostracods (subfamilies Cytherurinae and Paracytherideinae) was carried out in 500 bottom sediments samples recovered along the Brazilian continental shelf from Rio Grande do Sul (33º45’S/52ºW) to Espírito Santo (19º35’S/40ºW) states. New species belonging to the subfamily Cytherurinae are here identifi ed and described as follows: Eucytherura rara sp. nov., E. trifi da sp. nov., E. castellata sp. nov., and Semicytherura reticulocostata sp. nov. Three other species are kept in open nomenclature due to scarcity of material for study: Semicytherura sp. 1, Semicytherura sp. 2 and Hemingwayella sp., the last one representing the subfamily Paracytherideinae. The zoogeographical and stratigraphical analyses revealed that most of the species identifi ed do not exceed the latitude 19º30.1’S with the southernmost record at 33º52’S; some of these species extending to the Uruguayan and Argentinian shelves. Exceptions are the species Semicytherura parallelocostata and Semicytherura sp. 2 that reach the northeast and equatorial Brazilian continental shelves at latitudes 10º32’S and 00º08’S, respectively. Two of the studied species have a fossil record in the Pelotas Basin (Brazil): Hemicytherura auriculata (Miocene and Pleistocene) and Semicytherura rugosoreticulata (Holocene). Hemicytherura lapillata has been recorded in a Holocene outcrop in Bahia Blanca (Argentina). [ABSTRACT FROM AUTHOR]
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- 2024
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21. The modern natural tombolos of Greece.
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Petrakis, Stelios, Malliouri, Dimitra I., Vandarakis, Dimitrios, Moraitis, Vyron, Hatiris, Georgios-Angelos, Drakopoulou, Paraskevi, Arapis, Manolis, and Kapsimalis, Vasilios
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INTERNATIONAL environmental law ,LONG-Term Evolution (Telecommunications) ,REMOTE-sensing images ,BEACH erosion ,SEA level - Abstract
Formation and evolution processes of natural tombolos involve many interrelated geomorphological, sedimentary, oceanographic and anthropogenic factors, making their measurement and simulation an extremely difficult task. The present study attempts to fill this knowledge gap by detecting the natural tombolos in Greece, formed in the current sea level, through the statistical analysis of their morphometric and socio-environmental parameters. In addition, the long-term evolution of these coastal depositional landscapes has been determined by comparing old aerial photos taken in 1945 or 1960 and recent satellite images taken from 2020 to 2022. Two thirds of the twenty tombolos studied are subject to erosion, while eight are sporadically destroyed and turned into salients. The Greek tombolos are mildly or heavily exploited for touristic purposes, and fourteen of them are protected by national and international environmental laws. Future studies need to focus on the unstable type of these coastal landforms that are modified from tombolo to salient and vice versa to obtain helpful information about the morphodynamic conditions necessary for their evolution. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Uncovering paleoenvironmental evolution in Xinghua Bay of Southern China during the mid-to-late Holocene, insights from studies of biogeochemical elements in sediments
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Wang, Jinrong, Xu, Xin, Chi, Lianbao, Li, Xin, Wang, Yongchao, Jiang, Miaohua, Chen, Jianming, Li, Jing, and Fan, Xin
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- 2024
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23. Fecal Stanols in the Bottom Sediments of Lake Zapovednoe (Evenkia) Indicate an Insignificant Anthropogenic Load in the Lake Basin in the Late Holocene
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Sinner, E. K., Boyandin, A. N., and Rogozin, D. Y.
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- 2024
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24. Comparison of the Australian summer monsoon-ENSO relationship between the early and late Holocene
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Jing, Yunqing
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- 2024
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25. Elevation of basal lacustrine sediments along the mid-lower reaches of the Yangtze River and its implications for the reconstruction of Holocene water levels
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Yao, Shuchun, Li, Chunhai, and Xue, Bin
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- 2024
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26. Centennial-scale flood cyclicity in the second half of Holocene in the southeast Tunisian sediments: paleoenvironmental region gauge between the western and eastern Mediterranean
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Ben Ameur, Mariem, Masmoudi, Sameh, Omar, Hamdi, and Yaich, Chokri
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- 2024
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27. Amelioration of habitat since the early Holocene contributed to the origin of agriculture in the farming-pastoral zone of northern China
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Jia, Xin, Zhang, Zhiping, Sun, Yonggang, Jiang, Runqi, Yi, Shuangwen, Chen, Wei, Sun, Jue, Li, Guoqiang, Wang, Shuzhi, Li, Enrui, Hu, Xiaonong, Bao, Qingchun, Lee, Harry F., and Lu, Huayu
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- 2024
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28. Mineralogical Indicators of the Holocene Climate in Sediments of the High-Mountain Lake Sagan-Nur (East Sayan Mountains)
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Solotchina, E. P., Solotchin, P. A., Bezrukova, E. V., Zhdanova, A. N., Shchetnikov, A. A., Danilenko, I. V., and Kuzmin, M. I.
