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Special Zeszyt Title: Proceedings of the 2nd Asia Pacific Conference on Luminescence Dating, Ahmedabad, India, 2009. Part II Zeszyt Editors: Andrzej Bluszcz, Silesian University of Technology, Gliwice, Poland. Andrzej.Bluszcz@polsl.pl Sheng-Hua Li, The University of Hong Kong, Hong Kong, China. shli@hku.hk Ashok Kumar Singhvi, Physical Research Laboratory, Ahmedabad, India. singhvi@prl.res.in

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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1897-1695
Pierwsze wydanie
04 Jul 2007
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

Tom 42 (2015): Zeszyt 1 (January 2015)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1897-1695
Pierwsze wydanie
04 Jul 2007
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

23 Artykułów
access type Otwarty dostęp

Holocene Chronology of the Brattforsheden Delta and Inland Dune Field, Sw Sweden

Data publikacji: 11 Mar 2015
Zakres stron: -

Abstrakt

Abstract

Brattforsheden is a large glacifluvial deposit in southwestern Sweden and associated with it is one of Sweden’s largest inland dune fields. Although the relative ages of the Brattforsheden depos-its are well known, absolute ages from the area are few. In this study we have used optically stimulat-ed luminescence (OSL), surface exposure (10Be) and radiocarbon (14C) dating to provide an absolute chronology for the deglaciation and for the Holocene development of the aeolian dunes. Our data show that the deglaciation took place just before 11 ka (11.5 ± 0.6 ka OSL, 11.3 ± 0.8 ka 10Be), in line with the 14C-based regional deglaciation age. Aeolian dunes started forming immediately after degla-ciation and were active for at least 2000 years, well after vegetation had established. Renewed aeolian activity occurred 270-180 years ago, resulting in the deposition of sand sheets. Comparison between dating methods and studies of OSL dose distributions show that glacial, glacifluvial and littoral sedi-ments suffer from incomplete bleaching and thus that mean OSL ages from such deposits overesti-mate the true depositional age. By using small aliquots and statistical age models, this effect can part-ly be countered. Also, some of the 10Be ages appear too old, which may be due to previous exposure.

Keywords

  • luminescence (OSL) dating
  • surface exposure dating (10Be)
  • deglaciation
  • aeolian
  • Holo-cene
  • Sweden
access type Otwarty dostęp

Influence of in Situ Temperature on the Sensitization of Quartz: A Simulation Study

Data publikacji: 11 Mar 2015
Zakres stron: -

Abstrakt

Abstract

The influence of ambient geological and burial temperatures, prevailing in nature, on the charge population of the defect centers and, eventually, the sensitivity of the luminescence emission of quartz was simulated using empirical model. Various permutation and combination of these tem-peratures were incorporated so as to observe, both, the collective and independent impact of these two temperatures on the charge kinetics. The results of seem to demonstrate the role of the ambient tem-perature in the sensitization of quartz mineral

Słowa kluczowe

  • sensitization
  • quartz
  • in situ temperature
  • TL
  • OSL
access type Otwarty dostęp

Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus Petraea) in the Czech Republic

Data publikacji: 11 Mar 2015
Zakres stron: -

Abstrakt

Abstract

Unraveling climatic effects on growth of oak - Europe’s most ecologically and economically important forest species - has been the subject of many recent studies; however, more insight based on field data is necessary to better understand the relationship between climate and tree growth and to adapt forest management strategies to future climate change. In this report, we explore the influence of temperature, precipitation and drought variability on the productivity and vitality of oak stands in the Czech Highlands. We collected 180 cores from mature oaks (Quercus petraea) at four forest stands in the Czech Drahany Highlands. Standard dendromethods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Crown vitality was also evaluated, using the modified ICP Forests methodology. Late spring precipitation totals between May and June as well as the mean July temperature for the year of ring formation were found to be the most important factors for oak growth, whereas crown condition was significantly affected by spring and summer drought. This study is rep-resentative for similar bio-ecological habitats across Central Europe and can serve as a dendroclima-tological blueprint for earlier periods for which detailed meteorological information is missing

Słowa kluczowe

  • Central Europe
  • crown condition
  • precipitation
  • sessile oak
  • temperature
  • tree rings
access type Otwarty dostęp

The 443-Year Tree-Ring Chronology for the Scots Pine from Upper Silesia (Poland) as A Dating Tool and Climate Proxy

Data publikacji: 25 Mar 2015
Zakres stron: -

Abstrakt

Abstract

An annually resolved and absolutely dated ring-width chronology spanning 443 years has been constructed using the historical and living-tree Scots pine samples from the Upper Silesia, south of Poland. The constructed regional chronology, based on six object chronologies, covers the period of 1568-2010. It is composed of 178 wood samples with the mean correlation of 0.51, mean series length of 104 years and mean EPS of 0.85. In total, 65 extreme years were distinguished. Their inde-pendent verification, based on the historical and meteorological data, showed significant correlation with the exceptionally cold/mild winters as well as severe droughts. The comparison of the extreme years with the other Polish pine chronologies showed similarities in the years with the anomalous winter conditions. Some extreme years can be associated with the exceptional pluvial conditions; these years are common in the Central European hydroclimatic tree-ring records. The construction of this regional pine chronology enables for the absolute dating of many architectural monuments from investigated region. The application of the new chronology for the dating of local wood can support interpretations of changes in the environment of the Upper Silesian region. In the future it can also be used as the basis for climate reconstruction.

Keywords

  • long term chronology
  • tree-ring dating
  • cultural heritage
  • historic wood
  • Pinus sylvestris
  • S Poland
access type Otwarty dostęp

Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes

Data publikacji: 27 Mar 2015
Zakres stron: -

Abstrakt

Abstract

Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata tree-rings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater am-plitude than previous reconstructions derived from traditional tree-ring density data, and describes particularly cool conditions during the late 19th century. Some of these differences, including early warm periods in the 14th and 17th centuries, have been retained via δ13C timeseries detrending - a novel approach in tree-ring stable isotope chronology development. The overall reduced variance in earlier studies points to an underestimation of pre-instrumental summer temperature variability de-rived from traditional tree-ring parameters.

Keywords

  • Climate change
  • paleoclimatology
  • stable isotope geochemistry
  • tree-rings
  • Europe
access type Otwarty dostęp

Debris-flow activity in five adjacent gullies in a limestone mountain range

Data publikacji: 27 Mar 2015
Zakres stron: -

Abstrakt

Abstract

Debris-flows are infrequent geomorphic phenomena that shape steep valleys and can repre-sent a severe hazard for human settlements and infrastructure. In this study, a debris-flow event chro-nology has been derived at the regional scale within the Gesäuse National Park (Styria, Austria) using dendrogeomorphic techniques. Sediment sources and deposition areas were mapped by combined field investigation and aerial photography using an Unmanned Aerial Vehicle (UAV). Through the analysis of 384 trees, a total of 47 debris-flows occurring in 19 years between AD 1903 and 2008 were identified in five adjacent gullies. Our results highlight the local variability of debris-flow activi-ty as a result of local thunderstorms and the variable availability of sediment sources.

