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2. The lives of creatures obscure, misunderstood, and wonderful: a volume in honour of Ken Aplin 1958–2019. In Papers in Honour of Ken Aplin, ed. Julien Louys, Sue O’Connor, and Kristofer M. Helgen
- Author
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Kristofer M. Helgen, Julien Louys, and Sue O'Connor
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mammals ,rodentia ,muridae ,new guinea ,holocene ,quaternary ,pleistocene ,Museums. Collectors and collecting ,AM1-501 ,Evolution ,QH359-425 - Abstract
[Excerpt] He was always a modest man, but Ken was a genius and the toughest man we knew. He was also extraordinarily generous of spirit. The way he gave of himself, his time, and his hard-won stores of knowledge, was legendary amongst his friends and colleagues. We admired him and we loved him. Ken was a world-renowned comparative anatomist, vertebrate systematist, palaeontologist, and zooarchaeologist. He was a problem solver like few we’ve ever met, and a fieldworker and world traveller par excellence. Ken’s personal and professional outlook embraced the whole world, in all its true facets and flavours, its complexities and eccentricities—he took the world, and all of us in it, as we came. His intellectual reputation extended well beyond Australia and was known to thousands of colleagues who may never have had the chance to meet him.
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- 2020
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3. Special Paper: Comparison of Post-Glacial Molluscan and Vegetational Successions from a Radiocarbon-Dated Tufa Sequence in Oxfordshire
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Preece, R. C. and Day, S. P.
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- 1994
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4. RESEARCH PAPER An evaluation of the Lost World and Vertical Displacement hypotheses in the Chimantá Massif, Venezuelan Guayana.
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Rull, Valentí
- Subjects
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VEGETATION & climate , *LIFE zones , *BIOGEOGRAPHY , *ECOLOGY ,TEPUIS (Venezuela) - Abstract
To document the occurrence of vertical displacements of vegetation in the high plateaus of the Venezuelan Guayana ( tepuis) over the last c. 6000 years, and to discuss their significance for the origin of their flora, especially the endemism patterns observed in their flat summits. Two hypotheses have been proposed for the origin of the summit flora. One (the Lost World hypothesis) proposes a long history of evolution in isolation from the surrounding plains, while the other (the Vertical Displacement hypothesis) suggests that vertical movements of vegetation during the Pleistocene glacial-interglacial cycles would have resulted in floristic mixing within the lowlands, and genetic interchange among plateau summits. This work has been conducted on the flat summit of the Churí-tepui, in the Chimantá massif, at 5°15′ Lat. N and 62°01′ Long. W, around 2250 m altitude. Pollen analysis and radiocarbon dating of two peat outcrops, using modern analogue technique and numerical methods for palaeoecological interpretation were used. The replacement of a high-altitude plant community (a paramoid Chimantaea shrubland) by a lower elevation (< 2300 m) Stegolepis meadow, occurred about 2500 years before present (yr bp). This vegetation change is inferred to have resulted from a regional climatic shift to higher temperature and moisture. A subsequent decrease in temperature and moisture led to the establishment of present conditions after about 1450 yr bp. The highland vegetation of the tepuis responded to climate shifts with vertical displacements, supporting the hypothesis of vertical mixing. However, a physiographical analysis shows that around half of the tepuis would never have been connected by lowlands. Therefore, both hypotheses are needed to explain the origins of the summit flora in the tepuis. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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5. FOGO NA TOCA: USO DO FOGO E ANTRACOLOGIA NA TOCA DO SÍTIO DO MEIO (PIAUÍ, BRASIL).
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Mota, Leidiana and Scheel-Ybert, Rita
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FOREST plants ,COMBUSTION ,MATERIAL culture ,CHARCOAL ,FUELWOOD - Abstract
Copyright of Revista de Arqueologia is the property of Revista de Arqueologia 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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6. 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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7. 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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8. Estados alterados de consciencia en el arte postpaleolítico de la Península Ibérica: rituales de éxtasis, plantas psicoactivas y dinámicas sociales.
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Doce, Elisa Guerra
- Abstract
Copyright of Boletín del Museo Chileno de Arte Precolombino is the property of Museo Chileno de Arte Precolombino 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.)
- Published
- 2023
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9. An Efficient Approach to the Sequence Stratigraphic Study of Monotonous Holocene Sediments from the Arctic Shelf.
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Kolesnik, A. N., Selyutin, S. A., Kolesnik, O. N., Bosin, A. A., Astakhov, A. S., Vologina, E. G., Sukhoveev, E. N., and Bazhenov, I. I.
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SEQUENCE stratigraphy ,HOLOCENE Epoch ,STRATIGRAPHIC correlation ,MAGNETIC susceptibility ,SEDIMENTS - Abstract
This paper describes an approach assuming that already in the sea, based on the express analysis of visually similar cores of Arctic Holocene sediments and their comparison with dated and studied in detail cores of the regional sediments, it is possible to select a material that is promising for sequence stratigraphic correlation and paleoreconstructions. The range of lithological, colorimetric (CIE L*, CIE a*, and CIE b*), geophysical (magnetic susceptibility), and geochemical (Fe/Rb, Mn/Rb, and Ti/Rb) parameters is analyzed. The most informative characteristics include the CIE b* color coordinate, magnetic susceptibility, and Fe/Rb. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Anticipation, Discovery and Serendipity in Quaternary Paleoecology: Personal Experiences from the Iberian Pyrenees.
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Rull, Valentí
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SERENDIPITY ,EXPECTATION (Psychology) ,PALEOECOLOGY - Abstract
This essay is a personal insight based on my own experience in the Iberian Pyrenees, which addresses three situations common in paleoecological research, such as the verification of previously devised hypotheses (anticipation), the finding on unknown events in unstudied sites (discovery) and the finding of unexpected outputs in already known areas (serendipity). The account is concentrated on the value of the coring sites by themselves as generators of paleoecological knowledge, rather than on the actual findings, which are presented and discussed in the corresponding data papers. The main aim is to show that there is still much room for new findings, even in areas that have been surveyed for a long time and are supposed to be well known, from a paleoecological perspective. Finally, some general lessons are derived and conceptualized. [ABSTRACT FROM AUTHOR]
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- 2023
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11. Accelerating the Renewable Energy Revolution to Get Back to the Holocene.
