Rivista e Edizione

Volume 49 (2022): Edizione 1 (January 2022)

Volume 48 (2021): Edizione 1 (January 2021)

Volume 47 (2020): Edizione 1 (January 2020)

Volume 46 (2019): Edizione 1 (January 2019)

Volume 45 (2018): Edizione 1 (January 2018)

Volume 44 (2017): Edizione 1 (January 2017)

Volume 43 (2016): Edizione 1 (February 2016)

Volume 42 (2015): Edizione 1 (January 2015)

Volume 41 (2014): Edizione 4 (December 2014)

Volume 41 (2014): Edizione 3 (September 2014)

Volume 41 (2014): Edizione 2 (June 2014)

Volume 41 (2014): Edizione 1 (March 2014)

Volume 40 (2013): Edizione 4 (December 2013)
Special Edizione Title: Proceedings of the 3rd Asia Pacific Conference on Luminescence and Electron Spin Resonance Dating Okayama, Japan, 2012

Volume 40 (2013): Edizione 3 (September 2013)

Volume 40 (2013): Edizione 2 (June 2013)

Volume 40 (2013): Edizione 1 (March 2013)

Volume 39 (2012): Edizione 4 (December 2012)

Volume 39 (2012): Edizione 3 (September 2012)

Volume 39 (2012): Edizione 2 (June 2012)

Volume 39 (2012): Edizione 1 (March 2012)

Volume 38 (2011): Edizione 4 (December 2011)

Volume 38 (2011): Edizione 3 (September 2011)
Special Edizione Title: Proceedings of the 2nd Asia Pacific Conference on Luminescence Dating, Ahmedabad, India, 2009. Part II Edizione 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

Volume 38 (2011): Edizione 2 (June 2011)

Volume 38 (2011): Edizione 1 (March 2011)

Volume 37 (2010): Edizione -1 (December 2010)
Proceedings of the 2 Asia Pacific Conference on Luminescence Dating, Ahmedabad, India, 2009. Part I Editors Andrzej Bluszcz, Sheng-Hua Li and Ashok Kumar Singhvi

Volume 36 (2010): Edizione -1 (August 2010)

Volume 35 (2010): Edizione -1 (April 2010)

Volume 34 (2009): Edizione -1 (December 2009)

Volume 33 (2009): Edizione -1 (June 2009)

Volume 32 (2008): Edizione -1 (December 2008)

Volume 31 (2008): Edizione -1 (August 2008)

Volume 30 (2008): Edizione -1 (April 2008)

Volume 29 (2007): Edizione -1 (December 2007)

Volume 28 (2007): Edizione -1 (September 2007)

Volume 27 (2007): Edizione -1 (June 2007)

Volume 26 (2007): Edizione -1 (March 2007)

Dettagli della rivista
Formato
Rivista
eISSN
1897-1695
Pubblicato per la prima volta
04 Jul 2007
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

Volume 41 (2014): Edizione 3 (September 2014)

Dettagli della rivista
Formato
Rivista
eISSN
1897-1695
Pubblicato per la prima volta
04 Jul 2007
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

11 Articoli
access type Accesso libero

Review and assessment of the potential of post-IR IRSL dating methods to circumvent the problem of anomalous fading in feldspar luminescence

Pubblicato online: 22 Jun 2014
Pagine: 178 - 201

Astratto

Abstract

Quartz has been the main mineral used for optically stimulated luminescence (OSL) dating of sediments over the last decade. The quartz OSL signal, however, has been shown to saturate at relatively low doses of ∼200–400 Gy, making it difficult to be used for dating beyond about 200 thou-sand years (ka), unless the environmental dose rate is low. The infrared stimulated luminescence (IRSL) from feldspars has been shown to continue to grow to higher dose levels than quartz OSL. The application of IRSL dating of feldspars, however, has long been hampered by the anomalous fading effect. Recent progress in understanding anomalous fading of the infrared stimulated luminescence (IRSL) signals in potassium-feldspar has led to the development of post-IR IRSL (pIRIR) protocols and also a multiple elevated temperature (MET) stimulation (MET-pIRIR) protocol. These procedures have raised the prospect of isolating a non-fading IRSL component for dating Quaternary deposits containing feldspars. In this study, we review the recent progress made on (1) overcoming anomalous fading of feldspar, and (2) the development of pIRIR dating techniques for feldspar. The potential and problems associated with these methods are discussed.

