scholarly journals Mid and Late Holocene flooding reconstruction based on fluvial archives of the East Carpathian rivers

2018 ◽  
Vol 20 (1) ◽  
pp. 17-33
Author(s):  
Maria RĂDOANE ◽  
Francisca CHIRILOAEI ◽  
Nicolae RĂDOANE ◽  
Constantin NECHITA
Keyword(s):  
Iron Age ◽  
Late Holocene ◽  
General Pattern ◽  
Geographical Area ◽  
Ice Age ◽  
Lateral Migration ◽  
Eastern Carpathians ◽  
Study Results ◽  
Floodplain Deposits ◽  
Fluvial Archives

This paper focused on the analysis of the interpretation potential given by fluvial archives, in order to decipher the Mid- to Late Holocene sedimentary history. The database discussed here refers to 65 dated ages (mostly radiocarbon), mappings of the most representative floodplain reaches of Suceava, Moldova and Siret rivers, and 23 outcrops analysed in floodplain deposits (river banks or gravel pits). The study results concentrated on (a) describing the regional features of Eastern Carpathian floodplains, (b) the floodplain morphology and its correlation with the structure of fluvial deposits and (c) identifying the paleoevents of fluvial activity on a centennial timescale. In this way, we were able to identify a general pattern of the dynamic geomorphology history for the rivers situated eastward of the Carpathians, which resulted from combining the Mid- to Late Holocene sedimentation phases, the avulsion and lateral migration processes that occurred during high fluvial activity intervals and the morphological adjustment of the rivers channels, from braiding to wandering and sinuously–meandering. The chronological overlay of the events revealed that the time intervals with the most extensive fluvial processes on the rivers draining the Eastern Carpathians occurred (in years before present) during 6200, 5300, 4100–4080, 3600, 2300–2200 (Iron Age), 1300 (Migrations Period), 950–970 (Medieval Climate Anomaly), 750–520 BP (Little Ice Age)and that these intervals generally overlap the high precipitation palaeoclimatic episodes documented in Romania. The fluvial activity of the rivers during the Mid- to Late Holocene has been compared as well with several records of paleo–climates variability over the geographical area of Romania. The result showed that many flooding episodes were coincident with the wet and cold intervals which were also identified in the variation of the other proxydata, especially after 4.7 kcal BP.

Late Holocene Paleoecology and Sedimentary History of a Small Lowland Catchment in Central England

1985 ◽  
Vol 24 (1) ◽  
pp. 87-102 ◽  
Author(s):  
Antony G. Brown ◽  
Keith E. Barber
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Structural Damage ◽  
Late Holocene ◽  
Sediment Storage ◽  
Erosion Rates ◽  
History Of ◽  
Floodplain Deposits ◽  
Floodplain Sediments

A variety of paleoecological and sedimentary techniques were used to investigate the storage of sediment within a small lowland catchment during the Holocene. Radiocarbon dating of vertically accreted floodplain deposits allowed the calculation of inorganic accumulation rates. These rates show a dramatic increase in sediment deposition during the late Bronze Age and early Iron Age (2900-2300 yr B.P.) due to deforestation and cultivation of the catchment slopes and resultant soil erosion. The soils within the catchment were susceptible to structural damage, surface waterlogging, and slope-wash erosion. From the calculated increases in sediment storage estimates of catchment erosion were made which vary from around 20 to 140 tons km−2 yr−1. The study of alluvial chronology at this scale can provide unique information on the source areas of Holocene floodplain sediments and provide long-term erosion rates.

Paleoenvironmental and geoarchaeological reconstruction from late Holocene slope records (Lower Huerva Valley, Ebro Basin, NE Spain)

2014 ◽  
Vol 81 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Fernando Pérez-Lambán ◽  
José Luis Peña-Monné ◽  
Javier Fanlo-Loras ◽  
Jesús V. Picazo-Millán ◽  
David Badia-Villas ◽  
...  
Keyword(s):  
Iron Age ◽  
Little Ice Age ◽  
Late Holocene ◽  
Ice Age ◽  
Archaeological Remains ◽  
Ebro Basin ◽  
Late Chalcolithic ◽  
Slope Deposits ◽  
Excellent Preservation ◽  
Ne Spain