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Abbott, Benjamin W., Abrahamian, Chelsea, Newbold, Nicholas, Smith, Peter, Merritt, Marina, Sayedi, Sayedeh Sara, Bekker, Jeremy, Greenhalgh, Mitchell, Gilbert, Sophie, King, Michalea, Lopez, Gabriel, Zimmermann, Nils, and Breyer, Christian
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RENEWABLE energy sources ,ENVIRONMENTAL health ,HOLOCENE Epoch ,RENEWABLE energy costs ,STANDARD of living ,INDUSTRIAL energy consumption ,ENERGY consumption - Abstract
The UN's Paris Agreement goal of keeping global warming between 1.5 and 2°C is dangerously obsolete and needs to be replaced by a commitment to restore Earth's climate. We now know that continued use of fossil fuels associated with 1.5–2°C scenarios would result in hundreds of millions of pollution deaths and likely trigger multiple tipping elements in the Earth system. Unexpected advances in renewable power production and storage have radically expanded our climate response capacity. The cost of renewable technologies has plummeted at least 30‐year faster than projected, and renewables now dominate energy investment and growth. This renewable revolution creates an opportunity and responsibility to raise our climate ambitions. Rather than aiming for climate mitigation—making things less bad—we should commit to climate restoration—a rapid return to Holocene‐like climate conditions where we know humanity and life on Earth can thrive. Based on observed and projected energy system trends, we estimate that the global economy could reach zero emissions by 2040 and potentially return atmospheric CO2 to pre‐industrial levels by 2100–2150. However, this would require an intense and sustained rollout of renewable energy and negative emissions technologies on very large scales. We describe these clean electrification scenarios and outline technical and socioeconomic strategies that would increase the likelihood of restoring a Holocene‐like climate in the next 100 years. We invite researchers, policymakers, regulators, educators, and citizens in all countries to share and promote this positive message of climate restoration for human wellbeing and planetary stability. Plain Language Summary: New research in global ecology and public health shows that the consequences of burning fossil fuels are much more severe than previously understood. Current global warming targets are not enough to protect us from sea level rise, ecosystem collapse, and hundreds of millions of human deaths from fossil fuel pollution. Thankfully, the cost of renewable energy technologies has dropped below the cost of fossil fuels decades faster than predicted. This has triggered a renewable revolution that is transforming the global energy system. Our paper considers the feasibility of accelerating this transition through policy, investment, and strategic research. We conclude that there is a viable pathway to restoring Earth's climate through clean electrification and carbon capture. We call for a global commitment to restore pre‐industrial climate conditions within a century and describe what approaches would increase our chances of success. Accelerating the renewable revolution would move us toward a sustainable civilization by eliminating air pollution, stabilizing climate, reducing energy costs, and enhancing living standards worldwide. Because there is no safe level of climate disruption or pollution death, we believe it is our responsibility to restore a Holocene‐like climate, which we know can support human civilization and other life on Earth. Key Points: Goals of 1.5–2°C are not safe given current understanding of ecosystem climate sensitivity and high social costs of fossil fuel pollutionClimate restoration‐rapidly reestablishing Holocene‐like conditions‐has not been fully considered because of socioeconomic obstaclesStrategic financing and prioritization of clean electrification could create pathways back to the Holocene within a century [ABSTRACT FROM AUTHOR]
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- 2023
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12. An Assessment of Soil Phytolith Analysis as a Palaeoecological Tool for Identifying Pre-Columbian Land Use in Amazonian Rainforests.
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Hill, James, Black, Stuart, Araujo-Murakami, Alejandro, Boot, Rene, Brienen, Roel, Feldpausch, Ted, Leigue, John, Murakami, Samaria, Monteagudo, Abel, Pardo, Guido, Peña-Claros, Marielos, Phillips, Oliver L., Toledo, Marisol, Vos, Vincent, Zuidema, Pieter, and Mayle, Francis E.
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SOIL testing ,PALEOECOLOGY ,LAND use ,RAIN forests ,PHYTOLITHS ,DEFORESTATION ,CHARCOAL - Abstract
Phytolith analysis is a well-established archaeobotanical tool, having provided important insights into pre-Columbian crop cultivation and domestication across Amazonia through the Holocene. Yet, its use as a palaeoecological tool is in its infancy in Amazonia and its effectiveness for reconstructing pre-Columbian land-use beyond archaeological sites (i.e., 'off-site') has so far received little critical attention. This paper examines both new and previously published soil phytolith data from SW Amazonia to assess the robustness of this proxy for reconstructing pre-Columbian land-use. We conducted the study via off-site soil pits radiating 7.5 km beyond a geoglyph in Acre state, Brazil, and 50 km beyond a ring-ditch in northern Bolivia, spanning the expected gradients in historical land-use intensity. We found that the spatio-temporal patterns in palm phytolith data across our soil-pit transects support the hypothesis that pre-Columbian peoples enriched their forests with palms over several millennia, although phytoliths are limited in their ability to capture small-scale crop cultivation and deforestation. Despite these drawbacks, we conclude that off-site soil phytolith analysis can provide novel insights into pre-Columbian land use, provided it is effectively integrated with other land-use (e.g., charcoal) and archaeological data. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Variations in Spring Atmospheric Circulation on the Southwestern Tibetan Plateau During Holocene Linked to High‐ and Low‐Latitude Forcing.
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Ma, Qingfeng, Zhu, Liping, Wang, Junbo, Ju, Jianting, and Wang, Yong
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SPRING ,CLIMATE change ,HOLOCENE Epoch ,TIMBERLINE ,POLLEN ,PLANT phenology ,ATMOSPHERIC circulation - Abstract
Recent climate and environment over the Tibetan Plateau (TP) have undergone significant changes, dominated by variations in the Westerlies and the Indian summer monsoon. However, long‐term shifts in atmospheric circulation during the transitional seasons are still lacking. Here we investigate the modern distribution of Tsuga pollen over the central‐western TP and confirm it as an indicator of variable atmospheric circulation in spring. By combining our Tsuga record from Taro Co with existing records in the Tsuga pollen source area, we suggest that a potential particle transport pathway from the southern slope of the Himalayas to the interior of the plateau appeared in the spring of the late Holocene. Our results show that the springtime atmospheric circulation over the southwestern TP during the early and late Holocene is closely related to the substantial remnants of ice sheets at northern high latitudes and the frequency of El Niño events, respectively. Plain Language Summary: The spring climate over the Tibetan Plateau (TP) is undergoing significant changes that yield profound impacts on environmental changes such as variations in vegetation phenology and alpine treeline. Knowledge of long‐term variations in atmospheric circulation during spring can improve the understanding of current climatic and environmental change and the projection of future variability. In this paper, we use an exotic pollen grain, which can be transported long distances in the air, as an indicator to trace the variability of spring atmospheric circulation over the TP. The results indicate that the spring meridional atmospheric circulation from the southern slope of the TP to its interior has been enhanced in the last four thousand years, which is mainly influenced by the frequency of El Niño events. Key Points: Spring atmospheric circulation change over the southwestern Tibetan Plateau (TP) during Holocene is reconstructedMeridional atmospheric circulation in spring over the southwestern TP is strengthened in the late HoloceneHigh‐(low‐) latitude forcing mainly influence the variations in spring atmospheric circulation during the early (late) Holocene [ABSTRACT FROM AUTHOR]
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- 2023
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14. Comparison and Renormalization of Holocene Paleointensity Records From Central North America (17°N–51°N, 205°E–295°E).
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Lund, Steve P., Richardson, Marci, Verosub, Ken, King, John, Champion, Duane, and St‐Onge, Guillame
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HOLOCENE Epoch ,GEOMAGNETISM ,LAVA flows ,ELECTRIC generators ,OSCILLATIONS - Abstract
This paper develops a composite absolute paleointensity record for Holocene paleomagnetic secular variation (PSV) from central North America. Twelve full‐vector (inclination, declination, paleointensity) PSV records were assessed in order to build the composite record. Nine of the paleointensity records come from sediment paleomagnetic studies and are considered relative in intensity. Three of the paleointensity records come from absolute paleointensity measurements of archeological materials and lava flows. This paper develops a new method to normalize the sediment relative paleointensity records to the absolute intensity records. The final composite paleointensity record describes intensity variability over a region of Central North America delineated by 35°–48.6°N and 240.4–291.4°E (∼14° × 50°). This composite record shows a distinctive long‐duration (∼104 year) oscillation and a series of millennial‐scale intensity oscillations that are consistent over our study region. Plain Language Summary: This study develops a composite record of geomagnetic field intensity for the central North America for the last 8,000 years. This record is important for considering the total geomagnetic field variability I this region and its dynamo source(s). Key Points: We develop a new composite absolute paleointensity record for Holocene Central North AmericaWe develop a new renormalization technique to combine absolute paleointensity records and sediment relative paleointensity recordsThe final composite absolute paleointensity record has a distinctive long‐term trend and millennial‐scale variability [ABSTRACT FROM AUTHOR]
- Published
- 2021
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15. Application of holocene geological data for siting coastal nuclear power plants: An example from Puerto Rico
- Author
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Shlemon, R. J. and Capacete, J. L.