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- 2024
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29. Find of Eggs of the Nematode Dioctophyme renale (Goeze, 1782) (Nematoda, Dioctophymidae) from the Late Holocene of Northwestern Siberia
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Sivkova, T. N., Kosintsev, P. A., and Krapivina, V. V.
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- 2024
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30. Aboriginal earth mounds and ENSO on the Calperum floodplain, Murray-Darling Basin, South Australia.
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Jones, Robert, Roberts, Amy, Westell, Craig, Moffat, Ian, Jacobsen, Geraldine, and Scott Cummings, Linda
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SOUTHERN oscillation , *AQUATIC resources , *INDIGENOUS peoples , *RADIOCARBON dating ,EL Nino - Abstract
This paper presents new data derived from pollen, starch and radiocarbon samples that were collected from six Aboriginal earth (oven) mounds and middens on the Calperum and Pike floodplains, Murray-Darling Basin (MDB), South Australia (SA). Analyses of these samples were undertaken in order to enhance our understanding about the Holocene lifeways of Aboriginal people living in this region. The results from these analyses, combined with published data about the mounds’ contents, relevant ethno-historical information and climate data, allow us to infer that Aboriginal people adopted, in this region, an innovative food production system about 3800 years ago. Further, we argue that the timing of the change suggests this was in response to adverse El Niño Southern Oscillation (ENSO) related weather patterns and consequently fluctuations in both terrestrial and aquatic food resources. [ABSTRACT FROM AUTHOR]
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- 2024
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31. The Quaternary record of fossil bats in the Iberian Peninsula and the Balearic Islands: Palaeobiogeographical changes and palaeoenvironmental implications.
- Author
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Galán, Julia, López-García, Juan Manuel, Cuenca-Bescós, Gloria, and Sevilla, Paloma
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FOSSILS , *LAST Glacial Maximum , *BATS , *BAT conservation , *HORSESHOE bats , *SPELEOTHEMS , *STALACTITES & stalagmites - Abstract
Bats are a highly diversified order of mammals found all over the world; however, their population size and distribution are decreasing rapidly in Europe nowadays. The study of ancient bat populations by means of their fossil record is a valuable source of contextual information for modern bat conservation studies. This paper is a comprehensive review of published bat records in the Iberian Peninsula and the Balearic Islands through Quaternary times, representing the first attempt to update and standardize the knowledge of chiropters in southwestern Europe during this time period. The main goal is to identify changes in bat assemblages that might be correlatable to palaeoclimate and palaeoenvironmental changes. Our data show that the Quaternary record of bats in the area is fragmentary and strongly dependent on the presence of karstic cavities. Thus, a strong preservation bias towards colonial cave-dwelling bats exists, and species with alternative ecological requirements are under-represented. Nevertheless, this work reveals that most of the bats inhabiting the area today were already present in the region from at least the Middle Pleistocene. Interestingly, we observe a frequent association between certain cave-dwelling bats (i.e., Rhinolophus ferrumequinum , Miniopterus schreibersii , Myotis myotis and M. blythii) that is still observed in many caves today; this reflects a stable ecology that has remained undisturbed despite past climatic changes. Within the well-documented periods at the end of the Late Pleistocene and the Holocene, a reduction in some common components of Quaternary assemblages (Rhinolophus species and M. schreibersii) is observed, coinciding with the Late Glacial Maximum and the Northgrippian Neoglacial (a cooling event in the Holocene). Finally, the Balearic record shows interesting palaeobiogeographical characteristics, including some eastern taxa absent in the Iberian Peninsula (Rhinolophus variabilis and R. cf. blasii) as well as an unusual abundance of Rhinolophus hipposideros. • Most extant bats in the Iberian Peninsula were already present there ca. 600 ka. • A strong bias towards colonial, cave bats counting exists within the fossil record. • Three Mediterranean cave bats associate stably despite Quaternary climate shifts. • The Last Glacial Maximum and the Northgrippian Neoglacial events left a mark. • Two oriental taxa and higher reports on Rhinolophus for the Balearic fossil bats. [ABSTRACT FROM AUTHOR]
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- 2024
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32. Brine-boiling not using briquetage? Technical, socio-economical and ritual aspects of salt production at the Villafáfila lagoons (central Iberia) in Late Chalcolithic/Bronze Age.