AbstractSlope deposits in semiarid regions are known to be very sensitive environments, especially those that occurred during the minor fluctuations of the late Holocene. In this paper we analyse Holocene colluvium genesis, composition, and paleoenvironmental meaning through the study of slope deposits in NE Spain. Two cumulative slope stages are described during this period. In the study area, both slope accumulations are superimposed and this has enabled an excellent preservation of the aggregative sequence and the paleosols corresponding to stabilisation stages. 14C and TL dating, as well as archaeological remains, provide considerable chronological precision for this sequence. The origin of the accumulation of the lower unit is placed around 4295–4083 cal yr BP/2346–2134 cal yr BC (late Chalcolithic) and it developed until the Iron Age in a cooler and wetter climate (Cold Iron Age). Under favourable conditions, a soil A-horizon was formed on top of this unit. A new slope accumulation was formed during the Little Ice Age. Within the slope two morphogenetic periods ending with A-horizons are distinguished and related with two main cold–wet climatic events. The study of these slopes provides a great amount of data for the paleoenvironmental and geoarchaeological reconstruction of the late Holocene in NE Spain.

scholarly journals Late-Holocene diatom community response to climate driven chemical changes in a small, subarctic lake, Northwest Territories, Canada

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Paul B Hamilton ◽  
Scott J Hutchinson ◽  
R Timothy Patterson ◽  
Jennifer M Galloway ◽  
Nawaf A Nasser ◽  
...  
Keyword(s):  
Iron Age ◽  
Biological Diversity ◽  
Regional Climate ◽  
Natural Aging ◽  
Community Response ◽  
Warm Period ◽  
Ice Age ◽  
Diatom Assemblages ◽  
Subarctic Lake ◽  
Over Time

The paleolimnological record of diatoms and climate, spanning the last 2800 years, was investigated in a small subarctic lake (Pocket Lake) that from AD 1948 to 2004 was contaminated by gold smelting waste. An age-depth model was constructed using a combination of 210Pb, 14C, and tephra to determine a 2800 year history of lake ontogeny (natural aging), biological diversity, and regional climate variability. Diatoms form six strong paleoecological assemblages over time in response to changes in local hydrological and sedimentological conditions (including metals). Selected environmental variables explained 28.8% of the variance in the diatom assemblages, with Fe, Ca, and sediment end member distribution being important indicators. The diatom assemblages correlated to the Iron Age Cold Epoch (2800–2300 cal BP), Roman Warm Period (2250–1610 cal BP), Dark Age Cold Period (1500–1050 cal BP), Medieval Climate Anomaly (ca. 1100–800 cal BP), and the Little Ice Age (800–200 cal BP). The disappearance of Staurosira venter highlights the change from the Iron Age Cold Epoch to the Roman Warm Period. After deposition of the White River Ash (833–850 CE; 1117–1100 cal BP), transition to circumneutral conditions was followed in tandem by a transition to planktic influenced communities. Ten discrete peaks of Cu, Pb, and Zn were observed and attributed to soluble mobility from catchment soils through enhanced seepage and spring snowmelt. The prominent metal spikes were aligned with increases in Brachysira neoexilis. Downward mobilization of arsenic and antimony from contaminated surficial sediments highlight the problem of post depositional industrial contamination of paleosediments. Results demonstrate that paleoclimatic changes in the region, modulated by solar radiation, impacted temperature and precipitation in the lake catchment, influencing temporal shifts in diatom ecology. Changes in diatom taxa richness provided valuable information on the relative influence of water quality (planktic taxa) and sediment input (benthic taxa). The diatom assemblage succession also provides evidence that natural aging over time has played a role in the ecological evolution of the lake.

scholarly journals Protocol for a qualitative study to identify strategies to optimise hospital ePrescribing systems

BMJ Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. e044622
Author(s):  
Catherine Heeney ◽  
Stephen Malden ◽  
Aziz Sheikh
Keyword(s):  
Qualitative Interviews ◽  
Geographical Area ◽  
Health Resources ◽  
Round Table ◽  
Developed Countries ◽  
Care Quality ◽  
Electronic Prescribing ◽  
Study Results ◽  
Electronic Health ◽  
The Uk