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- 1976
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16. The Sedimentary Context of Open-Air Archaeology: A Case Study in the Western Cape's Doring River Valley, South Africa.
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Phillips, Natasha, Moffat, Ian, Mackay, Alex, and Jones, Brian G.
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CAVES ,ARCHAEOLOGY ,EOLIAN processes ,TAPHONOMY ,PLEISTOCENE Epoch - Abstract
Despite the wealth of Late Pleistocene archaeology that exists across southern Africa's open landscape, it is routinely neglected in favour of rock shelter (re)excavation, biasing interpretation of human–environment interaction. This is compounded by the scarcity of open-air studies that use geoarchaeological methods to investigate the history and processes involved in their formation. The open-air archaeology of the Doring River Valley is an example of this, despite nearly a decade of dedicated study and publication. Consequently, there remains a limited and untested understanding of the valley's formation history. This paper rectifies this by providing a sedimentary context for the surface archaeology exposed across one of the Doring River Valley's artefact-baring localities, Uitspankraal 7 (UPK7). Characterisation, particle size, mineralogical, morphometric, and geophysical analysis of UPK7′s sand mantle resulted in the identification of four artefact-bearing sedimentary units, the aeolian and pedogenic processes involved in their formation, and their proposed order of deposition. This provides a stratigraphic, taphonomic, and environmental context against which chronometric dating and an analysis of the taphonomic, spatio-temporal, and technological composition of UPK7′s surface archaeology can be compared. This work is the first vital step towards understanding the depositional and behavioural history of a landscape, irrespective of context type. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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17. Desertification and Related Climate Change in the Alashan Plateau since the Last 40 ka of the Last Glacial Period.
- Author
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Zhu, Bingqi and Yang, Limin
- Subjects
DESERTIFICATION ,GLACIATION ,CLIMATE change ,GLOBAL environmental change ,LAST Glacial Maximum ,WIND power - Abstract
Clues of climate change on the Alashan Plateau since the last glacial period (40 ka) are important for revealing the mechanism of desertification of middle-latitude deserts in the Northern Hemisphere (NH). Studies are still rare for the understanding of the specific relationship of climate changes between the Alashan Plateau and the global. Based on a systematic and comparative analysis of the existing research in China and the international academic community, this paper reviews the environmental evolution history of the Alashan Plateau since the last glacial period from the records of paleo-environment and geomorphological characteristics in different deserts of the plateau (e.g., Badanjilin, Tenggeli, and Wulanbuhe). From about 40 ka to the end of the last glacial maximum, the climate on the plateau was wetter than it is today, and to the end of the Pleistocene, the climate was generally dry and the aeolian activities were enhanced. However, the climate was arid during the whole last glacial period in the Wulanbuhe Desert, evidently different from the overall pattern of the plateau. The Tenggeli Desert was characterized by an arid climate in the early Holocene. The most controversial events for the Alashan Plateau are the drought events in the middle Holocene in the Badanjilin Desert. The role and impact of the westerlies and the East Asian Summer Monsoon (EASM) systems on the climate change of the desert and even the whole plateau is a vexed question that brings different views in different periods. There is still a lack of definite evidence representing the events of global environmental change that occurred on the plateau during the discussed period. The distinctive morphology of dune mountains and the distribution of sand dunes are mutually indicative of the direction and energy of wind systems on the plateau. It is suggested that appropriate wind energy is the significant key to the desertification in these middle-latitude deserts on the plateau. From a global-scale review of climate change, the desertification of the modern-scale sandy desert landscapes on the Alashan Plateau is generally related to the global glacial period and the cold and dry climate during the past 40 ka. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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18. Holocene history of the forest-alpine tundra ecotone in the Scandes Mountains (central Sweden).
- Author
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Kullman, Leif
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CLIMATE change ,TREE growth ,FOREST ecology ,DOWNY birch ,SCOTS pine ,ALNUS incana - Abstract
The Holocene history of the forest-alpine tundra ecotone in Central Sweden (Scandes Mountains) is inferred from radiocarbon analyses of subfossil wood remains. Pinus sylvestris was the dominant subalpine tree species during the early Holocene, when it ascended almost 200 m higher than currently. A short climatic episode (less than 100 years) is postulated to have triggered erosional processes around 6300 B.P., and extinguished the upper part of the subalpine pine woodland. Subsequently, a subalpine belt of Betula pubescens ssp. tortuosa and Alnus incana developed. A Holocene thermal optimum occurred around 6100 B.p., when the birch/alder belt flourished and the tree-limits probably reached their highest levels during the Holocene. Shortly after 6000 B.P., a long-term pine forest retrogression started and the birch/alder belt was disrupted by expanding snow-beds. Pine receded slightly at its tree-limit, but the uppermost belt of closed pine forest (presently dominated by birch) remained intact until c. 3300 B.p., when a severe climatic deterioration occurred. The present-day subalpine belt of pure birch forest developed successively and increased in vertical extent after c. 5300 B.P., when summer temperature declined. The evolution of the birch belt is postulated to have been ultimately a response to decreased seasonality, which favoured birch at the expense of pine. Because of the 'inertia' characterizing the highest pine forest, the birch belt was relatively narrow until a major thermal decline c. 3300 B.P., when it made a massive downslope expansion. The latest phase of pine recession was during the Little Ice Age, 800-300B.P. [ABSTRACT FROM AUTHOR]
- Published
- 1988
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19. First palynological results from Spila nad Procjepom cave, Mljet island (Croatia).
- Author
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Bakrač, Koraljka, Sirenko, Olena, Hruševar, Dario, Baniček, Ivona, Novak, Vibor, Kletečki, Nataša, and Sršen, Ankica Oros
- Subjects
- *
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]
- Published
- 2024
- Full Text
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20. Figurative representations of the Pali Aike volcanic field (Santa Cruz, Argentina - Magallanes, Chile) in comparative perspective with the southern extreme of Patagonia.
- Author
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Funes, Paula Daniela
- Subjects
VOLCANIC fields ,SPECIES distribution ,HOLOCENE Epoch ,INFORMATION sharing ,ROCK art (Archaeology) - Abstract
Copyright of Documenta Praehistorica is the property of Documenta Praehistorica 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.)
- Published
- 2023
- Full Text
- View/download PDF
21. Water Level Fluctuations in the Middle and Late Holocene in the Curonian Lagoon, Southeastern Baltic: Results of the Macrofossil and Phytolith Analyses.
