Landscape changes in the southern Amazonian foreland basin during the Holocene inferred from Lake Ginebra, Beni, Bolivia

2019 ◽  
Vol 94 ◽  
pp. 46-60
Author(s):  
Katerine Escobar-Torrez ◽  
Marie-Pierre Ledru ◽  
Teresa Ortuño ◽  
Umberto Lombardo ◽  
Jean-François Renno
Keyword(s):  
Rain Forest ◽  
Late Holocene ◽  
Environmental Changes ◽  
Foreland Basin ◽  
Lacustrine Sediment ◽  
Landscape Changes ◽  
The Holocene ◽  
Local Responses ◽  
Monsoon System ◽  
Western Side

AbstractOur study is located in northern Beni and aims to improve knowledge on regional landscape changes from the last 8600 years, based on pollen and charcoal analyses from a lacustrine sediment core from Lake Ginebra. Our results showed that gallery forest and lacustrine sediment were observed from 8645 until 3360 cal yr BP. After a change from a lacustrine to a swamp environment at 1700 cal yr BP, the Cerrados and the Mauritia swamp became installed 1000 years ago on our study site. The environmental changes we observed over the last 8600 years in the Ginebra record reinforce the evidence of a west–east climatic gradient with the persistence of rain forest throughout the Holocene on the western side and the presence of the Cerrados until the late Holocene on the eastern side. Moreover, the persistence of a wet forest in the early to mid-Holocene in southwestern Amazonia highlighted some local responses to the global trend that could be related to the distance from the Andes; while in the late Holocene, both an increase in insolation and strengthening of the South American summer monsoon system enabled the installation of a seasonal flooded savanna in northern Beni and of the rain forest in eastern Beni.

Crustal subsidence inferred from reconstruction of the Pleistocene–Holocene palaeogeography in the northern Lake Inba area, central Japan

2019 ◽  
Vol 94 ◽  
pp. 61-79
Author(s):  
Takashi Chiba ◽  
Shigeo Sugihara ◽  
Yoshiaki Matsushima ◽  
Yusuke Arai ◽  
Kunihiko Endo
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
Sea Level Changes ◽  
Diatom Assemblages ◽  
Central Japan ◽  
Lower Salinity ◽  
The Holocene ◽  
Holocene Transgression

ABSTRACTTo help characterise the palaeogeographic and lacustrine environmental changes that resulted from the Holocene transgression and residual subsidence in the eastern Kanto Plain of central Japan, we analysed four drill cores and reviewed other core data from the southern part of the Lake Inba area. Fossil diatom assemblages yielded evidence of centennial-scale palaeogeographic and salinity responses to sea-level changes since the late Pleistocene. We determined that the seawater incursion into the Lake Inba area during the Holocene transgression occurred at approximately 9000 yr. We also recognised a late Holocene regression event corresponding to the Yayoi regression, considered to have occurred from ca. 3000 to ca. 2000 yr, and a subsequent transgression. Our data clarify some of the palaeogeographic changes that occurred in the Lake Inba area and document an overall trend toward lower salinity in the lake during the regression. In particular, the environment in Lake Inba changed from brackish to freshwater no later than 1000 yr. From the detailed palaeogeographic and palaeo-sea-level reconstruction, we recognised that residual subsidence occurred during the Holocene in this area. Thus, comparison of sea-level reconstructions based on modelling and fossil diatom assemblages is effective in interpreting Holocene long-term subsidence.

scholarly journals Late-Holocene landscape evolution and human presence in the northern Danube delta (Chilia distributary lobes)

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Luminița Preoteasa ◽  
Alfred Vespremeanu-Stroe ◽  
Anca Dan ◽  
Laurențiu Țuțuianu ◽  
Cristian Panaiotu ◽  
...  
Keyword(s):  
Middle Ages ◽  
Economic History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Land Use Changes ◽  
Sedimentary Facies ◽  
The Black Sea ◽  
Danube Delta ◽  
Human Presence ◽  
Historical Texts

This paper documents the Late-Holocene environmental changes and human presence in the northern Danube delta using a multidisciplinary approach that combines geoscientific data with archaeological findings, historical texts, and maps. It follows the formation and progression of the Chilia distributary and the reconfiguration of socioeconomic activities. Sedimentary facies identified on five new cores by changes in texture properties, magnetic susceptibility, geochemistry, and macro- and microfauna composition together with the newly obtained chronology constrain the complex evolution of the Chilia branch as filling in a long-lasting bay and then of a giant lagoon (Thiagola) which covered most of the northern delta since the Old Danube lobe inception (ca. 7500 yrs BP) till modern Chilia development. It initiated during the Greek Antiquity (ca. 2500 yrs ar BP) at the delta apex, while in Roman times (ca. 1800 yrs BP) it pursued its slow flowing into the vast Thiagola Lagoon. The most dramatic transformations occurred in the last 800 years when the river passed east of the Chilia promontory, rapidly went through the present-day Matița-Merhei basin (several decades), and created its first open-sea outlet. Solid discharge increased in two distinct periods, once in the Middle Ages (ca. 750 yrs BP) and then in the Modern Period (ca. 150 yrs BP) due to human-induced land-use changes in the Danube watershed. The chronology of the cultural remains on the pre-deltaic Chilia promontory and the multiproxy analysis of a sediment core retrieved nearby downstream suggest the terrestrial connection of the island with the mainland in ancient times. The hitherto contended issue of the old Thiagola Lagoon and its location are redefined here, as are the original identifications of ancient and medieval toponyms and hydronyms, especially for Chilia-Licostomo, Byzantine, Genoese, Moldavian, Ottoman, and Russian trading point of great importance in the political and economic history of the Black Sea and neighboring regions.