Keywords

  • debris-flow
  • dendrogeomorphology
  • growth disturbances
access type Otwarty dostęp

Luminescence dating of loess deposits from the Remagen-Schwalbenberg site, Western Germany

Data publikacji: 27 Mar 2015
Zakres stron: -

Abstrakt

Abstract

This study describes the luminescence characteristics of quartz of Upper Pleistocene loess of the Middle Rhine area. The loess/palaeosol sequence of the Schwalbenberg near Remagen com-prises a multitude of interstadial soils and soil sediments that have been dedicated to the Marine Iso-tope Stage 3 (MIS 3). These weak calcaric cambisols and their derivates are underlain by loess and soil sediments of MIS 4 to MIS 5 and covered by loess sediments and intercalated gelic gleysols of MIS 2. We applied luminescence dating of quartz and feldspar of drill core samples and observed an age discrepancy within both data sets. The quartz ages were clearly younger than the feldspar ages, because of thermally unstable signal components of the quartz luminescence signal. Therefore, we re-garded the quartz samples of the lower parts of the drill core as unsuitable for luminescence dating. This underestimation did not affect the quartz samples of the upper part of the drill core which was indicated by age control that was provided by the Eltville tephra layer. Geochemical analysis based on X-ray fluorescence showed that the sediments in the upper part and the lower part of the drill core have different geogenic finger prints most likely due to changing source areas of dust and sediment allocation. We assumed that these different facies types were the reason for the luminescence behav-ior of the quartz samples.

Keywords

  • luminescence dating
  • loess
  • last glacial cycle
  • Middle Rhine
  • Eltville tephra
  • geochemical analysis
access type Otwarty dostęp

Erratum: Holocene chronology of the Brattforsheden delta and inland dune field, SW Sweden

Data publikacji: 19 May 2015
Zakres stron: -

Abstrakt

access type Otwarty dostęp

Historical water-powered ferrous metallurgy reconstructed from tree-rings and lacustrine deposits (Mała Panew basin, southern Poland)

Data publikacji: 20 May 2015
Zakres stron: -

Abstrakt

Abstract

According to historical sources in the basin of Mała Panew River there were at least 56 water-powered iron smelters from 14th-19th century. Now only two metallurgy plants work in the area. Many of the former smelting settlements ceased to exist. Historical data on the smelting industry in the area are often scarce. The aim of the study was to reconstruct the history of ferrous metallurgy from (1) the remains of wooden historical buildings, (2) remains of charcoal kilns and (3) deposits from former smelter pond. Results show that Regolowiec smelting settlement existed already in the 17th century (at least several decades earlier than historical written sources suggest) and was later re-paired after destruction caused probably by floods. Charcoal used for iron smelting in the ironworks in Brusiek on the Mała Panew River was burnt at the turn of the 18th century. This is in accordance with historical sources indicating particular prosperity of the metallurgy in that period. Upstream of the ironworks in Brusiek in the first half of the 17th century a large pond existed flooding the floor of the Mała Panew valley. Study has shown that the pond was at least 100 years older than historical sources have indicated.

Keywords

  • historical bloomery
  • iron smelting
  • charcoal kiln
  • smelter pond
  • dendrochronology
  • lacustrine deposits
access type Otwarty dostęp

Radial growth responses of Pinus halepensis Mill. and Pinus pinea L. forests to climate variability in Western Albania

Data publikacji: 21 May 2015
Zakres stron: -

Abstrakt

Abstract

In this study are presented chronologies of earlywood (EW), latewood (LW) and tree-ring widths (RW) of a Pinus halepensis (P. halepensis) and Pinus pinea (P. pinea) natural forest stand growing in western Albania. Bootstrapped correlations and pointer year analysis were combined in a dendroclimatological study to evaluate climate-growth relationships in both pine species as well as to assess the spatial outreach of our chronologies evaluating them with those of the same species from other Mediterranean countries. We found that both species responded positively to precipitation and Indexed Percentage Average Precipitation (%AvP) in late summer-early autumn, particularly the LW, whereas summer temperatures constrained the growth of P. halepensis tree-ring features. Current January temperature and Potential Evapotranspiration (PET) showed positive relationship with P. pinea LW and RW. The same association was observed when considering PET in spring and P. halepensis LW and RW. Pointer year analysis showed that inhibitory climatic drivers of radial growth for both species were low precipitation from previous winter and current summer, associated with low temperatures during autumn. Our P. halepensis chronology showed a wider spatial outreach than that of P. pinea when compared to those from other Mediterranean countries. We conclude that current January temperatures and September precipitation are very important for P. pinea growth influencing both EW and LW growth whereas P. halepensis is mostly affected by the summer-early autumn climate conditions.

Keywords

  • Pinus halepensis
  • Pinus pinea
  • radial growth
  • climate
  • bootstrapped correlations
  • pointer years.
access type Otwarty dostęp

The oldest seafloor massive sulfide deposits at the Mid-Atlantic Ridge: 230Th/U chronology and composition

Data publikacji: 22 May 2015
Zakres stron: -

Abstrakt

Abstract

A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest for the Quaternary hydrothermal ores ever found at the ocean floor. According to them the hydrothermal activity at Peterburgskoye field started at least 170 ka and continued down to 63 ka. The oldest hydrothermal ores from this field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.

Keywords

  • Mid-Atlantic Ridge
  • age of hydrothermal activity
  • ore formation
  • 230Th/U dating
  • geo-chronology
  • geochemistry
access type Otwarty dostęp

Luminescence Dating of Fluvial Deposits in the Rock Shelter of Cueva Antón, Spain

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

The fluvial sediments at Cueva Antón, a Middle Palaeolithic rock shelter located in the valley of the River Mula (Southeast Spain), produced abundant lithic assemblages of Mousterian affinities. Radiocarbon dates are available for the upper part of the archaeological succession, while for the middle to lower parts chronometric data have been missing. Here we present luminescence dating results for these parts of the succession. Quartz OSL on small aliquots and single grain measurements yield ages ranging from 69 ± 7 ka to 82 ± 8 ka with a weighted mean of 72 ± 4 ka for sub-complexes AS2 to AS5. Equivalent dose estimates from large aliquots were highest and inconsistent with those from single grains and small multiple grain aliquots. This is probably caused by the presence of over-saturating grains, which have been quantified by single grain measurements. Additional post-IR IRSL measurements on coarse grained feldspar give strong support to a well-bleached quartz OSL signal. While independent chronometric control is missing, the results are within the expected age range and support the notion of a rapid accumulation of the fluvial deposits.