- Author
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Druzhinina, Olga, Napreenko, Maxim, Napreenko-Dorokhova, Tatiana, Golyeva, Alexandra, and Bashirova, Leyla
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LAGOONS ,HOLOCENE Epoch ,TERRITORIAL waters ,WATER levels ,PLANT succession ,COASTAL sediments ,PLANT communities - Abstract
This paper presents the results of a study on fluctuations in the water level of the Curonian Lagoon (in the Baltic Sea). To date, the genesis of this inland bay as part of the complex postglacial development of the southeastern Baltic is poorly understood. The data from lithological, geochronological, and phytolith analyses, as well as assessments of plant and animal macroremains from the lagoonal sediments, provide a reconstruction of local coastal biocenoses and water level dynamics in the Middle and Late Holocene time. This study reveals the fairly dynamic evolution of the coastal zone of the Curonian Lagoon over the past 7000 years, as indicated by the traced succession of plant communities from forest to near-shore, open-water biocenoses and the alternations of the drying out and inundation of the area under consideration. Thus far, a connection with two stages of the Baltic Sea water level fluctuations has been traced: the regressional stage, which took place approximately 5600 cal years BP, and the Late Subatlantic transgression, which started at approximately 1100 cal BP. This study demonstrates that phytolith (microbiomorphic) analysis is a promising method for the study of temperate-latitude lagoonal sediments, providing information not only on the local plant communities, but also on the changes in the hydrological regime of the area. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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22. Responses of Caribbean Mangroves to Quaternary Climatic, Eustatic, and Anthropogenic Drivers of Ecological Change: A Review †.
- Author
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Rull, Valentí
- Subjects
MANGROVE plants ,ENDANGERED ecosystems ,SEA level ,LITTLE Ice Age ,FOSSIL hominids ,HOLOCENE Epoch - Abstract
Mangroves are among the world's most threatened ecosystems. Understanding how these ecosystems responded to past natural and anthropogenic drivers of ecological change is essential not only for understanding how extant mangroves have been shaped but also for informing their conservation. This paper reviews the available paleoecological evidence for Pleistocene and Holocene responses of Caribbean mangroves to climatic, eustatic, and anthropogenic drivers. The first records date from the Last Interglacial, when global average temperatures and sea levels were slightly higher than present and mangroves grew in locations and conditions similar to today. During the Last Glaciation, temperatures and sea levels were significantly lower, and Caribbean mangroves grew far from their present locations on presently submerged sites. The current mangrove configuration was progressively attained after Early Holocene warming and sea level rise in the absence of anthropogenic pressure. Human influence began to be important in the Mid-Late Holocene, especially during the Archaic and Ceramic cultural periods, when sea levels were close to their present position and climatic and human drivers were the most influential factors. During the last millennium, the most relevant drivers of ecological change have been the episodic droughts linked to the Little Ice Age and the historical developments of the last centuries. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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23. Application of Parameterized Grain-Size Endmember Modeling in the Study of Quaternary Oxbow Lake Sedimentation: A Case Study of Tövises Bed Sediments in the Eastern Great Hungarian Plain.
- Author
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Eltijani, Abdelrhim, Molnár, Dávid, Makó, László, Geiger, János, and Sümegi, Pál
- Subjects
MAGNETIC susceptibility ,SEDIMENTS ,LITHOFACIES ,PLAINS ,LAKES - Abstract
Abandoned channels are essential in the Quaternary floodplains, and their infill contains different paleoenvironment recorders. Grain-size distribution (GSD) is one proxy that helps characterize the alluviation and associated sedimentological processes of the abandoned channels. The classic statistical methods of the grain-size analysis provide insufficient information on the whole distribution; this necessitates a more comprehensive approach. Grain-size endmember modeling (EMM) is one approach beyond the traditional procedures that helps unmix the GSDs. This study describes the changes in the depositional process by unmixing the GSDs of a Holocene abandoned channel through parameterized EMM integrated with lithofacies, age–depth model, loss-on-ignition (LOI), and magnetic susceptibility (MS). This approach effectively enabled the quantification and characterization of up to four endmembers (EM1-4); the characteristics of grain-size endmembers imply changes in sedimentary environments since 8000 BP. EM1 is mainly clay and very fine silt, representing the fine component of the distribution corresponding to the background of quiet water sedimentation of the lacustrine phase. EM2 and EM3 are the intermediate components representing the distal overbank deposits of the flood. EM4 is dominated by coarse silt and very fine sand, representing deposition of overbank flow during the flood periods. This paper demonstrates that the parametrized grain-size EMM is reasonable in characterizing abandoned channel infill sedimentary depositional and sedimentation history. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
24. Data on Holocene Fossil Benthic Foraminifera from Sunda Shelf, Offshore Southeastern Peninsular Malaysia.
- Author
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SURIADI, ROKIAH, SHAARI, HASRIZAL, SURATMAN, SUHAIMI, and SULAIMAN, ABDULLAH
- Subjects
FOSSIL foraminifera ,HOLOCENE Epoch ,DRILL core analysis ,PALEOCEANOGRAPHY - Abstract
This paper documents a database of fossil foraminiferal occurrences from a core sample (2 m) retrieved from offshore southeastern Peninsular Malaysia, in 1993, with additional data on their modern distribution from published source. Five sub-samples were analysed for foraminiferal studies (0.1 m, 0.4 m, 0.6 m, 1.2 m, and 2.0 m), alongside with their diversity indices values. In addition, we also present the lithological description of the core sediment, together with the radiocarbon age of our sample. These data are potentially be reused in other paleoceanography related research, such as reconstructing paleo environments, and for future research on the Late-Quaternary/Holocene sedimentary and sea-level history of Sunda Shelf. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. An Energetic Perspective on the Holocene North American Monsoon.
- Subjects
HOLOCENE Epoch ,HYDROLOGIC cycle ,LONG-Term Evolution (Telecommunications) ,MONSOONS ,RAINFALL ,CORE & periphery (Economic theory) - Abstract
The North American Monsoon (NAM) is a critical component of the hydrologic cycle in southwestern North America. However, our understanding of the long‐term evolution of this monsoon system is incomplete due to a paucity of long‐term paleoclimatic records from the core and periphery of the NAM domain. C. Routson et al. (2022, https://doi.org/10.1029/2022gl099772) leverage a new compilation of Holocene proxy records to generate a new composite index of NAM evolution over the Holocene. They identify a relationship between NAM strength and the latitudinal temperature gradient over the Holocene. The authors suggest that shifts in the strength of the westerlies altered NAM convection via ventilation, a process whereby the large‐scale circulation imports low moist entropy air into the monsoon domain. These results highlight the importance of paleoclimatic records, especially from past "warm" intervals, for generating new insights about the evolution of regional monsoons. Plain Language Summary: The North American Monsoon is a circulation that brings summer rain to regions of the US southwest and western Mexico. Despite the fact that this circulation provides a majority of the precipitation in many parts of the arid southwest, we do not fully understand the factors that govern long‐term changes in this monsoon. A new paper by C. Routson et al. (2022, https://doi.org/10.1029/2022gl099772) uses proxy indicators of past summer rainfall, stretching from Central America to Arizona, to reconstruct changes in the monsoon over the geologic epoch known as the Holocene, or the last 11,000 years of Earth history. The results of this study suggest that Holocene changes in the temperature difference between the equator to pole, known as the "latitudinal temperature gradient," exerted an important influence over monsoon strength in the southwest. This has implications for the future of the summer monsoon, especially as the high latitudes of the northern hemisphere are expected to warm in the future. Key Point: The strength North American Monsoon tracks changes in the position of the midlatitude westerlies over the Holocene [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. Variaciones δ13C y δ15N en huemul (Hippocamelus bisulcus) durante el Holoceno en Cerro Casa de Piedra, Santa Cruz, Argentina. Implicancias para el estudio de su distribución pasada.