Environmental evolution and anthropogenic forcing in the Garigliano coastal plain (Italy) during the Holocene

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Halinka Di Lorenzo ◽  
Pietro Aucelli ◽  
Giuseppe Corrado ◽  
Mario De Iorio ◽  
Marcello Schiattarella ◽  
...  
Keyword(s):  
Human Activity ◽  
Coastal Plain ◽  
Forest Cover ◽  
Environmental Changes ◽  
Pollen Data ◽  
Human Environment ◽  
The Holocene ◽  
Natural Processes ◽  
History Of ◽  
The Rich

The Garigliano alluvial-coastal plain, at the Latium-Campania border (Italy), witnessed a long-lasting history of human-environment interactions, as demonstrated by the rich archaeological knowledge. With the aim of reconstructing the evolution of the landscape and its interaction with human activity during the last millennia, new pollen results from the coastal sector of the Garigliano Plain were compared with the available pollen data from other nearby sites. The use of pollen data from both the coastal and marine environment allowed integrating the local vegetation dynamics within a wider regional context spanning the last 8000 years. The new pollen data presented in this study derive from the analysis of a core, drilled in the coastal sector, which intercepted the lagoon-marshy environments that occurred in the plain as a response to the Holocene transgression and subsequent coastal progradation. Three radiocarbon ages indicate that the chronology of the analyzed core interval ranges from c. 7200 to c. 2000 cal yr BP. The whole data indicate that a dense forest cover characterized the landscape all along the Prehistoric period, when a few signs of human activity are recorded in the spectra, such as cereal crops, pasture activity and fires. The main environmental changes, forced by natural processes (coastal progradation) but probably enhanced by reclamation works, started from the Graeco-Roman period and led to the reduction of swampy areas that favoured the colonisation of the outer plain.

A 5000-year lacustrine sediment oxygen isotope record of late Holocene climate change in Newfoundland, Canada

2022 ◽  
Vol 278 ◽  
pp. 107376
Author(s):  
Matthew S. Finkenbinder ◽  
Byron A. Steinman ◽  
Broxton W. Bird ◽  
Ellen C. Heilman ◽  
Alexandria R. Aspey ◽  
...  
Keyword(s):  
Climate Change ◽  
Oxygen Isotope ◽  
Late Holocene ◽  
Lacustrine Sediment ◽  
Holocene Climate ◽  
Holocene Climate Change ◽  
Oxygen Isotope Record ◽  
Isotope Record

scholarly journals Holocene sea level and climate interactions on wet dune slack evolution in SW Portugal: A model for future scenarios?

The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 26-44 ◽  
Author(s):  
Manel Leira ◽  
Maria C Freitas ◽  
Tania Ferreira ◽  
Anabela Cruces ◽  
Simon Connor ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Environmental Changes ◽  
Sediment Accumulation ◽  
High Energy ◽  
Sediment Supply ◽  
Dune Slack ◽  
Ecological Stability ◽  
The Holocene ◽  
Climate Interactions

We examine the Holocene environmental changes in a wet dune slack of the Portuguese coast, Poço do Barbarroxa de Baixo. Lithology, organic matter, biological proxies and high-resolution chronology provide estimations of sediment accumulation rates and changes in environmental conditions in relation to sea-level change and climate variability during the Holocene. Results show that the wet dune slack was formed 7.5 cal. ka BP, contemporaneous with the last stages of the rapid sea-level rise. This depositional environment formed under frequent freshwater flooding and water ponding that allowed the development and post-mortem accumulation of abundant plant remains. The wetland evolved into mostly palustrine conditions over the next 2000 years, until a phase of stabilization in relative sea-level rise, when sedimentation rates slowed down to 0.04 mm yr−1, between 5.3 and 2.5 cal. ka BP. Later, about 0.8 cal. ka BP, high-energy events, likely due to enhanced storminess and more frequent onshore winds, caused the collapse of the foredune above the wetlands’ seaward margin. The delicate balance between hydrology (controlled by sea-level rise and climate change), sediment supply and storminess modulates the habitat’s resilience and ecological stability. This underpins the relevance of integrating past records in coastal wet dune slacks management in a scenario of constant adaptation processes.

scholarly journals Three distinct Holocene intervals of stalagmite deposition and nondeposition revealed in NW Madagascar, and their paleoclimate implications

