scholarly journals Results of Radiocarbon Analysis of Upper Weichselian Loess Sequences from Hungary

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 1023-1030 ◽  
Author(s):  
Pal Sümegi ◽  
Mihály Molnár ◽  
éva Svingor ◽  
Zsuzsanna Szántó ◽  
László Hum ◽  
...  
Keyword(s):  
Average Rate ◽  
Soil Development ◽  
Carpathian Basin ◽  
Sedimentation Rates ◽  
Quaternary Period ◽  
The Past ◽  
Rate Of Sedimentation ◽  
Dust Accumulation

Approximately 10% of Hungary is covered by dust sequences of the Quaternary period. Samples have been taken from more than 50 outcrops and boreholes during fieldwork in the past 20 yr. Some 81 bulk samples taken from 27 profiles of the Hungarian loess regions have been analyzed for radiocarbon. Based on the 14C results, loess layers that accumulated between 33,000 and 12,000 BP were selected for further investigation. The sedimentation rates of the 27 loess profiles suggest periods of slow and quick dust accumulation in the Carpathian Basin during the Upper Weichselian period. It seems to us that some soil development and intense weathering periods interrupted the loess development during the Upper Weichselian in Hungary. According to the 14C dates, the estimated average rate of sedimentation was 0.31 mm/yr in both the northern and southern parts of the Carpathian Basin between 33,000 and 12,000 BP.

Lead-210 and Pollen Geochronologies on Lake Superior Sediments

1975 ◽  
Vol 5 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Kenneth W. Bruland ◽  
Minoru Koide ◽  
Carl Bowser ◽  
Louis J. Maher ◽  
Edward D. Goldberg
Keyword(s):  
Average Rate ◽  
Lake Superior ◽  
Ragweed Pollen ◽  
Past Century ◽  
Sedimentation Rates ◽  
Human Settlement ◽  
The Past ◽  
Lead 210

AbstractRates of sedimentation in two Lake Superior deposits were determined by both ragweed pollen and 210Pb geochronologies. The former yields an average rate over the time since the first appearance of enhanced concentrations of the pollen as a consequence of human settlement. Sedimentation rates derived on these two bases can be brought into accord if the first appearance of ragweed pollen in the sediments was around 1830 and if the sedimentation rates have been uniform over the past century.

scholarly journals Hurricanes as a Major Driver of Coastal Erosion in the Mississippi River Delta: A Multi-Decadal Analysis of Shoreline Retreat Rates at Bay Champagne, Louisiana (USA)

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1480 ◽  
Author(s):  
Marianne Dietz ◽  
Kam-biu Liu ◽  
Thomas Bianchette
Keyword(s):  
Mississippi River ◽  
Average Rate ◽  
Landsat Imagery ◽  
Mississippi River Delta ◽  
Coastal Lake ◽  
Shoreline Retreat ◽  
The Past ◽  
Coastal Features ◽  
Mexico Coast

The Louisiana shoreline is rapidly retreating as a result of factors such as sea-level rise and land subsidence. The northern Gulf of Mexico coast is also a hotspot for hurricane landfalls, and several major storms have impacted this region in the past few decades. A section of the Louisiana (USA) coast that has one of the highest rates of shoreline retreat in North America is the Caminada-Moreau headland, located south of New Orleans. Bay Champagne is a coastal lake within the headland that provides a unique opportunity to investigate shoreline retreat and the coastal effects of hurricanes. In order to examine the influence of hurricanes on the rate of shoreline retreat, 35 years (1983–2018) of Landsat imagery was analyzed. During that period of time, the shoreline has retreated 292 m. The overall rate of shoreline retreat, prior to a beach re-nourishment project completed in 2014, was over 12 m per year. A period of high hurricane frequency (1998–2013) corresponds to an increased average shoreline retreat rate of >21 m per year. Coastal features created by multiple hurricanes that have impacted this site have persisted for several years. Bay Champagne has lost 48% of its surface area over the last 35 years as a result of long-term shoreline retreat. If shoreline retreat continues at the average rate, it is expected that Bay Champagne will disappear completely within the next 40 years.

scholarly journals Comparing skull formation of the Hungarian (Hortobágy) Zackel sheep breed by geometrics morphometrics