Parole chiave

  • K-feldspar
  • infrared stimulated luminescence
  • post-IR IRSL
  • MET-pIRIR
access type Accesso libero

Propagation of error formulas for K/Ar dating method

Pubblicato online: 22 Jun 2014
Pagine: 202 - 206

Astratto

Abstract

In this paper has been derived the most relevant propagation of error formula in the case when argon peaks are measured. The most frequently cited formula published by Cox and Dalrymple deals with the isotope ratios, instead of isotope peaks heights, considered as independent variables.

Parole chiave

  • K/Ar dating
  • error propagation
access type Accesso libero

Geochronology of plutonic rocks from the Sanandaj-Sirjan zone, Iran and new zircon and titanite U-Th-Pb ages for granitoids from the Marivan pluton

Pubblicato online: 22 Jun 2014
Pagine: 207 - 215

Astratto

Abstract

The Sanandaj-Sirjan zone of Iran is a metamorphic belt consisting of rocks which were metamorphosed under different pressure and temperature conditions and intruded by various plutons ranging in composition from gabbro to granite. The majority of these granitoids formed along the ancient active continental margin of the Neo-Tethyan ocean at the southeastern edge of the central Iranian microplate. Geochronological data published in recent years indicate periodic plutonism lasting from Carboniferous through Mesozoic to late-Paleogene times (from ca. 300 to ca. 35 Ma) with climax activity during the mid- and late-Jurassic. The age constraints for plutonic complexes, such as Siah-Kouh, Kolah-Ghazi, Golpayegan (Muteh), Azna, Aligoodarz, Astaneh, Borujerd, Malayer (Samen), Alvand, Almogholagh, Ghorveh, Saqqez, Marivan, Naqadeh and Urumieh, clearly indicate the periodic nature of magmatism. Therefore, the Sanandaj-Sirjan zone preserves the record of magmatic activity of a complete orogenic cycle related to (1) Permocarboniferous(?) rifting of Gondwana and opening of the Neo-Tethyan ocean, (2) subduction of the oceanic crust, (3) continental collision and (4) post-collision/post-orogenic activities. The formation of the Marivan granitoids, northwestern Sanandaj-Sirjan zone, for which we present U-Pb zircon and titanite ages of ca. 38 Ma, can be related to the collisional and post-collisional stages of this orogenic cycle.

Parole chiave

  • granitoid
  • Iran
  • Marivan
  • plutonic rocks
  • Sanandaj-Sirjan zone
  • U-Pb data
access type Accesso libero

On the influence of climatic factors on the ratio between the cosmogenic isotope 14C and total carbon in the atmosphere in the past

Pubblicato online: 22 Jun 2014
Pagine: 216 - 222

Astratto

Abstract

Radiocarbon 14C is a cosmogenic isotope, which is most extensively used by scientists from a wide variety of fields. Its rate of generation in the atmosphere depends on solar modulation and thus, studying 14C concentration in natural archives, one can reconstruct solar activity level in the past. The paper shows results of box-model calculations of generation of the 14C isotope in the atmosphere and its relative abundance during the time interval 1389–1800 AD, taking into account influence of changing climate. This interval includes the deep minimum of solar activity and period of significant change in atmospheric concentration of CO2 and global temperature. The performed analysis showed that concentration of 14C in the atmosphere reflects not only variations of the galactic cosmic rays intensity but as well changes of temperature and atmospheric CO2 concentration. It is shown that the decrease in CO2 concentration in the atmosphere during 1550–1600 can be connected with absorption of CO2 by the ocean surface layer. Thus, taking into account the climatic changes is an important condition for the reconstruction of solar activity in the past using data based on cosmogenic isotopes.