IntroductionElectronic prescribing (ePrescribing) is a key area of development and investment in the UK and across the developed world. ePrescribing is widely understood as a vehicle for tackling medication-related safety concerns, improving care quality and making more efficient use of health resources. Nevertheless, implementation of an electronic health record does not itself ensure benefits for prescribing are maximised. We examine the process of optimisation of ePrescribing systems using case studies to provide policy recommendations based on the experiences of digitally mature hospital sites.Methods and analysisQualitative interviews within six digitally mature sites will be carried out. The aim is to capture successful optimisation of electronic prescribing (ePrescribing) in particular health systems and hospitals. We have identified hospital sites in the UK and in three other developed countries. We used a combination of literature reviews and advice from experts at Optimising ePrescribing in Hospitals (eP Opt) Project round-table events. Sites were purposively selected based on geographical area, innovative work in ePrescribing/electronic health (eHealth) and potential transferability of practices to the UK setting. Interviews will be recorded and transcribed and transcripts coded thematically using NVivo software. Relevant policy and governance documents will be analysed, where available. Planned site visits were suspended due to the COVID-19 pandemic.Ethics and disseminationThe Usher Research Ethics Group granted approval for this study. Results will be disseminated via peer-reviewed journals in medical informatics and expert round-table events, lay member meetings and the ePrescribing Toolkit (http://www.eprescribingtoolkit.com/)—an online resource supporting National Health Service (NHS) hospitals through the ePrescribing process.

scholarly journals Late-Holocene forest resilience in the central Pyrenean highlands as deduced from pollen analysis of Lake Sant Maurici sediments

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Valentí Rull ◽  
Núria Cañellas-Boltà ◽  
Teresa Vegas-Vilarrúbia
Keyword(s):  
Bronze Age ◽  
Middle Ages ◽  
Iron Age ◽  
Late Holocene ◽  
High Elevation ◽  
Roman Period ◽  
High Mountain ◽  
Southern Central ◽  
Central Pyrenees ◽  
The Middle Ages

Palynological analysis of the last ca. 4300 cal year BP using a sediment core taken from high mountain (ca. 1900 m elevation) Lake Sant Maurici sediments (southern-central Pyrenees) showed remarkable vegetation constancy during the Bronze Age and the Middle Ages. Records of the Iron Age and the Roman period were missing due to a major sedimentary gap. During the studied periods, the vegetation around the lake was largely dominated by pine ( Pinus) forests with birch ( Betula), oak ( Quercus) and hazel ( Corylus) trees, as is the case today. The composition of these forests and the abundance of their components remained quite stable, despite the occurrence of temperature and moisture shifts. The degree of human disturbance, notably that of pastoralism and cereal cultivation by scattered and temporary settlements, was very low and had little or no effect on the dominant forests. This situation contrasts with most high-elevation (subalpine and alpine) environments of the central Pyrenees that were massively anthropized during the Middle Ages. Further research should be aimed at finding sediments corresponding to the Iron Age and the Roman period to verify whether the vegetation constancy can be extended throughout the Late-Holocene. Past records of this type may allow the estimation of natural and anthropogenic thresholds for irreversible forest changes, which would be useful for conservation purposes.

scholarly journals Tidal Flat Depositional Response to Neotectonic Cyclic Uplift and Subsidence (1–2 m) as Superimposed on Latest-Holocene Net Sea Level Rise (1.0 m/ka) in a Large Shallow Mesotidal Wave-Dominated Estuary, Willapa Bay, Washington, USA

2018 ◽  
Vol 10 (1) ◽  
pp. 109 ◽  
Author(s):  
Curt D. Peterson ◽  
Sandy Vanderburgh
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Flat ◽  
Late Holocene ◽  
Columbia River ◽  
Small Rivers ◽  
Intertidal Flat ◽  
Sedimentation Rates ◽  
Lateral Migration ◽  
Willapa Bay