- Author
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Tessone, Augusto, Fernández, Pablo, Fernández, Natalia, and De Nigris, Mariana
- Subjects
HOLOCENE Epoch ,ARCHAEOLOGICAL excavations ,STEPPES ,STABLE isotopes ,BONES - Abstract
Copyright of Intersecciones en Antropología is the property of Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Sociales 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.)
- Published
- 2020
- Full Text
- View/download PDF
27. Editorial: Paleolimnology: insights from sedimentary archives.
- Author
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Bao, Kunshan, Aranguiz-Acuna, Adriana, and Cao, Xiaofeng
- Subjects
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]
- Published
- 2024
- Full Text
- View/download PDF
28. Geomorphology of marine and glacio-lacustrine terraces and raised shorelines in the northern sector of Península Brunswick, Patagonia, Straits of Magellan, Chile.
- Author
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De Muro, Sandro, Tecchiato, Sira, Porta, Marco, Buosi, Carla, and Ibba, Angelo
- Subjects
GEOMORPHOLOGY ,HOLOCENE Epoch - Abstract
This paper illustrates a detailed geomorphological map (scale 1:50,000) of the marine and transitional terraces (glacio-lacustrine to marine) and raised shorelines linked to Holocene glacio-eustasy and neo-tectonics in the northern area of the Brunswick Penìnsula (Chilean region of the Strait of Magellan). The mapped area is located in Tierra del Fuego between the Segunda Angostura and Seno Otway. This map is the result of geomorphological field survey data integrated with the interpretation of aerial photographs and remote sensing imagery. The survey has allowed the mapping of a sequence of terraces and raised shorelines to be completed. The sequence mainly consists of four orders of marine and glacio-lacustrine terraced deposits, with elevations ranging from 25 to 1 m above mean sea level. The map also presents other landforms and deposits, with their formation linked to littoral, fluvial, glacial and aeolian processes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
29. ESTRATEGIAS DE APROVISIONAMIENTO Y MODALIDADES DE TALLA DURANTE EL HOLOCENO MEDIO EN EL CAMPO DE DUNAS DEL CENTRO PAMPEANO (PROVINCIA DE BUENOS AIRES). LAGUNA DE LOS PAMPAS COMO CASO DE ESTUDIO.
- Author
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Santos Valero, Florencia
- Subjects
HOLOCENE Epoch ,RAW materials ,DOLOMITE ,CHERT ,EMPLOYMENT - Abstract
Copyright of Relaciones de la Sociedad Argentina de Antropología is the property of Sociedad Argentina de Antropologia 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.)
- Published
- 2022
- Full Text
- View/download PDF
30. Holocene debris flows and snow avalanches in Anestølsdalen, western Norway - recorded from lake deposits and colluvial fans.
- Author
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Aa, Asbjørn Rune, Bondevik, Stein, and Sønstegaard, Eivind
- Subjects
HOLOCENE extinction ,LAKE sediments ,CLIMATE change ,GLACIERS ,SLOPES (Physical geography) - Abstract
Climate variability has probably affected the frequency and distribution of debris flows and snow avalanches throughout the Holocene. In this paper, we reconstruct the Holocene history of debris flows and snow avalanches by investigating outcrops in colluvial fans surrounding lake Anestølsvatnet in western Norway and sediment cores penetrating the lake-floor deposits. We made a detailed map of the surface deposits around the lake. The formation of a large end moraine that dams the lake was radiocarbon dated to 10,200-10,800 cal. yr BP, and correlates to the Erdalen event, a Preboreal glacial oscillation. There are colluvial fans and debris-flow paths and snow-avalanche paths eroded on the steep slopes around the lake. On the western slopes, the fans are dominated by snow avalanches, and on the eastern slopes by debris-flow activity. Three of the lake cores were taken distal to the largest avalanche fan on the western slope, Storeskreda ('Storeskreda' means 'the big landslide'). Clasts > 2 mm in the lake sediments are interpreted as traces of snow avalanches and sorted sand layers as being derived from debris flows. Loss-on-ignition and magnetic susceptibility measurements document an increased silt content in the lake sediments after c. 6000 cal. yr BP, probably due to the reappearance of local glaciers in the area. Our combined data from the onshore outcrops/pits and lake sediments shows almost continuous snowavalanche activity and debris-flow activity throughout the last 10,000 years. However, there may have been an increase in the snow-avalanche activity over the last 5000 years. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
31. Evolución ambiental y registro arqueológico de la cuenca del río Barrancas, provincia de Jujuy, Argentina.
- Author
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Morales, Marcelo R., Hoguin, Rodolphe, Oxman, Brenda, Pirola, Malena, Sirolli, Mercedes Rouan, Carbajo, Julia Merler, Bustos, Sabrina, Tchilinguirian, Pablo, Álvarez, Luciana Sofia, Samec, Celeste T., Kohan, Patricio, and Yacobaccio, Hugo D.
- Subjects
ROCK art (Archaeology) ,ARCHAEOLOGICAL excavations ,CULTURAL property ,CULTURAL values ,WATERSHEDS ,ARCHAEOLOGICAL chronology ,PETROGLYPHS - Abstract
Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR 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.)
- Published
- 2022
- Full Text
- View/download PDF
32. History of slope instability in the Oldina plantation, Tasmania.
- Author
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Slee, Adrian and McIntosh, Peter D.
- Subjects
LANDSLIDES ,CLIMATE change ,RAINFALL ,PINUS radiata ,RADIOCARBON dating ,HOLOCENE Epoch - Abstract
Background: This paper describes a landslide swarm generated by exceptionally high two-day rainfall (c. 300 mm) associated with a stationary cut-off low pressure system over northern Tasmania in early June 2016 and investigates evidence for previous slope instability. The landslide swarm occurred in a recently harvested plantation in the Inglis River catchment at Oldina, south of Wynyard in north-west Tasmania. Within a relatively small area of plantation underlain by weathered Permian tillite and minor siltstones more than thirty rapid earthflows, rotational and translational landslides occurred. Many landslides also occurred in the nearby Forth and Mersey River catchments. Methods: Field observations combined with a digital elevation model produced from high-resolution drone imagery were used to describe the morphology of the Oldina landslides, and to calculate the mass of soil, sediment, and woody debris displaced. Radiocarbon dating of charcoal exposed in landslide backwalls enabled palaeo-landslides and periglacial activity at Oldina to be dated. Results: An estimated 48,400-72,310 t of soil, sediment and woody debris was carried downslope by the major landslides but has been retained within the plantation area. The total sediment loss from the affected upper catchments is likely to be greater than the above estimate as the contribution from small riparian landslides, sheet, gully, and rill erosion has not been accounted for, nor has streambank erosion and sediment transported off the study site been measured. Radiocarbon dating of charcoal in sediments indicated that two landslides had evidence of previous instability in the Holocene. Most ages indicated that previous instability dated to 35-15 cal ka BP, i.e., to a time when the climate was cold and dry and freeze-thaw processes in a sparsely vegetated landscape were active. Conclusions: During planning for harvest the soils developed on Permian tillite were correctly described as having a low to moderate risk of landslide erosion. This study concludes that the landslides initiated in June 2016 resulted from exceptionally heavy rain falling on harvested steep and hilly land coupled with the decline in root strength of the harvested trees. The frequency of such a combination of circumstances may increase if high-intensity rainfall increases in Tasmania as the result of climate change. To improve the long-term stability of this terrain and the overall sustainability of plantation forestry it is recommended that landslides and riparian areas are seeded with native vegetation, and that the current assessment of landslide risk for this terrain is re-evaluated. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. The late Pleistocene and Holocene history of Pinus koraiensis (Korean Pine) in the south of the Russian Far East based on palynological data.