Słowa kluczowe

  • Cueva Antón
  • Middle Palaeolithic
  • Luminescence dating
  • fluvial sediment
  • single grain dating
  • post-IR IRSL
access type Otwarty dostęp

Luminescence Dating of Fluvial Deposits from the Weser Valley, Germany

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

Luminescence dating was applied on coarse-grained monomineralic potassium-rich feld-spar and polymineralic fine-grained minerals of five samples derived from fluvial deposits of the Riv-er Weser in northwestern Germany. We used a pulsed infrared stimulated luminescence (IRSL) single aliquot regenerative (SAR) dose protocol with an IR stimulation at 50°C for 400 s (50 μs on-time and 200 μs off-time). In order to obtain a stable luminescence signal, only off-time IRSL signal was rec-orded. Performance tests gave solid results. Anomalous fading was intended to be reduced by using the pulsed IRSL signal measured at 50°C (IR50), but fading correction was in most cases necessary due to moderate fading rates. Fading uncorrected and corrected pulsed IR50 ages revealed two major fluvial aggradation phases during the Late Pleistocene, namely during marine isotope stage (MIS) 5d (100 ± 5 ka) and from late MIS 5b to MIS 4 (77 ± 6 ka to 68 ± 5 ka). The obtained luminescence ages are consistent with previous 230Th/U dating results from underlying interglacial deposits of the same pit, which are correlated with MIS 7c to early MIS 6.

Słowa kluczowe

  • pulsed infrared stimulated luminescence
  • fluvial deposits
  • independent age control
  • Late Pleistocene
  • Weser valley
  • northern Germany
access type Otwarty dostęp

Comparative 230Th/U and 14C Dating of a Buried Stump Layer (Western Siberia)

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

Dating of late Pleistocene sediments remains a challenge in Quaternary chronology, due to the inherent limitations of the 14C and OSL methods. The 230Th/U radioisotope method is theoretically applicable to wood remnants contained within Pleistocene sediments, but few results have been pub-lished to date and in some cases, the age data are ambiguous. This paper tests the use of 230Th/U da-ting of fossil wood remnants dated earlier by radiocarbon method. We analyzed a buried larch trunk from a well-known stump layer in the Lipovka outcrop, located on the Tobol River bank in Western Siberia. The stump layer is preserved in situ. We determined the specific activities of U and Th iso-topes in samples of both modern pine and fossil larch and proposed a model for the incorporation and distribution of U and Th in the buried wood during aging. Complications related with the recognition of geochemical closed systems with respect to U did not allow obtaining completely reliable 230Th/U age. Despite this the 230Th/U age obtained for the uppermost heartwood sample and 14C ages of the same larch trunk and other wood and vegetation remnants gave consistent results. These age data in combination with previously obtained pollen data testify the stump layer formation during the late cooling stage of the Karganian time (MIS-3, Middle Valdai).

Słowa kluczowe

  • 230Th/U dating
  • 14C dating
  • buried larch trunk
  • isotopes geochemical behavior
  • Karganian time
  • MIS-3.
access type Otwarty dostęp

Determination of Slip-Rate by Optical Dating of Lake Bed Sediments from the Dasht-E-Bayaz Fault, Ne Iran

Data publikacji: 15 Oct 2015
Zakres stron: -

Abstrakt

Abstract

The Dasht-e-Bayaz left-lateral strike-slip fault in northeastern Iran ruptured in two destructive earthquakes in 1968 and 1979. The western half of the Dasht-e-Bayaz fault cuts across the dry lake-bed in the Nimbluk valley and has no measurable relief except for at a few localised jogs in the fault trace. We provide the first quantitative constraint on the slip-rate of the Dasht-e-Bayaz fault averaged over the Holocene. The western part of the fault cuts across the Nimbluk valley; the flat surface of which is composed of lake-bed sediments. Small streams cut into the surface of the lake-beds are displaced across the fault by 26 ± 2 m. Two OSL samples of the lake-bed sediments are success-fully dated at 8.6 ± 0.6 and 8.5 ± 1.0 ka, from which we calculate a minimum slip-rate of 2.6 mm/yr. This minimum slip rate remains constant with the previously proposed Holocene slip rate of 2.5 mm/yr and within the range of the Holocene slip rate of 2.4 ± 0.3 mm/yr estimated before on the central section of the Doruneh fault.

Keywords

  • slip-rate
  • OSL
  • Dasht-e-Bayaz fault
  • NE Iran
access type Otwarty dostęp

Erratum: Historical Water-Powered Ferrous Metallurgy Reconstructed from Tree-Rings and Lacustrine Deposits (Mała Panew Basin, Southern Poland)

Data publikacji: 15 Oct 2015
Zakres stron: -

Abstrakt

access type Otwarty dostęp

Comparing Varve Counting And 14C-Ams Chronologies In The Sediments Of Lake Żabińskie, Northeastern Poland: Implications For Accurate 14C Dating Of Lake Sediments

Data publikacji: 10 Nov 2015
Zakres stron: -

Abstrakt

Abstract

Varved lake sediments from Lake Zabihskie (northeastern Poland) provide a high- resolution calendar-year chronology which allows validation of 14C dating results. Microscopic analy­sis of the varve microfacies revealed that laminations found in Lake Zabihskie were biogenic (calcite) varves. Three independent counts indicated a good preservation quality of laminae in the 348 cm long sediment profile which contained 1000+12/-24 varves. The varve chronology was validated with the 137Cs activity peaks, the tephra horizon from the Askja eruption at AD 1875 and with the timing of major land-use changes of known age inferred from pollen analysis. 32 AMS 14C dates of terrestrial macrofossils distributed along the profile were compared with the varve chronology. After identifica­tion of outliers, the free-shape model performed with 21 14C dates provided the best possible fit with the varve chronology. We observed almost ideal consistency between both chronologies from the present until AD 1250 while in the lower part (AD 1000-1250) the difference increases to ca. 25 years. We demonstrate that this offset can be explained by too old radiocarbon ages of plant remains trans­ported to the lake by the inflowing creek. Results of this study highlight that careful interpretation of radiocarbon age-depth models is necessary, especially in lakes where no annual laminations are ob­served and no independent method are used for cross-validation.

Słowa kluczowe

  • lake sediments
  • varve chronology
  • AMS 14C dating
  • radionuclides
  • age-depth model
access type Otwarty dostęp

Geochronology and Palaeomagnetic Records of the Snaigupėlė Section in South Lithuania

Data publikacji: 10 Nov 2015
Zakres stron: -

Abstrakt

Abstract

The interglacial deposits in the South Lithuanian Snaigupėlė outcrop and borehole Snaigupėlė-705 are marked for different bedding conditions though the sections are in proximity of each other. In the borehole section, the interglacial deposits are thicker and bedding at a greater depth than the analogous deposits of the outcrop. In the Snaigupėlė outcrop, the highest compatibility of isochronic-correction dates, calculated using L/L (method of leaching) and TSD (method of total sample dissolution) models, was determined for combination of three samples. With the help of the f value (section of isochrones in the axis of ordinates), the contribution of the primary pollution with thorium was determined where, as based on corrected analytical data, isochronic-correction dating was performed: 127+18-14 ka years for the L/L model and 132+22-16 ka for the TSD model. Palaeomagnetic investigations showed that the section of lacustrine sediments in the lower part of Snaigupėlė outcrop were orientated by reversed magnetic excursion and in the upper part by normal magnetic polarity. Collation of the obtained data with the global geomagnetic scale showed that the palaeomagnetic in-version observed in the Snaigupėlė section was related with the Blake Event in the Eemian Interglacial.