Parole chiave

  • solar activity
  • climate change
  • cosmogenic isotopes 14C and 10Be
access type Accesso libero

A lake fortress, a floating chronology, and an atmospheric anomaly: the surprising results of a radiocarbon wiggle-match from Āraiši, Latvia

Pubblicato online: 22 Jun 2014
Pagine: 223 - 233

Astratto

Abstract

An Iron Age timber settlement which, in view of the defensive structures uncovered, is described as a lake fortress, on an island in Lake Āraiši, north-eastern Latvia, was excavated in 1965–69 and 1975–79 by teams led by Jānis Apals, who distinguished five construction phases. Dendrochronological analysis produced a c. 100-year floating chronology for Norway spruce (Picea abies (L.) Karst.) timbers from the earliest phase. A 14C wiggle-match was undertaken to obtain an absolute date range for the final year of the floating chronology, and thus for the construction of the settlement. Ten blocks of wood from one timber, each comprising 6-11 years and collectively spanning the whole 93-year tree-ring series, were dated by AMS. Using the IntCal13 calibration data, there is a 95% probability that the felling date of this timber falls in the range 775–784 cal AD. It appears, however, that the AD 775 spike in the atmospheric 14C level occurred within the 6-year span of the last sample. On this basis, we can narrow the date of construction to 776–780 cal AD. This date is significantly earlier than those reported in previous publications.

Parole chiave

  • dendrochronology
  • radiocarbon
  • wiggle-match
  • Latvia
  • AD775 cosmic event
access type Accesso libero

Tree-ring based temperature reconstruction for the west Qinling Mountains (China): linkages to the High Asia, solar activity and Pacific-Atlantic Ocean

Pubblicato online: 22 Jun 2014
Pagine: 234 - 244

Astratto

Abstract

We developed a Faxon fir (Abies faxoniana) tree-ring width chronology at the timberline in the western Qinling Mountains, China. Herein February–July mean temperature was reconstructed for Zhouqu in the western Qinling Mountains back to AD 1650 based on the standard chronology. The climate/tree-growth model accounts for 43.5% of the instrumental temperature variance during the period 1972–2006. Spatial correlation analyses with the gridded temperature data shows that the temperature reconstruction captures regional climatic variations over central and southeast China, and strong teleconnections with the nearby High Asia. There is a good agreement with cold and warm periods previously estimated from tree-rings in Nepal, India and southwest China. The temperature re-construction indicates that there was pronounced cooling in Zhouqu during the Maunder Minimum (late 1600s to early 1700s). The cold period (1813–1827) of the temperature reconstruction coincide with the volcanic eruptions. Significant spectral peaks are found at 56.9, 22.3, 11.4, 2.9, 2.8, 2.6, 2.2 and 2.0 years. The spatial correlation patterns between our temperature reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional temperature variations and the atmospheric circulations. It is thus revealed that the chronology has enough potential to reconstruct the climatic variability further into the past.

Parole chiave

  • tree rings
  • Western Qinling Mountains
  • Zhouqu
  • temperature reconstruction
  • spatial variability
  • solar activity
access type Accesso libero

Age constraints and denudation rate of a multistage fault line scarp: an example from Southern Italy

Pubblicato online: 22 Jun 2014
Pagine: 245 - 255

Astratto

Abstract

The morphological evolution of a carbonate fault line scarp from southern Italy, generated by transpressional faulting and evolved by slope replacement, has been reconstructed. 14C dating of faulted slope deposits (ages included between 18 ka and ∼8 ka BP) have been performed to constrain the Late Pleistocene — Holocene evolution of that scarp. Long-to short-term denudation rates have been also evaluated for the understanding of the mountain front origin. The slope shows well-defined triangular facets combined with the presence of N-S-striking mountainward-dipping fault planes. The envelope of the slope foot appears slightly curved in a planimetric view and shows an E-W-trending offset in its southern part, making such a feature quite different from the recurrent rectilinear fault scarps, often related to normal faulting. Morphostructural analysis showed that: i) the oldest displacement was generated by a fault with a reverse component of movement; ii) the slope represents an inherited feature, only recently exhumed, and developed starting from a high-angle curved surface; iii) the upper Pleistocene — Holocene extensional faulting has only affected the slope foot and associated waste deposits, causing a series of collateral morphological effects, as fluvial cut of preexisting valleys and the genesis of conspicuous mass movements.