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Guerra-Doce, Elisa, Abarquero Moras, F. Javier, Romero-Brugués, Susagna, Herrero-Otal, Maria, Homs, Anna, García Cuesta, José Luis, López Sáez, José Antonio, Piqué, Raquel, and Delibes de Castro, Germán
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BRONZE Age , *LAGOONS , *SODIUM sulfate , *BRACKISH waters , *ANIMAL sacrifice , *SALT - Abstract
By combining a multidisciplinary approach and an intensive program of scientific techniques, this paper provides a comprehensive overview of salt production at the Villafáfila lagoons (Zamora, Spain) in prehistoric times. During the Late Chalcolithic and the Early/Middle Bronze Age salt was obtained by boiling brine from salt lagoons. In many parts of western and central Europe at the time the standard procedure for forcing evaporation usually involved the use of crudely fired clay vessels (briquetage) to concentrate brine, and then to mould salt. We suggest that the methods during the final stages of the process differed at Villafáfila, having found evidence of basketry and textiles, which may have been used in the step of crystallization/transport of salt in cake, instead of the small ceramic salt moulds which would be expected in such sites. The role of salt within the socioeconomic setting of the 3rd and 2nd millennia BCE in Central Iberia is also assessed. It is argued that the production and distribution of salt contributed significantly to the political economy, as elites controlled this activity, supporting the idea that salt was a prestige good that contributed to the accumulation of wealth. There is also evidence of ritual practices in the salt-processing areas, as human burials and animal sacrifices have been documented in the excavated sites. • Archaeological evidence shows the production of salt at the Villafáfila lagoons by the late 3rd millennium BCE, during the Beaker period. • Brackish water was boiled in large ceramic vessels supported by clay or stone pedestals. • Techniques evolved during the Early Bronze Age, when pedestals were replaced by clay-walled kilns. • Absence of genuine briquetage, and of small ceramic pots used as salt moulds. • Possible use of baskets and textiles sacks as moulds. [ABSTRACT FROM AUTHOR]
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- 2024
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33. Length of astronomical seasons, total and average insolation over seasons.
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Berger, André, Yin, Qiuzhen, and Wu, Zhipeng
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SOLAR radiation , *EARTH'S orbit , *SEASONS , *CLIMATE change , *MILANKOVITCH cycles , *HOLOCENE Epoch , *LATITUDE - Abstract
Daily insolation at a given latitude is often used in the explanation of the long-term variations of paleoclimate records. However, the length of astronomical seasons, which has been paid less attention, could also be important. This paper provides an original calculation of the length of these seasons using the eccentric anomaly. The past and future long-term variations as well as the spectral characteristics of the length of astronomical seasons, of the total and average insolation over the astronomical seasons and of the caloric insolation are shown and compared. The length of astronomical seasons is only a function of climatic precession. The total irradiation for a given latitude and an astronomical season is mainly a function of obliquity except that it is mainly a function of eccentricity in a latitudinal band that is season dependent and from where the phase between obliquity and total irradiation reverses (e.g. ∼11.5°N for the astronomical northern hemisphere summer half-year). The spectral characteristic of the mean insolation over the astronomical summer half-year varies in latitude and time. It contains stronger obliquity signal in high latitudes than in low latitudes, but the obliquity signal already gets very weak at 45°N/S leaving the dominance of climatic precession between 45°N and 45°S. The variation of the mean summer half-year insolation over the last 1 Ma is characterized by a Mid-Brunhes transition at ∼450 ka BP, with a dominant role of climatic precession at all latitudes before ∼450 ka BP but significantly enhanced role of obliquity in high latitudes after this time. The simultaneous weakening of the variations of climatic precession and obliquity around 800 ka ago, a time corresponding to the Mid-Pleistocene Transition, leads to weak variations in both total and mean seasonal insolation. The insolation of a specific case, the Holocene, is finally discussed. Depending on the sensitivity to different types of insolation, different climate variables and regions could show different evolution and trend during the Holocene. • An original calculation of the length of the astronomical seasons is provided. • Precession and obliquity contribute differently to the length of astronomical seasons and to different insolation metrics. • Distinctive variations of total and mean seasonal insolation characterize the Mid-Brunhes and Mid-Pleistocene transitions. • Different insolation metrics display different trend over the Holocene. [ABSTRACT FROM AUTHOR]
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- 2024
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34. New macrofossil evidence detail the Holocene vegetation of the Iberian Central System.
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García-Álvarez, Salvia, Génova, Mar, García-Amorena, Ignacio, Morla, Carlos, Rastrero, Sergio, and Postigo-Mijarra, José M.
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HOLOCENE Epoch , *SCOTS pine , *CLUSTER pine , *SEA level , *OAK , *RADIOCARBON dating - Abstract
This paper presents the results of the explorations carried out in the western sector of the Iberian Central System (western Gredos, Béjar, Gata and Estrela mountain ranges). The macroremains found allow detailing the model of the landscape transformation, the composition and extension of their vegetal formations throughout the Holocene. Ninety-nine woody macroremains, 3 bark remains and 8 pinecones were located from eight sites between 875 and 1860 m above sea level, among which 15 radiocarbon dates were made. The taxonomic identification of two trunks found in Estrela allows us to document the local presence of Pinus cf. sylvestris ca. 6600 cal BP in this site. The same taxon also appears at the western end of Gredos between ca. 1700–2800 cal BP at approximately 1300 m. These remains expand the Holocene distribution of P. cf. sylvestris in the Central System known to date, both temporally and geographically. In parallel, the macroremains analysed document the composition of high mountain scrub (Cytisus type, Erica cf. arborea) in Béjar (ca. 1860 m), as well as mixed scrub-woodland formations in Gata (975–1180 m), which included deciduous Quercus , Betulaceae and Ericaceae. The presence of P. pinaster at ca. 6200 cal BP and 1180 m in this mountain range constitutes the earliest palaeobotanical evidence of this species recorded in Gata. The main results support the continuous persistence of plant formations in which P. sylvestris , P. nigra , and P. pinaster would have formed part throughout the Iberian Central System during the Holocene in a wide altitudinal range (1100–1840 m). • Above one hundred Holocene macrofossils from eight different sites were analysed. • Pinus sylvestris recently disappeared from the western Central System. • P. gr. sylvestris remained in Serra da Estrela until ˜6650 years ago. • First evidence of Pinus pinaster has been found in Gata ˜6200 years ago. • Betula , Quercus , Alnus and Ericaceae Holocene macroremains were found in Gata. [ABSTRACT FROM AUTHOR]
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- 2024
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35. The role of the Holocene transgression in the environmental changes of lagoons and marshes of the Mediterranean coast.