- Author
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BELYANIN, PAVEL and BELYANINA, NINA
- Subjects
PINUS koraiensis ,FOSSIL pollen ,HOLOCENE Epoch ,PLEISTOCENE Epoch ,POLLEN ,PINE - Abstract
This paper reviews the distribution of Pinus koraiensis in the south of the Russian Far East in the past based on palynological and chronological data. The aim is to determine the chronological timing of the spatial migration of Pinus koraiensis and to correlate it with climate fluctuations explaining the changes of the geographical range of Pinus koraiensis in the south of the Russian Far East during the Marine Isotope Stages MIS 5 (127 000--71 000 BP), MIS 3 (57 000 BP -- 28 000 cal BP), MIS 2 (28 000--11 700 cal BP), and MIS 1 (11 700 cal BP -- to present). The consideration of the obtained pollen fossil data suggests that the range of Pinus koraiensis was in the south of the Russian Far East during MIS 5, as it was proved based on significant pollen grain percentage in the sediments of this age. Pinus koraiensis was widespread along with Pinus densiflora, Quercus, Ulmus, Juglans, Carpinus, and Phellodendron. During MIS 3, Pinus koraiensis was a component of birch-fir and birch-broadleaved forests. In MIS 2, Pinus koraiensis disappeared from the vegetation of this region. In the early Holocene, Pinus koraiensis expanded its range northward and again appeared in the vegetation of the south of the Russian Far East. Soon enough, it became one of the leading components in spruce-fir forests with Quercus and Ulmus. The increase in its proportion in the vegetation in the Holocene coincided mostly with the periods of warming climate from 11 700 to 11 500 cal BP, from 10 100 to 9300 cal BP, from 8800 to 5300 cal BP, from 4700 to 3500 cal BP, and from 2600 to 1800 cal BP. In the present case, the most diverse vegetation with Pinus koraiensis was typical of the Holocene optimum of the south of the Russian Far East from 8800 to 5300 cal BP. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
34. Holocene impact craters on Earth.
- Author
-
Losiak, Anna
- Subjects
- *
IMPACT craters , *HOLOCENE Epoch , *RESEARCH personnel , *HYPERVELOCITY , *CRATERING , *GEOLOGISTS - Abstract
Impact craters are formed by collisions of cosmic bodies moving with hypervelocity. The formation of these features is not restricted to the distant geological past; new structures are constantly being created and at least 13 confirmed impact craters and crater fields have formed during the Holocene alone. This short review paper: (1) introduces the basics of the impact cratering process to physical geographers and Quaternary geologists; (2) provides a short description of representative examples of such features (Morasko, Kaali, Kamil, Ilumetsa); and (3) discusses the similarities and differences among very small craters, and contrasts these with larger impact structures. This manuscript may be useful to researchers planning to test whether a small Quaternary depression in the ground may be of impact origin. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. El rol de la espiga El Páramo en la transformación de la geografía cultural del norte de Tierra del Fuego (Argentina).
- Author
-
Borrero, Luis Alberto and Borrazzo, Karen
- Subjects
HISTORY of geography ,CULTURAL geography ,PHYSICAL geography ,ARCHAEOLOGICAL excavations ,HOLOCENE Epoch ,ARCHAEOLOGICAL geology ,ARCHAEOLOGICAL surveying - Abstract
Copyright of Revista Mundo de Antes is the property of Revista Mundo de Antes 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.)
- Published
- 2021
36. The coastal lowland of northwestern Germany as an archive of Holocene landscape evolution: basis for a spatial evaluation of Stone Age settlement patterns in the Dornumer tidal basin.
- Author
-
Becker, Thorsten and Siegmüller, Annette
- Abstract
The 'Wadden Sea Archive of landscape evolution, climate change and settlement history' project (WASA) focuses on the analysis of marine sediment archives from the East Frisian Wadden Sea region. It aims at understanding the formation of palaeolandscapes since the end of the last ice age. One part of the project studies the possible correlation and shift of archaeological settlement patterns, climate change and sea-level rise through time in order to derive archaeological expectancy maps. In this paper we present our findings for a quantifiable set of Stone Age sites in the area of the prehistorical Dornumer tidal basin, discussing them against the background of coastal environmental factors and the applied methodology of our modelling. To enable spatial analysis of these sites, we developed a palaeographic elevation model, which was subsequently flooded at 2000-year intervals between the Boreal and early Subboreal periods. Particular challenges are posed by the dynamics of marine transgression, the related changes in the natural environment and their spatial extent. As a result of our GIS-based approach, the model can be extended geographically and provides a basis for future research. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
37. Breve Histórico da Educação Ambiental, sua Adoção no Ordenamento Jurídico Brasileiro e Possíveis Reflexos das Atuais Mudanças Políticas.
- Author
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Cherubini, Karina Gomes, Sampaio, Rubens Jesus, and Damásio da Silva, Paulo Sávio
- Subjects
ENVIRONMENTAL history ,ENVIRONMENTAL education ,JUSTICE administration ,CONFERENCES & conventions ,GOVERNMENT policy ,HUMAN beings - Abstract
Copyright of Pesquisa em Educação Ambiental is the property of Pesquisa em Educacao Ambiental 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.)
- Published
- 2021
- Full Text
- View/download PDF
38. The Age of Peatlands and Peatland Formation Stages in Polesie Landscapes of the East European Plain.
- Author
-
Dyakonov, K. N., Novenko, E. Yu., Mazei, N. G., and Kusilman, M. V.
- Subjects
PEATLANDS ,HOLOCENE Epoch ,RADIOCARBON dating ,UPLANDS ,WATERSHEDS ,WATERLOGGING (Soils) - Abstract
This paper presents the results of a study on peat deposits and radiocarbon dating of basal peat horizons in 43 peatlands located on three key sites within Meshchera Lowlands and Moksha Polesie. Peatlands formed by upland paludification processes and located on watersheds and terraces rising above floodplains were selected for the analysis. The obtained data indicate that the peatland formation process has been ongoing in these regions throughout the entire Holocene epoch and that this process has been affected by the fire regime in the area. In periods with higher wildfire frequencies (8800–5800 and 4200–3200 calendar years BP), changes in the water balance on flat and poorly drained plains occurring after the destruction of forest stands intensified the waterlogging processes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
39. Englacial Architecture and Age‐Depth Constraints Across the West Antarctic Ice Sheet.
- Author
-
Ashmore, David W., Bingham, Robert G., Ross, Neil, Siegert, Martin J., Jordan, Tom A., and Mair, Douglas W. F.