Parole chiave

  • geomorphology of slopes
  • 14C dating
  • denudation rates
  • southern Apennines
  • Italy
access type Accesso libero

Different approaches to date bricks from historical buildings

Pubblicato online: 22 Jun 2014
Pagine: 256 - 264

Astratto

Abstract

The application of Thermally (TL) and Optically (OSL) Stimulated Luminescence on bricks used as building material has allowed solving an chronological issue in the field of historical building dating.

The possibility to use one or more methodologies of dating is closely related to the luminescent and granulometric characteristics of the sample. Using some brick samples collected in the church of Sain Seurin in Bordeaux (France), this paper discusses the implications and the possibility to use different approaches and techniques for dating. With this aim luminescence measurements were performed on both polymineral fine grain and quartz inclusion phases extracted from each brick. For Equivalent Dose (ED) and consequently age determination, TL on mixed fine grain fraction (FG), OSL on quartz inclusions (QI) and on mixed fine grain (FG*) fraction, were used. The results obtained suggest the advantage of using OSL technique on fine grain fraction cleaned up by IR stimulation (FG*), but the use of quartz inclusion represents indeed a good alternative.

Parole chiave

  • luminescence dating
  • polymineral fine grain technique
  • IR stimulation time
  • [Post-IR] OSL
  • quartz inclusion technique
  • preheat plateau
access type Accesso libero

A palaeotemperature record for the Finnish Lakeland based on microdensitometric variations in tree rings

Pubblicato online: 22 Jun 2014
Pagine: 265 - 277

Astratto

Abstract

X-ray based tree-ring data of maximum latewood densities (MXD) was combined for south-eastern Finland. This data originated from subfossil and modern pine (Pinus sylvestris L.) materials comprising a continuous dendroclimatic record over the past millennium. Calibrating and verifying the MXD chronologies against the instrumental temperature data showed a promising opportunity to reconstruct warm-season (May through September) temperature variability. A new palaeotemperature record correlated statistically significantly with the long instrumental temperature records in the region and adjacent areas since the 1740s. Comparisons with tree-ring based (MXD and tree-ring width) reconstructions from northern Fennoscandia and northern Finland exhibited consistent summer temperature variations through the Medieval Climate Anomaly, Little Ice Age, and the 20th century warmth. A culmination of the LIA cooling during the early 18th century appeared consistently with the Maunder Minimum, when the solar activity was drastically reduced. A number of coolest reconstructed events between AD 1407 and 1902 were coeval to years of crop failure and famine as documented in the agro-historical chronicles. Results indicate an encouraging possibility of warm-season temperature reconstructions using middle/south boreal tree-ring archives to detail and enhance the understanding of past interactions between humans, ecosystems and the earth.

Parole chiave

  • dendroclimatology
  • geochronology
  • Maunder Minimum
  • Medieval Climate Anomaly
  • Little Ice Age
  • crop failure
access type Accesso libero

Absolute chronology of fluvial events in the Upper Dnieper River system and its palaeogeographic implications

Pubblicato online: 22 Jun 2014
Pagine: 278 - 293

Astratto

Abstract

A set of 121 radiocarbon and OSL dates has been compiled from the Upper Dnieper River and tributary valleys, Western European Russia. Each date was attributed according to geomorphic/sedimentological events and classes of fluvial activity. Summed probability density functions for each class were used to establish phases of increasing and reducing fluvial activity. The oldest detected reduction of fluvial activity was probably due to glacial damming at LGM. Within the Holocene three palaeohydrological epochs of millennial-scale were found: (1) high activity at 12,000–8,000 cal BP marked by large river palaeochannels; (2) low activity at 8,000–3,000 cal BP marked by formation of zonal-type soils on -floodplains; short episodes of high floods occurred between 6,500—4,400 cal BP; (3) contrasting hydrological oscillations since 3,000 cal BP with periods of high floods between 3,000–2,300 (2,000) and 900–100 cal BP separated by long interval of low floods 2,300 (2,000)-900 cal BP when floodplains were not inundated — zonal-type soils were developing and permanent settlements existed on floodplains. In the last millennium, four centennial-scale intervals were found: high flooding intervals are mid-11–mid-15th century and mid-17–mid-20th century. Intervals of flood activity similar to the present-day were: mid-15–mid-17th century and since mid-19th century till present. In the context of palaeohydrological changes, discussed are selected palaeogeographic issues such as: position of the glacial boundary at LGM, role of changing amounts of river runoff in the Black Sea level changes, floodplain occupation by Early Medieval population.