Słowa kluczowe

  • 230Th/U dating
  • palaeomagnetic record
  • Late Pleistocene
  • Eemian Interglacial
  • South Lithuania
access type Otwarty dostęp

Palaeodose Underestimation Of Heated Quartz In Red-TL Dating Of Volcanic Contexts

Data publikacji: 07 Nov 2015
Zakres stron: -

Abstrakt

Abstract

Thermoluminescence (TL) dating is a valuable tool for chronometric dating of heated minerals and has been shown to agree very well with independent age control. Comparison with argon dating of samples from identical events, however, revealed age underestimations of volcanic eruptions dated by orange-red TL (R-TL) of quartz extracts from some xenolith samples, while good agreement was obtained for others. The underestimation is attributed to an apparent signal loss (“anomalous fading”) which was experimentally observed for some, but not all samples investigated. The presence of significant amounts of feldspar or tridymite, which could be related to the observations, is excluded by IRSL (Infrared Stimulated Luminescence) and XRD analysis. While the data is not entirely conclusive, it leads to the current working hypothesis that exposure to high temperatures might be responsible for an effect similar to the anomalous fading phenomena observed for some feldspar luminescence. It therefore appears to be prudent not to sample xenoliths from high temperature context, like basalt dykes in volcanic context.

Słowa kluczowe

  • thermoluminescence dating
  • red TL
  • volcanism
  • xenolith
  • quartz
  • fading
access type Otwarty dostęp

Kohonen Artificial Neural Networks and the IndVal Index as Supplementary Tools for the Quantitative Analysis of Palaeoecological Data

Data publikacji: 03 Dec 2015
Zakres stron: -

Abstrakt

Abstract

We applied two widely-used methods for data partitioning - constrained incremental sum-of-squares (CONISS) and Optimal Partitioning (OP) along with two supplementary methods, a Kohonen artificial neural network (self-organising map, SOM) and the indicator value (IndVal) index, for the quantitative analysis of subfossil chironomid assemblages from a palaeolake in Central Poland. The samples, taken from 79 core depths, were divided into 5-11 groups (five by SOM, seven by CONISS, 11 by OP), for which different numbers of indicator taxa were determined with the use of the IndVal index (18 for CONISS, 15 for SOM, 11 for OP). Only six indicator taxa were common to all three methods. The number of highly specific (p < 0.001) taxa was highest for SOM. Only the SOM analysis clearly reflected the rate of the changes in chironomid assemblages, which occurred rapidly in the Late Glacial (as a result of greater climate variability) and slowly in the Holocene (as a reflection of slow long-term changes in the local habitat, such as paludification). In summary, we recommend using SOM and the IndVal index in combination with CONISS and/or OP in order to detect different aspects of temporal variability in complex multivariate palaeoecological data.

Słowa kluczowe

  • Late Quaternary
  • Chironomidae
  • self-organising map (SOM)
  • CONISS
  • Optimal Parti-tioning
access type Otwarty dostęp

Lexsyg smart — a luminescence detection system for dosimetry, material research and dating application

Data publikacji: 04 Dec 2015
Zakres stron: -

Abstrakt

Abstract

Following the luminescence system lexsyg research, which was designed for research, the luminescence reader lexsyg smart for the application of luminescence detection was developed by Freiberg Instruments. It is suited for routine measurements of luminescence (thermoluminescence, photoluminescence, photon-stimulated, optically stimulated and infrared stimulated luminescence) for a wide range of materials because of the availability of several stimulation sources. The possibility for user definition and change of most parameters provides a great deal of flexibility and also allows re-search applications. While detection is limited to a single unit and sample storage to 40 positions, the lexsyg smart is much faster in aliquot transportation compared to the lexsyg research, and allows fast mass measurements in luminescence dating, retrospective and personal dosimetry, etc. Cross talk of optical stimulation is absent and cross-irradiation is negligible from the single radioactive source (α, β or x-ray) because of a disconnected sample storage wheel from the measurement chamber, which has a small volume and therefore gas consumption is small. Thermoluminescence measure-ments and pre-heatings are possible with a versatile heater, which can be programmed for linear/non-linear heating at varying rates and durations for an almost unlimited number of steps. Optical excita-tion for up to three wavelength bands (violet, blue, green, yellow, infrared) is provided from high power LEDs or laser diodes, with an optional filter wheel to vary detection wavelength bands accord-ing the material specific requirements. Either can be programmed to change at almost any time within measurement sequences.

Słowa kluczowe

  • luminescence equipment
  • dosimetry
  • luminescence dating
  • PL
  • TL-OSL
  • PSL
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Drip rate and tritium activity in the Niedźwiedzia Cave system (Poland) as a tool for tracking water circulation paths and time in karstic systems

Data publikacji: 31 Dec 2015
Zakres stron: -

Abstrakt

Abstract

The Niedźwiedzia Cave system is composed of 3 horizontal levels of passages and cham-bers. Changes in the drip rate of water from the upper level stalactites correlate well with changes in precipitation intensity. The transition time between the surface and the upper level of the cave was es-timated to 14 days. Drip sites in the middle and lower levels of the cave exhibited two types of re-charge: some did not correlate with precipitation intensity, whereas others correlated well with rain events. The transition times for the latter sites were estimated to be greater than 6 months. This esti-mate was confirmed by the calculation of the transition time based on tritium activity. The oldest wa-ter in the entire karst system was observed in a karst spring. The mean tritium age for this water dur-ing winter was estimated to be 3.9 ± 0.6 yr. More precise calculations of the tritium age of karst water require longer precipitation activity datasets.

Słowa kluczowe

  • karst hydrology
  • drip rate
  • speleothems
  • tritium
  • transitional time
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Some considerations in the reconstruction of lead levels using laser ablation: lessons from the design stage of dendrochemistry study, St.John's, Canada

Data publikacji: 31 Dec 2015
Zakres stron: -

Abstrakt

Abstract

Study of soils in St. John’s, Canada showed elevated Pb levels representing a potential ex-posure risk for young children. Old trees growing in the city present a potential annually-resolved record of Pb levels over past centuries that provides important temporal and spatial dimensions to Pb exposure risk assessment. This paper reports the results of our analytical tests to develop a fast, relia-ble and cost-efficient method using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for measuring Pb concentration in annual tree rings from available tree species. Our tests focused on approaches to sample preparation as they affect the laser ablation process, the relative merits of the ablation sampling method, and the response of our available tree species, which have contrasting wood structures, to laser ablation. The range of annual Pb concentrations (ppm) measured for each of the study species were as follows: spruce (0.18–6.42); elm (0.12–7.91); and horse chestnut (0.40–14.09). Our results demonstrate that the cutting procedure for preparing tree cores produced the most consistent Pb concentrations of the three methods, although they each displayed problematic anomalies. The selection of the best laser ablation technique appears to be highly dependent on study species and goals. In general, spot analysis permits detailed and targeted studies of tree-ring struc-tures, but requires careful sampling attention for species with complex wood anatomy. The line scan method is ideal for reconstructing annually resolved element concentrations from trees and to some degree mitigates the complicating issue of intra-ring variability. Horse chestnut was determined to be the best of the available tree species because it exhibited a good response to laser ablation and pro-duced the lowest intra-ring variations in Pb concentration.