- Subjects
ICE sheets ,ANTARCTIC ice ,ICE shelves ,GLACIAL landforms ,ICE streams ,ATMOSPHERIC deposition ,GEOPHYSICAL surveys - Abstract
The englacial stratigraphic architecture of internal reflection horizons (IRHs) as imaged by ice‐penetrating radar (IPR) across ice sheets reflects the cumulative effects of surface mass balance, basal melt, and ice flow. IRHs, considered isochrones, have typically been traced in interior, slow‐flowing regions. Here, we identify three distinctive IRHs spanning the Institute and Möller catchments that cover 50% of West Antarctica's Weddell Sea Sector and are characterized by a complex system of ice stream tributaries. We place age constraints on IRHs through their intersections with previous geophysical surveys tied to Byrd Ice Core and by age‐depth modeling. We further show where the oldest ice likely exists within the region and that Holocene ice‐dynamic changes were limited to the catchment's lower reaches. The traced IRHs from this study have clear potential to nucleate a wider continental‐scale IRH database for validating ice sheet models. Plain Language Summary: Ice‐penetrating radar is widely used to measure the thickness of ice sheets, critical to assessments of global sea level rise potential. This technique also captures reflections from chemical contrasts within the ice sheet, caused by the atmospheric deposition of conductive impurities, known as "internal reflection horizons" (IRHs) that can be traced over large distances. As these deposits are laid down in distinct events, most IRHs are isochronous age tracers and contain valuable information on past ice sheet processes. In this paper we trace and place age constraints on stratigraphic horizons across a large portion of the West Antarctic Ice Sheet, including regions where fast ice flow has disrupted the ice sheet stratigraphy. The resulting data set allows us to identify where the oldest ice is buried in the study region and provides evidence that flow of the ice sheet interior has been stable during the Holocene. Our results can be used to test the performance of ice sheet models, which seek to simulate the response of ice sheets to long‐term environmental change. Key Points: We measure and date individual isochronal radar internal reflection horizons across the Weddell Sea sector of the West Antarctic Ice SheetHorizons dated to 1.9–3.2, 3.5–6.0, and 4.6–8.1 ka are widespread and linked to previous radar surveys of the Ross and Amundsen Sea sectorsThese form the basis for a wider database of ice sheet architecture for validating and calibrating ice sheet models of West Antarctica [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
40. Possible Tsunami Deposits on the Caribbean Coast of the Yucatán Peninsula.
- Author
-
Shaw, Charles E. and Benson, Larry
- Subjects
BEACHES ,TSUNAMI damage ,SEDIMENT transport ,SEDIMENTATION & deposition ,BOULDERS - Abstract
Shaw, C.E. and Benson, L., 2015. Possible tsunami deposits on the Caribbean coast of the Yucatán peninsula. The western Caribbean Basin is notable for its tectonic stability. It has experienced no historical earthquakes or the tsunami that sometimes accompany them. This paper describes a single, wedge-shaped, boulder-covered, coastal berm on the Yucatán coast of México that stretches unbroken for 50 km across a coastal segment characterized by rocky headlands that alternate with crescent beaches. The remainder of the 350 km of Yucatán coast consists mostly of mangrove that extends 1 to 30 km inland, often behind long, sandy beaches. On the headlands, the surface of the berm is densely paved with boulders-large boulders on its seaward face and smaller boulders and cobbles on its gently sloping inland surface. The top of the berm reaches an elevation >4 m, above the reach of all but the largest modern storm waves. Berm sediments on the headlands consist of two distinct layers of unbedded coarse sand with numerous randomly distributed boulders and cobbles in the lower layer and a crudely textured gravel and sand layer above. At first glance the two layers appear to be separated by 20 cm of white sand above a thin, discontinuous zone of dark, greyish sand that contains isolated balls and smears of black organic material, apparently derived from a soil, or possibly leaf litter. The berm and its associated boulders track the modern coastal morphology in precise detail as it follows the form of modern headlands, bays, and transcoastal channels, indicating that deposition took place after development of the present coast. The berm sediments record two or three large waves, depending on whether the wave that deposited the boulder pavement is regarded as part of the second wave or as a separate wave. Radiocarbon dating indicates that at least one wave struck the coast approximately 1500 years before present. Minimum wave run-up exceeds 4 m above present sea level, and inland inundation reached 400 m along bays and transcoastal channels. The position and elevation of the berm, its lack of well-developed internal bedding, the paving of the berm surface by thousands of boulders, and its 400-m extent inland along channels and bays are features commonly associated with tsunami. However, some recent studies conclude that all of the features listed also can be produced by mega-hurricanes. Placed in the context of our literature search of the recent history of hurricanes and tsunami in the Caribbean Basin, we conclude that the single berm on the Yucatán coast represents an anomalous event for this area and that the berm sediments bear a strong similarity to descriptions of sediments from some historical tsunami and are unlike sedimentary features associated with historical hurricanes. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
41. A Holocene fire history from Terra Nova National Park, Newfoundland, Canada: vegetation and climate change both influenced the fire regime.
- Author
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Lake, Nickolas F., Arsenault, Andre, Cwynar, Les C., Willard, Debra, and Ali, Adam A.
- Subjects
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]
- Published
- 2024
- Full Text
- View/download PDF
42. Reconstruction of Late Glacial Conditions of Exogenic Landscape Formation of Central Kamchatka: Data on Spore–Pollen Analysis
- Author
-
Mukhametshina, E. O., Zelenin, E. A., and Pendea, I. F.
- Published
- 2022
- Full Text
- View/download PDF
43. Mineralogical Indicators of the Holocene Climate in Sediments of the High-Mountain Lake Sagan-Nur (East Sayan Mountains)
- Author
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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.
- Published
- 2024
- Full Text
- View/download PDF
44. TRACES OF SEISMIC ACTIVITY IN THE LAKE BOTTOM SEDIMENTS OF EASTERN FENNOSCANDIA
- Author
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S. B. Nikolaeva
- Subjects
earthquake-induced deformation ,earthquake ,bottom sediment ,lake ,fault ,fennoscandian shield ,kola region ,karelia ,holocene ,Science - Abstract
This paper presents the results of a study on traces of ancient earthquakes in the lake bottom sediments of eastern Fennoscandia (Kola region and Karelia). Based on the sediment cores from six lake basins located within large active structures of the region, consideration is being given to the most typical features of sedimentation affected by neotectonic movements of the Earth’s crust. The data presented here provide lithological-stratigraphical, paleobotanical and chronometrical evidence for lakes. The paper causes and mechanisms of formation of seismic structures in bottom sediments and their distinction from deformations of another origin.Generalized earthquake history in provided an opportunity to organize the existing information on the time of paleoearthquake manifestations and distinguish three active periods in paleoseismicity. These are Late Glaciation-Early Holocene marked by the most rapid uplift after the retreat of the last ice sheet (13500–8100 cal yr BP), Middle Holocene (6800–6600 cal yr BP), and Late Holocene (3100–200 cal yr BP). The results of this study showed that the number and intensity of seismic events changed at different stages of sedimentation. Since the Younger Dryas, fault zones (or their segments) have been repeatedly activated. Combined with the data on paleoseismicity in adjacent parts of Fennoscandia, our studies indicate an irregular pattern of the Late Pleistocene-Holocene seismic activity in stable areas formerly covered by glaciers. The obtained data make further adjustments to the neogeodynamic and seismic estimates of intraplate areas.
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- 2022
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45. The limited link between accommodation space, sediment thickness, and inner platform facies distribution (Holocene–Pleistocene, Bahamas).
- Author
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Weij, Rieneke, Reijmer, John J. G., Eberli, Gregor P., and Swart, Peter K.