Parole chiave

  • glacial damming
  • Holocene palaeohydrology
  • palaeofloods
  • buried floodplain soils
  • Dnieper River
  • Black Sea
access type Accesso libero

Charcoal in alluvium of mountain streams in the Bieszczady Mountains (Polish Carpathians) as a carrier of information on the local palaeoenvironment

Pubblicato online: 22 Jun 2014
Pagine: 294 - 305

Astratto

Abstract

Fragments of charcoal are present in floodplain alluvium of the San and Strwiąż rivers in the Polish part of the Bieszczady Mountains, Polish East Carpathians. They occur as single clasts or in lenses in the basal part of fine-grained alluvium, together with unburnt wood debris, or in the middle part of the vertical sequence of the floodplain alluvium. 14 samples of charcoal from the upper courses of the San (ca. 50 km) and the Strwiąż (ca. 10 km) were dated with radiocarbon. The obtained dates fall mainly in the 15th through 19th century interval; only one sample is markedly older (9th–10th century). Taxonomic composition of the charcoal source wood was also studied and compared with that of coeval forests. Correlation of the charcoal age with the history of economic development of the studied region indicates that charcoal is of anthropogenic origin: older charcoal from intense slash-and-burn deforestation, while younger charcoal was produced by local industries.

Parole chiave

  • charcoal
  • alluvium
  • slash-and-burn agriculture
  • Bieszczady Mountains
11 Articoli
access type Accesso libero

Review and assessment of the potential of post-IR IRSL dating methods to circumvent the problem of anomalous fading in feldspar luminescence

Pubblicato online: 22 Jun 2014
Pagine: 178 - 201

Astratto

Abstract

Quartz has been the main mineral used for optically stimulated luminescence (OSL) dating of sediments over the last decade. The quartz OSL signal, however, has been shown to saturate at relatively low doses of ∼200–400 Gy, making it difficult to be used for dating beyond about 200 thou-sand years (ka), unless the environmental dose rate is low. The infrared stimulated luminescence (IRSL) from feldspars has been shown to continue to grow to higher dose levels than quartz OSL. The application of IRSL dating of feldspars, however, has long been hampered by the anomalous fading effect. Recent progress in understanding anomalous fading of the infrared stimulated luminescence (IRSL) signals in potassium-feldspar has led to the development of post-IR IRSL (pIRIR) protocols and also a multiple elevated temperature (MET) stimulation (MET-pIRIR) protocol. These procedures have raised the prospect of isolating a non-fading IRSL component for dating Quaternary deposits containing feldspars. In this study, we review the recent progress made on (1) overcoming anomalous fading of feldspar, and (2) the development of pIRIR dating techniques for feldspar. The potential and problems associated with these methods are discussed.

Parole chiave

  • K-feldspar
  • infrared stimulated luminescence
  • post-IR IRSL
  • MET-pIRIR
access type Accesso libero

Propagation of error formulas for K/Ar dating method

Pubblicato online: 22 Jun 2014
Pagine: 202 - 206

Astratto

Abstract

In this paper has been derived the most relevant propagation of error formula in the case when argon peaks are measured. The most frequently cited formula published by Cox and Dalrymple deals with the isotope ratios, instead of isotope peaks heights, considered as independent variables.

Parole chiave

  • K/Ar dating
  • error propagation
access type Accesso libero

Geochronology of plutonic rocks from the Sanandaj-Sirjan zone, Iran and new zircon and titanite U-Th-Pb ages for granitoids from the Marivan pluton