Słowa kluczowe

  • tree rings
  • dendrochemistry
  • laser ablation
  • ICP-MS
  • urban lead contamination
23 Artykułów
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Holocene Chronology of the Brattforsheden Delta and Inland Dune Field, Sw Sweden

Data publikacji: 11 Mar 2015
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Abstrakt

Abstract

Brattforsheden is a large glacifluvial deposit in southwestern Sweden and associated with it is one of Sweden’s largest inland dune fields. Although the relative ages of the Brattforsheden depos-its are well known, absolute ages from the area are few. In this study we have used optically stimulat-ed luminescence (OSL), surface exposure (10Be) and radiocarbon (14C) dating to provide an absolute chronology for the deglaciation and for the Holocene development of the aeolian dunes. Our data show that the deglaciation took place just before 11 ka (11.5 ± 0.6 ka OSL, 11.3 ± 0.8 ka 10Be), in line with the 14C-based regional deglaciation age. Aeolian dunes started forming immediately after degla-ciation and were active for at least 2000 years, well after vegetation had established. Renewed aeolian activity occurred 270-180 years ago, resulting in the deposition of sand sheets. Comparison between dating methods and studies of OSL dose distributions show that glacial, glacifluvial and littoral sedi-ments suffer from incomplete bleaching and thus that mean OSL ages from such deposits overesti-mate the true depositional age. By using small aliquots and statistical age models, this effect can part-ly be countered. Also, some of the 10Be ages appear too old, which may be due to previous exposure.

Keywords

  • luminescence (OSL) dating
  • surface exposure dating (10Be)
  • deglaciation
  • aeolian
  • Holo-cene
  • Sweden
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Influence of in Situ Temperature on the Sensitization of Quartz: A Simulation Study

Data publikacji: 11 Mar 2015
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Abstrakt

Abstract

The influence of ambient geological and burial temperatures, prevailing in nature, on the charge population of the defect centers and, eventually, the sensitivity of the luminescence emission of quartz was simulated using empirical model. Various permutation and combination of these tem-peratures were incorporated so as to observe, both, the collective and independent impact of these two temperatures on the charge kinetics. The results of seem to demonstrate the role of the ambient tem-perature in the sensitization of quartz mineral

Słowa kluczowe

  • sensitization
  • quartz
  • in situ temperature
  • TL
  • OSL
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Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus Petraea) in the Czech Republic

Data publikacji: 11 Mar 2015
Zakres stron: -

Abstrakt

Abstract

Unraveling climatic effects on growth of oak - Europe’s most ecologically and economically important forest species - has been the subject of many recent studies; however, more insight based on field data is necessary to better understand the relationship between climate and tree growth and to adapt forest management strategies to future climate change. In this report, we explore the influence of temperature, precipitation and drought variability on the productivity and vitality of oak stands in the Czech Highlands. We collected 180 cores from mature oaks (Quercus petraea) at four forest stands in the Czech Drahany Highlands. Standard dendromethods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Crown vitality was also evaluated, using the modified ICP Forests methodology. Late spring precipitation totals between May and June as well as the mean July temperature for the year of ring formation were found to be the most important factors for oak growth, whereas crown condition was significantly affected by spring and summer drought. This study is rep-resentative for similar bio-ecological habitats across Central Europe and can serve as a dendroclima-tological blueprint for earlier periods for which detailed meteorological information is missing

Słowa kluczowe

  • Central Europe
  • crown condition
  • precipitation
  • sessile oak
  • temperature
  • tree rings
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The 443-Year Tree-Ring Chronology for the Scots Pine from Upper Silesia (Poland) as A Dating Tool and Climate Proxy

Data publikacji: 25 Mar 2015
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Abstrakt

Abstract

An annually resolved and absolutely dated ring-width chronology spanning 443 years has been constructed using the historical and living-tree Scots pine samples from the Upper Silesia, south of Poland. The constructed regional chronology, based on six object chronologies, covers the period of 1568-2010. It is composed of 178 wood samples with the mean correlation of 0.51, mean series length of 104 years and mean EPS of 0.85. In total, 65 extreme years were distinguished. Their inde-pendent verification, based on the historical and meteorological data, showed significant correlation with the exceptionally cold/mild winters as well as severe droughts. The comparison of the extreme years with the other Polish pine chronologies showed similarities in the years with the anomalous winter conditions. Some extreme years can be associated with the exceptional pluvial conditions; these years are common in the Central European hydroclimatic tree-ring records. The construction of this regional pine chronology enables for the absolute dating of many architectural monuments from investigated region. The application of the new chronology for the dating of local wood can support interpretations of changes in the environment of the Upper Silesian region. In the future it can also be used as the basis for climate reconstruction.

Keywords

  • long term chronology
  • tree-ring dating
  • cultural heritage
  • historic wood
  • Pinus sylvestris
  • S Poland
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Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes

Data publikacji: 27 Mar 2015
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Abstrakt

Abstract

Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata tree-rings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater am-plitude than previous reconstructions derived from traditional tree-ring density data, and describes particularly cool conditions during the late 19th century. Some of these differences, including early warm periods in the 14th and 17th centuries, have been retained via δ13C timeseries detrending - a novel approach in tree-ring stable isotope chronology development. The overall reduced variance in earlier studies points to an underestimation of pre-instrumental summer temperature variability de-rived from traditional tree-ring parameters.

Keywords

  • Climate change
  • paleoclimatology
  • stable isotope geochemistry
  • tree-rings
  • Europe
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Debris-flow activity in five adjacent gullies in a limestone mountain range

Data publikacji: 27 Mar 2015
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Abstrakt

Abstract

Debris-flows are infrequent geomorphic phenomena that shape steep valleys and can repre-sent a severe hazard for human settlements and infrastructure. In this study, a debris-flow event chro-nology has been derived at the regional scale within the Gesäuse National Park (Styria, Austria) using dendrogeomorphic techniques. Sediment sources and deposition areas were mapped by combined field investigation and aerial photography using an Unmanned Aerial Vehicle (UAV). Through the analysis of 384 trees, a total of 47 debris-flows occurring in 19 years between AD 1903 and 2008 were identified in five adjacent gullies. Our results highlight the local variability of debris-flow activi-ty as a result of local thunderstorms and the variable availability of sediment sources.