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Blázquez, A.M., López-Belzunce, M., Rodríguez-Pérez, A.E., Guillem, J., Ferrer, C., Nieto, M., Torres, T., and Ortiz, J.E.
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HOLOCENE Epoch , *MARSHES , *LAGOONS , *ABSOLUTE sea level change , *WETLANDS , *FOSSIL foraminifera , *SALT marshes - Abstract
The aim of this paper is to evaluate the position of the Holocene transgression on the coast of the Valencia Gulf. To achieve this goal, a sedimentological and micropaleontological analysis of samples of fossil benthic foraminifera in cores from six boreholes drilled in three different wetlands (Almenara marsh, Moro marsh and Valencia lagoon) was carried out. In order to assess the extent of sea level change, at least three factors must be taken into account: 1) eustatic rise (global scale) 2) neotectonics (regional scale) and 3) the sedimentary factor (local and regional scale). Regarding the first factor, some authors have noted that the Holocene transgression reached +1 m above the current sea level in this area. As for the second factor, while the Valencia lagoon is located on a subsiding coast the northernmost marshes are located on a tectonically stable coast. Finally, sedimentation rates are highly variable depending on the area; whereas in the Valencia lagoon the shoreline generally shifts seawards (progradation) in the northernmost areas the coast is currently undergoing retrogradation, although the anthropic factor clearly interferes with this pattern. One of the main conclusions is that in the Valencian coast the Holocene maximum relative sea level did not exceed the present-day one, except in the case of the subsiding area of the Valencia lagoon. The calculation of sedimentation rates, the relative sea-level curve and the evolution of the water column in the different wetlands seem to corroborate it. Radiocarbon and AAR analyses allowed us to date the maximum extent of the Holocene transgression on the Valencian coast at around 5500 cal yr BP in all cases. Despite the different subsidence the three studied wetlands reflected the predominant marine influence until 5500–5200 BP, which was later followed by a growing fluvial or continental incidence, when glacioeustatic adjustments defined the patterns of coastal progradation. [Display omitted] • Location of the MIS 1 coastline position in three West Mediterranean wetlands. • The global Holocene eustatic rise invaded the three wetlands at least 5300 years BP. • Subsidence rate determined different MIS 1 relative sea-level rise in the wetlands. • Tectonic stability in the northern wetlands involved slower relative sea-level rise. [ABSTRACT FROM AUTHOR]
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- 2024
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36. Grain Size Distribution and Provenance of Holocene Sand from the Sava River (Zagreb, Croatia).
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Barudžija, Uroš, Blatančić, Matteo, and Malvić, Tomislav
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PARTICLE size distribution ,SAND bars ,RIVER sediments ,ALLUVIAL streams ,NATURE parks - Abstract
This study involves an investigation into the grain size distribution and provenance of the sand deposited near Zagreb (Croatia) in the riverbed of the regionally important, almost 1000 km long Sava River, which connects several SE European countries. Recent research in the study area has mainly focused on the deposits forming the Zagreb alluvial aquifer system, rather on the Sava River sediment deposited in its riverbed, which is the focus of this study. The grain size distribution results obtained by dry sieving and laser granulometry showed a predominately fine and medium sand deposition at riverbanks and sand point bars. Medium sand increased downstream towards the east, within the artificially more channelized riverbed in the urban area. Fine sand prevailed 50 km further downstream in a more meandering low-relief area, near the city of Sisak and Lonjsko Polje Nature Park. Provenance analysis showed predominately carbonate sand in the western part of the city of Zagreb, originating from distant (Alpine) and local (Medvednica Mt. and Samobor Hills) sources. More siliciclastic sand was deposited in the Sava riverbed in the middle and eastern parts of Zagreb, originating mainly from the Medvednica Mt. The prevailing siliciclastic sand further downstream of the Sava River is probably sourced from the Kupa River tributary. Although various studies of the Zagreb alluvial aquifer system have been conducted so far, this study represents a novelty in its investigation into the grain size distribution of the Sava riverbed sand itself, setting the foundations for investigations in the future. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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37. Holocene Paleoclimate Changes around Qinghai Lake in the Northeastern Qinghai-Tibet Plateau: Insights from Isotope Geochemistry of Aeolian Sediment.