Pubblicato online: 22 Jun 2014
Pagine: 207 - 215

Astratto

Abstract

The Sanandaj-Sirjan zone of Iran is a metamorphic belt consisting of rocks which were metamorphosed under different pressure and temperature conditions and intruded by various plutons ranging in composition from gabbro to granite. The majority of these granitoids formed along the ancient active continental margin of the Neo-Tethyan ocean at the southeastern edge of the central Iranian microplate. Geochronological data published in recent years indicate periodic plutonism lasting from Carboniferous through Mesozoic to late-Paleogene times (from ca. 300 to ca. 35 Ma) with climax activity during the mid- and late-Jurassic. The age constraints for plutonic complexes, such as Siah-Kouh, Kolah-Ghazi, Golpayegan (Muteh), Azna, Aligoodarz, Astaneh, Borujerd, Malayer (Samen), Alvand, Almogholagh, Ghorveh, Saqqez, Marivan, Naqadeh and Urumieh, clearly indicate the periodic nature of magmatism. Therefore, the Sanandaj-Sirjan zone preserves the record of magmatic activity of a complete orogenic cycle related to (1) Permocarboniferous(?) rifting of Gondwana and opening of the Neo-Tethyan ocean, (2) subduction of the oceanic crust, (3) continental collision and (4) post-collision/post-orogenic activities. The formation of the Marivan granitoids, northwestern Sanandaj-Sirjan zone, for which we present U-Pb zircon and titanite ages of ca. 38 Ma, can be related to the collisional and post-collisional stages of this orogenic cycle.

Parole chiave

  • granitoid
  • Iran
  • Marivan
  • plutonic rocks
  • Sanandaj-Sirjan zone
  • U-Pb data
access type Accesso libero

On the influence of climatic factors on the ratio between the cosmogenic isotope 14C and total carbon in the atmosphere in the past

Pubblicato online: 22 Jun 2014
Pagine: 216 - 222

Astratto

Abstract

Radiocarbon 14C is a cosmogenic isotope, which is most extensively used by scientists from a wide variety of fields. Its rate of generation in the atmosphere depends on solar modulation and thus, studying 14C concentration in natural archives, one can reconstruct solar activity level in the past. The paper shows results of box-model calculations of generation of the 14C isotope in the atmosphere and its relative abundance during the time interval 1389–1800 AD, taking into account influence of changing climate. This interval includes the deep minimum of solar activity and period of significant change in atmospheric concentration of CO2 and global temperature. The performed analysis showed that concentration of 14C in the atmosphere reflects not only variations of the galactic cosmic rays intensity but as well changes of temperature and atmospheric CO2 concentration. It is shown that the decrease in CO2 concentration in the atmosphere during 1550–1600 can be connected with absorption of CO2 by the ocean surface layer. Thus, taking into account the climatic changes is an important condition for the reconstruction of solar activity in the past using data based on cosmogenic isotopes.

Parole chiave

  • solar activity
  • climate change
  • cosmogenic isotopes 14C and 10Be
access type Accesso libero

A lake fortress, a floating chronology, and an atmospheric anomaly: the surprising results of a radiocarbon wiggle-match from Āraiši, Latvia

Pubblicato online: 22 Jun 2014
Pagine: 223 - 233

Astratto

Abstract

An Iron Age timber settlement which, in view of the defensive structures uncovered, is described as a lake fortress, on an island in Lake Āraiši, north-eastern Latvia, was excavated in 1965–69 and 1975–79 by teams led by Jānis Apals, who distinguished five construction phases. Dendrochronological analysis produced a c. 100-year floating chronology for Norway spruce (Picea abies (L.) Karst.) timbers from the earliest phase. A 14C wiggle-match was undertaken to obtain an absolute date range for the final year of the floating chronology, and thus for the construction of the settlement. Ten blocks of wood from one timber, each comprising 6-11 years and collectively spanning the whole 93-year tree-ring series, were dated by AMS. Using the IntCal13 calibration data, there is a 95% probability that the felling date of this timber falls in the range 775–784 cal AD. It appears, however, that the AD 775 spike in the atmospheric 14C level occurred within the 6-year span of the last sample. On this basis, we can narrow the date of construction to 776–780 cal AD. This date is significantly earlier than those reported in previous publications.