2015 ◽  
pp. 29-33
Author(s):  
Zsuzsanna Csóri ◽  
András Gáspárdy ◽  
András Jávor
Keyword(s):  
Morphological Changes ◽  
Time Change ◽  
Carpathian Basin ◽  
Sheep Breed ◽  
Geometric Morphometric ◽  
The Past ◽  
Morphometric Methods ◽  
Skull Formation ◽  
Over Time

This work seeks to explore the morphological changes of the Hungarian (Hortobágy) Zackel sheep's skull, which occurred in the past 50–70 years. In this study, we compared individuals skull forms by geometric morphometric methods. The origin of the breed is not known, we do not know when entering the Carpathian Basin. Therefore, the comparison involved the only known early archaeological findings. We have shown that there is no difference between each period colour variations, but over time change has occurred in the skull formation of the breed.

scholarly journals Sex and age dependent migration phenology of the Pied Flycatcher in a stopover site in the Carpathian Basin

2015 ◽  
Vol 23 (2) ◽  
pp. 10-19 ◽  
Author(s):  
Andrea Harnos ◽  
Zsolt Lang ◽  
Péter Fehérvári ◽  
Tibor Csörgő
Keyword(s):  
Wing Length ◽  
Carpathian Basin ◽  
Stopover Site ◽  
The Past ◽  
Age Related ◽  
Phenological Changes ◽  
Comprehensive Picture ◽  
Migration Phenology ◽  
And Gender ◽  
Gender Groups

Abstract Very little is known about Pied Flycatchers crossing the Carpathian Basin. We give a comprehensive picture about its migration based on the data collected during the past 26 years (1989–2014) at a stopover site in Hungary: (1) sex and age related phenological changes over the years, (2) sex, age and size dependent migration patterns during and (3) between migration periods, (4) sex and age composition in spring and in autumn and their change over years. The timing of spring migration shifted to earlier dates in the case of males, while that of females did not change implying an increasing rate of protandry. In autumn the timing did not change, but juveniles leave the area earlier than adults. The average wing length increased during the past decades in spring in the case of both sexes. In autumn, wing length did not change significantly during the years, but it increased during the seasons in all age and gender groups. The proportion of males is about 60% in spring and among juveniles in autumn, and it is around 39% in the adult group in autumn. The male ratio diminishes during spring, but it does not change during the autumn season. The average wing of adults is shorter in spring than in autumn. Based on this fact and the different sex ratios in the two seasons we may hypothesize that Pied Flycatchers are loop migrants on this area, and even the sexes of the same population take different routes.

Trends in Chesapeake Bay Sedimentation Rates during the Late Holocene

1990 ◽  
Vol 34 (1) ◽  
pp. 33-46 ◽  
Author(s):  
Joseph F. Donoghue
Keyword(s):  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
Late Holocene ◽  
Tide Gauge ◽  
Past Century ◽  
Sedimentation Rates ◽  
Relative Sea Level ◽  
The Past ◽  
Relative Sea Level Rise

AbstractTrends are discernible in the estimates of late Holocene rates of sedimentation and sea-level rise for the Chesapeake Bay. During most of the Holocene Epoch sedimentation rates and relative sea-level rise were equal, within the limits of measurement, at approximately 1 mm yr−1. Sedimentation rates measured over the past century, however, are nearly an order of magnitude higher, while the rate of relative sea-level rise for the Chesapeake Bay now averages 3.3 mm yr−1, as measured on long-term tide gauge records. When the acceleration in these rates occurred is uncertain, but it appears to have been confined to the past millennium, and probably to the past few centuries. The rapid sedimentation rates recorded during historic time may be a temporary disequilibrium that has resulted from a recent acceleration in the rate of relative sea-level rise.

Evidence of Acidification of Some Nova Scotian Rivers and Its Impact on Atlantic Salmon, Salmo solar

1983 ◽  
Vol 40 (4) ◽  
pp. 462-473 ◽  
Author(s):  
W. D. Watt ◽  
C. D. Scott ◽  
W. J. White
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
River Discharge ◽  
Average Rate ◽  
Metamorphic Rocks ◽  
Ph Variation ◽  
The Past ◽  
Discharge Rates ◽  
Ph Range ◽  
Nova Scotian