2017 ◽  
Vol 13 (12) ◽  
pp. 1771-1790 ◽  
Author(s):  
Ny Riavo Gilbertinie Voarintsoa ◽  
Loren Bruce Railsback ◽  
George Albert Brook ◽  
Lixin Wang ◽  
Gayatri Kathayat ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
High Resolution ◽  
Late Holocene ◽  
Intertropical Convergence Zone ◽  
Convergence Zone ◽  
High Resolution Data ◽  
The Holocene ◽  
Middle Holocene ◽  
Resolution Data

Abstract. Petrographic features, mineralogy, and stable isotopes from two stalagmites, ANJB-2 and MAJ-5, respectively from Anjohibe and Anjokipoty caves, allow distinction of three intervals of the Holocene in NW Madagascar. The Malagasy early Holocene (between ca. 9.8 and 7.8 ka) and late Holocene (after ca. 1.6 ka) intervals (MEHI and MLHI, respectively) record evidence of stalagmite deposition. The Malagasy middle Holocene interval (MMHI, between ca. 7.8 and 1.6 ka) is marked by a depositional hiatus of ca. 6500 years. Deposition of these stalagmites indicates that the two caves were sufficiently supplied with water to allow stalagmite formation. This suggests that the MEHI and MLHI intervals may have been comparatively wet in NW Madagascar. In contrast, the long-term depositional hiatus during the MMHI implies it was relatively drier than the MEHI and the MLHI. The alternating wet–dry–wet conditions during the Holocene may have been linked to the long-term migrations of the Intertropical Convergence Zone (ITCZ). When the ITCZ's mean position is farther south, NW Madagascar experiences wetter conditions, such as during the MEHI and MLHI, and when it moves north, NW Madagascar climate becomes drier, such as during the MMHI. A similar wet–dry–wet succession during the Holocene has been reported in neighboring locations, such as southeastern Africa. Beyond these three subdivisions, the records also suggest wet conditions around the cold 8.2 ka event, suggesting a causal relationship. However, additional Southern Hemisphere high-resolution data will be needed to confirm this.

scholarly journals Stepwise Weakening of Aeolian Activities During the Holocene in the Gannan Region, Eastern Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengli Yang ◽  
Xiaojing Liu ◽  
Ting Cheng ◽  
Yuanlong Luo ◽  
Qiong Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Environmental Changes ◽  
Climatic Changes ◽  
Early Holocene ◽  
Eastern Tibetan Plateau ◽  
Aeolian Desertification ◽  
The Holocene ◽  
Aeolian Sediments ◽  
Aeolian Activity ◽  
History Of

Aeolian sediments hold key information on aeolian history and past environmental changes. Aeolian desertification and extensive land degradation have seriously affected the eco-environment in the Gannan region on the eastern Tibetan Plateau. Understanding the history of aeolian activities can deepen our understanding of the impacts of climatic changes on aeolian activities in the future. This study uses a detailed chronology and multiple proxy analyses of a typical aeolian section in Maqu to reconstruct aeolian activities in the region during the Holocene. Our results showed that aeolian activities have occurred in the eastern Tibetan Plateau since the early Holocene. Magnetic susceptibility, grain size records, and paleosols formation indicated a trend of stepwise weakening in aeolian activities from the early Holocene to the present. The weakening of aeolian activities was divided into three stages: ∼10.0–8.0 ka BP, ∼8.0–4.0 ka BP, and ∼4.0 ka BP to the present. Paleosols were primarily formed after ∼8.0 ka BP, and episodically interrupted aeolian activities processes in the Gannan region. Aeolian activity may increase in the Gannan region as the climate gradually warms. Climatic changes and local hydrological conditions have jointly affected the history of aeolian activities in this region.

Penguin occupation in the Vestfold Hills

2008 ◽  
Vol 21 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Tao Huang ◽  
Liguang Sun ◽  
Yuhong Wang ◽  
Renbin Zhu
Keyword(s):  
Sediment Core ◽  
Environmental Changes ◽  
Sediment Cores ◽  
East Antarctica ◽  
Before Present ◽  
The Holocene ◽  
History Of ◽  
Vestfold Hills ◽  
Free Area ◽  
Ornithogenic Sediment

AbstractDuring CHINARE-22 (December 2005–March 2006), we investigated six penguin colonies in the Vestfold Hills, East Antarctica, and collected several penguin ornithogenic sediment cores, samples of fresh guano and modern penguin bone and feather. We selected seven penguin bones and feathers and six sediments from the longest sediment core and performed AMS14C dating. The results indicate that penguins occupied the Vestfold Hills as early as 8500 calibrated years before present (cal. yrbp), following local deglaciation and the formation of the ice free area. This is the first report on the Holocene history of penguins in the Vestfold Hills. As in other areas of Antarctica, penguins occupied this area as soon as local ice retreated and the ice free area formed, and they are very sensitive to climatic and environmental changes. This work provides the foundation for understanding the history of penguins occupation in Vestfold Hills, East Antarctica.

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