- Author
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Peng, Qiang, E, Chongyi, Li, Xiangzhong, Sun, Yongjuan, Zhang, Jing, Zhang, Shuaiqi, Shi, Yunkun, Ji, Xianba, and Zhang, Zhaokang
- Subjects
CLIMATE change ,LAKE sediments ,ATMOSPHERIC temperature ,FREQUENCIES of oscillating systems ,ISOTOPE geology - Abstract
The stable carbon isotope composition of total organic matter (δ
13 Corg ) has been utilized in aeolian sediments, serving as an indicator for reconstructing terrestrial paleoenvironments. The Qinghai Lake (QHL) Basin is a climate-sensitive region of significant importance in paleoclimatic reconstruction. However, the reconstructed climatic variations based on δ13 Corg in aeolian sediments in the QHL Basin in the northeastern Qinghai-Tibet Plateau (QTP) are lacking, and their paleoclimatic significance remains poorly understood. By conducting δ13 Corg measurements on the Niaodao (ND) aeolian profile near QHL, we reconstructed the paleoclimate changes of 11 ka–present. The variation range of the δ13 Corg values in the ND profile indicated the terrestrial ecosystems were not the sole contributor to lacustrine organic matter. The δ13 Corg values are an indicator of historical temperature changes in the study area, exhibiting similar trends with the reconstruction of Chinese summer temperatures, East Asian air temperature, global temperature, and Northern Hemisphere summer insolation at 37° N. The temperature increased with high frequency and amplitude oscillations, with strong aeolian activity and low total organic carbon accumulation during the Early Holocene. The temperature was maintained at a high and stable level, with the weakest aeolian activity and intensified pedogenesis during the Middle Holocene. The temperature decreased at a high rate, with renewed aeolian activity and weak pedogenesis during the Late Holocene. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
38. Contribution of campaign GNSS toward parsing subsidence rates by time and depth in coastal Bangladesh.
- Author
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Steckler, Michael S., Jaman, Md. Hasnat, Grall, Céline Jo, Goodbred, Steven L., Wilson, Carol A., Oryan, Bar, Bruno, Luigi, Rossi, Veronica, and Tornqvist, Torbjorn
- Subjects
GLOBAL Positioning System ,BUILDING foundations ,LAND subsidence ,SEDIMENT compaction ,ABSOLUTE sea level change ,ARSENIC ,COASTS - Abstract
Coastal regions are vulnerable to rising seas, increasing storm magnitude, and decimation of ecologically-fragile areas. Deltas are particularly sensitive to the balance between sea-level rise, land subsidence and sedimentation that determine relative elevation. Bangladesh has been highlighted as being at risk from sea-level rise. Integrating measurements from different methods can approach a more complete understanding of factors controlling areally and temporally varying subsidence rates. To augment our compilation of rates from stratigraphic wells, historic buildings, vertical strainmeters, RSETMH, and continuous Global Navigation Satellite System, we resurveyed 48 geodetic monuments in coastal Bangladesh ~18 years after the monuments were installed. A later resurvey of 4 sites showed that some sites with higher subsidence may be unstable, but we consider the subsidence pattern of all the sites. Sites with rates <2 mm/yr overlie thin (<35 m), sandy Holocene deposits located along interfluves between the main paleo-river valleys. As Holocene strata thicken seaward and become muddier, subsidence rates increase to 20-25 mm/y. Sites in incised valleys of the Ganges, Brahmaputra and Meghna Rivers, with Holocene sediments >100 m show subsidence rates of 20 ± 10 mm/y, with a slight seaward increase. Overall, subsidence rates increase with Holocene sediment thickness and the seaward shift from sandy to muddy sediments. Together with earlier measurements, we parse the different rates and mechanisms of subsidence. Earlier models show 2-3 mm/yr correspond to deep processes, such as isostasy. Within the shallow Holocene (<10 m), we estimate 5-8 mm/yr of subsidence from shallow, edaphic effects (tree roots, burrows, organic matter decomposition) and shallow (<10 m) sediment consolidation on short timescales. Below this, we estimate 3-6 mm/yr from compaction of the upper Holocene strata, with 2-5 mm/yr occurring in deeper Holocene strata. Subsidence rates in areas of active sedimentation, such as rice fields and mangrove forests, are greater than buildings and structures with deep foundations. Subsidence on timescales >300 y, which do not include edaphic effects, are up to ~5 mm/y. We note subsidence can be offset by active deltaic sedimentation, and does not necessarily indicate elevation loss. Collectively, the integration of these approaches allows us to begin quantifying the varied contributions to land subsidence from edaphic effects, Holocene sediment compaction, lithology, and time. Similar factors may contribute to the highly variable subsidence rates observed at other deltas worldwide. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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39. Holocene Paleohydrological Changes Reflected in Lake-Level Fluctuations in Lake Annecy (French Pre-Alps): Climatic Significance and Archeological Implications.