River pH's in Nova Scotia are closely related to geology, and seasonal pH variation is well correlated with river discharge rates. In the geologically sensitive areas (granite and metamorphic rocks), river pH's have fallen significantly over the past 27 yr at an apparent average rate of 0.017 pH units/year. Concomitant with this decrease are a decline in [Formula: see text] concentrations and increases in Al+++ and [Formula: see text]. On average, 73% of the increase in acid is attributable to increased [Formula: see text]. Changes in Na+, K+, Ca++, and Mg++ concentrations were not significant. In rivers presently at mean annual pH's < 4.7, the Atlantic salmon (Salmo salar) runs have disappeared and are presumed extinct. Rivers in the pH range 4.7–5.0 show a decline in salmon angling returns of 2.8%/yr, beginning about 1954, and low densities of juvenile salmon. Rivers presently of pH > 5.0 generally have normal juvenile densities and show no significant trend in angling returns.

Quaternary and active faulting observed on the 1985 Academia Sinica - Royal Society Geotraverse of Tibet

1988 ◽  
Vol 327 (1594) ◽  
pp. 337-363 ◽  
Keyword(s):  
Average Rate ◽  
Strike Slip ◽  
Fault System ◽  
Ground Moraine ◽  
Normal Faulting ◽  
Stream Channels ◽  
Quaternary Period ◽  
Terminal Moraine ◽  
Northern Half ◽  
Southern Half

Active and recent faulting along the main north—south road in Tibet is dominated by normal faulting occurring on northerly-trending planes and by strike-slip faulting, both of which reflect an east-west extension of the plateau. Normal faulting is prevalent in the southern half of the plateau, but we saw no evidence for any major graben in the northern half. Strike-slip faulting on roughly easterly-trending structures is m ore prevalent in the northern half, but conjugate faulting, with right-lateral slip on northwesterly-trending planes and left-lateral slip on northeasterly-trending planes, is common in the southern half. In two areas, we also observed components of thrust faulting, apparently in association with young strikeslip faulting. Our most important results are bounds on the rates of slip on the two main strands of the Kunlun strike-slip fault system, which trends east-w est through the Kunlun range. Ground moraine containing boulders of pyroxenite is separated by 30 km from the nearest outcrop of such rock, implying that amount of displacement in the last 1.5 to 3 M a. Therefore the average rate of slip during the Quaternary period has been between 10 and 20 mm/a , with a likely value of 13 mm/a . Abundant fresh tension cracks and mole tracks imply continued slip on the main strand, the Xidatan -Tuosuohu-Maqu fault, and the likely occurrence of a major earthquake in the last few hundred years. Consistent offsets of gullies and dry stream channels of about 10 m may reflect slip of that amount during such an earthquake, and possible multiple offsets at one site suggest that slip may occur by large displacements of 10 m during infrequent great earthquakes. Along the other strand, the Kunlun Pass fault, offsets of roughly 50 to 150 m of, apparently, post-glacial valleys and of one glacier and its terminal moraine suggest a Holocene rate of slip between 5 and 20 mm/a , and most likely about 10 mm/a , on this fault. These rapid rates of displacement imply that Tibet is being extruded rapidly eastward, at a rate com parable to the rate at which India is penetrating into Eurasia, and therefore that, at present, a substantial fraction of this penetration is being absorbed by the eastward extrusion of Tibet.

scholarly journals Late Pleistocene Paleoclimatology of the Central Equatorial Pacific: A Quantitative Record of Eolian and Carbonate Deposition

1987 ◽  
Vol 28 (3) ◽  
pp. 323-339 ◽  
Author(s):  
John M. Chuey ◽  
David K. Rea ◽  
Nicklas G. Pisias
Keyword(s):  
Atmospheric Circulation ◽  
Accumulation Rate ◽  
Source Region ◽  
Marked Change ◽  
Equatorial Pacific ◽  
Sedimentation Rates ◽  
Glacial Cycle ◽  
The Past ◽  
Mass Accumulation Rate ◽  
Mass Accumulation