Keywords

  • debris-flow
  • dendrogeomorphology
  • growth disturbances
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Luminescence dating of loess deposits from the Remagen-Schwalbenberg site, Western Germany

Data publikacji: 27 Mar 2015
Zakres stron: -

Abstrakt

Abstract

This study describes the luminescence characteristics of quartz of Upper Pleistocene loess of the Middle Rhine area. The loess/palaeosol sequence of the Schwalbenberg near Remagen com-prises a multitude of interstadial soils and soil sediments that have been dedicated to the Marine Iso-tope Stage 3 (MIS 3). These weak calcaric cambisols and their derivates are underlain by loess and soil sediments of MIS 4 to MIS 5 and covered by loess sediments and intercalated gelic gleysols of MIS 2. We applied luminescence dating of quartz and feldspar of drill core samples and observed an age discrepancy within both data sets. The quartz ages were clearly younger than the feldspar ages, because of thermally unstable signal components of the quartz luminescence signal. Therefore, we re-garded the quartz samples of the lower parts of the drill core as unsuitable for luminescence dating. This underestimation did not affect the quartz samples of the upper part of the drill core which was indicated by age control that was provided by the Eltville tephra layer. Geochemical analysis based on X-ray fluorescence showed that the sediments in the upper part and the lower part of the drill core have different geogenic finger prints most likely due to changing source areas of dust and sediment allocation. We assumed that these different facies types were the reason for the luminescence behav-ior of the quartz samples.

Keywords

  • luminescence dating
  • loess
  • last glacial cycle
  • Middle Rhine
  • Eltville tephra
  • geochemical analysis
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Erratum: Holocene chronology of the Brattforsheden delta and inland dune field, SW Sweden

Data publikacji: 19 May 2015
Zakres stron: -

Abstrakt

access type Otwarty dostęp

Historical water-powered ferrous metallurgy reconstructed from tree-rings and lacustrine deposits (Mała Panew basin, southern Poland)

Data publikacji: 20 May 2015
Zakres stron: -

Abstrakt

Abstract

According to historical sources in the basin of Mała Panew River there were at least 56 water-powered iron smelters from 14th-19th century. Now only two metallurgy plants work in the area. Many of the former smelting settlements ceased to exist. Historical data on the smelting industry in the area are often scarce. The aim of the study was to reconstruct the history of ferrous metallurgy from (1) the remains of wooden historical buildings, (2) remains of charcoal kilns and (3) deposits from former smelter pond. Results show that Regolowiec smelting settlement existed already in the 17th century (at least several decades earlier than historical written sources suggest) and was later re-paired after destruction caused probably by floods. Charcoal used for iron smelting in the ironworks in Brusiek on the Mała Panew River was burnt at the turn of the 18th century. This is in accordance with historical sources indicating particular prosperity of the metallurgy in that period. Upstream of the ironworks in Brusiek in the first half of the 17th century a large pond existed flooding the floor of the Mała Panew valley. Study has shown that the pond was at least 100 years older than historical sources have indicated.

Keywords

  • historical bloomery
  • iron smelting
  • charcoal kiln
  • smelter pond
  • dendrochronology
  • lacustrine deposits
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Radial growth responses of Pinus halepensis Mill. and Pinus pinea L. forests to climate variability in Western Albania

Data publikacji: 21 May 2015
Zakres stron: -

Abstrakt

Abstract

In this study are presented chronologies of earlywood (EW), latewood (LW) and tree-ring widths (RW) of a Pinus halepensis (P. halepensis) and Pinus pinea (P. pinea) natural forest stand growing in western Albania. Bootstrapped correlations and pointer year analysis were combined in a dendroclimatological study to evaluate climate-growth relationships in both pine species as well as to assess the spatial outreach of our chronologies evaluating them with those of the same species from other Mediterranean countries. We found that both species responded positively to precipitation and Indexed Percentage Average Precipitation (%AvP) in late summer-early autumn, particularly the LW, whereas summer temperatures constrained the growth of P. halepensis tree-ring features. Current January temperature and Potential Evapotranspiration (PET) showed positive relationship with P. pinea LW and RW. The same association was observed when considering PET in spring and P. halepensis LW and RW. Pointer year analysis showed that inhibitory climatic drivers of radial growth for both species were low precipitation from previous winter and current summer, associated with low temperatures during autumn. Our P. halepensis chronology showed a wider spatial outreach than that of P. pinea when compared to those from other Mediterranean countries. We conclude that current January temperatures and September precipitation are very important for P. pinea growth influencing both EW and LW growth whereas P. halepensis is mostly affected by the summer-early autumn climate conditions.

Keywords

  • Pinus halepensis
  • Pinus pinea
  • radial growth
  • climate
  • bootstrapped correlations
  • pointer years.
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The oldest seafloor massive sulfide deposits at the Mid-Atlantic Ridge: 230Th/U chronology and composition

Data publikacji: 22 May 2015
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Abstrakt

Abstract

A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest for the Quaternary hydrothermal ores ever found at the ocean floor. According to them the hydrothermal activity at Peterburgskoye field started at least 170 ka and continued down to 63 ka. The oldest hydrothermal ores from this field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.

Keywords

  • Mid-Atlantic Ridge
  • age of hydrothermal activity
  • ore formation
  • 230Th/U dating
  • geo-chronology
  • geochemistry
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Luminescence Dating of Fluvial Deposits in the Rock Shelter of Cueva Antón, Spain

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

The fluvial sediments at Cueva Antón, a Middle Palaeolithic rock shelter located in the valley of the River Mula (Southeast Spain), produced abundant lithic assemblages of Mousterian affinities. Radiocarbon dates are available for the upper part of the archaeological succession, while for the middle to lower parts chronometric data have been missing. Here we present luminescence dating results for these parts of the succession. Quartz OSL on small aliquots and single grain measurements yield ages ranging from 69 ± 7 ka to 82 ± 8 ka with a weighted mean of 72 ± 4 ka for sub-complexes AS2 to AS5. Equivalent dose estimates from large aliquots were highest and inconsistent with those from single grains and small multiple grain aliquots. This is probably caused by the presence of over-saturating grains, which have been quantified by single grain measurements. Additional post-IR IRSL measurements on coarse grained feldspar give strong support to a well-bleached quartz OSL signal. While independent chronometric control is missing, the results are within the expected age range and support the notion of a rapid accumulation of the fluvial deposits.

Słowa kluczowe

  • Cueva Antón
  • Middle Palaeolithic
  • Luminescence dating
  • fluvial sediment
  • single grain dating
  • post-IR IRSL
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Luminescence Dating of Fluvial Deposits from the Weser Valley, Germany

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

Luminescence dating was applied on coarse-grained monomineralic potassium-rich feld-spar and polymineralic fine-grained minerals of five samples derived from fluvial deposits of the Riv-er Weser in northwestern Germany. We used a pulsed infrared stimulated luminescence (IRSL) single aliquot regenerative (SAR) dose protocol with an IR stimulation at 50°C for 400 s (50 μs on-time and 200 μs off-time). In order to obtain a stable luminescence signal, only off-time IRSL signal was rec-orded. Performance tests gave solid results. Anomalous fading was intended to be reduced by using the pulsed IRSL signal measured at 50°C (IR50), but fading correction was in most cases necessary due to moderate fading rates. Fading uncorrected and corrected pulsed IR50 ages revealed two major fluvial aggradation phases during the Late Pleistocene, namely during marine isotope stage (MIS) 5d (100 ± 5 ka) and from late MIS 5b to MIS 4 (77 ± 6 ka to 68 ± 5 ka). The obtained luminescence ages are consistent with previous 230Th/U dating results from underlying interglacial deposits of the same pit, which are correlated with MIS 7c to early MIS 6.