- Author
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Magny, Michel, Morin, Eymeric, Vérot, Agnès, Richard, Hervé, Marguet, André, Brigand, Robin, Gabayet, Franck, Hinschberger, Florent, Mouthon, Jacques, and Thirault, Eric
- Subjects
HOLOCENE Epoch ,WATERSHEDS ,FOSSIL collection ,LAKES ,CLIMATE change ,FRESH water - Abstract
Lakes are threatened by contemporary climate change and human activities. Paleohydrological records provide important evidence for developing scenarios for future changes in the availability of freshwater resources. This study presents a synthesis of a sedimentological, archeological, and chronological dataset collected from Lake Annecy (eastern France) to reconstruct a lake-level record documenting the whole Holocene. This dataset shows a pronounced minimum in the lake level during the Holocene thermal maximum (HTM) (ca. 9000–7000 cal BP), preceded by a general lowering trend (early Holocene), and followed by a general rising trend (Neoglacial). On both the millennial and centennial scales, the Lake Annecy record appears to match the regional pattern of Holocene lake-level fluctuations established for West-Central Europe. In agreement with other extra-regional paleoclimatic records, it shows the dominant influence of orbital forcing. The high magnitude of the lake-level lowering (more than 5 m) during the HTM, with a 2–2.5 °C difference between the HTM and the pre-industrial mean summer temperatures, suggests possible drastic lake-level lowering phases in the near future depending on the IPCC scenarios following climate change. This would mean dramatic impacts on human activities and the preservation of exceptional archeological remains in regional lake basins. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Holocene loess in the Himalayas piedmont of southeastern Nepal.
- Author
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Latrubesse, Edgardo M. and Nugraha, Abang M. S.
- Subjects
OPTICALLY stimulated luminescence ,LOESS ,HOLOCENE Epoch ,FARMS - Abstract
Loess, loess-like, sandy loess, and sandy-silty fluvial–aeolian deposits are intercalated to fluvial sediments and lie on a flat surface under intense agricultural land use in Bardibas, Mahottari district, central Nepal. To identify the depositional processes and provenance, we carried out geochemical, mineralogical, SEM, and grain-size analyses. Optically stimulated luminescence (OSL) dating shows the aeolian deposits are from the late Holocene (1.0–4.8 ka). Our results demonstrate that the loess and loess-like deposits (i) were dominantly sourced locally from deflation Quaternary sediments of the Terai Plain; (ii) are related to the composition of Siwalik rocks; and (iii) were deposited during dry periods of weak activity of the Indian Summer Monsoon. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. The Middle and Late Holocene climate change in Bohai Bay revealed by diatom proxy
- Author
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Shang, Zhiwen, Li, Jianfen, Wang, Fu, and Wang, Hong
- Published
- 2024
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42. Multi-centennial ENSO-like variability response to solar activity during the holocene
- Author
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Sun, Weiyi, Ma, Yanan, Liu, Jian, Chen, Deliang, Ning, Liang, Yan, Mi, and Chen, Kefan
- Published
- 2024
- Full Text
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43. Grain size and surface micro-texture characteristics and their paleoenvironmental significance of Holocene sediment in southern margin of the Gurbantunggut Desert, China
- Author
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Ma, Yunqiang, Li, Zhizhong, Tan, Dianjia, Zou, Xiaojun, and Tao, Tonglian
- Published
- 2024
- Full Text
- View/download PDF
44. Reconstruction of rock avalanche history in Val Viola, (Upper Valtellina, Italian Central Alps) through 10Be exposure ages, Schmidt Hammer R values, and surface roughness
- Author
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Longhi, Alessandro, Morgan, Daniel, and Guglielmin, Mauro
- Published
- 2024
- Full Text
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45. Hydrodynamic reconstruction of the paleoflood from the Early Holocene ice-dammed lake Nedre Glomsjø, Norway
- Author
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Katherine R. Aurand, Fredrik Høgaas, Oddvar Longva, and Thomas Vikhamar Schuler
- Subjects
Glacial lake outburst flood ,Ice-dammed lakes ,Numerical flood simulation ,Paleostage indicators ,Scandinavia ,Holocene ,Physical geography ,GB3-5030 ,Geology ,QE1-996.5 - Abstract
Study region: Norway Study focus: Numerous geological traces provide evidence for the existence, size and catastrophic drainage of the Early Holocene glacial lake Nedre Glomsjø in southern Norway. We present, for the first time, a hydraulic reconstruction that links the three domains of the glacial lake outburst flood process chain: lake hypsometry, tunneling under the remnant ice sheet and subsequent deluge downstream. This is done by first reconstructing the hypsometry of the lake using paleo shorelines observed from modern high-resolution elevation data. The development of an ice tunnel under the remnant ice sheet is then simulated using an ensemble approach to determine a suite of hydrographs for the range of possible parameter combinations. These hydrographs are applied as upstream input to a 2D hydrodynamic model of the flood propagation. The flood marker dataset includes abundant landforms and flood traces at multiple scales, such as erosive paleostage indicators, sediment records and large-scale flood bars. The results from each domain are constrained by the flood marker dataset, which adds to the robustness of our interpretation. New hydrological insights for the region: The reconstruction shows that glacial lake Nedre Glomsjø covered roughly 1250 km2, and that ∼100 km3 of water was available for drainage. The peak discharge of the glacier lake outburst flood was at least 1.5 ×106 m3/s and probably closer to 2.0 ×106 m3/s. Our results demonstrate the benefit of assembling the entire process chain from glacial lake, tunnel expansion and flood propagation in a single modeling framework to give robust results that satisfy multiple geological constraints for each component of the glacial lake outburst flood (GLOF) system. The methodology described in this paper can be applied to contemporary and future glacial lakes to better predict GLOFs in a changing climate.