The late-Holocene record of tidal flat deposition in the large shallow Willapa Bay estuary (43 km in length), located in the Columbia River Littoral Cell (CRLC) system (160 km length), was investigated with new vibracores (n=30) and gouge cores (n=8), reaching 2–5 m depth subsurface. Reversing up-core trends of muddy sand to peaty mud deposits in marginal tidal flat settings demonstrate episodic submergence events resulting from cyclic tectonic uplift and subsidence (1–2 m) in the Cascadia subduction zone. These short-term reversals are superimposed on longer-term trends of overall sediment coarsening-up, which represent the transgression of higher-energy sandy tidal flats over pre-existing lower-energy tidal flat mud and peaty mud deposits in late-Holocene time. Fining-up trends associated with channel lateral migration and accretionary bank deposition occurred only infrequently in the broad intertidal flats of Willapa Bay. Vibracores and gouge cores were dated by 14C (n=16) and paleo-subsidence event contacts (n=17). Vibracore median probability 14C ages ranged from 0 to 6,992 yr BP and averaged 2,174 yr BP. Dated sample ages and corresponding depths of tidal flat deposits yield net sedimentation rates of 0.9–1.2 m ka-1, depending on the averaging methods used. Net sedimentation rates in the intertidal flat settings (~1.0 m ka-1) are comparable to the rate of net sea level rise (~1.0 m ka-1), as based on dated paleo-tidal marsh deposits in Willapa Bay. Reported modern inputs of river sand (total=1.77x104 m3 yr-1), from the three small rivers that flow into Willapa Bay, fall well short of the estimated increasing accommodation space (1.9x105 m3 yr-1) in the intertidal (MLLW-MHHW) setting (1.9x108 m2 surface area) during the last 3 ka, or 3.0 m of sea level rise. The under-supply of tributary sand permitted the influx of littoral sand (1.1x105 m3 yr-1) into Willapa Bay, as based on the net sedimentation rate (~1.0 m ka-1) and textural composition (average 60 % littoral sand) in analyzed core sections (n=179). The long-term littoral sand sink in Willapa Bay’s intertidal setting (55 % of total estuary area) is estimated to be about 5 % of the Columbia River supply of sand to the CRLC system, and about 30% relative to the littoral sand accumulated in barrier spits and beach plains during late-Holocene time. A 2.0 m rise in future sea level could yield a littoral sand sink of 2.2x108 m3 in the Willapa Bay intertidal setting, resulting in an equivalent shoreline retreat of 600 m along a 50 km distance of the barrier spit and beach plains that are located adjacent to the Willapa Bay tidal inlet. Willapa Bay serves as proxy for potential littoral sand sinks in other shallow mesotidal estuary-barrier-beach systems around the world following future global sea level rise.

scholarly journals Late Holocene intensification of the westerly winds at the subantarctic Auckland Islands (51° S), New Zealand

2017 ◽  
Author(s):  
Imogen M. Browne ◽  
Christopher M. Moy ◽  
Christina R. Riesselman ◽  
Helen L. Neil ◽  
Lorelei G. Curtin ◽  
...  
Keyword(s):  
New Zealand ◽  
Late Holocene ◽  
Drainage Basin ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Ice Age ◽  
The Pacific ◽  
Westerly Winds ◽  
Latitudinal Position ◽  
Paleoclimate Records

Abstract. The Southern Hemisphere westerly winds (SHWW) play a major role in controlling wind-driven upwelling of Circumpolar Deep Water (CDW) and outgassing of CO2 in the Southern Ocean on interannual to glacial-interglacial timescales. Despite their significance in the global carbon cycle, our understanding of millennial-scale changes in the strength and latitudinal position of the westerlies during the Holocene (especially since 5000 yr BP) is limited by a scarcity of paleoclimate records from comparable latitudes. Here, we reconstruct middle to late Holocene variability in the SHWW using a fjord sediment core collected from the subantarctic Auckland Islands (51° S, 166° E), located in the modern centre of the westerly wind belt. Drainage basin response to variability in the strength of the SHWW at this latitude is reconstructed from downcore variations in magnetic susceptibility (MS) and bulk organic δ13C and atomic C/N, which monitor influxes of lithogenous and terrestrial vs marine organic matter, respectively. The hydrographic response to SHWW variability is reconstructed using benthic foraminifer δ18O and δ13C, both of which are influenced by the isotopic composition of shelf water masses entering the fjord. Using these data, we provide marine and terrestrial-based evidence for increased wind strength from ~ 1600–900 yr BP at subantarctic latitudes that is broadly consistent with previous studies of vegetation response to climate at the Auckland Islands. Comparison with a SHWW reconstruction using similar proxies from Fiordland suggests a northward migration of the SHWW over New Zealand at the beginning of the Little Ice Age (LIA). Comparison with paleoclimate and paleoceanographic records from southern South America and the western Antarctic Peninsula indicates a late Holocene strengthening of the SHWW after ~ 1600 yr BP that appears to be broadly symmetrical across the Pacific basin, although our reconstruction suggests that this symmetry breaks down during the LIA. Contemporaneous increases in SHWW at localities either side of the Pacific in the late Holocene are likely controlled atmospheric teleconnections between the low and high latitudes and by variability in the Southern Annular Mode (SAM) and El Niño Southern Oscillation (ENSO).