Słowa kluczowe

  • pulsed infrared stimulated luminescence
  • fluvial deposits
  • independent age control
  • Late Pleistocene
  • Weser valley
  • northern Germany
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Comparative 230Th/U and 14C Dating of a Buried Stump Layer (Western Siberia)

Data publikacji: 11 Jul 2015
Zakres stron: -

Abstrakt

Abstract

Dating of late Pleistocene sediments remains a challenge in Quaternary chronology, due to the inherent limitations of the 14C and OSL methods. The 230Th/U radioisotope method is theoretically applicable to wood remnants contained within Pleistocene sediments, but few results have been pub-lished to date and in some cases, the age data are ambiguous. This paper tests the use of 230Th/U da-ting of fossil wood remnants dated earlier by radiocarbon method. We analyzed a buried larch trunk from a well-known stump layer in the Lipovka outcrop, located on the Tobol River bank in Western Siberia. The stump layer is preserved in situ. We determined the specific activities of U and Th iso-topes in samples of both modern pine and fossil larch and proposed a model for the incorporation and distribution of U and Th in the buried wood during aging. Complications related with the recognition of geochemical closed systems with respect to U did not allow obtaining completely reliable 230Th/U age. Despite this the 230Th/U age obtained for the uppermost heartwood sample and 14C ages of the same larch trunk and other wood and vegetation remnants gave consistent results. These age data in combination with previously obtained pollen data testify the stump layer formation during the late cooling stage of the Karganian time (MIS-3, Middle Valdai).

Słowa kluczowe

  • 230Th/U dating
  • 14C dating
  • buried larch trunk
  • isotopes geochemical behavior
  • Karganian time
  • MIS-3.
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Determination of Slip-Rate by Optical Dating of Lake Bed Sediments from the Dasht-E-Bayaz Fault, Ne Iran

Data publikacji: 15 Oct 2015
Zakres stron: -

Abstrakt

Abstract

The Dasht-e-Bayaz left-lateral strike-slip fault in northeastern Iran ruptured in two destructive earthquakes in 1968 and 1979. The western half of the Dasht-e-Bayaz fault cuts across the dry lake-bed in the Nimbluk valley and has no measurable relief except for at a few localised jogs in the fault trace. We provide the first quantitative constraint on the slip-rate of the Dasht-e-Bayaz fault averaged over the Holocene. The western part of the fault cuts across the Nimbluk valley; the flat surface of which is composed of lake-bed sediments. Small streams cut into the surface of the lake-beds are displaced across the fault by 26 ± 2 m. Two OSL samples of the lake-bed sediments are success-fully dated at 8.6 ± 0.6 and 8.5 ± 1.0 ka, from which we calculate a minimum slip-rate of 2.6 mm/yr. This minimum slip rate remains constant with the previously proposed Holocene slip rate of 2.5 mm/yr and within the range of the Holocene slip rate of 2.4 ± 0.3 mm/yr estimated before on the central section of the Doruneh fault.

Keywords

  • slip-rate
  • OSL
  • Dasht-e-Bayaz fault
  • NE Iran
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Erratum: Historical Water-Powered Ferrous Metallurgy Reconstructed from Tree-Rings and Lacustrine Deposits (Mała Panew Basin, Southern Poland)

Data publikacji: 15 Oct 2015
Zakres stron: -

Abstrakt

access type Otwarty dostęp

Comparing Varve Counting And 14C-Ams Chronologies In The Sediments Of Lake Żabińskie, Northeastern Poland: Implications For Accurate 14C Dating Of Lake Sediments

Data publikacji: 10 Nov 2015
Zakres stron: -

Abstrakt

Abstract

Varved lake sediments from Lake Zabihskie (northeastern Poland) provide a high- resolution calendar-year chronology which allows validation of 14C dating results. Microscopic analy­sis of the varve microfacies revealed that laminations found in Lake Zabihskie were biogenic (calcite) varves. Three independent counts indicated a good preservation quality of laminae in the 348 cm long sediment profile which contained 1000+12/-24 varves. The varve chronology was validated with the 137Cs activity peaks, the tephra horizon from the Askja eruption at AD 1875 and with the timing of major land-use changes of known age inferred from pollen analysis. 32 AMS 14C dates of terrestrial macrofossils distributed along the profile were compared with the varve chronology. After identifica­tion of outliers, the free-shape model performed with 21 14C dates provided the best possible fit with the varve chronology. We observed almost ideal consistency between both chronologies from the present until AD 1250 while in the lower part (AD 1000-1250) the difference increases to ca. 25 years. We demonstrate that this offset can be explained by too old radiocarbon ages of plant remains trans­ported to the lake by the inflowing creek. Results of this study highlight that careful interpretation of radiocarbon age-depth models is necessary, especially in lakes where no annual laminations are ob­served and no independent method are used for cross-validation.

Słowa kluczowe

  • lake sediments
  • varve chronology
  • AMS 14C dating
  • radionuclides
  • age-depth model
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Geochronology and Palaeomagnetic Records of the Snaigupėlė Section in South Lithuania

Data publikacji: 10 Nov 2015
Zakres stron: -

Abstrakt

Abstract

The interglacial deposits in the South Lithuanian Snaigupėlė outcrop and borehole Snaigupėlė-705 are marked for different bedding conditions though the sections are in proximity of each other. In the borehole section, the interglacial deposits are thicker and bedding at a greater depth than the analogous deposits of the outcrop. In the Snaigupėlė outcrop, the highest compatibility of isochronic-correction dates, calculated using L/L (method of leaching) and TSD (method of total sample dissolution) models, was determined for combination of three samples. With the help of the f value (section of isochrones in the axis of ordinates), the contribution of the primary pollution with thorium was determined where, as based on corrected analytical data, isochronic-correction dating was performed: 127+18-14 ka years for the L/L model and 132+22-16 ka for the TSD model. Palaeomagnetic investigations showed that the section of lacustrine sediments in the lower part of Snaigupėlė outcrop were orientated by reversed magnetic excursion and in the upper part by normal magnetic polarity. Collation of the obtained data with the global geomagnetic scale showed that the palaeomagnetic in-version observed in the Snaigupėlė section was related with the Blake Event in the Eemian Interglacial.