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TIDAL currents ,WATER depth ,SEDIMENTS ,SEAWATER ,CLIMATE change ,MILANKOVITCH cycles - Abstract
Cyclic facies variations in shallow‐water carbonate platforms often show repetitive facies patterns that are frequently interpreted to reflect the sedimentary response to variations in sea‐level related to changes in climate linked to orbital variations, the Milankovitch frequencies. Whether these shallow‐marine carbonates represent a complete infill of accommodation space, or are subtidal cycles, has been discussed in numerous papers. The extent to which the thickness of a single depositional cycle is a direct measure of the amplitude of relative sea‐level change is not fully understood. New shallow seismic data from Great Bahama Bank reveal that accommodation space created during the Holocene sea‐level rise is not filled in a predictable way. Three seismic horizons were identified: the seabed, the Pleistocene top, and a horizon within the Pleistocene. Depth surface and thickness maps of the Holocene and Pleistocene layers were combined with 326 in situ water‐depth measurements to assess the upper limit of the present accommodation space. The analysis showed that accommodation space and Holocene sediment thickness, and water depth are not correlated. In addition, the actual water depth and inner platform facies distribution showed no straightforward link. The energy distribution across the shallow‐water platform appears to control the facies type rather than water depth. Mud‐dominated sediments prevail in shallow low‐energy areas protected by a topographic barrier, whereas mud‐free coarse‐grained sediments mainly occur in deeper areas with hydrodynamic energy induced by strong tidal currents, ocean water influx, and winds. Hence, the uneven energy distribution not only results in unpredictable differences in the carbonate‐cycle thickness on the platform but also to a water depth independent facies distribution pattern within the inner platform. Therefore, care should be taken when deducing sea‐level signals from inner platform facies distribution and sediment thickness patterns on ancient platforms. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Fechamiento arqueomagnético de flujos de lava del Holoceno provenientes del volcán Ceboruco, occidente de México.
- Author
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Cifuentes-Nava, Gerardo, Cervantes-Solano, Miguel Ángel, Díaz-Ortega, Ulises, Goguitchaichvili, Avto, López-Loera, Hector, Rosas-Elguera, José, Delgado-Granados, Hugo, Morales-Contreras, Juan, Cejudo-Ruíz, Rubén, and Urrutia-Fucugauchi, Jaime
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VOLCANIC fields ,LAVA flows ,RADIOMETRIC methods ,GEOMAGNETISM ,REMANENCE ,CARBON isotopes ,TRANSCRANIAL magnetic stimulation - Abstract
Copyright of Boletín de la Sociedad Geológica Mexicana is the property of Sociedad Geologica Mexicana 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.)
- Published
- 2019
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47. Development of the western Limfjord, Denmark, after the last deglaciation: a review with new data.
- Author
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BENNIKE, OLE, NØRGAARD-PEDERSEN, NIELS, JENSEN, JØRN BO, ANDRESEN, KATRINE JUUL, and SEIDENKRANTZ, MARIT-SOLVEIG
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SEDIMENTATION & deposition ,SEDIMENT transport ,MARINE animals ,SEA level ,GLACIAL melting ,STRAITS ,ABSOLUTE sea level change - Abstract
This paper presents new marine evidence of Lateglacial and Holocene environmental changes in the western part of Limfjorden, and provides a review of the geological history/development of this part of northern Jylland, Denmark. Lateglacial clay without fossils is widespread in the region and is probably a glaciolacustrine deposit. Limfjorden began to form as a strait in the Early Holocene due to rising relative sea level and the oldest marine shells are dated to c. 9300 cal. years BP. We propose a new relative sealevel curve for the region based on new and published data, which appear to confirm that the relative sea-level change was not extremely rapid, which was suggested earlier. During the Mid-Holocene a wide connection existed from the western part of Limfjorden to the North Sea in the west and more narrow connections existed between Limfjorden and Skagerrak in the north. The marine fauna included several species that indicate warmer and more salty waters than at present. Gradually, the connections to the North Sea and Skagerrak closed due to long-shore sediment transport and deposition of aeolian sand combined with a fall in the relative sea level during the Middle- to Late Holocene. During the Viking Age, 800-1050 CE (Common Era), the western connection to the North Sea was still open, but around 1200 CE it was closed by a coastal sandy barrier and the western part of Limfjorden became brackish. The coastal barrier was flooded on several occasions but soon formed again. After 1825 CE the western connection from Limfjorden to the North Sea has been maintained artificially. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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48. Rapid size change associated with intra-island evolutionary radiation in extinct Caribbean “island-shrews”
- Author
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Woods, Roseina, Turvey, Samuel T., Brace, Selina, McCabe, Christopher V., Dalén, Love, Rayfield, Emily J., Brown, Mark J. F., and Barnes, Ian
- Published
- 2020
- Full Text
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49. Holocene sedimentary history of South Danamandıra Lake: a peatland in west of İstanbul, Çatalca Peninsula, NW Turkey.
- Author
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MAKAROĞLU, Özlem, KÜÇÜKDEMİRCİ, Melda, KILIÇ, Nurgül KARLIOĞLU, ACAR, Dursun, GÜREL, Ali, DAĞDEVİREN, Rüya YILMAZ, YAKUPOĞLU, Nurettin, SABUNCU, Asen, ALTUN, Damla ŞAHİN, Ömer KARAÖZ, M., and Namık ÇAĞATAY, M.
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HOLOCENE Epoch ,PHRAGMITES australis ,MAGNETIC susceptibility ,LAKES ,MINERAL properties ,PHRAGMITES - Abstract
This study investigates the sedimentological evolution of the South Danamandıra Lake (SDL) lake in Çatalca Peninsula, 70 km west of İstanbul, using Georadar data and multiproxy analyses of five sediment cores. The lake is a 1.3-m deep, endorheic freshwater peatland, heavily colonised by common reed (Phragmites sp.). The multiproxy core investigations include a lithological core description and environmental magnetism, physical properties (gamma density and magnetic susceptibility), geochemical elemental, pollen and radiocarbon dating analyses. The lithological sequence in the lake consists of an upper peat unit and a lower sand-silt-clay unit. The peat unit is characterized by lower magnetic susceptibility, density and lithophile elements (K, Fe, Ti, and Zr) concentrations than the sand-silt-clay unit. Overall interpretation of the multiproxy data and the age-depth model suggest that the SDL was formed in a shallow depression of a fluvial channel at ca 10.9 cal kyr BP, and became a eutrophic lake at 8.1 cal kyr BP during the early Holocene warm period. Redox-sensitive element (i.e. Mn) distribution and mineral magnetic properties indicate that the peat unit has accumulated under anoxic conditions below a thin oxic surficial layer. Increase in the Taraxacum, Asteraceae, and Poaceae pollen percentages, together with high siliciclastic inputs in the lake, indicate that anthropogenic influence in the area started at 5.4 cal kyr BP [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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50. SE Saline Everglades Transgressive Sedimentation in Response to Historic Acceleration in Sea-Level Rise: A Viable Marker for the Base of the Anthropocene?
- Author
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Meeder, John F. and Parkinson, Randall W.
- Subjects
ABSOLUTE sea level change ,ANTHROPOCENE Epoch ,ANTHROPOCENTRISM ,HOLOCENE extinction ,GLOBAL warming - Abstract
Rate of global eustatic sea-level rise during the Holocene Epoch has been identified as the principle cause of observed changes or inferred evolution of nontectonic coastal systems in mid- to low-latitude areas. The rate of rise is now three times faster than it was for the past several thousand years and similar to values associated with the middle Holocene marine transgression. This acceleration can be attributed to human-caused global warming. In this investigation, the effects of accelerating sea-level rise on coastal sedimentary environments of the SE Saline Everglades were quantified. The results reveal historic changes to coastal habitat, sedimentation, and stratigraphy that are transgressive. These changes initiated during the early 20th century and are attributed to accelerating sea-level rise. As this acceleration and the resulting geologic record is a suspected consequence of human-induced global warming, the paper concludes with a discussion of the relevance of these observations, in tandem with others, to the current debate over the utility and use of the proposed Anthropocene. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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