Parole chiave

  • dendrochronology
  • radiocarbon
  • wiggle-match
  • Latvia
  • AD775 cosmic event
access type Accesso libero

Tree-ring based temperature reconstruction for the west Qinling Mountains (China): linkages to the High Asia, solar activity and Pacific-Atlantic Ocean

Pubblicato online: 22 Jun 2014
Pagine: 234 - 244

Astratto

Abstract

We developed a Faxon fir (Abies faxoniana) tree-ring width chronology at the timberline in the western Qinling Mountains, China. Herein February–July mean temperature was reconstructed for Zhouqu in the western Qinling Mountains back to AD 1650 based on the standard chronology. The climate/tree-growth model accounts for 43.5% of the instrumental temperature variance during the period 1972–2006. Spatial correlation analyses with the gridded temperature data shows that the temperature reconstruction captures regional climatic variations over central and southeast China, and strong teleconnections with the nearby High Asia. There is a good agreement with cold and warm periods previously estimated from tree-rings in Nepal, India and southwest China. The temperature re-construction indicates that there was pronounced cooling in Zhouqu during the Maunder Minimum (late 1600s to early 1700s). The cold period (1813–1827) of the temperature reconstruction coincide with the volcanic eruptions. Significant spectral peaks are found at 56.9, 22.3, 11.4, 2.9, 2.8, 2.6, 2.2 and 2.0 years. The spatial correlation patterns between our temperature reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional temperature variations and the atmospheric circulations. It is thus revealed that the chronology has enough potential to reconstruct the climatic variability further into the past.

Parole chiave

  • tree rings
  • Western Qinling Mountains
  • Zhouqu
  • temperature reconstruction
  • spatial variability
  • solar activity
access type Accesso libero

Age constraints and denudation rate of a multistage fault line scarp: an example from Southern Italy

Pubblicato online: 22 Jun 2014
Pagine: 245 - 255

Astratto

Abstract

The morphological evolution of a carbonate fault line scarp from southern Italy, generated by transpressional faulting and evolved by slope replacement, has been reconstructed. 14C dating of faulted slope deposits (ages included between 18 ka and ∼8 ka BP) have been performed to constrain the Late Pleistocene — Holocene evolution of that scarp. Long-to short-term denudation rates have been also evaluated for the understanding of the mountain front origin. The slope shows well-defined triangular facets combined with the presence of N-S-striking mountainward-dipping fault planes. The envelope of the slope foot appears slightly curved in a planimetric view and shows an E-W-trending offset in its southern part, making such a feature quite different from the recurrent rectilinear fault scarps, often related to normal faulting. Morphostructural analysis showed that: i) the oldest displacement was generated by a fault with a reverse component of movement; ii) the slope represents an inherited feature, only recently exhumed, and developed starting from a high-angle curved surface; iii) the upper Pleistocene — Holocene extensional faulting has only affected the slope foot and associated waste deposits, causing a series of collateral morphological effects, as fluvial cut of preexisting valleys and the genesis of conspicuous mass movements.

Parole chiave

  • geomorphology of slopes
  • 14C dating
  • denudation rates
  • southern Apennines
  • Italy
access type Accesso libero

Different approaches to date bricks from historical buildings

Pubblicato online: 22 Jun 2014
Pagine: 256 - 264

Astratto

Abstract

The application of Thermally (TL) and Optically (OSL) Stimulated Luminescence on bricks used as building material has allowed solving an chronological issue in the field of historical building dating.

The possibility to use one or more methodologies of dating is closely related to the luminescent and granulometric characteristics of the sample. Using some brick samples collected in the church of Sain Seurin in Bordeaux (France), this paper discusses the implications and the possibility to use different approaches and techniques for dating. With this aim luminescence measurements were performed on both polymineral fine grain and quartz inclusion phases extracted from each brick. For Equivalent Dose (ED) and consequently age determination, TL on mixed fine grain fraction (FG), OSL on quartz inclusions (QI) and on mixed fine grain (FG*) fraction, were used. The results obtained suggest the advantage of using OSL technique on fine grain fraction cleaned up by IR stimulation (FG*), but the use of quartz inclusion represents indeed a good alternative.