- Published
- 2024
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46. Mobility and the use of littoral resources in the Late Mesolithic of Northern Spain: the case of La Chora cave (Voto, Cantabria, N Spain)
- Author
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León-Cristóbal, Alejandro, García-Escárzaga, Asier, Fano, Miguel Ángel, Arniz-Mateos, Rosa, Quesada, José Manuel, Abril-Orzaiz, Jon, and Gutiérrez-Zugasti, Igor
- Published
- 2024
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- View/download PDF
47. Genesis and evolution of peat deposits on island territories of the southwestern Okhotsk Sea Region in the Holocene
- Author
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Vladimir V. Chakov, Mikhail A. Klimin, Victoria A. Kuptsova, Elena N. Zakharchenko, Nadezhda G. Razjigaeva, Lyudmila M. Mokhova, Larisa A. Ganzey, and Tatyana A. Grebennikova
- Subjects
holocene ,bog formation ,peat deposit ,cryolithic zone ,biodiversity ,sphagnum cover ,transgression ,Dynamic and structural geology ,QE500-639.5 ,Stratigraphy ,QE640-699 ,Engineering geology. Rock mechanics. Soil mechanics. Underground construction ,TA703-712 ,Petrology ,QE420-499 - Abstract
The paper considers the results of studying of wetland ecosystems within the boundaries of the “Shantar Islands” National Park in 2016–2018. The characteristics of peat deposits in main bog areas that developed over the Holocene on the surfaces dating back to the Late Pleistocene are described. The features of waterlogging in the flattened watersheds of the Bolshoy Shantar Island in different periods of the evolution of studied peat bogs are considered on the basis of the results of botanical, palynological and radiocarbon analyzes. The settlement of green mosses among areas sparsely vegetated by shrub-sedge communities in small closed depression with a melting substrate during the growth season was determined as the initial centers of waterlogging on the archipelago. The regressive effect of cryogenic processes on the formation of specific organogenic landforms in oligotrophic bogs of the permafrost zone of the southwestern Okhotsk Sea Region has been identified by analyzing cartographic materials, Earth remote sensing data of medium and high spatial resolution (Landsat 8, Sentinel-2), as well as aerial images taken by DJI Phantom 4 UAV. There is a relationship between the thickness of the peat deposit, the natural and climatic circumstances of different Holocene stages, and successional changes in bog vegetation. These shifts' chronometric parameters and order have been established. The order and chronologic parameters of these shifts have been determined. In contrast to the mainland, the transgression of the sea and the confinement of the archipelago to the cryolithic zone of eastern Eurasia were the main factors that defined the features of the development of island swamp phytocenoses and surrounding vegetation.
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- 2024
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48. Speleothem records from western Thailand indicate an early rapid shift of the Indian summer monsoon during the Younger Dryas termination.
- Author
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Jacobson, Matthew J., Chawchai, Sakonvan, Scholz, Denis, Riechelmann, Dana F.C., Holmgren, Karin, Vonhof, Hubert, Wang, Xianfeng, and Liu, Guangxin
- Subjects
- *
YOUNGER Dryas , *SPELEOTHEMS , *MONSOONS , *STALACTITES & stalagmites , *STABLE isotopes , *SUMMER , *COMPLEX variables - Abstract
Mainland Southeast Asia experiences complex and variable hydroclimatic conditions, mainly due to its location at the intersection of Asian monsoon subsystems. Predicting future changes requires an in-depth understanding of paleoclimatic conditions that is currently hindered by a paucity of records in some regions. In this paper, we present the first speleothem stable isotope records from western Thailand detailing the Bølling-Allerød interstadial, Younger Dryas termination, and early- to mid-Holocene period. We find evidence of higher precipitation during the Bølling-Allerød (14,321–12,824 years before present (1950: BP)) compared to a Younger Dryas termination that starts 11,702–11,674 BP, has a rapid shift centered on 11,660–11,641 BP, and ends 11,603–11,589 BP. In addition, our records show Holocene monsoon intensity peaking at 8250 BP or before, a multi-millennia delay from the Northern Hemisphere summer insolation peak, followed by a trend to drier conditions until at least 750 BP. Assessment of the timing of the Younger Dryas termination in paleoclimate records across Southeast Asia reveals an earlier shift of the Indian Summer Monsoon to global climate shifts when compared to East Asian Summer Monsoon records. The causes of this are currently unknown. Some potentially important aspects include: an Indian Summer Monsoon influence on East Asian Summer Monsoon strength via the Indian Ocean Dipole climate pattern, the role of the Tibetan Plateau in monsoon dynamics, and exposure of the Sundaland shoreline. More high-resolution paleoclimate records, especially on the pathway of Indian Summer Monsoon to East Asian Summer Monsoon, are required for further discussion on the mechanisms controlling the differences between climate regimes. • We present two new speleothem stable isotope records from western Thailand. • Conditions trend wetter during the Bølling-Allerød. • Early and abrupt termination of the Younger Dryas (11,675–11,600 BP, ±73 years). • Change Point Analysis of records finds earlier rapid shift in Indian Summer Monsoon. • Distinct trend of increasing δ18O and δ13C values throughout Holocene. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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49. Tropical forcing and ENSO dominate Holocene climates in South Africa's southern Cape.