Słowa kluczowe

  • 230Th/U dating
  • palaeomagnetic record
  • Late Pleistocene
  • Eemian Interglacial
  • South Lithuania
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Palaeodose Underestimation Of Heated Quartz In Red-TL Dating Of Volcanic Contexts

Data publikacji: 07 Nov 2015
Zakres stron: -

Abstrakt

Abstract

Thermoluminescence (TL) dating is a valuable tool for chronometric dating of heated minerals and has been shown to agree very well with independent age control. Comparison with argon dating of samples from identical events, however, revealed age underestimations of volcanic eruptions dated by orange-red TL (R-TL) of quartz extracts from some xenolith samples, while good agreement was obtained for others. The underestimation is attributed to an apparent signal loss (“anomalous fading”) which was experimentally observed for some, but not all samples investigated. The presence of significant amounts of feldspar or tridymite, which could be related to the observations, is excluded by IRSL (Infrared Stimulated Luminescence) and XRD analysis. While the data is not entirely conclusive, it leads to the current working hypothesis that exposure to high temperatures might be responsible for an effect similar to the anomalous fading phenomena observed for some feldspar luminescence. It therefore appears to be prudent not to sample xenoliths from high temperature context, like basalt dykes in volcanic context.

Słowa kluczowe

  • thermoluminescence dating
  • red TL
  • volcanism
  • xenolith
  • quartz
  • fading
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Kohonen Artificial Neural Networks and the IndVal Index as Supplementary Tools for the Quantitative Analysis of Palaeoecological Data

Data publikacji: 03 Dec 2015
Zakres stron: -

Abstrakt

Abstract

We applied two widely-used methods for data partitioning - constrained incremental sum-of-squares (CONISS) and Optimal Partitioning (OP) along with two supplementary methods, a Kohonen artificial neural network (self-organising map, SOM) and the indicator value (IndVal) index, for the quantitative analysis of subfossil chironomid assemblages from a palaeolake in Central Poland. The samples, taken from 79 core depths, were divided into 5-11 groups (five by SOM, seven by CONISS, 11 by OP), for which different numbers of indicator taxa were determined with the use of the IndVal index (18 for CONISS, 15 for SOM, 11 for OP). Only six indicator taxa were common to all three methods. The number of highly specific (p < 0.001) taxa was highest for SOM. Only the SOM analysis clearly reflected the rate of the changes in chironomid assemblages, which occurred rapidly in the Late Glacial (as a result of greater climate variability) and slowly in the Holocene (as a reflection of slow long-term changes in the local habitat, such as paludification). In summary, we recommend using SOM and the IndVal index in combination with CONISS and/or OP in order to detect different aspects of temporal variability in complex multivariate palaeoecological data.

Słowa kluczowe

  • Late Quaternary
  • Chironomidae
  • self-organising map (SOM)
  • CONISS
  • Optimal Parti-tioning
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Lexsyg smart — a luminescence detection system for dosimetry, material research and dating application

Data publikacji: 04 Dec 2015
Zakres stron: -

Abstrakt

Abstract

Following the luminescence system lexsyg research, which was designed for research, the luminescence reader lexsyg smart for the application of luminescence detection was developed by Freiberg Instruments. It is suited for routine measurements of luminescence (thermoluminescence, photoluminescence, photon-stimulated, optically stimulated and infrared stimulated luminescence) for a wide range of materials because of the availability of several stimulation sources. The possibility for user definition and change of most parameters provides a great deal of flexibility and also allows re-search applications. While detection is limited to a single unit and sample storage to 40 positions, the lexsyg smart is much faster in aliquot transportation compared to the lexsyg research, and allows fast mass measurements in luminescence dating, retrospective and personal dosimetry, etc. Cross talk of optical stimulation is absent and cross-irradiation is negligible from the single radioactive source (α, β or x-ray) because of a disconnected sample storage wheel from the measurement chamber, which has a small volume and therefore gas consumption is small. Thermoluminescence measure-ments and pre-heatings are possible with a versatile heater, which can be programmed for linear/non-linear heating at varying rates and durations for an almost unlimited number of steps. Optical excita-tion for up to three wavelength bands (violet, blue, green, yellow, infrared) is provided from high power LEDs or laser diodes, with an optional filter wheel to vary detection wavelength bands accord-ing the material specific requirements. Either can be programmed to change at almost any time within measurement sequences.

Słowa kluczowe

  • luminescence equipment
  • dosimetry
  • luminescence dating
  • PL
  • TL-OSL
  • PSL
access type Otwarty dostęp

Drip rate and tritium activity in the Niedźwiedzia Cave system (Poland) as a tool for tracking water circulation paths and time in karstic systems

Data publikacji: 31 Dec 2015
Zakres stron: -

Abstrakt

Abstract

The Niedźwiedzia Cave system is composed of 3 horizontal levels of passages and cham-bers. Changes in the drip rate of water from the upper level stalactites correlate well with changes in precipitation intensity. The transition time between the surface and the upper level of the cave was es-timated to 14 days. Drip sites in the middle and lower levels of the cave exhibited two types of re-charge: some did not correlate with precipitation intensity, whereas others correlated well with rain events. The transition times for the latter sites were estimated to be greater than 6 months. This esti-mate was confirmed by the calculation of the transition time based on tritium activity. The oldest wa-ter in the entire karst system was observed in a karst spring. The mean tritium age for this water dur-ing winter was estimated to be 3.9 ± 0.6 yr. More precise calculations of the tritium age of karst water require longer precipitation activity datasets.

Słowa kluczowe

  • karst hydrology
  • drip rate
  • speleothems
  • tritium
  • transitional time
access type Otwarty dostęp

Some considerations in the reconstruction of lead levels using laser ablation: lessons from the design stage of dendrochemistry study, St.John's, Canada

Data publikacji: 31 Dec 2015
Zakres stron: -

Abstrakt

Abstract

Study of soils in St. John’s, Canada showed elevated Pb levels representing a potential ex-posure risk for young children. Old trees growing in the city present a potential annually-resolved record of Pb levels over past centuries that provides important temporal and spatial dimensions to Pb exposure risk assessment. This paper reports the results of our analytical tests to develop a fast, relia-ble and cost-efficient method using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for measuring Pb concentration in annual tree rings from available tree species. Our tests focused on approaches to sample preparation as they affect the laser ablation process, the relative merits of the ablation sampling method, and the response of our available tree species, which have contrasting wood structures, to laser ablation. The range of annual Pb concentrations (ppm) measured for each of the study species were as follows: spruce (0.18–6.42); elm (0.12–7.91); and horse chestnut (0.40–14.09). Our results demonstrate that the cutting procedure for preparing tree cores produced the most consistent Pb concentrations of the three methods, although they each displayed problematic anomalies. The selection of the best laser ablation technique appears to be highly dependent on study species and goals. In general, spot analysis permits detailed and targeted studies of tree-ring struc-tures, but requires careful sampling attention for species with complex wood anatomy. The line scan method is ideal for reconstructing annually resolved element concentrations from trees and to some degree mitigates the complicating issue of intra-ring variability. Horse chestnut was determined to be the best of the available tree species because it exhibited a good response to laser ablation and pro-duced the lowest intra-ring variations in Pb concentration.

Słowa kluczowe

  • tree rings
  • dendrochemistry
  • laser ablation
  • ICP-MS
  • urban lead contamination

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