Parole chiave

  • luminescence dating
  • polymineral fine grain technique
  • IR stimulation time
  • [Post-IR] OSL
  • quartz inclusion technique
  • preheat plateau
access type Accesso libero

A palaeotemperature record for the Finnish Lakeland based on microdensitometric variations in tree rings

Pubblicato online: 22 Jun 2014
Pagine: 265 - 277

Astratto

Abstract

X-ray based tree-ring data of maximum latewood densities (MXD) was combined for south-eastern Finland. This data originated from subfossil and modern pine (Pinus sylvestris L.) materials comprising a continuous dendroclimatic record over the past millennium. Calibrating and verifying the MXD chronologies against the instrumental temperature data showed a promising opportunity to reconstruct warm-season (May through September) temperature variability. A new palaeotemperature record correlated statistically significantly with the long instrumental temperature records in the region and adjacent areas since the 1740s. Comparisons with tree-ring based (MXD and tree-ring width) reconstructions from northern Fennoscandia and northern Finland exhibited consistent summer temperature variations through the Medieval Climate Anomaly, Little Ice Age, and the 20th century warmth. A culmination of the LIA cooling during the early 18th century appeared consistently with the Maunder Minimum, when the solar activity was drastically reduced. A number of coolest reconstructed events between AD 1407 and 1902 were coeval to years of crop failure and famine as documented in the agro-historical chronicles. Results indicate an encouraging possibility of warm-season temperature reconstructions using middle/south boreal tree-ring archives to detail and enhance the understanding of past interactions between humans, ecosystems and the earth.

Parole chiave

  • dendroclimatology
  • geochronology
  • Maunder Minimum
  • Medieval Climate Anomaly
  • Little Ice Age
  • crop failure
access type Accesso libero

Absolute chronology of fluvial events in the Upper Dnieper River system and its palaeogeographic implications

Pubblicato online: 22 Jun 2014
Pagine: 278 - 293

Astratto

Abstract

A set of 121 radiocarbon and OSL dates has been compiled from the Upper Dnieper River and tributary valleys, Western European Russia. Each date was attributed according to geomorphic/sedimentological events and classes of fluvial activity. Summed probability density functions for each class were used to establish phases of increasing and reducing fluvial activity. The oldest detected reduction of fluvial activity was probably due to glacial damming at LGM. Within the Holocene three palaeohydrological epochs of millennial-scale were found: (1) high activity at 12,000–8,000 cal BP marked by large river palaeochannels; (2) low activity at 8,000–3,000 cal BP marked by formation of zonal-type soils on -floodplains; short episodes of high floods occurred between 6,500—4,400 cal BP; (3) contrasting hydrological oscillations since 3,000 cal BP with periods of high floods between 3,000–2,300 (2,000) and 900–100 cal BP separated by long interval of low floods 2,300 (2,000)-900 cal BP when floodplains were not inundated — zonal-type soils were developing and permanent settlements existed on floodplains. In the last millennium, four centennial-scale intervals were found: high flooding intervals are mid-11–mid-15th century and mid-17–mid-20th century. Intervals of flood activity similar to the present-day were: mid-15–mid-17th century and since mid-19th century till present. In the context of palaeohydrological changes, discussed are selected palaeogeographic issues such as: position of the glacial boundary at LGM, role of changing amounts of river runoff in the Black Sea level changes, floodplain occupation by Early Medieval population.

Parole chiave

  • glacial damming
  • Holocene palaeohydrology
  • palaeofloods
  • buried floodplain soils
  • Dnieper River
  • Black Sea
access type Accesso libero

Charcoal in alluvium of mountain streams in the Bieszczady Mountains (Polish Carpathians) as a carrier of information on the local palaeoenvironment

Pubblicato online: 22 Jun 2014
Pagine: 294 - 305

Astratto

Abstract

Fragments of charcoal are present in floodplain alluvium of the San and Strwiąż rivers in the Polish part of the Bieszczady Mountains, Polish East Carpathians. They occur as single clasts or in lenses in the basal part of fine-grained alluvium, together with unburnt wood debris, or in the middle part of the vertical sequence of the floodplain alluvium. 14 samples of charcoal from the upper courses of the San (ca. 50 km) and the Strwiąż (ca. 10 km) were dated with radiocarbon. The obtained dates fall mainly in the 15th through 19th century interval; only one sample is markedly older (9th–10th century). Taxonomic composition of the charcoal source wood was also studied and compared with that of coeval forests. Correlation of the charcoal age with the history of economic development of the studied region indicates that charcoal is of anthropogenic origin: older charcoal from intense slash-and-burn deforestation, while younger charcoal was produced by local industries.

Parole chiave

  • charcoal
  • alluvium
  • slash-and-burn agriculture
  • Bieszczady Mountains

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