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Chase, Brian M., Boom, Arnoud, Carr, Andrew S., and Reimer, Paula J.
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HOLOCENE Epoch , *SOUTHERN oscillation , *TEMPERATE climate , *RAINFALL ,EL Nino ,AGULHAS Current - Abstract
This paper explores the Holocene climatic dynamics of South Africa's southern Cape, a region that supports a large proportion of the Greater Cape Floristic Region and contains an array of important archaeological sites. While South African climates are generally characterised by marked rainfall seasonality, the southern Cape is currently situated at the interface between tropical and temperate climate systems, resulting in a largely aseasonal rainfall regime. This regime, however, is thought to have been particularly sensitive to past changes in late Quaternary boundary conditions, meaning that variability in either tropical or temperate systems could have significant environmental impacts. Evidence of past climate change, however, remains limited. We present a 9000-year record of hydroclimatic variability obtained from rock hyrax midden stable nitrogen records, from Papkuilsfontein, on the southern slope of the Anysberg Mountains. Resolved to an average 6-year resolution and spanning the period c. 9050 cal yr BP to 1990 CE, this is the highest resolution Holocene record from southern Africa and presents a unique opportunity for the detailed study of the primary drivers and spatial gradients of Holocene climate change in the southern Cape. The data indicate a long-term decrease in aridity across the Holocene and a pattern of variability that reveals remarkable similarities with records from the South African tropics and El Niño–Southern Oscillation proxies, highlighting the significance of tropical systems as drivers of Holocene climate change in the region. This substantially expands what has been previously considered to be the zone of tropical influence, extending from a coastal phenomenon associated with heat transport via the Agulhas Current to encompass much, if not all, of the Agulhas Plain south of the Cape Fold Mountains. These findings provide a valuable new climatic framework for contextualizing changes in ecological and archaeological records in the southern Cape, and contribute to a more comprehensive understanding of the spatio-temporal dynamics of climate systems in southern Africa. • Sub-decadal 9000-year record of aridity from South Africa's southern Cape. • Reveals dominance of tropical forcing across the southern Cape and Agulhas Plain. • ENSO variability indicated to be important driver of regional climate change. • Presents high-resolution framework for study of human-environment interactions. [ABSTRACT FROM AUTHOR]
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- 2024
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50. Provenance of fine-grained sediments along the South Bohai Coast, China since the mid-Holocene, and its implications for understanding coastal evolution and anthropogenic influences.
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Sun, Xiao, Li, Yan, Yi, Liang, Zhang, Jingran, Bi, Jianhua, Chen, Guangquan, and Hu, Ke
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PALEOGEOGRAPHY , *OPTICALLY stimulated luminescence dating , *ACCELERATOR mass spectrometry , *SEDIMENTATION & deposition , *ANTHROPOGENIC effects on nature , *SEDIMENTS - Abstract
Discriminating the provenance of fine-grained sediments is crucial for reconstructing paleogeography, sedimentary processes, and paleoclimate. In this paper, we investigate the South Bohai Coast to better understand source-to-sink systems in East Asia. This region is influenced by both distant sources such as the large-scale Yellow River and small local river sources flowing from the Luzhong Mountain area. Two Holocene sedimentary cores, dated using optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C chronology, were used to investigate the provenance of the fine-grained sediments over the last 7 kyrs. Clay mineralogy and relevant non-linear modeling were employed for provenance discrimination. The results show that the fine-grained sediments along the South Bohai Coast were mainly derived from the Yellow River during the periods of 7.0–5.4 ka and 4.5–2.6 ka, respectively, while the input from the Luzhong Mountain-derived rivers was greater during 5.4–4.5 ka and 2.6–0.2 ka, respectively. Fluvial activities and marine-terrestrial interaction driven by climate factors such as East Asian winter monsoon, temperature, and precipitation in river basins, dominantly influenced the provenance of fine-grained sediments from 7.0 to 2.6 ka. Anthropogenic impact on provenance increased after 2.6 ka. The chronology of the two cores showed extremely rapid sedimentation rate transitions at 5.2 ka and 1.5 ka, respectively, very likely attributed to anthropogenic-induced rapid progradation. Our study provides a model for better understanding the paleoenvironmental and paleogeographic evolution of a coastal area where multiple sources exist. • Anthropogenically high sedimentation rate in the South Bohai Coast in late Holocene. • Provenance discrimination of the fine-grained sediments in the South Bohai Coast since the mid-Holocene. • The major source of the fine-grained sediments in the South Bohai Coast changed episodically. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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