AbstractDetailed records of δ18O, δ13C, percentage and mass accumulation rate of CaCO3, and eolian percentage, mass accumulation rate, and grainsize generated for core RC11-210 from the equatorial Pacific reveal the timing of paleoclimatic events over the past 950,000 yr. The CaCO3 percentage record shows the standard Pacific correlation of high CaCO3 content with glacial periods, but displays a marked change of character about 490,000 yr ago with older stages showing much less variability. The carbonate mass flux record, however, does not show such a noticeable change. Sedimentation rates vary from about 0.5 to 3.0 cm/1000 yr and, during the past 490,000 yr, sections with enhanced sedimentation rates correspond to periods of high CaCO3 percentage. Eolian mass accumulation rates, an indication of the aridity of the source region, are usually higher during glacial times. Eolian grainsize, an indication of the intensity of atmospheric circulation, generally fluctuates at a higher frequency than the 100,000-yr glacial cycle. The mid-Brunhes climatic event centered at 300,000 yr ago appears as a 50,000-yr interval of low intensity and reduced variability of atmospheric circulation. Furthermore, the nature of this entire record changes then, with the younger portion indicating less variation in wind intensity than the older part of the record. The late Matuyama increase in amplitude of paleoclimatic signals begins 875,000 yr ago in the eolian record, 25,000 yr before the δ18O and CaCO3 percentage amplitude increases about 850,000 yr ago.

Cas historique de sédimentation du barrage Péligre, Haïti

1982 ◽  
Vol 9 (2) ◽  
pp. 206-223
Author(s):  
M. Frenette ◽  
J. P. Tournier ◽  
T. J. Nzakimuena
Keyword(s):  
Average Rate ◽  
Sedimentation Rates ◽  
Average Increase ◽  
Physical Processes ◽  
Straight Line ◽  
Average Sedimentation Rate ◽  
The Future ◽  
Reservoir Geometry ◽  
Consolidation Effect

The Péligre Dam in Haïti, on the Artibonite River, was built in 1956 for an expected life of about 180 years. Based on sedimentation data collected in 1925 and 1926, the average rate of silting in the reservoir was estimated at 3.45 × 106 m3/year. In 1979, however, an average sedimentation rate of 9.6 × 106 m3/year was established.Systematic observations were undertaken in 1961, 1977, and 1979 to explain the phenomenon and to predict the future rate of silting in the reservoir. The studies led to simulation, by means of a mathematical model, of the processes involved and have permitted reconstruction of the hydro-sedimentological events since 1956 as well as prediction of the future rate of sedimentation.In order to develop a methodology that has widespread applicability for predicting the rate of sedimentation, the main physical processes responsible for the patterns of deposition were used as common denominators: degradation of watershed and rivers, effects of deforestation, urbanisation, and agriculture, effects of flocculation and consolidation, effect of the reservoir geometry, expected sediment inflow, water inflow versus outflow, etc.On the whole, the model indicates very well the acceleration of the silting rate with an average increase of about 18% per year. The study thus shows that the sediment inflow took the form of a quadratic or exponential growth curve instead of a straight line. After 23 years the average silting is three times that of the design. The results show in conclusion how we must be careful in predicting long-term sedimentation rates in a reservoir since the lifetime of the dam is notably reduced. Keywords: erosion, sedimentation, reservoir, lifetime, simulation, degradation, watershed, design.

scholarly journals Chronology and Stratigraphy of the Imlay channel in Lapeer County, Michigan, USA

2021 ◽  
Author(s):  
Jonathan N. Luczak ◽  
Timothy G. Fisher ◽  
Kenneth Lepper
Keyword(s):  
Cross Sections ◽  
Lake Erie ◽  
Early Holocene ◽  
Glacial Lake ◽  
Sedimentation Rates ◽  
Alluvial Fans ◽  
Radiocarbon Age ◽  
The Past ◽  
Water Well ◽  
A Current

The Imlay channel in Lapeer County, Michigan was one of two outlets for the glacial Lake Maumee phase of ancestral Lake Erie. Fifteen new radiocarbon and optical ages from within and adjacent to the Imlay channel constrain sedimentation rates within the channel and the timing of regional deglaciation. For nearly 50 years the deglaciation of this region of Michigan has been based on a single age from the Weaver Drain site located near the Imlay channel, and a new radiocarbon age of 16.7–17.0 cal ka BP from 3 km east of the Imlay channel supports this long-standing deglacial age. On average there is a 14 m thick sediment fill within the channel. Radiocarbon and OSL ages reveal that much of the alluvial fill was deposited by 14.9 ka, and alluvial fans building into the channel stabilized in the early Holocene. Cross-sections along and perpendicular to the Imlay channel, built from geotechnical borings and water-well records, reveal a current-day bedrock sill elevation at 235 masl that would have permitted drainage of all stages of glacial Lake Maumee in the past.

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