Microlithic occurrences associated with sediments dated to terminal Pleistocene-late Holocene in the central Narmada basin, Madhya Pradesh, India

2021 ◽  
pp. SP515-2020-216
Author(s):  
Nupur Tiwari ◽  
P. Morthekai ◽  
K. Krishnan ◽  
Parth R. Chauhan
Keyword(s):  
Sri Lanka ◽  
South Asia ◽  
Late Pleistocene ◽  
Iron Age ◽  
Late Holocene ◽  
Indian Subcontinent ◽  
Central India ◽  
Madhya Pradesh ◽  
Doctoral Research ◽  
Terminal Pleistocene

AbstractThe earliest occurrence of microliths in South Asia dates back to the Late Pleistocene at Mehtakheri (45 ka) and Dhaba (48 ka) in Central India, Jwalapuram 9 in Southern India (38 ka), Kana and Mahadebbara in Northeastern India (42-25 ka) and Batadomba-Lena (35-36 ka) and Fa Hien Lena (48 ka) in Sri Lanka. Microlithic technology is distributed across the entire Indian Subcontinent and chronologically continues up to the Iron Age and Early Historic periods. This paper discusses new data acquired from the first author's doctoral research in the two districts of Madhya Pradesh (Hoshangabad and Sehore), which fall within the central part of the Narmada Basin in central India. We present here the preliminary dates from key areas of distribution to understand the geo-chronological contexts of microliths at Pilikarar, Morpani, and Gurla-Sukkarwada. Initial dates from these respective occurrences range between 12.5 ka and 2.3 ka.

Mid to late Holocene climate evolution of the Lake Telmen Basin, North Central Mongolia, based on palynological data

2003 ◽  
Vol 59 (3) ◽  
pp. 353-363 ◽  
Author(s):  
Sarah J. Fowell ◽  
Barbara C.S. Hansen ◽  
John A. Peck ◽  
P. Khosbayar ◽  
Enebish Ganbold
Keyword(s):  
Late Holocene ◽  
Ice Age ◽  
Cold Temperatures ◽  
North Central ◽  
Central Mongolia ◽  
Decadal Scale ◽  
Moisture Balance ◽  
Climate Evolution ◽  
Maximum Humidity

AbstractPalynological and sedimentological data from Lake Telmen, in north-central Mongolia, permit qualitative reconstruction of relative changes in moisture balance throughout the mid to late Holocene. The climate of the Atlantic period (7500–4500 yr ago) was relatively arid, indicating that Lake Telmen lay beyond the region of enhanced precipitation delivered by the expanded Asian monsoon. Maximum humidity is recorded between ∼4500 and 1600 cal yr B.P., during the Subboreal (4500–2500 yr ago) and early Subatlantic (2500 yr–present) periods. Additional humid intervals during the Medieval Warm Epoch (∼1000–1300 A.D. or 950–650 ago) and the Little Ice Age (1500– 1900 A.D. or 450–50 yr B.P.) demonstrate the lack of long-term correlation between temperature and moisture availability in this region. A brief aridification centered around 1410 cal yr B.P. encompasses a decade of cold temperatures and summer frost between A.D. 536 and 545 (1414–1405 yr B.P.) inferred from records of Mongolian tree-ring widths. These data suggest that steppe vegetation of the Lake Telmen region is sensitive to centennial- and decadal-scale climatic perturbations.

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